Novel process for promoting hydrosilation reactions using a second hydrosilane

Abstract: In the process of preparing compounds containing sili­ con-carbon bonds by the hydrosilation reaction of a hydrosilyl reactant with an olefinic reactant in the presence of a soluble platinum catalyst, the improvement which comprises operating the process at a temperature below 150°C and employing, as a reaction promoter, a hydrosilyl compound whereby said hy­ drosilyl reactant has a composition different from the composi­ tion of said promoter and whereby said promoter provides (i) a 20% increase in the amount of silicon-carbon compounds, or (ii) a 20% increase in reaction rate relative to an umpromoted reaction.

Description: This invention relates to processes for improving rates and yields in hydrosilation reactions, those being addition reactions of compounds containing hydrosilyl groups. i.e., ≡SiH groups, to unsaturated compounds to form carbon-functional silicon compounds. In particular. the present invention relates to the use of a hydrosilyl compound as a promoter in these hydrosilation reactions. The hydrosilation reaction was discovered in 1947 and is now one of the best known and most widely practiced reactions in organosilicon chemistry, including use in a wide variety of large scale commercial applications. This reaction has been the subject of several extensive reviews. l C. Earborn & R. W. Bott, Organometillic Compounds of the Group IV Elements (1968); E. Lukevics & M. G. Voronkov, Organic Insertion Reactions of Group IV Elements (1966). A number of patents In the art have shown that platinum compounds can have important catalytic effects in these reactions. U.S. - A - 2,632,013 for example, is an early patent showing that various forms or compounds of platinum can be effective catalysts for hydrosilation reactions. U.S. -A- 2,823,218 showed that chloroplatinic acid, a soluble form of platinum, was a particularly effective catalyst. A variety of additives to or derivatives of chloroplatinic acid have been claimed as offering some advantage over chloroplatinic acid, H₂PtCl₆. None of these patents teaches the use of a second hydrosilyl compound used in combination with the soluble platinum catalyst to promote the rate or yields of the first reaction. Of the many hydrosilation reactions taught in the prior art, very few involve the hydrosilation reactions between two different hydrosilyl compounds and one unsaturated compound. Moreover, that art which does discuss this area focuses on the competitive reactivity order of the hydrosilyl compounds with regard to the unsaturated compound. That is, the art teaches which of the two hydrosilyl compounds reacts better with a third unsaturated one; there is no teaching of the positive effect one such hydrosilyl compound might have on the other in increasing the yield of the hydrosilation reaction product, i.e., the product of the reaction between the hydrosilyl reactant and the unsaturated compound, or in decreasing the reaction time in the formation of such product. For example, work by Bailey, D. L. Bailey, remarks at the 137th National Meeting of the American Chemical Society (April 5-14, 1960), and by Benkeser, R. A. Benkeser, remarks at the 165th National Meeting of the American Chemical Society (April 8-13, 1973), has established the competitive reactivity order H₃SiCl > H₂SiCl₂ > Cl₃SiH for reactions with alkenes, this being the reverse of the reactivity order these compounds display when they are not competing with one another. The reversal occurs because the compounds, which are more reactive competitively, effectively reduce the reactivity of the other compounds, i.e., they have a negative effect on hydrosilation reactivity. The work done by Bailey did not study and did not note any promotional effects. Other studies, have also concentrated on the competitive effect among hydrosilyl reactants. Ponomarenko et al in Izv. Akad. Nauk SSSR, Otdel. Khim. Nauk 1610 (1960); Engl. trans. in Bull. Acad. Sci. USSR, Chem. Sci. Section 1496 (1960). In none of this prior art is there found an example of a second hydrosilyl compound having a positive effect on the reactivity of another hydrosilyl compound. This prior art always shows the two compounds in competition with one another rather than the one promoting the other in a non-competitive hydrosilation reaction. Ponomarenko et al in Dokl. Akad. Nauk, SSSR, 124 , 838 (1959); English translation as Proc. Acad. Sci. USSR, 124 , 95 (1959) do note such a positive effect, whereby Cl₃SiH and EtSiHCl₂ increase yields of products from reactions of Et₂MeSiH with allyl ethers (CH₂= CH-CH₂OCF₂CFClH or CH₂=CHCH₂OCF₂CF₂H) using Pt/C (platinum on carbon) catalyst. In these cases, however, high temperatures (164°-198°C) and long reaction times (3 h) were used. These studies also involved the use of insoluble platinum catalysts. The same workers reacted Et₂MeSiH with CH₂=CHCH₂OCF₂CF₂H using H₂PtCl₆ at lower temperature/time (25°C/30 min), but did not use a second hydrosilyl compound in the H₂PtCl₆ - catalyzed reaction. The authors of those Papers specifically commented that no promotional effects were observed in using a second hydrosilyl compound together with chloroplatinc acid in a hydrosilation reaction conducted under mild reaction temperatures (cf. Ponomarenko et al in Izv. Akad. Nauk SSSR, Otdel. Khim. Nauk. No. 9, pp. 1610-1618 (1960); Engl. trans. in Bull. Acad. Sci. USSR, Chem. Sci. Section pp. 1496-1503, (1960), especially page 1496). There has also been some prior art in which chloroplatinic acid, H₂PtCl₆, has been treated with Cl₃SiH or MeSiHCl₂ to give solutions which served as hydrosilation catalysts. Benkeser, 90 J. Am. Chem. Soc., 1871 (1968). In those studies, however, the same reactant, i.e. Cl₃SiH, was evaluated as both the starting reactant and the promoter. No advantage in either rate or yield was found. Similarly, in studies involving MeSiHCl₂, the MeSiHCl₂ was evaluated as both the starting reactant and promoter, and again no promotional advantages were observed. In U.S. - A - 3,576,027 a catalyst was prepared by treating H₂PtCl₆·6H₂O with Me₂SiHCl in a separate step, which catalyst was then isolated and used to catalyze a reaction of MeSiHCl₂ with l-octene. The catalyst there was formed in a precombination step rather thin being generated in situ . Additionally, large promotional effects were not observed. These tests show once more that it would be quite unexpected to find that a second hydrosilyl compound, used in a hydrosilation reaction at mild temperatures, could actually promote the rates and yields of that reaction. From CS-A-228 449 there is known the preparation of (3-bromopropyl)-trichlorosilane and (3-bromopropyl)-trichlorosilane and (3-bromopropyl)-methyldichlorosilane by hydrosilation of BrCH₂CH:CH₂ with HSiCl₂ or MeHSiCl₂ in the presence of H₂PtCl₆ (catalyst) and an alkyl-, aryl- or alkoxysilane. The use of a second hydrosilyl compound and soluble platinum catalysts to promote the large rate and/or yield enhancements disclosed in the present invention under relatively mild temperatures has not been disclosed in the prior art, and is in fact contradicted by the above prior art. Thus, there is a need in the art for a process which can be applied to hydrosilation reactions, i.e., those between hydrosilyl groups and unsaturated compounds, which process is characterized by relatively mild temperatures and relatively fast rates, by relatively inexpensive catalysts from which the active catalysts of the invention are generated in situ , and by greatly enhanced yields of carbon-functional silicon compounds formed from the hydrosilation reaction. It is thus an object of this invention to provide a process for improving the yields and rates of hydrosilation reactions under relatively mild conditions using a second hydrosilyl promoter and a relatively inexpensive catalysts, such as soluble platinum catalysts whereby the active catalyst is generated in situ . This invention relates to a process for greatly improving the reaction rates and yields/selectivities in hydrosilation reactions, i.e., reactions of compounds containing hydrosilyl groups with unsaturated compounds to form carbon-functional silicon compounds: In the process of the invention compounds containing silicon-carbon bonds are prepared by a hydrosilation reaction of (A) a hydrosilyl reactant with (B) an olefinic reactant and (C) a hydrosilyl promoter in the presence of a soluble platinum catalyst at a temperature below 150°C wherein: (A) the hydrosilyl reactant has the formula: R₃SiH where R is selected from the group consisting of (i) a monovalent hydrocarbon group which is in aliphatic group having 1 to 10 carbon atoms or an aromatic group having 6 to 20 carbon atoms free of terminal unsaturation, possibly substituted with halogen, cyano, carboalkoxy (ester), ether or thioether, with the proviso that when such hydrosilyl reactant is substituted with functional groups, said functional groups do not interfere with the promotion mechanism for hydrosilane-promoted hydrosilations; (ii) an alkoxy group; (iii) an acyloxy group; (iv) a carbomoyloxy group; (v) a siloxy group; (vi) a halogen or (vii) two R groups taken together form a hetero-cyclic ring including the silicon atom; (B) the olefinic reactant is used at 0.1 to 2.0 molar amounts relative to the hydrosilyl reactant (A); (C) the hydrosilyl promoter is selected from the group consisting of Cl₃SiH, MeSiHCl₂, Me₂SiHCl, Et₃SiH, F₃SiH and Br₃SiH, with the proviso that the hydrosilyl promoter and the hydrosilyl reactant may not be the same compound when used in the same reaction, the hydrosilyl promoter (C) is used at 0.0001 to 0.1 molar amounts relative to the hydrosilyl reactant (A), and said promoter (C) provides (1) at least a 20% increase in the amount of silicon-carbon compounds, or (2) at least a 20% increase in reaction rate relative to an unpromoted reaction of (A) and (B). The use of the hydrosilyl promoter eliminates the induction period associated with the use of H₂PtCl₆ thus resulting in large rate increases in certain cases. This elimination of the induction period can also make external heating unnecessary and result in large energy savings. The hydrosilyl promoter further results in substantial improvements in product selectivity in certain hydrosilation reactions, thus increasing the commercial utility of such reactions and, in combination with the large reaction rate increases mentioned above, significantly increasing effective production capacity without building additional production facilities. Finally, an important aspect of the invention is that, in certain cases, the hydrosilyl promoter can be useful at sub-ambient temperatures. This enables some reactions to be run at ambient pressure, obviating the need for pressure-resistant equipment. Thus the key discovery of the invention is the use of a hydrosilyl promoter in a platinum-catalyzed hydrosilation reaction which surprisingly increases catalytic effectiveness. Although the degree to which the promotional effects may vary depending on which hydrosilyl reactant, hydrosilyl promoter, platinum compound or unsaturated olefin is selected, the invention is characterized by increases in yield or selectivity of at least 20 percent. The most striking or positive promotion effects, in terms of reaction rate and selectivity, are observed from those reactions in which the electron environment of the hydrosilyl promoter is most nearly opposite the electron environment of the hydrosilyl starting reactant. Further, strong promotional effects are observed in reactions which are normally sluggish, i.e., those which require extended heating or high catalyst levels. In the process according to the invention the promoter reacts with a soluble platinum catalyst and a starting hydrosilyl reactant to greatly increase the yield, selectivity or rate of the hydrosilation product. While not wishing to be bound by theory, the active catalyst is believed to be generated when platinum catalysts such as chloroplatinic acid undergo a series of reactions involving both the hydrosilyl reactant and the hydrosilyl promoter to produce a species containing Pt-Si bonds. The following is a possible representation of such reactions involving Cl₃SiH and Et₃SiH as the promoter and reactant, respectively. The Pt-Cl is one such group in a soluble Pt catalyst containing Pt-Cl bonds, such as H₂PtCl₆: Pt-Cl + Et₃SiH → Et₃SiCl + Pt-H Pt-H + Cl₃SiH → H₂ + Pt-SiCl₃ It has been reported that Et₃SiH reacts with Pt-Cl bonds as shown, while Cl₃SiH does not. It has also been reported that Cl₃SiH reacts with Pt-H bonds to form H₂ and Pt-SiCl₃ bonds, while Et₃SiH does not undergo such a reaction. It should be noted that these reactions explain the formation of Pt-Si species by established chemistry and that such species need only to be sufficiently stable in solution to act as highly efficient hydrosilation catalysts. Such species, because of their inherently high reactivity, may not be sufficiently stable to allow isolation and identification by normal chemical methods. The catalysts for the instant invention are platinum compounds used in the form of solutions, such as solutions of H₂PtCl₆ (in hydrated or unhydrated form), solutions of PtCl₄ or PtCl₂, solutions of other soluble Pt compounds such as ethylene bis(platinous chloride), or Pt catalyst solutions as disclosed, for example, in U.S. - A - 3,220,972. Platinum catalysts containing strongly bound stabilizing ligands such as trialkyl or triarylphosphines or acetylacetonate groups are less effective. Phosphines or other strongly bound Pt ligands appear to interfere with the mutual interaction of hydrosilyl promoter and hydrosilyl reactant with the platinum catalyst, preventing or retarding the formation of the active catalyst species of the present invention. Because of its availability and relatively low cost (for platinum compounds), chloroplatinic acid is the preferred catalyst, although other soluble platinum compounds such as PtCl₄ and ethylene bis(platinous chloride) are considered equally effective. The platinum solution is added to the reaction in a concentration range of 10⁻³ to 10⁻⁸ molar relative to the combined starting reactant and promoter, preferably 10⁻⁴ to 10⁻⁶ molar. The olefinic coreactant may be any one of a variety of functional or non-functional terminally unsaturated compounds and has the general formula CH₂=C . The following are examples of compounds whose hydrosilation reactions can be promoted via processes of the instant invention: CH₂=CYCH₂Cl CH₂=CYCH₂OR where Y=H or R as defined below for hydrosilyl reactant CH₂=CYCMe₃ CH₂=CYCH₂CHMe₂ CH₂=CYØ CH₂=CYCH₂OAc CH₂=CYOAc CH₂=CYCH₂O₂CCY=CH₂ CH₂=CYCH₂O₂CY CH₂=CYO₂CY CH₂=CHCHYCl CH₂=CYCH₂CN Thus included are allyl and methallyl compounds, vinyl compounds, terminal alkenes, including halides, ethers, esters and nitriles with the proviso that when the olefinic reactant is substituted to functional groups, the functional groups do not interfere with the promotion mechanism of the hydrosilation reaction. The allyl and methallyl compounds include the allyl and methallyl polyalkylene oxide ethers typical of those used commercially to prepare silicone-polyether copolymers. The olefinic coreactant is preferably used at 0.5-1.5 and most preferably 0.8-1.2 molar amounts relative to the hydrosilyl reactant. Illustrative hydrosilyl reactants include hydrosilanes such as triethylsilane, a hydrochlorosilane such as Cl₃SiH, a hydrosiloxane such as (ME₃SiO)₂SiMeH, or a polyhydrosiloxane containing hydrosilyl groups at either internal or terminal positions, or both. The following represent hydrosilyl reactants of the hydrosilane type whose hydrosilation reactions may be promoted with a hydrosilyl promoter: Me₃SiH MeEt₂SiH Me₂EtSiH Et₃SiH Pr₃SiH Ø₃SiH Ø₂MeSiH ØSiMe₂H Illustrative of the hydrosiloxanes are the following: (Me₃SiO)₂SiMeH, (Me₃O)₃SiH Me₃Si(OSiMe₂) x (OSiMeH) y SiMe₃, x = 0-300, y = 1-300 HSiMe₂(OSiMe₂) x OSiMe₂H, MeSi[(OSiMe₂) x OSiMe₂H]₃ HSiMe₂(OSiMe₂) x (OSiMeH) y OSiMe₂H, Me₃SiOSiMe₂H where Me groups can be replaced by functional groups free of terminal unsaturation and which do not otherwise interfere with the promotion mechanism, such as haloalkyl, cyanoalkyl, phenylalkyl and acyloxyalkyl. Other hydrosilyl reactants include halosilanes, hydroalkoxysilanes and hydroacyloxysilanes, of which the following are representative: Cl₃SiH F₃SiH Br₃SiH MeSiHCl₂ Me₂SiHCl MeSiHF₂ Me₂SiFH MeSiHBr₂ Me₂SiHBr Me(MeO)₂SiH (MeO)₃SiH Me(MeCO₂)₂SiH (EtO)₃SiH In another embodiment of the invention, two R-groups taken together may form a hetero-cyclic ring including the silicon atom, as in where n = 3-6. The structure of the hydrosilyl reactant may thus vary widely including to the structures shown above, which merely exemplify some of the possibilities. The most effective promotion effects are observed when the hydrosilyl reactant and the hydrosilyl promoter differ substantially in structure, or in the electronic environment of the respective ≡SiH groups. The hydrosilyl promoter can be used in a wide range of concentrations relative to the hydrosilyl reactant or the olefinic or unsaturated coreactant. The hydrosilyl promoter is used at 0.0001-0.1 molar amounts relative to the hydrosilyl reactant. The greatest advantages from a commercial standpoint are attained when very low concentrations of hydrosilyl promoter are effective. In most cases, even with small amounts of promoter, it can simply be added to the hydrosilyl reactant and the platinum catalyst. While the reactants, catalyst, and promoter can generally be combined in total and allowed to react, there are specific cases in which it is advantageous to vary the order of combination of either reactant, or the promoter, or combinations thereof, to obtain maximum degree of promotion. For example, promotion of the reaction between Et₃SiH and allyl chloride by Cl₃SiH appears to be optimum when a 10/1 molar mixture of allyl chloride/Cl₃SiH is added to Et₃SiH containing the chloroplatinic acid. The reaction process of this invention may reach a reaction temperature as high as 150°C, although temperatures below 100°C are preferred. The reaction can also be promoted at sub-ambient temperatures. The reaction can be run under a pressurized atmosphere as high as 10 bar in pressure. Alternatively, if, for example, the reaction is run at sub-ambient temperatures, the reaction can be run at ambient pressures. Finally, the reaction may be run in time periods ranging from minutes to hours in duration, preferably 3-1000 minutes, more preferably 5-300 minutes and most preferably 10-100 minutes. Not all reactions between hydrosilyl reactants and unsaturated compounds are promoted by all hydrosilane promoters. Within the almost infinite number of possible combinations of hydrosilane reactants, unsaturated reactants, and hydrosilane promoters, and the possible variations in reaction conditions, i.e., temperature, sequence of combination, and relative concentrations, under which these three components can be reacted, there will be combinations for which promotion effects are not observed. A greater element of predictability, however, can be found by controlling certain variables. The most effective promotion effects, for example, are observed when the hydrosilyl reactant and the hydrosilyl promoter differ substantially in structure, or in electronic environment of the respective ≡SiH groups. For example, Cl₃SiH. which has strong electron attracting halogen groups, is an effective promoter for hydrosilation reactions of trialkylsilanes, such as Et₃SiH. Conversely, Et₃SiH is an effective promoter for hydrosilation reactions of Cl₃SiH. The conditions and variables for optimal promotional effect can be readily ascertained to one skilled in the art from the disclosure and examples herein. The reactions encompassed within the present invention are characterized by increases in either rate or selectivity of at least 20%. EXAMPLES The following specific examples and procedures are presented to illustrate the invention.The examples representing this invention are numbered; those examples that are lettered are comparative examples which do not illustrate the invention. Only those examples which satisfied the requirements of 20% yield or reaction rate improvement were numbered. Reported yields are in molar percentages and, in most examples, are given only for the desired hydrosilation product. Other by-products are obtained in many of the examples; their yields are not reported herein. In the examples and throughout the specification, all percentages and parts are on a molar basis unless specified otherwise. Definitions EqM Equ Ac -COCH₃ Me methyl Et ethyl D₃D' heptamethylcyclotetrasiloxane: or the corresponding derivative MD'M heptamethyltrisiloxane: or the corresponding derivative: All the reactions above were run in standard laboratory glassware or flasks of various sizes as noted in each example using magnetic stirring under nitrogen atmosphere with heat being applied by electric mantles. Flasks were also fitted with Hopkins condensers and thermometers, temperatures being recorded in Centigrade. All reaction products were identified by vapor phase chromatography (VPC) and nuclear magnetic resonance (NMR) spectroscopy. Reported yields were based on the amount of hydrosiloxane or hydrosilane charged. Comparative Example A Reaction of D₃D' with methallyl chloride; reactants combined at start. In a 200 ml apparatus, there were combined 56.4g (0.2 mol) of D₃D', 20.0g (0.22 mol) of methallyl chloride, and 0.2 ml of a reduced platinum catalyst (prepared according to Example 1, U.S. - A - 3,220,972). Heat was applied to about 80°C when an exothermic reaction occurred to a maximum temperature of 141°C. Reaction was complete after 1 h, 17 min and was followed by cooling. The reaction mixture was suction filtered into a 100 ml flask which was fitted for vacuum distillation. The following products were isolated: Product Boiling Point/Pressure g Yield D₃D'Cl 76°/22.6 mbar (aspirator) 17.0 27.0% D₃D'CH₂C(CH₃) = CH₂ 80°/22.6 mbar (aspirator) 3.0 4.4% D₃D'CH₂CH(CH₃)₂ 80°/22.6 mbar (aspirator) 1.6 2.4% D₃D'CH₂CH(CH₃)CH₂Cl 60°/0.33 mbar 44.8 60.0% Heavies 1.2 -- Comparative Example B Reaction of equimolar mixture ofD₃D'/MD'M with methallyl chloride. In a 100 ml apparatus, there were combined 30.5g (0.1 mol) of 92% D₃D', 22.2g (0.1 mol) of MD'M, and 9.1g (0.1 mol) of methallyl chloride, followed by 0.05 mol of Pt catalyst solution. Heat was applied to 100°C over 152 min, when an exothermic reaction occurred to 130°C. Vacuum distillation of the complete reaction yielded 4.26g (13.6%) of M₂D'CH₂CHMeCH₂Cl and 21.37g (57.4%) of D₃D'CH₂CHMeCH₂Cl. This example shows that neither D₃D' nor MD'M is an effective promoter for reaction of the other with methallyl chloride at the equimolar level. Comparative Example C Reaction of D₃D' with methallyl chloride; olefin added to hydrosiloxane. In a 500 ml apparatus were placed 282g (1.0 mol) of D₃D' which was heated to 85°C., followed by addition of 0.3 ml of a solution of 4.0 wt.% of H₂PtCl₆·6H₂O in 1,2-dimethoxyethane. Dropwise addition of 90.5g (1.0 mol) of methallyl chloride was begun and continued at a rate which maintained the reaction temperature at 87°-93°C. Addition was complete in 1.5 hr., and the reaction mixture was distilled directly, yielding the following products: Product Boiling Point/Pressure g Yield D₃D'Cl 77°/22.6 mbar (aspirator) 55.0 17.4% D₃D'CH₂C(CH₃) = CH₂ 31°/0.27 mbar trace --- D₃D'CH₂CH(CH₃)₂ 31°/0.27 bar 30.5 9.0% D₃D'CH₂CH(CH₃)CH₂Cl 55°/0.16 mbar 246.2 66.1% Heavies ----- 11.0 --- Example 1 Reaction of equimolar mixture of D₃D'/Cl₃SiH with methallyl chloride. In a 50 ml apparatus there were combined 24.7g (0.085 mol) of D₃D', 11.4g (0.085 mol) of Cl₃SiH, and 7.7g (0.085 mol) of methallyl chloride. Pt catalyst solution (0.05 ml) was added at 20°C causing a gentle exothermic reaction to 78°C in 10 min. Reaction was complete in 15 min. The yield of D₃D'CH₂CHMeCH₂Cl as analyzed by VPC was greater than 90%, a substantial improvement over the yields of Comparative Examples A, B or C, and a demonstration of non-competitive promotion by Cl₃SiH of hydrosiloxane reactivity. Example 2 Reaction of D₃D' with methallyl chloride promoted by 9 mol-% Cl₃SiH. In the apparatus of Example 3, there were combined 30.5g of 92% D₃D' (8% D₄, 0.1 mol of D₃D'), 9.1 g (0.1 mol) of methallyl chloride, and 0.5g Cl₃SiH. Pt catalyst solution (0.05 ml) was added at 20°C; after 42 min temperature was 29°C and 0.7g additional Cl₃SiH was added. Reaction temperature rose gradually to 107°C over 87 min, when reaction was complete. Vacuum distillation yielded 32.85g (88.2%) of D₃D'CH₂CHMeCH₂Cl, the yield being similar to that of Example 1 which employed a much larger amount of Cl₃SiH promoter. Example 3 Reaction of D₃D' with methallyl chloride promoted by 11 mol-% Cl₃SiH at 50°C. The reaction of Example 2 was repeated except that 1.5g Cl₃SiH was added at the start and the reaction mixture was heated to 50°C prior to addition of Pt catalyst. There was a rapid exothermic reaction to 148.5°C in 7 min at which point the reaction was complete, yielding 28.49g (76.5%) of D₃D'CH₂CHMeCH₂Cl on distillation. The lower yield relative to Examples 1 and 2, and the higher amount of non-volatile products (11.5% of total) indicate little advantage to adding catalyst at the higher temperature. Example 4 Reaction of equimolar mixture of D₃D'/MeSiHCl₂ with methallyl chloride. In a 50 ml apparatus, there were combined 9.7g (0.085 mol) of MeSiHCl₂, 24.2g (0.085 mol) of D₃D', and 7.8g (0.085 mol) of methallyl chloride. Pt catalyst solution (0.05 ml) was added at 20°C. Heat was applied intermittently causing an exothermic reaction to 75°C after 26 min. Reaction was complete after 40 min, and was vacuum distilled. yielding 23.8g (76.1%) of D₃D'CH₂CHMeCH₂Cl. This example shows that MeSiHCl₂ is slightly less effective than Cl₃SiH as a promoter for the reaction of D₃D' with methallyl chloride. Comparative Example D Reaction of equimolar mixtures of D₃D'/Et₃SiH with methallyl chloride. In a 100 ml apparatus, there were combined 28.4g (0.1 mol) of 98% D₃D', 11.6g (0.1 mol) of Et₃SiH, and 9.1g (0.1 mol) of methallyl chloride. Pt catalyst solution (0.05 ml was added at 21°C. Heat was applied to 99°C over 108 min, when a later exothermic reaction to 118°C occurred. Reaction was complete and was vacuum distilled, yielding 24.3g (65.2%) of D₃D'CH₂CHMeCH₂Cl. This example shows that Et₃SiH is much less effective than Cl₃SiH or MeSiHCl₂ as a promoter for the reaction of D₃D' with methallyl chloride when used at the equimolar level. Comparative Example E Reaction of D₃D' with methallyl chloride promoted by 10 mol-% MeSiCl₃. In a 50 ml apparatus, there were combined 30.5g (0.1 mol) of 92% D₃D', 9.1g (0.1 mol) of methallyl chloride, and 1.5g (0.01 mol) of MeSiCl₃. Pt catalyst solution (0.05 ml) was added at 21°C. Heat was applied to 89°C over 41 min followed by a gentle exothermic reaction to 123.5°C. Reaction was complete in 45 min, and was vacuum distilled, yielding 26.6g (71.4%) of D₃D'CH₂CHMeCH₂Cl. This example shows that MeSiCl₃ is not as effective as either Cl₃SiH or MeSiHCl₂ in promoting the reaction of D₃D' with methallyl chloride, although it did demonstrate a positive effect. Comparative Example F Reaction of equimolar mixture of D₃D'/Me₃SiHCl with methallyl chloride. In a 100 ml apparatus, there were combined 30.5g (0.1 mol) of 92% D₃D', 9.1g (0.1 mol) of methallyl chloride, and 9.5g (0.1 mol) of Me₂SiHCl. Heat was applied to 43°C and 0.05 ml Pt catalyst solution added, causing an exothermic reaction to 95.5°C in 26 min, with the heat source removed. Vacuum distillation of the complete reaction yielded 7.82g (42.3%) of Me₂SiClCH₂CHMeCH₂Cl and 16.89g (45.3%) of D₃D'CH₂CHMeCH₂Cl. This example shows that neither Me₂SiHCl nor D₃D' is an effective promoter for reaction of the other with methallyl chloride when used at the equimolar level. PROMOTION OF D₃D' AND METHALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. A D₃D' CH₂=CMeCH₂Cl -- 60 77 min Comp. B D₃D' CH₂=CMeCH₂Cl EqM. MD'M 57.4 152 min Comp. C D₃D' CH₂=CMeCH₂Cl -- 66.1 90 min 1 D₃D' CH₂=CMeCH₂Cl EqM. Cl₃SiH >90 15 min 2 D₃D' CH₂=CMeCH₂Cl 9 mol-%Cl₃SiH 88.2 87 min 3 D₃D' CH₂=CMeCH₂Cl 11 mol-%Cl₃SiH 76.5 7 min 4 D₃D' CH₂=CMeCH₂Cl EqM. MeSiHCl₂ 76.1 40 min Comp. D D₃D' CH₂=CMeCH₂Cl EqM. Et₃SiH 65.2 108 min Comp. E D₃D' CH₂=CMeCH₂Cl 10 mol-% MeSiCl₃ 71.4 45 min Comp. F D₃D' CH₂=CMeCH₂Cl EqM. Me₂SiHCl 45.3 26 min This table shows that yields and rates of D₃D' can be greatly improved depending on the nature and quantity of the promotor. Example 1 shows the most dramatic increase, relative to an unpromoted reaction, in both yield (greater than 30% absolute) and rate when using equimolar Cl₃SiH. Using a much smaller quantity of Cl₃SiH, i.e., equimolar versus 9 mol-%, gave substantially equivalent yields even though the rate of the reaction was not diminished (compare Example 1 to Example 2). As observed from this table, order of reactivity for greatest yield production is as follows: Cl₃SiH > MeSiHCl₂ > MeSiCl₃ > Et₃SiH Me₂SiHCl. Comparative Example G Reaction of MD'M with methallyl chloride; reactants combined at start. In the apparatus of Comparative Example A, there were combined 43.1 (0.194 mol) of MD'M, 19.0g (0.21 mol) methallyl chloride, and 0.2 ml of the catalyst used in Comparative Example A. Heat was applied to 94°C. at which point the reaction mixture was refluxing. The reflux temperature increased over 2 h to 143°C. The product mixture was transferred to a 100 ml flask and distilled, yielding the following products: Product Boiling Point/Pressure g Yield Unreacted MD'M 41°/232.6 mbar (aspirator) 5.9 13.7% M₂D'Cl 50°/22.6 mbar (aspirator) 16.5 32.2% M₂D'CH₂C(CH₃) = CH₂ 56°/22.6 mbar (aspirator) 3.9 7.1% M₂D'CH₂CH(CH₃)₂ --- nil --- M₂D'CH₂CH(CH₃)CH₂Cl 36°/0.4 mbar 21.3 34.1% Heavies --- 2.2 Comparative Example H Reaction of MD'M with methallyl chloride; olefin added to hydrosiloxane. In a 100 ml flask, there were placed 39.1g (0.176) mol) of MD'M which was heated to 75°, when 0.1 ml of the catalyst used in Comparative Example A was added. Addition of 16.3g (0.18 mol) of methyallyl chloride was begun, with reaction proceeding slowly for 30 min, followed by an exothermic temperature rise to 119°C. Reaction was complete after 1.5 h from start of addition. Direct vacuum distillation yielded the following products: Product Boiling Point/Pressure g Yield M₂D'Cl 50°/22.6 mbar (aspirator) 7.9 17.5% M₂D'CH₂C(CH₃) = CH₂ 31°/0.29 mbar (aspirator) 0.7 1.4% M₂D'CH₂CH(CH₃)₂ 31°/0.29mbar 4.9 10.0% M₂D'CH₂CH(CH₃)CH₂Cl 33°/0.24mbar 27.6 50.2% Heavies --- 3.7 Example 5 Reaction of equimolar mixture of MD'M/Cl₃SiH with methallyl chloride. In a 100 ml apparatus, there were combined 11.1g (0.05 mol) of MD'M, 4.5g (0.05 mol) of methallyl chloride, and 6.8g (0.05g mol) of Cl₃SiH. Pt catalyst solution (0.01 ml) was added at 40°C, causing a violent exothermic reaction to more than 100°C in 1 min. Vacuum distillation of the complete reaction yielded 12.78g (81.8%) of M₂D'CH₂CHMeCH₂Cl, indicating that Cl₃SiH is an effective promoter for the reaction of MD'M with methallyl chloride. The yield here is significantly higher than in Comparative Examples G or H, and the reaction time much shorter. Note that MD'M and D₃D' are chemical models for polyhydrosiloxane fluids which are articles of commerce, demonstrating clearly that reactions of such fluids with methallyl chloride will also be promoted. Example 6 Reaction of equimolar mixture of MD'M/MeSiHCl₂ with methallyl chloride. In a 100 ml apparatus, there were combined 16.7g (0.075 mol) of MD'M, 8.6g (0.075 mol) of MeSiHCl₂, and 6.8g (0.075 mol) of methallyl chloride, followed by addition of 0.01 ml Pt catalyst solution at 48°C. There was an exothermic reaction to 92°C in 9 min, with the reaction being complete in 50 min. Vacuum distillation yielded 16.57g (70.7%) of M₂D'CH₂CHMeCH₂Cl, showing that MeSiHCl₂ is slightly less effective than Cl₃SiH as a promoter for the reaction of MD'M with methallyl chloride at the equimolar level. Example 7 Reaction of equimolar mixture MD'M/Et₃SiH with methallyl chloride. In a 100 ml apparatus, there were combined 11.1g (0.05 mol) of MD'M, 5.8g (0.05 mol) of Et₃SiH, and 4.5g (0.05 mol) of methallyl chloride, followed by addition of 0.01 ml Pt catalyst solution at 55°C. Heat was applied over 80 min to 95°C when reaction was complete. Distillation yielded 51.3% of M₂D'CH₂CHMeCH₂Cl, indicating that Et₃SiH is not a very effective promoter for the reaction of MD'M with methallyl chloride when used at the equimolar level. Comparative Example I Reaction of equimolar mixture MD'M/Me₂SiHCl with methallyl chloride. In a 100 ml apparatus, there were combined 22.3g (0.1 mol) of MD'M, 9.5g (0.01 mol) of Me₂SiHCl, and 9.1g (0.1 mol) of methallyl chloride, followed by 0.015 ml Pt catalyst solution at 50°C. There was an exothermic reaction to 96°C in 6 min. The complete reaction was vacuum distilled yielding 13.28g (71.8%) of Me₂SiClCH₂CHMeCH₂Cl and 8.63g (27.6%) of M₂D'CH₂CHMeCH₂Cl. This example indicates that neither MD'M nor Me₂SiHCl is an effective promoter for reaction of the other with methallyl chloride when used at the equimolar level. The yield based on methallyl chloride was 99.4%, indicating very efficient reaction of the olefinic reactant. PROMOTION OF MD'M AND METHALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. G Md'M CH₂=CMeCH₂Cl -- 34.1 120 min Comp. H MD'M CH₂=CMeCH₂Cl -- 50.2 90 min 5 MD'M CH₂=CMeCH₂Cl EqM. C1₃SiH 81.8 1 min 6 MD'M CH₂=CMeCH₂Cl EqM. MeSiHCl₂ 70.7 50 min 7 MD'M CH₂=CMeCH₂Cl EqM. Et₃SiH 51.3 80 min Comp. I MD'M CH₂=CMeCH₂Cl EqM. Me₂SiHCl 27.6 6 min As can be seen from Table II, Cl₃SiH is again the best promoter (almost 300% relative increase) in the reaction of MD'M with methallyl chloride to produce M₂D'CH₂CHMeCH₂Cl. This increased yield is particularly significantly because it represents an accurate chemical model for a commercially used polyhydrosiloxane. The order of reactivity for greatest yield production is as follows: Cl₃SiH > MeSiHCl₂ > Et₃SiH. As observed in Comparative Example I. Me₂SiHCl actually interfered rather than promoted the reaction with MD'M since 71.8% of the yield was Me₂SiClCH₂CHMeCH₂Cl rather than the desired M₂D'CH₂CHMeCH₂Cl. Comparative Example J Reaction of Et₃SiH with methallyl chloride. A mixture of Et₃SiH (10.5g, 0.09 mol) and methallyl chloride (8.2g, 0.09 mol) was combined in a 150 ml apparatus and 0.05 ml Pt catalyst solution added, followed by heating at reflux (115°C) for 50 h. Additional Pt catalyst solution (0.025 ml) was added at 40 hr. The incomplete reaction was distilled, yielding 4.98g (36.8%) of Et₃SiCl and 3.48g (18.7%) of Et₃SiCH₂CHMeCH₂Cl. This example shows that the unpromoted reaction of Et₃SiH with methallyl chloride is very slow and endothermic. Example 8 Reaction of equimolar mixture of Et₃SiH/Cl₃SiH with methallyl chloride. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 13.6g (0.1 mol) of Cl₃SiH, and 9.1g of methallyl chloride, followed by addition of 0.05 ml Pt catalyst solution at 21°C. There was a rapid and exothermic reaction to 61°C in 2 min. Reaction appeared to have stopped and was heated to reflux over 4 h when VPC showed complete reaction. Vacuum distillation yielded 17.03g (82.5%) of Et₃SiCH₂CHMeCH₂Cl, indicating that Cl₃SiH is an effective promoter for the reaction of Et₃SiH with methallyl chloride. Example 9 Reaction of Et₃SiH with methallyl chloride promoted by 10 mol-% Cl₃SiH. The reaction of Example 14 was repeated except that only 1.3g of Cl₃SiH was used. The reaction exothermed from 21°C to 118.5°C in 3 min, when reaction was complete. Vacuum distillation yielded 18.2g (88.1%) of Et₃SiCH₂CHMeCH₂Cl. This example shows that the use of 10 mol-% Cl₃SiH as promoter for the reaction between Et₃SiH and methallyl chloride reduces reaction time by a factor of 1,000, increases the yield of the desired hydrosilation product by a factor of 5, and eliminates the need for external heating, relative to the unpromoted reaction of Comparative Example J. It also demonstrates that 10 mol-% Cl₃SiH is more effective than equimolar Cl₃SiH in promoting this reaction. Comparative Example J' Reaction of Et₃SiH with methallyl chloride promoted by 13 mol-% MeSiCl₃. The reaction of Example 9 was repeated except that 2.0g MeSiCl₃ was used instead of Cl₃SiH. The reaction was heated up to 96°C over 8 h, and the complete reaction vacuum distilled, yielding 10.06g (48.7%) of Et₃SiCH₂CHMeCH₂Cl. This example shows that MeSiCl₃ is a promoter but less effective than Cl₃SiH for the reaction of Et₃SiH with methallyl chloride. Comparative Example L Reaction of equimolar mixture of Et₃SiH/MeSiHCl₂ with methallyl chloride. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 11.5g (0.1 mol) of MeSiHCl₂, and 9.1g (0.1 mol) of methallyl chloride. After heating to 50°C, the heat source was removed and 0.05 ml Pt catalyst solution added, causing an exothermic reaction to 83.5°C in 4 min. The complete reaction was vacuum distilled, yielding 13.83g (67.3%) of MeSiCl₂CH₂CHMeCH₂Cl and 4.31g (20.9%) of Et₃SiCH₂CHMeCH₂Cl. This example shows that while MeSiHCl₂ at the equimolar level promotes the reaction between Et₃SiH and methallyl chloride, it also competes with Et₃SiH, reducing the yield of Et₃SiCH₂CHMeCH₂Cl. Comparative Example M Reaction of equimolar mixture of Et₃SiH/Me₂SiHCl with methallyl chloride. In a 100 ml apparatus, there were combined 7.1g (0.075 mol) of Me₂SiHCl, 8.7g (0.075 mol) of Et₃SiH, and 6.8g (0.075 mol) of methallyl chloride. Pt catalyst solution (0.01 ml) was added at 32°C, causing an exothermic reaction to 94°C in 4 min. Distillation of the complete reaction yielded 81.1% Me₂SiClCH₂CHMeCH₂Cl and 3.6% Et₃SiCH₂CHMeCH₂Cl. Et₃SiH does promote slightly the reaction of Me₂SiHCl with methallyl chloride. Example 11 Reaction between Et₃SiH and methallyl chloride promoted by Cl₃SiH at sub-ambient temperature. In a 50 ml apparatus, there was combined 11.6g (0.1 mol) of Et₃SiH, 9.1g (0.1 mol) of methallyl chloride, and 1.4g (0.01 mol) of Cl₃SiH. The reaction mixture was cooled to 1°C and was catalyzed with 0.05 ml of Pt catalyst solution. After 98 min at 1-6°C, VPC analysis showed 47.9% conversion of reactants to Et₃SiCH₂CHMeCH₂Cl with a Et₃SiCH₂CHMeCH₂Cl/Et₃SiCl selectivity ratio of 24. This example shows that Cl₃SiH is an effective promoter for the reaction between Et₃SiH and methallyl chloride even at sub-ambient temperatures. Comparative Example K Reaction of Et₃SiH with methallyl chloride promoted by 10 mol-% Cl₃CH. In a 50 ml apparatus, there were combined 7.0g (0.06 mol) of Et₃SiH, 5.4g (0.06 mol) of methallyl chloride, and 0.7g (0.006 mol) of trichloromethane, followed by addition of 0.02 ml of Pt catalyst solution at 37°C. Heat was applied up to 80°C over 2 h. Analysis by VPC showed no reaction, indicating that Cl₃CH is ineffective as a promoter for the reaction of Et₃SiH with methallyl chloride. Note that Cl₃CH is the carbon analog of Cl₃SiH. PROMOTION OF Et₃SiH AND METHALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YEILD % TIME COMP. J Et₃SiH CH₂=CMeCH₂Cl -- 18.7 3000 min 8 Et₃SiH CH₂=CMeCH₂Cl EqM. Cl₃SiH 82.5 242 min 9 Et₃SiH CH₂=CMeCH₂Cl 10 mol% Cl₃SiH 88.1 3 min Comp. J' Et₃SiH CH₂=CMeCH₂Cl 13 mol% MeSiCl₃ 48.7 480 min Comp. K Et₃SiH CH₂=CMeCH₂Cl 10 mol% Cl₃CH -- 120 min Comp. L Et₃SiH CH₂=CMeCH₂Cl MeSiHCl₂ 20.9 Comp. M Et₃SiH CH₂=CMeCH₂Cl Me₂SiHCl 3.6 11 Et₃SiH CH₂=CMeCH₂Cl 10 mol% Cl₃SiH 47.9 98 min From Table III, it can be seen that the most dramatic improvement in yield and in time are once more with Cl₃SiH (almost 500% relative yield increase). Another important advantage of the invention is illustrated by Example 11. Example 11 is very significant because promotion is being done at subambient temperatures. The lowest temperature tested was 0°C but this was by no means the lower limit. This is apparently the first example of a low temperature, platinum-catalyzed hydrosilation reaction involving a trialkylsilane. The most effective promoter tested with these reactants was Cl₃SiH. Comparative Example K is to illustrate that the non-siloxane Cl₃CH has no promotional effect. Comparative Example N Reaction of Et₃SiH with methallyl chloride promoted by SnCl₂. A solution of 0.43g SnCl₂·2H₂O in 5.0g of Pt catalyst solution was prepared. A 50 ml apparatus was charged with 10.5g (0.09 mol) of Et₃SiH and 9.2g (0.09 mol) of methallyl chloride, and the contents heated to 62°C. The Pt/Sn solution (0.05 ml) was added, and heat applied to reflux (83°C) over 3 h 40 min. VPC analysis showed no enhancement of Et₃SiCH₂CHMeCH₂Cl yield, indicating that the H₂PtCl₆/SnCl₂ couple as disclosed in prior art (U.S. - A - 4,089,882) is an ineffective hydrosilation catalyst for this reaction. Example 12 Reaction of Et₃SiH with methallyl chloride promoted by F₃SiH. Gaseous F₃SiH was generated by adding Cl₃SiH to C₆H₅SiF₃ containing Bu₃N and the F₃SiH so generated was bubbled through a reaction mixture of 11.6g (0.1 mol) of Et₃SiH, 9.1g (0.1 mol) of methallyl chloride, and 0.02 ml Pt catalyst solution for 20 min periods at 21-48°C, with reaction being stirred at room temperature between periods. Analysis by VPC showed 34.6% conversion of reactants to Et₃SiCH₂CHMeCH₂Cl with a Et₃SiCH₂CHMeCH₂Cl/Et₃SiCl ratio of 24 on a weight basis. This example shows that F₃SiH does promote the reaction of Et₃SiH with methallyl chloride, but not as effectively as Cl₃SiH. F₃SiH has the disadvantage of being a gas at room temperature, and is considered to be unstable. Example 13 Reaction of Et₃SiH with methallyl chloride promoted by Br₃SiH. In a 50 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 9.1g (0.1 mol) of methallyl chloride, and 2.6g (0.011 mol) of Br₃SiH. Pt catalyst solution was added (0.02 ml) at 60°C, followed by heating up to 70°C over 100 min. Analysis by VPC showed 66.3% conversion of reactants to Et₃SiCH₂CHMeCH₂Cl, indicating that Br₃SiH also promotes the reaction between Et₃SiH and methallyl chloride, but not as effectively as Cl₃SiH. Br₃SiH has the disadvantage of being pyrophoric. Comparative Example O Reaction of Et₃SiH with methallyl chloride promoted by Cl₃GeH. In a 50 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 9.1g (0.1 mol) of methallyl chloride, and 0.05 ml of Pt catalyst solution. Cl₃GeH (0.18g. 0.001 mol) was added at 23°C, with an additional 0.09g being added 19 min later. Reaction was heated to 68°C over 51 min and allowed to stand overnight at room temperature. Analysis by VPC showed no formation to Et₃SiCH₂CHMeCH₂Cl indicating that Cl₃GeH is not an effective promoter for the reaction of Et₃SiH with methallyl chloride. Comparative Example P Reaction of Et₃SiH with methallyl chloride promoted by PCl₃. The reaction of Comparative Example O was repeated, except that in one case, 1.4g of PCl₃ was used instead of Cl₃GeH, and in the other case, 0.05 ml PCl₃ was precombined with the 0.05 ml Pt catalyst solution. In neither case was there any formation of Et₃SiCH₂CHMeCH₂Cl even after heating several hours, indicating PCl₃ is not an effective promoter for the reaction between Et₃SiH and methallyl chloride. PROMOTIONAL EFFECTS OF OTHER PROMOTERS Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. J Et₃SiH CH₂=CMeCH₂Cl -- 18.7 3000 min Comp. N Et₃SiH CH₂=CMeCH₂Cl SnCl₂ =18.00 220 min 12 Et₃SiH CH₂=CMeCH₂Cl F₃SiH 34.6 60 min 13 Et₃SiH CH₂=CMeCH₂Cl Br₃SiH 66.3 100 min Comp. O Et₃SiH CH₂=CMeCH₂Cl Cl₃GeH -- 51 min Comp. P Et₃SiH CH₂=CMeCH₂Cl PCl₃ -- 7120 min Table IV is to illustrate that the second silane really is the key to the invention since comparative experiments involving other promoters either do not function or have other serious problems associated with them. Comparative Example Q Reaction of Cl₃SiH with methallyl chloride. In a 50 ml apparatus, there were combined 13.6g (0.1 mol) of Cl₃SiH and 9.1g (0.1 mol) of methallyl chloride, followed by 0.05 ml Pt catalyst solution. Reaction was heatedto reflux (44°C) in 55 min, and was heated at reflux temp. which increased to 84°C after 6 h, followed by standing at room temp. overnight. VPC analysis indicated 67.3% conversion of reactants to a single product, Cl₃SiCH₂CHMeCH₂Cl. This example shows that the unpromoted reaction of Cl₃SiH with methallyl chloride is relatively slow. Example 14 Reaction of Cl₃SiH with methallyl chloride promoted by Et₃SiH. The reaction of Comparative Example Q was repeated except that 0.08g (0.5 mol-%) of Et₃SiH was added after the Pt catalyst. The reaction was heated intermittently up to 100°C over 170 min, followed by vacuum distillation, which yielded 19.73g (87.3%) of Cl₃SiCH₂CHMeCH₂Cl. This example shows that low levels of Et₃SiH effectively promote the reaction between Cl₃SiH and methallyl chloride. Comparative Example R Reaction of equimolar mixture of Cl₃SiH/MeSiHCl₂ with methallyl chloride. In a 100 ml apparatus, there as combined 13.6g (0.1 mol) of Cl₃SiH, 9.1g (0.1 mol) of methallyl chloride, and 11.5g (0.1 mol) of MeSiHCl₂, followed by 0.05 ml Pt catalyst solution at 21°C. Gentle heating caused an exothermic reaction to 52°C in 22 min. The complete reaction was vacuum distilled, yielding 14.14g (68.8%) of MeSiCl₂CH₂CHMeCH₂Cl and 4.86g (21.5%) of Cl₃SiCH₂CHMeCH₂Cl. This example indicates that at the equimolar level, neither Cl₃SiH nor MeSiHCl₂ is an effective promoter for reactions of the other with methallyl chloride. Comparative Example S Reaction of equimolar mixture of Cl₃SiH/Me₂SiHCl with methallyl chloride. In a 50 ml apparatus, there was combined 7.1g (0.075 mol) of Me₂SiHCl, 10.2g (0.075 mol) of Cl₃SiH, and 6.8g (0.075 mol) of methallyl chloride. Pt catalyst solution (0.02 ml) was added at 31°C causing a violent exothermic reaction to more than 60°C in 3 min. VPC analysis of the complete reaction showed 73.5% conversion to Me₂SiClCH₂CHMeCH₂Cl and 2.9% conversion to Cl₃SiCH₂CHMeCH₂Cl. This example shows that Cl₃SiH is an effective promoter for the reaction of Me₂SiHCl with methallyl chloride, and suggests that lower levels of Cl₃SiH would be just as effective. PROMOTION OF Cl₃SiH AND METHALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. Q Cl₃SiH CH₂=CMeCH₂Cl -- 67.3 360 min 14 Cl₃SiH CH₂=CMeCH₂Cl 0.5 mol-% Et₃SiH 87.3 170 min Comp. R Cl₃SiH CH₂=CMeCH₂Cl EqM. MeSiHCl₂ 21.5 22 min Comp. S Cl₃SiH CH₂=CMeCH₂Cl EqM. Me₂SiHCl 2.9 Table V shows that Promotional effects depend on the nature of the reactant and promoter. If the promoter itself can compete with the reactant to react with the olefin, the reactant may in effect be acting as nothing more than a promoter itself as is seen in Comparative Examples R and S. Comparative Example T Reaction of MeSiHCl₂ with methallyl chloride. In a 50 ml apparatus, there were combined 12.2g (0.106 mol) of MeSiHCl₂ and 9.6g (0.106 mol) of methallyl chloride, followed by 0.05 ml Pt catalyst solution at 21°C. Gentle heating caused a smooth exothermic reaction to 120° in 18 min. VPC analysis showed 97.7% conversion to MeSiCl₂CH₂CHMeCH₂Cl. This example shows that the unpromoted reaction of MeSiHCl₂ with methallyl chloride is relatively rapid, and the yield high. Comparative Example U Reaction of Me₂SiHCl with methallyl chloride. In a 100 ml apparatus, there were combined 14.2g (0.15 mol) of Me₂SiHCl and 13.6g (0.15 mol) of methallyl chloride, followed by 0.05 ml Pt catalyst solution at 21°C. Gentle heating caused a smooth exothermic reaction to 90°C in 16 min. Reaction was heated at 80°C until completed (50 min). Vacuum distillation yielded 23.14g (83.4%) of Me₂SiClCH₂CHMeCH₂Cl. Comparative Example V Reaction of equimolar mixture of equimolar mixture of MeSiHCl₂/Me₂SiHCl with methallyl chloride. In a 100 ml apparatus, there were combined 8.6g (0.75 mol) of MeSiHCl₂, 7.1g (0.075 mol) of Me₂SiHCl, and 6.8g (0.075 mol) of methallyl chloride. Pt catalyst solution (0.01 ml) was added at 32° causing an exothermic reaction to 57°C and completion in 10 min. Distillation yielded 54.0% of Me₂SiClCH₂CHMeCH₂Cl and 19.6% of MeSiCl₂CH₂CHMeCH₂Cl, indicating that at the equimolar level, neither MeSiHCl₂ nor Me₂SiHCl is a very effective promoter for reactions of the other with methallyl chloride, in terms of yield, but that reaction rates are increased. PROMOTION OF MeSiHCL₂ AND Me₂SiHCl AND METHALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME COMP. T MeSiHCl₂ CH₂=CMeCH₂Cl -- 97.7 18 min Comp. U Me₂SiHCl CH₂=CMeCH₂Cl -- 83.4 50 min Comparative Example W Reaction of Et₃SiH with methallyl chloride promoted by Cl₃SiH using other noble metal catalysts. A standard solution of 69.8g (0.6 mol) of Et₃SiH, 54.3g (0.6 mol) of methallyl chloride, and 8.1g (0.6 mol) of Cl₃SiH was made up to simulate the stoichiometry of Example 9. Other noble metal hydrosilation catalyst including platinum acetylacetonate, ethylene platinous chloride, platinum on carbon, bis(triphenylphosphine) platinum dichloride, ruthenium acetylacetonate, dichlorodicarbonyl-bis(triphenylphosphine) ruthenium, rhodium dicarbonyl dichloride dimer, and chloroiridic acid hexahydrate were tested at appropriate concentrations in aliquots of the standard solution. Only ethylene platinous chloride was as effective as the standard H₂PtCl₆ catalyst solution, with none being more effective. This example indicates that only soluble Pt compounds not containing strongly bound ligands such as acetylacetonate or phosphine groups are effective catalysts in the processes of the present invention. Note, in particular, that platinum on carbon (Pt/C) was ineffective at the lower temperatures (ambient or sub-ambient) where H₂PtCl₆ is effective, differentiating the instant invention from the prior art. The compounds (CH₂PØ₂)₂PtClSiMe₃, (CH₂PØ₂)₂Pt(SiMe₃)₂ and and [CH₂(PØ₂)₂PtCl]₂ were also ineffective as catalysts in the above standard reaction. Comparative Example X Reaction of D₃D' with allyl chloride; reactants combined at start. In a 100 ml flask there were combined 62.0g of 90% D₃D' (containing 0.2 mol of D₃D'), 17.0g (0.22 mol) of allyl chloride, and 0.2 ml of the catalyst used in Comparative Example A. Heat was applied to reflux temperature which increased gradually from 68°C to 125°C over 1.5 hrs. The reaction mixture was suction filtered into a 100 ml distillation flask and distilled, yielding the following products: Product Boiling Point/Pressure g Yield D₃D'Cl 33°/ 0.4 mbar 37.8 59.7% D₃D'CH₂CH₂CH₃ 44°/ 0.4 mbar 4.0 6.2% D₃D'CH₂CH₂CH₂Cl 63°/ 0.27 mbar 8.0 11.2% D₃D'CH₂CH₂CH₂D'D₃ 117°/0.33 mbar 2.4 -- Comparative Example Y Reaction of D₃D' with allyl chloride; olefin added to hydrosiloxane. In the apparatus of Comparative Example X, there were placed 56.4g (0.2 mol) of D₃D' which was heated to 78°C, when 0.2 ml of the catalyst used in Example 2 was added. Dropwise addition of 15.3g (0.2 mol) of allyl chloride was begun and the reaction temperature was maintained at 95°-124°C. until completion (37 min). The reaction mixture was distilled yielding the following products; Product Boiling Point/Pressure g Yield D₃D'Cl 27°/ 0.93 mbar 22.0 34.8% D₃D'CH₂CH₂CH₃ 29°/ 0.93 mbar 16.6 33.0% D₃D'CH₂CH₂CH₂Cl 53°/ 0.27 mbar 13.9 19.4% D₃D'CH₂CH₂CH₂D'D₃ ---------- trace -- Heavies ---------- 1.6 -- Example 15 Reaction of equimolar mixture of D₃D'/Cl₃SiH with allyl chloride. In a 100 ml apparatus, there were combined 15.5g (0.114 mol) of Cl₃SiH, 32.3g (0.114 mol) of D₃D' and 8.8g (0.114 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 21°C, causing a gentle exothermic reaction to 83°C in 52 min. Vacuum distillation yielded 7.02g (29.0%) of Cl₃SiCH₂CH₂CH₂Cl and 10.2g (24.9%) of D₃CH₂CH₂CH₂Cl. This example shows that Cl₃SiH at the equimolar level increases both rate and yield of the reaction between D₃D' and allyl chloride. Example 16 Reaction of equimolar mixture of D₃D'/MeSiHCl₂ with allyl chloride. In a 100 ml apparatus, there were combined 15.8g (0.14 mol) of MeSiHCl₂, 38.6g (0.14 mol) of D₃D', and 10.5g (0.1 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 19°C and the reaction mixture allowed to stir overnight at 28°C (heat generated by magnetic stirrer). Gentle heat was applied to the unreacted mixture, causing an exothermic reaction to 95°C in 45 min. Vacuum distillation yielded 5.82g (22.2%) of MeSiCl₂CH₂CH₂CH₂Cl and 15.65g (31.8% of D₃D'CH₂CH₂CH₂Cl, indicating that at the equimolar level, MeSiHCl₂ is more effective than Cl₃SiH at increasing the yield of the reaction between D₃D' end allyl chloride. Comparative Example Z Reaction of equimolar mixture of D₃D'/MeSiHCl₂ with allyl chloride in the presence of tributylamine. The reaction of Example 16 was repeated except at 0.1 mol of each reactant was used and 0.05 ml of Bu₃N was added after the Pt catalyst. The reaction exothermed from 22°C to 48°C in 108 min, and was vacuum distilled, yielding 10.09g (52.7%) of MeSiCl₂CH₂CH₂CH₂Cl and 0.8g (2.2%) of D₃D'CH₂CH₂CH₂Cl. The tertiary amine promoter (Bu₃N is claimed as a promoter for MeSiHCl₂ in its reaction with allyl chloride) enhances the hydrochlorosilane reactivity, and interferes with the hydrochlorosilane promotion of the hydrosiloxane reactivity. Note that the relative reactivities of D₃D' and MeSiHCl₂ are reversed in Examples 16 and Comparative Example Z. Example 17 Reaction of equimolar mixture of D₃D'/Et₃SiH with allyl chloride. In a 100 ml apparatus, there were combined 28.3g (0.1 mol) of 98% D₃D', 11.6g (0.1 mol) of Et₃SiH, and 7.7g (0.1 mol of allyl chloride. Pt catalyst solution (0.05 ml) was added at 22°C, followed by heating up to 66°C over 145 min. Vacuum distillation yielded 7.15g (19.9%) of D₃D'CH₂CH₂CH₂Cl, and a trace of Et₃SiCH₂CH₂CH₂Cl. This example shows that neither D₃D' nor Et₃SiH are very effective promoters at the equimolar level for reactions of the other with allyl chloride. Example 18 Reaction of equimolar mixture of D₃D'/MD'M with allyl chloride. In a 100 ml apparatus, there were combined 22.2g (0.1 mol of MD'M, 30.5g (0.1 mol) of 92% D₃D', and 7.7 g (0.1 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 25°C, and heat applied to 80°C over 40 min, followed by an exothermic reaction to 140°C over 15 min. Vacuum distillation yielded 1.15g (3.9%) of M₂D'CH₂CH₂CH₂Cl and 6.91g (19.3%) of D₃D'CH₂CH₂CH₂Cl, indicating that neither D₃D' nor MD'M are very effective promoters for reaction of the other with allyl chloride when used at the equimolar level. Example 19 Reaction of equimolar mixture of D₃D'/Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 30.5g (0.1 mol) of 92% D₃', 9.5g (0.1 mol) of Me₂SiHCl, and 7.7g (0.1 mol) of allyl chloride. Pt catalysts solution (0.05 ml was added at 42°C and heat applied to 97.5°C over 144 min. Vacuum distillation yielded 3.99g (23.3%) of Me₂SiClCH₂CH₂CH₂Cl and 11.15g (31.1%) of D₃D'CH₂CH₂CH₂Cl. This example shows that Me₂SiHCl is slightly less effective than MeSiHCl₂ in promoting the reaction between D₃D' and allyl chloride when used at the equimolar level. PROMOTION OF D₃D' AND ALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. X D₃D' CH₂=CHCH₂Cl -- 11 90 min Comp. Y D₃D' CH₂=CHCH₂Cl -- 19.4 37 min 15 D₃D' CH₂=CHCH₂Cl EqM. Cl₃SiH 24.9 52 min 16 D₃D' CH₂=CHCH₂Cl EqM. MeSiHCl₂ 31.8 45 min Comp. Z D₃D' CH₂=CHCH₂Cl EqM. MeSiHCl₂ and tributylamine 2.2 108 min 17 D₃D' CH₂=CHCH₂Cl EqM. Et₃SiH 19.9 145 min 18 D₃D' CH₂=CHCH₂Cl EqM. MD'M 19.3 55 min 19 D₃D' CH₂=CHCH₂Cl EqM. Me₂SiHCl 31.1 144 min Several observations may be made from Table VII. First, Comparative Example Z shows how tributylamine interferes with promotion relative to Example 16. Second, comparing Table VII to Table I, it can be seen that the yields of the reaction may vary merely by changing the olefin reactant. For example, both MeSiHCl₂ and MeSiHCl are stronger promoters than Cl₃SiH when using allyl chloride while, when methallyl chloride is used as the reactant olefin (Table I), the opposite is true. Comparative Example AA Reaction of MD'M with allyl chloride. In a 100 ml apparatus, there were combined 22.3g (0.1 mol) of MD'M and 7.7g (0.1 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 48°C, causing a gradual exothermic reaction to 120°C in 41 min. Vacuum distillation yielded 4.50g (15.1%) of M₂D'CH₂CH₂CH₂Cl as one of the several products. Comparative Example BB Reaction of MD'M with allyl chloride promoted by SnCl₂. The reaction of Comparative Example AA was repeated except that the Pt/Sn catalyst solution of Comparative Example K was used instead of the standard H₂PtCl₆ solution. There was an exothermic reaction from 45°C to 73°C over 53 min. VPC analysis showed M₂D'Cl was the major product with only a trace of M₂D'CH₂CH₂CH₂Cl, such that SnCl₂ does not promote the hydrosilation reaction between MD'M and allyl chloride. Example 20 Reaction of equimolar mixture of MD'M/Cl₃SiH with allyl chloride. In a 100 ml apparatus, there were combined 11.1g (0.05 mol) of MD'M, 6.8g (0.05 mol) of Cl₃SiH, and 3.9g (0.05 mol) of allyl chloride. Pt catalyst solution (0.025 ml) was added at 23°C, causing a violent exothermic reaction to 96°C in 3 min. Vacuum distillation yielded 0.13g of Cl₃SiCH₂CH₂CH₂Cl and 5.99g (40.1%) of M₂D'CH₂CH₂CH₂Cl. This example shows that Cl₃SiH at the equimolar level is an effective promoter for the reaction of MD'M with allyl chloride, enhancing both rate and yield relative to the unpromoted reaction of Comparative Example AA. Example 21 Reaction of equimolar mixture of MD'M/MeSiHCl₂ with allyl chloride. In a 100 ml apparatus, there were combined 16.7g (0.075 mol) of MD'M, 8.6 g (0.075 mol) of MeSiHCl₂, and 5.7g (0.075 mol) of allyl chloride. Pt catalyst solution (0.01 ml) was added at 54°C and the reaction heated up to 84°C over 2 hr. Vacuum distillation yielded 44.4% of M₂D'CH₂CH₂CH₂Cl and 7.6% of MeSiCl₂CH₂CH₂CH₂Cl. This example shows that MeSiCl₂H at the equimolar level effectively enhances yield, but not rate, of the reaction between MD'M and allyl chloride. Comparative Example CC Reaction of equimolar mixture of MD'M/Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 22.3g (0.1 mol) of MD'M, 9.5g (0.1 mol) of Me₂SiHCl, and 7.7g (0.1 mol) of allyl chloride. Pt catalyst solution was added at 74°C (0.05 ml). followed by heating up to 92°C over 162 min. Vacuum distillation of the reaction yielded 18.1% of M₂D'CH₂CH₂CH₂Cl and 10.3% of Me₂SiClCH₂CH₂CH₂Cl. This example shows that neither MD'M nor Me₂SiHCl is an effective promoter at the equimolar level for reactions of the other with allyl chloride. Example 22 Reaction of equimolar mixture of MD'M/Et₃SiH with allyl chloride. In a 100 ml apparatus, there were combined 11.1g (0.05 mol) of MD'M. 5.8g (0.05 mol) of Et₃SiH, and 3.8g (0.05 mol) of allyl chloride. Pt catalyst solution (0.01 ml) was added at 54°C and the reaction heated to 90°C over 28 min. VPC analysis of the reaction mixture showed 23.9% of M₂D'CH₂CH₂CH₂Cl and 7.2% Et₃SiCH₂CH₂CH₂Cl, indicating that both MD'M and Et₃SiH are slightly effective promoters at the equimolar level for reactions of the other with allyl chloride. PROMOTION OF MD'M AND ALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. AA MD'M CH₂=CHCH₂Cl -- 15.1 41 min Comp. BB MD'M CH₂=CHCH₂Cl Sn₂Cl₂ -- 53 min 20 MD'M CH₂=CHCH₂Cl EqM. Cl₃SiH 40.1 3 min 21 MD'M CH₂=CHCH₂Cl EqM. MeSiHCl₂ 44.4 120 min Comp. CC MD'M CH₂=CHCH₂Cl EqM. Me₂SiHCl 18.1 162 min 22 MD'M CH₂=CHCH₂Cl EqM. Et₃SiH 23.9 28 min Again, although Table II varies from Table VIII only by the olefin employed, differences are observed. For example, MeSiHCl₂ promotes greater yield than Cl₃SiH (although rate is much slower). Both, however, are still greater than Et₃SiH which in turn is greater than Me₂SiHCl. Comparative Example DD Reaction of Et₃SiH with allyl chloride. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 7.7g (0.1 mol of allyl chloride, and 0.05 ml Pt catalyst solution at 19°C. After stirring 1 h , temperature had increased to 27°C, followed by heating at 70°C for 17 hr. The incomplete reaction was vacuum distilled, yielding 8.9g (42%) of Et₃SiCl, and 3.0g (15.5%) of Et₃SiCH₂CH₂CH₂Cl. The Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl molar selectivity ratio was 0.37. This example shows that the unpromoted reaction between Et₃SiH and CH₂ = CHCH₂Cl is very slow. Comparative Example EE Reaction of equimolar mixture of Et₃SiH/Cl₃SiH with allyl chloride. In a 50 ml apparatus, there were combined 11.6g (0.01 mol) of Et₃SiH, 13.6g (0.1 mol) of Cl₃SiH, and 7.7g (0.01 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added, causing a gentle exothermic reaction from 19°C to 36°C in 35 min. Heat was applied up to 66°C over the next 75 min. Vacuum distillation yielded 0.80g (4.2%) of Et₃SiCH₂CH₂CH₂Cl and 11.48g (54.2%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that Et₃SiH at the equimolar level is an effective promoter for the reaction between Cl₃SiH and allyl chloride, since that reaction is very slow at reflux temperature in the absence of a promoter. Comparative Example FF Reaction of equimolar mixture of Et₃SiH/Cl₃SiH with allyl chloride, latter added to former. The reaction of Comparative Example EE was repeated except that the allyl chloride was added dropwise to a mixture of the two silanes and the Pt catalyst beginning at 39°C. There was a smooth exothermic reaction up to 80° over the addition (30 min) followed by 15 min at 80°C. Vacuum distillation yielded 3.17g (16.5%) of Et₃SiCH₂CH₂CH₂Cl, and 10.67g (50.3%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that adding the olefin as above allows both Cl₃SiH and Et₃SiH to promote the hydrosilation reaction rate of the other toward allyl chloride. Selectivity and yield were also improved for Et₃SiH, with a Et₃SiCH₂CH₂Cl/Et₃SiCl molar selectivity ratio of 2.5. Example 23 Reaction of equimolar mixture of Et₃SiH/Cl₃SiH with allyl chloride, former added to latter. The reaction of Comparative Example FF was repeated except that the silane mixture was added dropwise to the allyl chloride containing the Pt catalyst, beginning at 40.5°C. Heat was applied up to 50°C over 132 min (time of addition). Vacuum distillation yielded 6.30g (32.7%) of Et₃SiCH₂CH₂CH₂Cl and 7.71g (36.4%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that while this sequence of combination of reactants causes a lower reaction rate, yield and selectivity of the Et₃SiH reaction with allyl chloride are improved further. The Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl molar ratio was 2.82. Example 24 Reaction of Et₃SiH with 10/1 molar mixture of allyl chloride/Cl₃SiH, latter added to former. In a 25 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH and 0.05 ml of Pt catalyst solution. Heat was applied to 60°C and addition of a mixture of 7.7g (0.1 mol) of allyl chloride and 1.4g (0.01 mol) of Cl₃SiH begun. There was a smooth exothermic reaction up to 80°C by the end of the addition (15 min) with temperature continuing to rise to 129°C 5 min later. Vacuum distillation yielded 12.12g (63.0%) of Et₃SiCH₂CH₂CH₂Cl, with a Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl molar ratio of 2.73. This example shows that low levels of Cl₃SiH effectively promote both rate and yield of the reaction between Et₃SiH and allyl chloride, particularly when the low levels are maintained throughout the reaction by replenishment. Example 25 Reaction of 8/1 molar mixture of Et₃SiH/Cl₃SiH with allyl chloride, latter added to former. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 1.7g (0.0125 mol) of Cl₃SiH and 0.05 ml of Pt catalyst solution. The mixture was heated to 65°C and addition of 7.7 g (0.1 mol) of allyl chloride begun. There was an exothermic reaction to 108.5°C over 16 min, followed by a temperature drop. Addition of allyl chloride was complete in 31 min, with heat then applied at reflux (up to 114°C) over 170 min. Vacuum distillation yielded 7.88g (40.9%) of Et₃SiCH₂CH₂CH₂Cl with a Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl selectivity ratio of 1.13. This example shows that this sequence of combination of reactants allows the Cl₃SiH promoter to be consumed, at which point the reaction of Et₃SiH with allyl chloride proceeds at the low rate and selectivity exhibited in Comparative Example DD. Example 26 Reaction of 10/1 molar mixture of Et₃SiH/Cl₃SiH with allyl chloride, former added to latter. In a 50 ml apparatus, there were combined 7.7g (0.1 mol) of allyl chloride and 0.05 ml of Pt catalyst solution. the mixture was heated to 44°C and addition of a mixture of 11.6g (0.1 mol) of Et₃SiH and 1.4g (0.01 mol) of Cl₃SiH begun. Reaction was heated up to 54.5°C during addition (30 min). There was a violent exothermic reaction from 62°C to 110°C 16 min later. Vacuum distillation yielded 7.79g (40.5%) of Et₃SiCH₂CH₂CH₂Cl, with a Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl selectivity ratio of 1.23. This example and the previous one show that the preferred sequence of combination of reactants for most effective Cl₃SiH promotion of the reaction of Et₃SiH with allyl chloride is that of Example 24. Example 27 Reaction of Et₃SiH with allyl chloride using Cl₃SiH/H₂PtCl₆ solution as catalyst. The reaction of Comparative Example DD was repeated except that 0.1 ml of the Cl₃SiH/H₂PtCl₆ catalyst solution of Example 16 was used instead of the standard H₂PtCl₆ solution. Heat was applied over 205 min up to 90°C, followed by vacuum distillation which yielded 4.36g (22.6%) Et₃SiCH₂CH₂CH₂Cl, with a Et₃SiCH₂CH₂CH₂Cl/Et₃SiCl ratio of 0.35. This example shows that very low levels of Cl₃SiH cause modest rate increases in the reaction between Et₃SiH and allyl chloride, but do not affect selectivity. PROMOTION OF Et₃SiH AND ALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp.DD Et₃SiH CH₂=CHCH₂Cl -- 15.5 1000 min Comp.EE Et₃SiH CH₂=CHCH₂Cl EqM. Cl₃SiH 4.2 110 min Comp.FF Et₃SiH CH₂=CHCH₂Cl EqM. Cl₃SiH 16.5 45 min 23 Et₃SiH CH₂=CHCH₂Cl EqM. Cl₃SiH 32.7 132 min 24 Et₃SiH CH₂=CHCH₂Cl 10/1 Olefin/Cl₃SiH 63.0 20 min 25 Et₃SiH CH₂=CHCH₂Cl 13mol.% Cl₃SiH 40.9 170 min 26 Et₃SiH CH₂=CHCH₂Cl 10 mol.% Cl₃SiH 40.5 46 min 27 Et₃SiH CH₂=CHCH₂Cl 0.1 ml Cl₃Si/H₂PtCl₆ 22.6 205 min Table IX again illustrates a number of interesting observations. First, in comparing Examples FF and 23 to Example EE, the only difference is in the order the reactants are combined. Adding the olefin to a mixture of Et₃SiH and Cl₃SiH promoter later rather than at the start increased the yield to 16.5% while, when Et₃SiH and Cl₃SiH were precombined and added to the olefin later, the yield rose to 32.7%. Similarly, the order of combination effects lower yields in Examples 25 and 26 compared to Example 24. In Example 24, the olefin and Cl₃SiH are given a chance to precombine before being added to Et₃SiH. By contrast, both the Cl₃SiH and Et₃SiH are precombined in Examples 25 and 26 whether they are added to the olefin (Example 26) or the olefin is later added to them (Example 25). Finally, comparing Examples EE and 27 to Example 8 in Table III, it can be observed once more that yields may be greatly affected merely by changing the olefin of the reaction. Comparative Example GG Reaction of Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 18.9g (0.2 mol) of Me₂SiHCl, 15.3g (0.2 mol) of allyl chloride, and 0.05 ml Pt catalyst solution at 18.5°C, followed by heating at reflux for 50 hr. An equivalent quantity of Pt catalyst solution was added during the reflux period. Vacuum distillation of the incomplete reaction yielded 12.6% of Me₂SiClCH₂CH₂CH₂Cl. This example shows that the unpromoted reaction of Me₂SiHCl with allyl chloride proceeds very slowly at reflux temperature. Example 28 Reaction of equimolar mixture of Et₃SiH/Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 7.1g (0.075 mol) of Me₂SiHCl, 8.7g (0.075 mol) of Et₃SiH and 5.7g (0.075 mol) of allyl chloride. Pt catalyst solution was added (0.05 ml) at 34°C. Gentle heating caused a smooth exothermic reaction to 92° over 36 min. Vacuum distillation yielded 42.5% of Me₂SiClCH₂CH₂CH₂Cl and 4.8% of Et₃SiCH₂CH₂CH₂Cl. This example shows that Et₃SiH at the equimolar level is an effective promoter for the reaction between Me₂SiHCl and allyl chloride. Example 29 Reaction of equimolar mixture of Et₃SiH/MeSiHCl₂ with allyl chloride. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 11.5g (0.1 mol) of MeSiHCl₂, and 7.7g (0.1 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 21°C, gentle heating caused an exothermic reaction to 88°C over 150 min. Vacuum distillation yielded 40.4% of MeSiCl₂CH₂CH₂CH₂Cl and 13.0% of Et₃SiCH₂CH₂CH₂CH₂Cl. This example shows that both MeSiHCl₂ and Et₃SiH are promoters at the equimolar level for reactions of the other with allyl chloride. The promotion effects are milder than those between Et₃SiH and Cl₃SiH as shown in Comparative Example FF. The unpromoted reaction between MeSiHCl₂ and allyl chloride is known to be slow at reflux. Comparative Example HH Reaction of equimolar mixture of Cl₃SiH/MeSiHCl₂ with allyl chloride. In a 50 ml apparatus, there were combined 13.1g (0.097 mol) of Cl₃SiH, 11.1g (0.097 mol) of MeSiHCl₂, and 7.4g (0.097 mol) of allyl chloride. Pt catalyst solution (0.05 ml) was added at 21.5°C, causing a smooth exothermic reaction to 55°C over 42 min, followed by heating at reflux (up to 67°C) over 330 min. Vacuum distillation yielded 12.14g of a mixture of Cl₃SiCH₂CH₂CH₂Cl/MeSiCl₂CH₂CH₂CH₂Cl in a 2.04/1 ratio. This example shows that neither Cl₃SiH nor MeSiHCl₂ is a very effective promoter at the equimolar level for reactions of the other with allyl chloride. Comparative Example II Reaction of equimolar mixture of Cl₃SiH/Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 7.1g (0.075 mol) of Me₂SiHCl, 10.2g (0.075 mol) of Cl₃SiH, and 5.7g (0.075 mol) of allyl chloride. Pt catalyst solution(0.01 ml) was added at 33°C, causing an exothermic reaction to 47°C in 7 min. VPC analysis 14 min. later showed a complete reaction. Vacuum distillation yielded 60.4% Cl₃SiCH₂CH₂CH₂Cl and 8.6% Me₂SiClCH₂CH₂CH₂Cl. This example shows that Me₂SiHCl is an effective promoter for the reaction of Cl₃SiH with allyl chloride at the equimolar level. Example 30 Reaction of equimolar mixture of MeSiHCl₂/Me₂SiHCl with allyl chloride. In a 100 ml apparatus, there were combined 8.6g (0.075 mol) of MeSiHCl₂, 7.1g (0.075 mol) of Me₂SiHCl, and 5.7g (0.075 mol) of allyl chloride. Pt catalyst solution (0.01 ml) was added at 37°C, followed by heating up to 45°C over 1 h. Vacuum distillation yielded 31.3% of MeSiCl₂CH₂CH₂CH₂Cl and 22.6% of Me₂SiClCH₂CH₂CH₂Cl. This example shows that neither Me₂SiHCl nor MeSiHCl₂ is a very effective promoter at the equimolar level for reactions of the other with allyl chloride. PROMOTION OF Me₂SiHCl AND ALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp. GG Me₂SiHCl CH₂=CHCH₂Cl -- 12.6 3000 min 28 Me₂SiHCl CH₂=CHCH₂Cl EqM. Et₃SiH 42.5* 36 min Comp. II Me₂SiHCl CH₂=CHCH₂Cl EqM. Cl₃SiH 8.6 7 min 30 Me₂SiHCl CH₂=CHCH₂Cl Eqm. Me₂SiHCl₂ 22.6 > 60 min This Table shows again how varying the olefin and reactant also changes the yields. For example, the same quantity of Et₃SiH and Me₂SiHCl(Comparative Example M versus Example 28) promotes 81.1% yield with methallyl chloride and only 42.5% yield with allyl chloride. Comparative Example JJ Reaction of Cl₃SiH with allyl chloride, former added to latter. In a 50 ml apparatus, there were combined 7.7g (0.1 mol) of allyl chloride and 0.05 ml Pt catalyst solution. The mixture was heated to reflux (43°C) and the addition of 13.6g (0.1 mol) of Cl₃SiH begun. Addition was complete in 33 min, during which the reflux temp. had increased to 47°C. After another 16 min, reflux temp. was 70°C and reaction was complete. Vacuum distillation yielded 14.01g (66.1%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that the reaction between Cl₃SiH and allyl chloride, which is slow at the reflux temperature of the combined reactants, can be accelerated by beginning at the higher reflux temperature of the allyl chloride. Comparative Example KK Reaction of Cl₃SiH with allyl chloride promoted by Cl₃GeH. The reaction of Comparative Example JJ was repeated except that all reactants and catalyst were combined at the start and 0.18g of Cl₃GeH added at once (instead of Et₃SiH). VPC analysis showed no promotion of the reaction between Cl₃SiH and allyl chloride even after heating at reflux for 3 h. Cl₃GeH is not an effective promoter for the reaction between Cl₃SiH and allyl chloride under these conditions. Example 31 Reaction of 10/1 molar mixture of Cl₃SiH/Et₃SiH with allyl chloride, former added to latter. In a 50 ml apparatus, there were combined 7.7g (0.1 mol) of allyl chloride and 0.05 ml of Pt catalyst solution. At 42°C, addition of a mixture of 13.6g (0.1 mol) of Cl₃SiH and 1.2g (0.01 mol) of Et₃SiH was begun. There was an exothermic reaction during addition (27 min) to 77°C. Vacuum distillation yielded 13.98g (65.9%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that Et₃SiH is an effective promoter for the reaction between Cl₃SiH and allyl chloride, increasing the reaction rate, but not the yield or selectivity. Example 32 Reaction of 15/1 molar mixture of Cl₃SiH/Et₃SiH with allyl chloride, latter added to former. In a 50 ml apparatus, there were combined 12.0g (0.09 mol) of Cl₃SiH, 0.7g (0.006 mol) of Et₃SiH, and 0.04 ml of Pt catalyst solution. The addition of 6.8g (0.09 mol) of allyl chloride was begun at 24°C causing an exothermic reaction to 63°C during addition (18 min). Vacuum distillation yielded 11.92g (63.2%) of Cl₃SiCH₂CH₂CH₂Cl, showing that Et₃SiH promotes the reaction between Cl₃SiH and allyl chloride at lower temperatures than phenothiazine, such that no external heating is required. This example also shows that the reactant combination sequence has little effect effect on yield or selectivity of the reaction between Cl₃SiH and allyl chloride. Example 33 Reaction between Cl₃SiH and allyl chloride promoted by Et₃SiH. To a mixture of 13.6g (0.1 mol) of Cl₃SiH and 0.05 ml Pt catalyst solution in a 50 ml apparatus, there was added dropwise 7.7g (0.1 mol) of allyl chloride at 24°C. VPC analysis 1 hr. after start of addition (30 min. after completion of addition) showed less than 1% conversion of reactants to products. Et₃SiH (0.04 ml) was added, causing a smooth exothermic reaction to 67°C in 24 min. Vacuum distillation yielded 14.29g (67.4%) of Cl₃SiCH₂CH₂CH₂Cl. This example shows that the reaction between Cl₃SiH and allyl chloride is promoted very effectively in rate by very low levels (0.33 mol.%) of Et₃SiH, with the elimination of external heating. PROMOTION OF Cl₃SiH AND ALLYL CHLORIDE Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp.JJ Cl₃SiH CH₂=CHCH₂Cl -- 66.1 49 min Comp.KK Cl₃SiH CH₂=CHCH₂Cl Cl₃GeH No Promotion 7180 min 31 Cl₃SiH CH₂=CHCH₂Cl 10/1 Cl₃SiH/Et₃SiH 65.9 27 min 32 Cl₃SiH CH₂=CHCH₂Cl 15/1 Cl₃SiH/Et₃SiH 63.2 18 min 33 CH₃SiH CH₂=CHCH₂Cl 0.33 mol.% Et₃SiH 67.4*** 24 min This Table XI shows that Cl₃SiH and allyl chloride can be promoted primarily in their rate by both Et₃SiH and EtMe₂SiH and slightly in yield by EtMe₂SiH. Very small quantities of Et₃SiH may be used to promote rate (Example 33), and the order of mixing does not seem to matter (Contrast to Comparative Examples EE and FF and Examples 23-26 as discussed in Table IX.) Comparative Example OO Reaction of Et₃SiH with 3-chloro-1-butene. In a 50 ml apparatus, there were combined 4.5g (0.039 mol) of Et₃SiH and 3.5g (0.039 mol) of 3-chloro-1-butene. Pt catalyst solution (0.01 ml) was added at 22°C, followed by heating up to 77°C over 70 min. Vacuum distillation yielded 3.46g (58.9%) of Et₃SiCl and 0.61g (7.6%) of Et₃SiCH₂CH₂CHMeCl. This example demonstrates the low yield of Et₃SiCH₂CH₂CHMeCl from the unpromoted reaction of Et₃SiH with 3-chloro-1-butene. Example 34 Reaction of Et₃SiH with 3-chloro-1-butene promoted by Cl₃SiH. The reaction of Comparative Example OO was repeated except that 1.0g (0.007 mol) of Cl₃SiH was also added. There was a smooth exothermic reaction to 55°C in 52 min with no external heating. Vacuum distillation yielded 2.54g (22.5%) of Et₃SiCl and 11.40g (73.6%) of Et₃SiCH₂CH₂CHMeCl. This example shows that Cl₃SiH is a very effective promoter for the reaction between Et₃SiH and 3-chloro-1-butene, increasing both rate and yield, and eliminating external heating. Comparative Example PP Reaction of Et₃SiH with 4-methyl-1-pentene. In a 50 ml apparatus, there were combined 6.3g (0.075 mol) of 4-methyl-1-pentene, 8.7g (0.075 mol) of Et₃SiH, and 0.01 ml of Pt catalyst solution at 22°C. Heat was applied over 2 h up to 58°C, with VPC analysis showing 11.0% conversion of reactants to Et₃SiCH₂CH₂CH₂CHMe₂. This example demonstrates the low rate of the unpromoted reaction between Et₃SiH and 4-methyl-1-pentene. Example 35 Reaction of Et₃SiH with 4-methyl-1-pentene promoted by Cl₃SiH. The reaction of Comparative Example PP was repeated except that Cl₃SiH (1.0g, 0.0075 mol) was also added. There was a rapid exothermic reaction from 23°C to 70°C in 8 min. VPC analysis at that point showed 29.7% conversion of reactants to Et₃SiCH₂CH₂CH₂CHMe₂, demonstrating that Cl₃SiH is an effective promoter for the reaction of Et₃SiH with 4-methyl-1-pentene. Comparative Example QQ Reaction of equimolar mixture of Et₃SiH,/MeSiHCl₂ with 4-methyl-1-pentene. In a 50 ml apparatus, there were combined 8.1g (0.07 mol) of Et₃SiH, 8.1g (0.07 mol) of MeSiHCl₂, and 5.9g (0.07 mol) of 4-methyl-1-pentene. Pt catalyst solution (0.05 ml) was added at 21°C. Gentle heating caused and exothermic reaction to 55°C in 38 min. VPC analysis of the complete reaction 90 min later showed a mixture of MeSiCl₂CH₂CH₂CH₂CHMe₂/Et₃SiCH₂CH₂CH₂CHMe₂ in a molar ratio of 3.3/1. This example shows that neither MeSiHCl₂ nor Et₃SiH is a very effective promoter at the equimolar level for reactions of the other with 4-methyl-1-pentene. Comparative Example RR Reaction of equimolar mixture of EtMe₂SiH/MeSiHCl₂ with 4-methyl-1-pentene. In a 25 ml apparatus, there were combined 2.6g (0.023 mol) of MeSiHCl₂, 2.0g (0.023 mol) of EtMe₂SiH, and 1.9g (0.023 mol) of 4-methyl-1-pentene. A few droplets of Pt catalyst solution were added at 22°C. Gentle heating caused an exothermic reaction to 53°C over 21 min followed by heating at 50°C for 130 min. VPC analysis of the complete reaction showed equivalent yields of MeSiCl₂CH₂CH₂CH₂CHMe₂ and EtMe₂SiCH₂CH₂CH₂CHMe₂. This example shows that while the promoting effect of EtMe₂SiH is nearly equivalent to that of Et₃SiH for the reaction of MeSiHCl₂ with 4-methyl-1-pentene, its competitive reactivity is significantly higher. Comparative Example SS and Example 36 Reaction with Et₃SiH with 3,3-dimethyl-1-butene promoted by Cl₃SiH. In a 50 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 8.4g (0.01 mol) of 3,3-dimethyl-1-butene, and 0.01 ml Pt catalyst solution at 14°C. Heat was applied up to 86.5°C over 113 min, when VPC analysis showed 38.4% conversion of reactants to Et₃SiCH₂CH₂CMe₃. Reaction was cooled to 60°C and 0.7g (5 mol-%) of Cl₃SiH added, causing a rapid exothermic reaction to 83°C in 3 min, and complete conversion of reactants to Et₃SiCH₂CH₂CMe₃. This example demonstrates both the low rate of the unpromoted reaction and the effectiveness of Cl₃SiH as a promoter for the reaction between Et₃SiH and 3,3-dimethyl-1-butene. Example 37 Reaction of equimolar mixture of Cl₃SiH/Et₃SiH with 3,3-dimethyl-1-butene. In a 100 ml apparatus, there were combined 11.6g (0.1 mol) of Et₃SiH, 8.4g (0.1 mol) of 3,3-dimethyl-1-butene, and 13.6g (0.1 mol) of Cl₃SiH. Pt Catalyst solution was added (0.05 ml) at 24°C, causing a rapid exothermic reaction to 57°C in 4 min. Vacuum distillation yielded 1.82g (8.3%) of Cl₃SiCH₂CH₂CMe₃ and 11.95g (59.8%) of Et₃SiCH₂CH₂CMe₃. This example shows that Cl₃SiH is an effective promoter at the equimolar level for the reaction between Et₃SiH and 3,3-dimethyl-1-butene. Comparative Example TT Reaction of Et₃SiH with allyl phenyl ether. In a 50 ml apparatus, there were combined 10.1g (0.075 mol) of allyl phenyl ether and 8.7g (0.075 mol) of Et₃SiH. Pt catalyst solution (0.02 ml) was added at 22°C, followed by heating up to 55°C over 3 hrs. Vacuum stripping left 14.7g (78.4%) of Et₃SiCH₂CH₂CH₂OC₆H₅. Example 38 Reaction of Et₃SiH with allyl phenyl ether promoted by Cl₃SiH. The reaction of Comparative Example TT was repeated except that 1.4g (0.01 mol) of Cl₃SiH was also added. Gentle heating caused a violent exothermic reaction from 40°C to 137°C over 18 min. Vacuum stripping left 19.7g (78.8%) of Et₃SiCH₂CH₂CH₂OC₆H₅. This example shows that Cl₃SiH is an effective promoter for the rate of the reaction between Et₃SiH and allyl phenyl ether. Comparative Example VV Reaction of Et₃SiH with methallyl phenyl ether. In a 50 ml apparatus, there were combined 5.8g (0.05 mol) of Et₃SiH, 7.4g (0.04 mol) of methallyl phenyl ether, and 0.02 ml of Pt catalyst solution at 21°C. Heat was applied to 86°C over 115 min. VPC analysis showed only 21.9% conversion of reactants to Et₃SiCH₂CHMeCH₂OC₆H₅. - Example 39 Reaction of Et₃SiH with methallyl phenyl ether promoted by Cl₃SiH. The reaction of Comparative Example VV was repeated except that 0.7g (0.005 mol) of Cl₃SiH was also added. There was a rapid exothermic reaction from 23°C to 131°C in 90 sec. VPC showed 88.4% conversion of reactants to Et₃SiCH₂CHMeCH₂OC₆H₅, demonstrating that Cl₃SiH is a very effective promoter for the reaction of Et₃SiH with methallyl phenyl ether. Note that the allyl and methallyl phenyl ethers are chemical models for allyl and methallyl polyalkylene oxide ethers which are articles of commerce. Comparative Example WW Reaction of Et₃SiH with styrene. In a 50 ml apparatus, there were combined 8.6g (0.075 mol) of Et₃SiH, 7.8g (0.075 mol) of styrene, and 0.05 ml Pt catalyst solution at 20°C. There was a slow reaction to 29°C over 33 min (heat rise due to magnetic stirrer), with VPC analysis showing 1.8% conversion of reactants to Et₃SiCH₂CH₂C₆H₅. Example 40 Reaction of Et₃SiH with styrene promoted by Cl₃SiH. The reaction of Comparative Example WW was repeated except that 1.0g (0.0075 mol) of Cl₃SiH was also added. There was an exothermic reaction to 39°C over 38 min, with 24.1% conversion of reactants to Et₃SiCHMeC₆H₅/Et₃SiCH₂CH₂C₆H₅ (0.59 molar ratio). This example shows that Cl₃SiH is an effective promoter for the reaction between Et₃SiH and styrene. Comparative Example XX Reaction of D₃D' with vinyl acetate. In a 100 ml apparatus, there were combined 30.5g (0.1 mol) of 92% D₃D' and 0.05 ml Pt catalyst solution. Heat was applied to 125°C and addition of 8.6g (0.1 mol) of vinyl acetate begun. Continued heating during addition caused an exothermic reaction to 195°C over 220 min. Vacuum distillation yielded 11.42g (31.0%) of D₃D'CHMeOAc and 4.62g (12.6%) of D₃D'CH₂CH₂OAc. Example 41 Reaction of D₃D' with vinyl acetate promoted by Cl₃SiH. The reaction of Comparative Example XX was repeated except that all reactants were combined at the start and 1.4g (0.01 mol) of Cl₃SiH was also added. Heat was applied to a maximum temp. of 147°C over 360 min, followed by vacuum distillation, which yielded 5.46g (14.8%) of D₃D'CHMeOAc and 18.78g (51.0% ) of D₃D'CH₂CH₂OAc. This example shows that Cl₃SiH is an effective promoter for the reaction between D₃D' and vinyl acetate, allowing reaction completion at significantly lower temp. with a much higher yield of the more stable and useful D₃D'CH₂CH₂OAc isomer. PROMOTION USING OTHER OLEFINS Example REACTANT A OLEFIN PROMOTER YIELD % TIME Comp.OO Et₃SiH 3-chloro-1-butene -- 7.6 70 min 34 Et₃SiH 3-chloro-1-butene 18 mol-% Cl₃SiH 73.6 52 min Comp.PP Et₃SiH 4-methyl-1-pentene -- 11.0 7120 min 35 Et₃SiH 4-methyl-1-pentene 10 mol-% Cl₃SiH 29.7 8 min Comp.SS Et₃SiH 3,3-dimethyl-1-butene -- 38.4 113 min 36 Et₃SiH 3,3-dimethyl-1-butene 5 mol-% Cl₃SiH Comp. 3 min 37 Et₃SiH 3,3-dimethyl-1-butene Eqm. Cl₃SiH 59.8 4 min Comp.TT Et₃SiH allyl phenyl ether -- 78.4 >180 min 38 Et₃SiH allyl phenyl ether 13 mol-% Cl₃SiH 78.8** 18 min Comp.VV Et₃SiH methallyl phenylether -- 21.9 115 min 39 Et₃SiH methallyl phenylether 10 mol-% Cl₃SiH 88.4 1 1/2 min Comp.WW Et₃SiH Styrene -- 1.8 33 min 40 Et₃SiH Styrene 10 mol-% Cl₃SiH 24.1 38 min Comp.XX D₃D' Vinyl acetate -- 12.6 220 min 41 D₃D Vinyl acetate 10 mol-% Cl₃SiH 51 360 min This Table shows, except for the last 2 examples, the effect of Cl₃SiH used as a promoter in a reaction between Et₃SiH and various other olefins. In each case, this table shows clearly that small amounts (i.e., about 10 mol-%) of Cl₃SiH significantly increases either rate or yield of these reactions. The last two examples show the same effect in a reaction between D₃D' and vinyl acetate also promoted by Cl₃SiH. Example 42 A 250 cm³three-necked flask equipped with a 125 cm³ dropping addition funnel, magnetic stirrer, reflux condenser, thermometer, heating mantle, and nitrogen inlet was charged with 71.5 grams (0.638 moles) allyl acrylate, 0.150 grams phenothiazine inhibitor, 0.150 grams Diphenyl-p-phenylenediamine inhibitor and heated to 50°C with stirring. When 50°C was reached, 80 microliters of 10% chloroplatinic acid solution (20 ppm of platinum as based on total reaction charge) was injected into the flask followed by 100 µl of triethylsilane promoter. A feed of trichlorosilane was introduced slowly to the olefin with continuous stirring over a period of two hours. An exotherm was apparent immediately at the start of the addition. An ice bath was necessary to maintain the reaction mixture between 50-65°C throughout the addition. A total of 78.5 grams (0.580 moles) of trichlorosilane was added. Following the complete addition, the reaction mixture was cooled to room temperature and samples for gas chromatographic analysis. Results indicated approximately 70% product of 3-acryloxypropyltrichlorosilane. The identification was verified later by gc/mass spec analysis. Recovery was 145 grams of reaction material. This example shows the promotional effects of a second silane when the olefin is allyl acrylate. This reaction is important because the generated catalyst allows the reaction to occur at 50°-65°C, thus preventing the polymerization associated with usage of unstable acrylates at higher temperatures. While some product would form without promotion, it is uncertain when reaction initiation would occur. Thus the effective yield increase is great compared to the unpromoted reaction.

Claims: A process of preparing compounds containing silicon-carbon bonds by a hydrosilation reaction of (A) a hydrosilyl reactant with (B) an olefinic reactant and (C) a hydrosilyl promoter in the presence of a soluble platinum catalyst at a temperature below 150°C wherein: (A) the hydrosilyl reactant has the formula: R₃SiH where R is selected from the group consisting of (i) a monovalent hydrocarbon group which is an aliphatic group having 1 to 10 carbon atoms or an aromatic group having 6 to 20 carbon atoms free of terminal unsaturation, possibly substituted with halogen, cyano, carboalkoxy (ester), ether or thioether, with the proviso that when such hydrosilyl reactant is substituted with functional groups, said functional groups do not interfere with the promotion mechanism for hydrosilane-promoted hydrosilations; (ii) an alkoxy group; (iii) an acyloxy group; (iv) a carbomyloxy group; (v) a siloxy group; (vi) a halogen or (vii) two R groups taken together form a heterocyclic ring including the silicon atom; (B) the olefinic reactant is used at 0.1 to 2.0 molar amounts relative to the hydrosilyl reactant (A); and (C) the hydrosilyl promoter is selected from the group consisting of Cl₃SiH, MeSiHCl₂, Me₂SiHCl, Et₃SiH, F₃SiH and Br₃SiH, with the proviso that the hydrosilyl promoter and the hydrosilyl reactant may not be the same compound when used in the same reaction, the hydrosilyl promoter(C) is used at is 0.0001 to 0.1 molar amounts relative to the hydrosilyl reactant (A), and said promoter (C) provides (l) at least a 20% increase in the amount of silicon-carbon compounds, or (2) at least a 20% increase in reaction rate relative to an unpromoted reaction of (A) and (B). The process according to claim 1 wherein the hydrosilyl reactant has the general formula R₃SiH where R is halogen or siloxy. The process of claim 1 wherein the hydrosilyl reactant has at leas two R groups to form a heterocyclic ring including the silicon of the formula where n=3-6. The process according to claim 1 where the promoter is Cl₃SiH and the hydrosilyl reactant is (CH₃CH₂)₃SiH. The process according to claim 1 where the promoter is (CH₃CH₂)₃SiH and the hydrosilyl reactant is (CH₃O)₃SiH. The process according to any one of claims 1 to 5 wherein the olefinic reactant has the general formula CH₂=C , and is preferably selected from allyl and methallyl compounds, vinyl compounds, terminal alkenes, including halides, ethers, esters and nitriles, with the proviso that when the olefinic reactant is substituted to functional groups, the functional groups do not interefere with the hydrosilation reaction, especially allyl or methallyl polyalkylene oxide ether or allyl acrylate. The process according to any one of claims 1 to 6 wherein the reaction is run at sub-ambient temperatures. The process according to any one of claims 1 to 7 wherein the soluble platinum catalyst is chosen from the group consisting of solutions of H₂PtCl₆, in hydrated or unhydrated form, solutions of PtCl₄ or PtCl₂ and solutions of ethylene-bis-(platinum chloride).

Inventors: SCHILLING CURTIS LOUIS JR, SCHILLING, CURTIS LOUIS, JR.
Applicants: UNION CARBIDE CORP, UNION CARBIDE CORPORATION
Application year: 1986
Main classification: C07F7
IPC codes: C07F7, B01J27, B01J31, C07B61