HYDANTOINYLSILANES AND BIS(HYDANTOINYL)DISILOXANES AND METHOD FOR PREPARING SAME

Abstract: This invention relates to a novel class of organosilanes and bis(hydantoinyl)disiloxanes. The characteristic feature of these silanes and disiloxanes is the presence of a hydantoin residue that is bonded to silicon through an alkylene group. Methods are disclosed for their production. The said com­ pounds are useful coupling agents for bonding glass fibres to organic resins and as self-bonding adhesion promoters for room temperature curable silicone adhesives.

Description: "HYDANTOIN¯SILUsES AND BIS(HYDANTOINYL) DISILOXANES AND METHOD FOR PREPARING SM.'1 This invention relates to a novel class of organosilanes and disiloxanes. The characteristic feature of these silanes and disiloxanes is the presence of a hydantoin residue that is bonded to silicon through an alkylene group. According to one aspect of the invention there is provided a hydantoinyl silane having the general formula EMI1.1 wherein R is alkyl, aryl , cyanoalkyl, trifluoropropyl, alkenyl, alkynyl or halophenyl; R is alkyl, alkaryl or cycloalkyl; R is alkylene; R4 and R5 are independently chosen from hydrogen, alkyl, aryl, aralkyl and alkyl; R6 is hydrogen, alkyl, aryl, aralkyl, alkaryl or a group having the general formula EMI1.2 wherein R , R and R are as defined above and n for both formulae (I) and (II) is O, 1, 2 or 3 with the proviso that for either of formulae (I) and (II) any alkyl or alkylene group contains from 1 to 12 carbon atoms and any alkenyl or alkynyl group contains from 2 to 12 carbon atoms. A method for preparing a hydantoinyl silane having the general formula (I) as defined above comprises 1) reacting substantially equimolar amounts of (a) an anhydrous alkali metal salt of a hydantoin having the general formula EMI2.1 wherein M is an alkali metal and R4, R5 and R6 are as defined in formula (I) and (b) a haloalkylsilane having the general formula EMI2.2 wherein X is halogen and Rl, RL, RJ and n are as defined in formula (I) in a reaction medium comprising a dipolar apratic liquid; 2) maintaining the reaction mixture of (a) and (b) at a temperature of from ambient to the boiling point of the mixture for sufficient time to substantially complete the reaction, and 3) isolating the resultant hydantoinyl silane from the reaction mixture. According to another aspect of the invention there is provided a bis(bydantoinyl)disiloxane having the general formula EMI3.1 wherein R1, R3, R4, R5 and R6 are as defined in formula (1) and with the proviso that for either of formulae (V) and (11) any alkyl or alkylene group contains from 1 to 12 carbon atoms and any alkenyl or alkynyl group contains from 2 to 12 carbon atoms. Particularly preferred compounds are those of general formulae (I) and (V) in which R1 (if present) is alkyl, more especially methyl, and R2(if present) is alkyl, more especially methyl. Of the possible meanings of R4 and R5, hydrogen and alkyl may be particularly mentioned, and again the preferred alkyl radical is methyl. R6 may suitably be hydrogen or a group having the general formula (II) and R3 may suitably be trimethylene. The novel silanes of this invention can be prepared using conventional procedures employed for reacting halosilanes with compounds containing a labile proton. A preferred method involves the reaction of an anhydrous alkali metal salt of hydantoin or one of the substituted hydantoins represented by the general formula EMI4.1 45 6 wherein R ,R and R are as defined above with a haloalkylsilane represented by the general formula (IV) wherein R1 R2 R3 and n are as defined above and X represents chlorine, bromine or iodine. This reaction is preferably conducted in the presence of a dipolar aprotic organic liquid medium which is a solvent for the aforementioned alkali metal salt of the hydantoin. Especially suitable dipolar aprotic liquids include N,Ndimethylformamide, N-methylpyrrolidone and dimethylsulphoxide. Since the reaction between the hydantoin salt and the haloalkyl silane may be exothermic, it is preferable to first dissolve the hydantoin salt in the liquid reaction medium and gradually add the haloalkylsilane to the resultant solution under an inert atmosphere such as nitrogen to exclude even trace amounts of water, which would rapidly hydrolyze the alkoxy groups present on the haloalkylsilane. It is often desirable to heat the reaction mixture at ten.peratu1-es of from 40 to about 100 C for from 0.5 to 5 hours or longer to ensure that the reaction is complete. The reaction product is often soluble in the reaction medium, in which instance the product is readily isolated by filtering to remove the solid alkali metal halide byproduct and distilling the dipolar aprotic liquid under reduced pressure to minimize heat-induced decomposition of the desired product. The product of the aforementioned reaction contains one silicon atom and one hydantoin residue that is bonded to silicon through an alkylene group represented by R3 in the foregoing formula (I). Compounds containing three hydrocarbyl groups and one hydrocarbyloxy group bonded to silicon are readily converted to the corresponding bis(hydantoinylalkyl)tetrahydrocarbyldisiloxane (formula (V)) by hydrolysis in the presence of a methanol-water or ethanol-water mixture containing a trace amount of an alkali metal hydroxide such as potassium hydroxide. The hydantoin employed to prepare the compounds ((I) and (V)) of this invention can be unsubstituted,in which instance the substituents represented by R4, R5 and R6 in the foregoing formulae are hydrogen. Alternatively, one can employ any of the available substituted hydantoins or a compound containing the desired substituents can be prepared using synthetic procedures and reactions disclosed in the chemical literature. Representative substituted hydantoins which are commercially available or have been reported in the chemical literature include 5,5-dimethylhydantoin 5, 5-diphenylhydantoin 5-ethyl-5-(2-methylbutyl)hydantoin 9-phenylhydantoin. The synthesis of hydantoin, also referred to as 2,4-diketoiminazolidine, and a number of substituted hydantoins, is described in a text entitled "Chemistry of Carbon Compounds" edited by E.H. Rodd (Elsiner Publishing Company, 1957) and in an article by E. Ware [Chemical Reviews 46, 403-470 (1950]. The following examples describe the preparation of four preferred species selected from the present class of novel silanes and disijoxanes. These examples should not be considered as limiting the scope of the accompanying claims. EXAMPLE 1 - Preparation of 5,5-dimethyl-3-trimethoxy silylpropyl Hydantoin. A mixture containing 12.8 g (0.1 mole) 5,5-dimethyl-hydantoin, 5.6 g (0.1 mole) potassium hydroxide and 100 cc ethanol was heated to the boiling point until a clear solution was obtained. The ethanol was then evaporated under reduced pressure to isolate the solid, anhydrous salt. The salt was combined with 100 cc of dry N,-dimethylfolmamide and the resultant mixture was heated at 50 C until a clear solution formed. A 19.8 g (0.1 mole) portion of chloropropyl trimethoxysilane was then added dropwise to the aforementioned salt solution under a nitrogen atmosphere with stirring. The temperature of the reaction mixture increased slightly during the addition, which is indicative of an exothennic reaction, and a white precipitate (potassiuni chloride) began to form when the silane addition was begun. Following completion of the addition the reaction mixture was heated at 950C for three hours. Analysis by vapour phase chromatography of the liquid phase demonstrated that the initial chloropropyl trimethoxysilane had been converted to a product exhibiting a high retention time. The reaction mixture was then cooled and filtered, following which the liquid phase was distilled to remove the NN-dimethylformamide. A second fraction was collected at a temperature of 194 C and a pressure of 4 mm of mercurv and subsequently silidified to a white solid. Analysis by vapour phase chromatography indicated that this material was 09% pure and contained a trace amount of the initial hydantoin. The infrared spectrum of the material was consistent with the proposed structure. EMI7.1 The product was found to contain 9.74% by weight of silicon and 9.92% nitrogen. The calculated values for the expected product are 9*64% silicon and 9.66% nitrogen. EXAMPLE 2 - Preparation of 3-Dimethoxymethylsilylpropyl hydantoinX A mixture containing 10.0 g (0.1 mole) hydantoin, 5.6 g (0.1 mole) potassium hydroxide and 100 cc ethanol was heated to the boiling point until a clear solution was obtained. The resultant salt was then isolated and dried as described in the preceding example, following which it was solubilized in 100 cc of anhydrous N,N-dimethylform amide and reacted with 1X8.2 g of chloropropylmethyldimethoxysilane under a nitrogen atmosphere using dropwise addition. The reaction mixture was heated at 1100C for about sixteen hours following completion of the silane addition. The reaction mixture was then cooled and filtered to remove the potassium chloride byproduct. Analysis of the liquid phase by vapour phase chromatography demonstrated that the original silane had been consumed and replaced bya material having a significantly longer retention tire. The desired product was recovered following distillatioll to remove the N,N-ditnethylformamide. EX.MIPLE 3 - 3-Preparation of Bist(5,5-dimethylhydantoin- -vl)-propyll tetramethyldisiloxane. A sample of 5,5-dimethyl-3-dimethylmethoxysilylpro- pylhydantoin was prepared and isolated using the general procedure described in the preceding examples with 0.1 mole of each of the three reagents, namely 5,5-dimethylhydan- toxin, 3-chloropropyldimethylmethoxysilane and potassium hydroxide, A 24.4 g portion of the final product was dissolved in a mixture of 5.4 g of water and 300 cc methanol containing one pellet of- potassium hydroxide. The resultant mixture was stirred at ambient temperature for 16 hours, at which time the methanol-water mixture was removed by distillation under reduced pressure. The identity of the final product as a disiloxane was confirmed by its infra-red spectrum and by vapour phase chromatography. EXAMPLE 4 - Preparation of 1,3-Bis(trimethoxys ilylpropyl) 5,5-dimethylhydantoin. A 2.4 g portion of a dispersion containing 50% by weight of sodium hydride in a liquid paraffin was added in portions under an inert atmosphere to a solution containing 14.5 g (0.05 mole), 5,5-dimethyl-3-trimethoxysilyl- propyl hydantoin and 150 cc of anhydrous N,N-dimethylformamide. The temperature of the reaction mixture was maintained at from 15 to 20 C during the addition of the hydride. Following completion of the addition the mixture was stirred until hydrogen evolution ceased, at which time it was heated to 85 C, and 98.8 g of chloropropyltrimethoxysilane were added dropwise to the reaction mixture. A white precipitate formed as the addition progressed. Following completion of the addition the reaction mixture was heated at 95 C for 16 hours, at which time the reaction mixture was cooled, filtered and the liquid phase distilled under reduced pressure to remove the N,N-dimethylformamide, The liquid paraffin was washed from the product using hexane. The identity of the residue as the expected silylhydantoin was confirmed using infra-red and nuclear magnetic resonance spectroscopy. The silanes and disiloxanes of this invention are particularly useful as coupling agents for bonding glass fibres to organic resins and as self-bonding adhesion promoters for room temperature curable silicone adhesives. Some prior art room temperature curable polysiloxane products employing an acetoxysilane as the curing agent require a primer to achieve adequate adhesion with the substrate to which they are applied. Primers are not required using the hydantoinyl silanes of this invention.

Claims: CLAIMS: 1. A hydantoinyl silanehaving the general formula EMI10.1 wherein R1 is alkyl, aryl, cyanoalkyl, trifluoropropyl, alkenyl, alkynyl or halophenyl; R2 is alkyl, alkaryl or cycloalkyl; R3 is alkylene; R4 and RD are independently chosen from hydrogen, alkyl, aryl, aralkyl and alkaryl; R6 is hydrogen, alkyl, aryl, aralkyl, alkaryl or a group having the general formula EMI10.2 wherein R1 2 and R3 are as defined above and n for both formulae (I) and (II) is 0, 1, 2 or 3 with the proviso that for either of formulae (I) and (II) any alkyl or alkylene group contains from 1 to 12 carbon atoms and any alkenyl or alkynyl group contains from 2 to 12 carbon atoms. 2. A bis(hydantoinyl)disiloxane having the general formula EMI10.3 wherein R1, R3 R4, R5 and R6 are as defined in formula (I) and with the proviso that for either of formulae (V) and (Il) any alkyl or alkylene group contains from 1 to 12 carbon atoms and any alkenyl or alkynyl group contains from 2 to 12 carbon atoms. 3. A compound according to either of the preceding claims, wherein R1 if present is alkyl if if present is alkyl. 4. A compound according to Claim 3, wherein the said alkyl is methyl. 5. A compound according to any one of the preceding claims, in which R4 and R5 are each hydrogen or alkyl. 6. A compound according to Claim S, in which R4 and R5 are both methyl. 7. A compound according to any one of the preceding claims, in which R6 is hydrogen or a group having the general formula (II) as defined in Claim 1. 8. A compound according to any one of the preceding claims, in which R3 is -tCH2)-. 9. A method for preparing a hydantoinyl silane having the general formula (I) as defined in Claim 1, the method comprising: 1) reacting substantially equimolar amounts of (a) an anhydrous alkali metal salt of a hydantoin having the general formula EMI12.1 wherein M is an alkali metal and R4, R5 and R6 are as defined in formula (I) and (b) a haloalkylsilane having the general formula EMI12.2 wherein X is halogen and R1, R2, R3 and n are as defined in formula (I) in a reaction medium comprising a dipolar aprotic liquid; ; 2) maintaining the reaction mixture of (a) + (b) a a temperature of from ambient to the boiling point of the mixture for sufficient time to substantially complete the reaction, and D) isolating the resultant hydantoinyl silane from the reaction mixture. 10. A method according to Claim 9,wherein M is potassium.

Inventors: BERGER, ABE
Applicants: M & T CHEMICALS, INC.
Application year: 1980
Main classification: C07F7
IPC codes: C07F7, C09J11