PRODUCTION OF HIGH (Z,Z) CONTENT 1,5,9-TETRADECATRIENEAND 1,5,9-TETRADECATRIENE

Abstract: Method for the production of high cis content 1,5,9-tetradecatriene is provided which comprises disproportionating 1,5-cyclooctadiene and 1-hexene in the presence of a catalyst consisting essentially of molybdenum oxide on a high purity, high surface area, high pore volume silica support. The resulting high cis content 1,5,9-tetradecatriene is a useful precursor for the preparation of gossyplure, a known insect sex attractant.

Description: This invention relates to the conversion of 1,5-cyclooctadiene and 1-hexene to produce high (Z,Z) content 1,5,9-tetradecatriene. BACKGROUND Gossyplure, a 60/40 mixture of Z,Z and Z,E stereoisomers of 7,11-hexadecadienyl acetate, is a known pheromone for several insect species. In order to make this compound widely available for use in insect control, economic large scale synthetic conversion processes must be developed. One of the most promising synthetic conversion processes developed to date is the process whereby 1,5,9-tetradecatriene is metallated to produce a 1-metallo-5,9-tetradecadiene, which compound is then homologized by addition of a C₂-synthon, then esterified as needed to produce the desired gossyplure-like product. Such a process is described in EP-A-0 195 342. A key to the success of the above-described synthetic route is the availability of a triene starting material with a stereochemical content that approaches as closely as possible the 60/40 Z,Z to Z,E ratio for the internal double bonds of the triene, as observed in naturally occurring gossyplure. US-A-3 586 731 discloses a catalyst containing, for example molybdenum oxide on a silica support, which catalyst contains a small amount of a metal selected from alkaline and alkaline earth metals to decrease the coke content on the catalyst with the disproportionation of olefins. OBJECTS OF THE INVENTION An object of the present invention, therefore, is a method for the production of 1,5,9-tetradecatriene which has a high 5Z,9Z to 5Z,9E ratio. Another object of the present invention is to provide 1,5,9-tetradecatriene compositions of matter which comprise at least fifty percent cis (or Z) content at the 9-carbon, and essentially 100 percent cis content at the 5-carbon. These and other objects of the invention will become apparent from further study of the disclosure and claims herein provided. STATEMENT OF THE INVENTION In accordance with the present invention 1,5,9-tetradecatriene having a cis content at the 9-carbon of at least 50% and essentially all cis content at 5-carbon is obtained when 1,5-cyclooctadiene and 1-hexene are contacted in the presence of a catalyst containing molybdenum oxide on a silica support, wherein said silica support has a surface area of at least 200 m²/g, a pore size volume of at least 0.6 cm³/g and contains no more than 0.2 wt % Al₂O₃. DETAILED DESCRIPTION OF THE INVENTION In accordance with one embodiment of the present invention, there is provided as a composition of matter 1,5,9-tetradecatriene which has a cis content at the 9-carbon of at least fifty percent, and an essentially all cis orientation at the 5-carbon. The catalyst useful in the practice of the present invention is prepared from a high purity, high surface area, high pore volume silica support as defined in the claim. For purposes of this disclosure, high purity means an essentially dry support containing at least about 99 percent silica by weight, preferably containing at least about 99.6 percent silica by weight and no greater than about 0.2 weight percent alumina. The silica has a surface area of at least 200 m²/g, preferably 250 m²/g and higher. The pore volume of the silica is at least 0.6 cm³/g, preferably of 1.0 cm³/g and higher. Those of skill in the art recognize that, in general, the higher the surface area, the lower the pore volume of a given support material will be, and vice versa. Thus, silica supports having substantially higher surface areas than those specified herein will not be able to simultaneously achieve the desired high pore volumes; and conversely, silica supports having substantially higher pore volumes than those specified herein will not be able to simultaneously achieve the desired high surface areas. Therefore, the required minimum values set forth herein for surface area and pore volume indirectly place an upper limit as to how high these values may go. The support is contacted with molybdenum oxide or a precursor thereof, such as for example, ammonium molybdate and optionally, additional support treating reagents such as alkali metal hydroxides, e.g., potassium hydroxide or sodium hydroxide. Support-treating agent contacting is carried out in any suitable manner. For example, the silica and molybdenum oxide or molybdenum oxide precursor can be mixed in an open vessel. When the molybdenum oxide or molybdenum oxide precursor is provided as a solution, such as for example, an aqueous solution, once the silica support and support treating solution are mixed, then any excess liquid can be decanted or removed by filtration. Alternatively, the technique of incipient wetness can be employed whereby only enough liquid is employed to thoroughly wet the silica support, with no free residual liquid. Thus, only as much support-treating solution is employed as the silica support can absorb. This can be accomplished, for example, by spraying support-treating solution over a quantity of silica which is being tumbled in a rotating, baffled drum. Such treatment can also be carried out by simply pouring a predetermined quantity of support-treating solution over a quantity of silica support contained in an open vessel. Alternatively, a measured quantity of silica support could be added to a volume of support-treating solution such that all the liquid is imbibed by the added support. Other techniques as are known to those skilled in the art can also be employed. For example, a quantity of silica support may be placed in a tubular reactor, a volume of support-treating solution may be percolated therethrough, followed by further treatment/activation as necessary. The conditions of silica support/support-treating reagent contact are not critical. Any temperature and any period of contact time is generally suitable. For convenience, contacting is generally carried out at about room temperature, although both higher or lower temperatures can be employed. When support-treating reagents are provided as an aqueous solution, contacting is preferably carried out at a temperature not exceeding about 100°C. A time period sufficient to allow the support and reagents to come into intimate contact is all that is necessary. Thus, the silica support and support-treating reagents may be brought into contact for as little time as a few seconds to several hours or more, as convenient. Following contact of the silica support and support-treating reagents, any excess liquid (if solvent or diluent is employed) can be removed by suitable means, such as, for example, decantation or filtration. The treated support can then be dried to remove absorbed solvent. Any suitable means, as well known by those skilled in the art, may be employed, such as for example, oven drying, azeotropic removal of solvent or passing a vigorous stream of dry (i.e., moisture-free) gas over the treated support. For example, the treated support can be dried by heating at an elevated temperature of about 200°C or higher by passage of an inert gas such as nitrogen over the treated support. This can be accomplished within the reactor or in other suitable catalyst preparation equipment. Calcination, when used, is conducted by heating the treated catalyst in the presence of an oxygen-containing gas, such as for example, air, under conditions sufficient to activate the molybdenum oxide or to convert the molybdenum compound present to the active oxide form. Temperatures in the range of 300 to 800°C are generally satisfactory for such calcination. The time for subjecting the treated silica support to calcination is an amount of time sufficient to activate the treated support. Anywhere from a few minutes to several hours is suitable. Typically, from 15 minutes to 20 hours of calcination will be sufficient. Preferably, for most efficient use of reaction equipment, calcination will be carried out for in the range of 30 minutes to 6 hours. Typically, less time is required at higher temperatures and vice versa. After calcination, the activated catalyst can optionally be treated under reducing conditions, such as for example, with carbon monoxide, hydrogen, or a hydrocarbon, at a temperature in the range of 400 to 750°C in order to enhance the diproportionation activity of the catalyst. Such reducing treatment is carried out preferably at temperatures in the range of 500 to 650°C, because good catalyst activity with reasonably short activation periods of 1 to 6 hours is achieved. Such optional reducing treatment can suitably be carried out for a period of time ranging from 1 minute to 30 hours. If desired, the thus calcined disproportionation catalyst can further be treated with an inert gas such as nitrogen prior to use in a conversion process in order to remove materials from the catalyst which may have a detrimental effect on subsequent disproportionation reactions. The proportion of molybdenum oxide or oxide precursor combined with the silica support can vary appreciably, but generally the support will contain at least about 0.1 percent by weight of the metal, calculated as the oxide and based on the combined weight of metal oxide and inorganic oxide support. Generally, the support will contain an upper limit of about 40 percent by weight of molybdenum, calculated as the oxide and based on the combined weight of metal oxide and silica support. Amounts of 0.2 to 40 percent by weight of the metal, calculated as the oxide, are preferred, with amounts in the range of 2 to 20 percent by weight of the metal, calculated as the oxide. being especially preferred because good catalyst reactivities and product selectivities are obtained within this concentration range. Optional treating reagents such as potassium hydroxide can be added in amounts ranging from 0.1 to 5 percent by weight of metal, calculated as the oxide and based on the combined weight of silica support and the total weight of treating reagents. Typically the reaction is carried out at a temperature in the range of 0 to 400°C; preferably for good conversion in relatively short reaction times, temperatures in the range of 50 to 250°C are employed. The reaction can be carried out by contacting the olefins with the catalyst in the liquid phase or the gas phase. Pressure during the disproportionation reaction can vary between wide limits. For example, pressures between 0.01 and 50 MPa (0.1 and 500 atmospheres) are suitable, although pressures in the range of 0.1 to 4 MPa (1 to 40 atmospheres) are preferred because good conversions are obtained with readily available reaction equipment. If the reaction is carried out in the liquid phase, solvents or diluents for the reactants can be used. Aliphatic saturated hydrocarbons, e.g., pentanes, hexanes, cyclohexanes, dodecanes, and aromatic hydrocarbons, such as benzene and toluene are suitable. If the reaction is carried out in the gaseous phase, diluents such as saturated aliphatic hydrocarbons, for example, methane, ethane, and/or substantially inert gases, e.g., nitrogen or argon, can be present. Preferably, for high product yield, the reaction is effected in the absence of significant amounts of deactivating materials such as water and oxygen. The olefin reactants, 1,5-cyclooctadiene and 1-hexene, can be contacted in any ratio. For efficient use of starting materials, the molar ratio of 1,5-cyclooctadiene to 1-hexene will generally vary within the range of 5:1 to 1:5, with ratios in the range of 2:1 to 1:2 preferred. The contact time needed to obtain a reasonable yield of reaction products depends upon several factors, such as for example, the metals loading on the catalyst, reactor dimensions, temperature or pressure. The length of time during which the olefinic reactants to be disproportionated are contacted with the catalyst can conveniently vary between 0.1 seconds and 24 hours, although longer and shorter contact times can be used. Preferably, for efficient use of reactor equipment, times in the range of 1 second to 1 hour are used. This can alternatively be expressed in terms of liquid hourly space velocity (LHSV) which can vary in the range of 0.1 to 100. The process of the present invention can be carried out batch wise or continuously employing fixed catalyst beds, slurried catalyst, fluidized beds, or by using any other conventional contacting techniques. A further understanding of the present invention and its advantages will be provided by reference to the following non-limiting examples. EXAMPLE I Catalyst Preparation Several different silica supports were impregnated with about 1,2 grams of ammonium molybdate by contacting about 10 grams of support with about 12 milliliters of water in which the ammonium molybdate was dissolved. Once intimate contact between the support and support-treating solution had been achieved, the treated silica was dried in a forced air oven at about 120°C for about 3 hours, then calcined at about 350°C for about three hours in a steady flow of air, resulting in a catalyst containing about 10 weight percent molybdenum oxide, calculated as the oxide and based on the total weight of support and oxide. The designations given the resulting catalysts and some physical and chemical properties of the different supports used are summarized in Table I. EXAMPLE II All runs were made by passing a mixture of 1,5-cyclooctadiene and 1-hexene downflow through a vertical pipe reactor of 1.3 cm diameter and 51 cm length (½ inch diameter and 20 inches in length) positioned in a temperature-controlled electric furnace. A thermocouple was positioned in the catalyst bed to monitor reaction temperature. About 15 cm (6 inches) depth of quartz chips of a size of a size of 1.7 to 2.2 mm (minus 9 plus 12 mesh) were placed at the bottom of the pipe reactor supported by a layer of quartz wool. Another layer of quartz wool was placed on top of the quartz chips as support for a combined catalyst bed comprising about 1.5 grams of silica supported molybdenum, oxide catalyst mixed with about 5 grams of α-alumina as an inert catalyst diluent. This was topped with another layer of quartz wool and the remainder of the reactor filled with quartz chips. The catalyst bed was activated by heating at 538°C in flowing air for three hours, followed by about 15 minute treatment with flowing carbon monoxide at the same temperature, and finally the catalyst was cooled under flowing nitrogen to the desired reaction temperature of about 200°C. The olefinic reactants were first percolated through a 13X molecular sieve drier, then alumina and finally magnesium oxide prior to use. A cyclooctadiene/hexene feed ratio of about 40/60 was used for all runs. All runs were carried out at a reaction temperature of about 200°C and at a reaction pressure of about 1.38 MPa gauge (200 psig). The mixed cyclooctadiene/hexene feed was introduced at a rate of about 4 ml/min., or at a weight hourly space velocity (WHSV) of about 120 grams of feed/grams of catalyst/hour. The hot reactor effluent was vented to a hood; periodically the total effluent was sampled for analysis on a gas liquid chromatograph (GLC) by collection in a bomb held in dry ice. Analyses were carried out by injecting a portion of the chilled effluent on a 25 meter cyanopropyl silicone capillary column operated at 110°C isothermal. Reaction results are summarized in Table II. Only invention catalyst D, which has both high surface area, high pore volume and very low levels of impurities, especially low levels of alumina, gives a Z,Z to Z,E ratio in excess of 1:1, i.e., only invention catalyst D gives a triene product with greater than 50 percent cis content at the 9-carbon. In addition, invention catalyst D gives substantially higher yields of triene than do the comparison catalysts.

Claims: A method for producing 1,5,9-tetradecatriene having a cis content at the 9-carbon atom of at least 50% and an essentially all cis orientation at the 5-carbon atom, by reacting 1,5-cyclooctadiene and 1-hexene in the presence of a catalyst containing molybdenum oxide on a silica support, characterized by utilizing a silica support having a surface area of at least 200 m²/g, a pore volume of at least 0.6 cm³/g, and containing no more than 0.2 wt % Al₂O₃. The method of claim 1, characterized in that said reacting comprises a temperature in the range of 0 to 4000°C, a pressure in the range of 0.01 to 50.7 MPa, and a LHSV in the range of 0.1 to 100. The method of claim 1 or 2, characterized in that said silica support is at least 99.6 percent silica by weight. The method of any of the preceding claims, characterized in that said catalyst contains from 0.2 to 40 weight percent MoO₃ on said silica support, calculated as the oxide and based on the combined weight of oxide and support. The method of any of the preceding claims characterized in that said 1,5-cyclooctadiene and 1-hexene are reacted in a molar ratio in the range of 5:1 to 1:5. 1,5,9-tetradecatriene having a cis content at the 9-carbon of at least 50%, and an essentially all cis orientation at the 5-carbon. The compound of claim 6 characterized in that the cis content at the 9-carbon is within the range of 50-60%.

Inventors: DRAKE, CHARLES ALFRED, WELCH, MELVIN BRUCE
Applicants: PHILLIPS PETROLEUM COMPANY
Application year: 1987
Main classification: C07C11
IPC codes: B01J23, C07B61, C07C1, C07C11, C07C6, C07C67