Patent GB-1015867-A (GB)
Title: Improvements relating to the production of dienes
IPC: B01J31/16
Filed: 1964-03-09
Abstract: 1,4-Dienes, which may be linear or cyclic, are prepared by reacting an a -olefin of formula R11-CH = CH2 wherein R11 is H or C1-C4 16 carbon atoms to form a product free from allylic halide in presence of a catalyst made by combining (a) at least two molar proportions of at least one organometallic compound of the formula RMXn, wherein R is alkyl, aryl or aralkyl; M is Al, Zn, Cd or Mg; n is an integer one less than the valency of M and the X radicals are the same or different and are alkyl, aryl, aralkyl, Cl or Br with (b) one molar proportion of at least one nickel compound complexed with at least one monodentate phosphorous III ligand, said nickel compound being a nickel halide, nitrate or carbonyl.  The conjugated dienes used have the formula <FORM:1015867/C4-C5/1> wherein Y1 and Y2, which may be the same or different, are H3 or C1-C8 alkyl groups and Y3 and Y4, which may be the same or different, are H, C1 to C8 alkyl group or Cl, or any two are furnished and starting materials listed. of the Y groups are joined together to form a cycloaliphatic ring having at least 6 carbon atoms, at least one Y being H.  The ratio of a -olefin to diene may vary from 10:1 to 1:10. The reaction is carried out at - 10 DEG  to 150 DEG  C. in batch or continuous processes in presence of an inert atmosphere and an inert diluent, e.g. tetrachloroethylene, toluene, xylenes, octane, decalin &c. and anisole.  Pressure is up to 2,000 atmospheres and reaction times may be 5 minutes to 4 hours.  The preferred type (b) catalysts have the following formulae (R13P)2NiX12; (R1O)3PnNi(CO)m; and (R13P)yNi(CO)z wherein R1 is alkyl, aryl or allyl; X1, which may be the same or different may be Cl, Br, I or NO3; n is 2 or 3 and n+m=4; y is 1 or 2 and y+z=4.  The mole ratio of organo metallic compound (a) to nickel complex (b) may be 2:1 to 60:1. The amount of catalyst present corresponds to at least 0.000025 up to 0.01 gram atom of nickel per gram mole of diene starting material.  Examples describe the codimerization of ethylene and butadiene to form hexadiene-1,4 together with hexadiene-2,4; pentadiene-1,3 and ethylene to form 3-methylhexadiene-1,4; hexadiene-2,4 and ethylene to form 3-ethylhexadiene-1,4 and 3-methylheptadiene-1,4; isoprene and ethylene to form 4-methylhexadiene-1,4; butadiene and propylene to form 2-methylhexadiene-1,4; butadiene and hexene-1 to form 2-butylhexadiene-1,4; isoprene and propylene to form 2,4-dimethylhexadiene-1,4; cyclohexadiene-1,3 and ethylene to form 3-vinylcyclohexene; and cyclooctadiene-1,3 and ethylene to form 3-vinylcyclooctene.ALSO:Examples 26, 27 and 28 describe the preparation of 4-chloro-1,4-hexadiene and 4,5-dichlorohexadiene by reacting ethylene with 2-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene respectively.  In Examples 26 and 27 the catalyst used consists of a mixture of 0.008 gram moles of diisobutyl aluminium chloride and 0.001 gram moles of (Bu3P)2NiCl2, the reaction proceeding at 50 DEG  to 59 DEG  C. in presence of n-hexane as diluent.  In Example 28 diethyl zinc is used instead of the aluminium compound with decalin and n-hexane as diluents.  Fractional distillation of the liquid residue gave 4-chloro-1 4-hexadiene.ALSO:Catalysts, used in the production of 1,4 dienes, comprise (a) at least two molar proportions of at least one organometallic compound of the formula RMXn wherein R is alkyl, aryl or aralkyl, M is Al, Zn, Cd, or Mg, n is an integer one less than the valency of M and the X radicals which may be the same or different are alkyl, aryl, aralkyl, Cl or Br, and (b) one molar proportion of at least one nickel compound complexed with at least one monodentate phosphorus III ligand, said nickel compound being a nickel halide, nitrate or carbonyl.  The molar ratio of (a) to (b) is preferably between 2 : 1 and 12 : 1.  Numerous examples are given.