Patent GB-1002721-A (GB)
Title: Production of liquid oligomers of 1,3-dienes
Inventor: WITTENBERG DIETMAR
IPC: C07C2/40
Filed: 1962-06-04
Abstract: Liquid, mainly acyclic, oligomers of 1,3-diolefins are obtained from the dienes in the presence of a catalyst obtained from a cobalt compound and a reducing agent the ratio of cobalt in mols. to reducing agent in equivalents being below 1.  Optionally the catalyst is prepared in the presence of an olefinic or acetylenic compound as activator and a polymerization inhibitor and/or a base may be added. The diolefin may be butadiene, isoprene, 2,3-dimethyl butadiene, 2-ethylbutadiene, pentadiene-1,3, hexadiene-2,4 or a dimer of butadiene obtained by the process, e.g. 3-methyltheptatriene-1,4,6 or octatriene-1,3,6.  The cobalt compound may be an organic or inorganic salt or a chelate compound and is used in amounts of 0.1-10% by weight of the diene. Suitable reducing agents are metals of Group Ia, IIa, IIb, IIIa or IIIb, or a hydride or organo-derivative or complex thereof of a metal of Group Ia, IIa, IIb, IIIa or IVa (non-transition metals being in the B sub-groups).  A compound containing up to 4 olefinic or up to 3 acetylenic groups may also be added in a molar proportion to cobalt of 1 : 1 or greater, such compound being a hydrocarbon or containing inert groups, e.g. ether, hydroxy, carboxylic ester, nitrile, carboxylicamide, amine, imine, epoxy, aldehyde, lactone or sulphide groups.  If used in excess the activator can be used as solvent or a hydrocarbon or ether solvent may be used in an amount up to 100 times that of the cobalt compound. The catalyst is formed by mixing the ingredients at - 50 DEG  to 150 DEG  C. and ageing if desired; undissolved material may be filtered off.  If the reducing agent is a polymerization catalyst an inhibitor must be added, e.g. water, an alcohol, phenol, aldehyde, ketone or primary or secondary amine in an amount sufficient to react with excess reducing agent.  Also if a halide is present an inhibitor containing a lone electron pair is added, e.g. an ether, thioether, amine, phosphine, organic phosphite, phosphate or phosphine oxide, sulphoxide, sulphone, nitrile, carboxylate, carboxylic acid or amide or anhydride thereof, nitro compound or arylhydrazine. In a preferred embodiment a base is added, e.g. oxide, hydroxide, alkoxide, amide, carbonate, bicarbonate, acetate or phenolate of an alkali or alkaline earth metal or a strong organic base such as guanidine or tetralkyl ammonium hydroxide, in an amount of 0.001 to 0.2 that of the diene; this increases the production of conjugated triene dimers.  The base is added in solution in water or an alcohol or on a carrier such as alumina or silica gel.  Oligomerization is effected at 0-250 DEG  C. for up to 30 hours at a pressure up to 30 atm. to maintain the liquid phase.  All the diene may be added at the beginning which favours the production of dimers or gradually or in increments when higher oligomers are formed.ALSO:Liquid, mainly acyclic, oligomers of 1,3-diolefins are obtained from the dienes in the presence of a catalyst obtained from a cobalt compound and a reducing agent the ratio of cobalt in mols to reducing agent in equivalents being below 1.  Optionally the catalyst is prepared in the presence of an olefinic or acetylenic compound as activator and a polymerization inhibitor and/or a base may be added.  The cobalt compound may be an organic or inorganic salt of a chelate compound and is used in amounts of 0,1-10% by weight of the diene.  Suitable reducing agents are metals of Group Ia, IIa, IIb, IIIa or IIIb, or a hydride or organo-derivative or complex thereof of a metal of Group Ia, IIa, IIb, IIIa or IVa (non-transition metals being in the B sub group). A compound containing up to 4 olefinic or up to 3 acetylenic groups may also be added in a molar proportion to cobalt of 1 : 1 or greater, such compound being a hydrocarbon or containing inert groups, e.g. ether, hydroxy, carboxylic ester, nitrile, carboxylic amide, amine, imine, epoxy, aldehyde, lactone or sulphide groups. If used in excess the activator can be used as solvent or a hydrocarbon or ether solvent may be used in an amount up to 100 times that of the cobalt compound.  The catalyst is formed by mixing the ingredients at -50 DEG C. to 150  DEG C. and ageing if desired; undissolved material may be filtered off.  If the reducing agent is a polymerization catalyst an inhibitor must be added, e.g. water, an alcohol, phenol, aldehyde, ketone or primary or secondary amine in an amount sufficient to react with excess reducing agent.  Also if a halide is present an inhibitor containing a lone electron pair is added, e.g. an ether, thioether, amine, phosphine, organc phosphite, phosphate or phosphine oxide, sulphoxide, sulphone, nitrile, carboxylate, carboxylic acid or amide or anhydride thereof, nitro compound or arylhydrazine.  In a preferred embodiment a base is added, e.g. oxide, hydroxide, alkoxide, amide, carbonate, bicarbonate, acetate or phenolate of an alkali or alkaline earth metal or a strong organic base such as guanidine or tetralkyl ammonium hydroxide, in an amount of 0,001-0,2 that of the diene; this increases the production of conjugated triene dimers.  The base is added in solution in water or an alcohol or on a carrier such as alumina or silica gel.