Patent GB-972246-A (GB)
Title: Preparation of initiators and use thereof
IPC: C08F2/00
Filed: 1961-09-21
Abstract: An initiator for the polymerization of conjugated dienes comprises the product of contacting lithium with a conjugated diene or a vinylidene-substituted aromatic compound in an aliphatic mono-ether (other than a methyl ether) in the presence of a polycyclic aromatic compound or a polyaryl-substituted ethylene containing 2 to 4 phenyl or naphthyl groups.  Preferably the conjugated diene is a 2,3-dialkyl-1, 3-butadiene in which the alkyl groups contain 1-3 carbon atoms. A list of other suitable dienes containing 4 to 12 carbon atoms in the molecule, and a list of to 12 carbon atoms in the molecule, and a list of suitable vinylidene-substituted aromatic compounds are given. The products contain 1 to 5 diene groups per 2 lithium atoms. Many polyaryl-substituted ethylenes and polycyclic aromatic compounds are also specified. Suitable ethers are of the formula ROR1 where R-R1 are each C2- 12 alkyl groups. The initiator is prepared by mixing the diene solvent, lithium (in the form of wire, chunks, shot, or finely divided) and the polycyclic aromatic compound in an inert atmosphere of e.g. argon or nitrogen at a temperature between -40 and 170 DEG F. In Example 1 lithium adducts of 2,3-dimethyl-1, 3-butadiene are prepared using trans-stilbene as the polyaryl substituted ethylene. In Example XIX lithium is reacted in ether with 2,3-dimethyl-1, 3-butadiene in the ratio of 0.8 gram atoms Li to 0.4 mole DMBD, and after three hours two further 0.2 mole portions of DMBD are added. Approximately half of the ether is distilled off and 0.8 mole 1,3-butadiene added. The product was of formula Li(C6H4)(DMBD)2(C6H4)Li. Specification 906,315 is referred to.ALSO:A polymer of a conjugated diene having a vinyl content below 40% is prepared by contacting a conjugated diene having 4 to 12 carbon atoms in the molecule in a predominantly hydrocarbon medium with an initiator prepared by reacting lithium with a conjugated diene or a vinylidene-substituted aromatic compound in an aliphatic monoether other than a methyl ether in the presence of a polycyclic aromatic compound or a polyaryl substituted ethylene containing 2 to 4 phenyl or naphthyl groups (see Division C2). The ether in the initiator should be replaced by a hydrocarbon either by evaporating to dryness and dissolving the lithium initiator therein, or by adding a high boiling hydrocarbon diluent and evaporating off the ether. Suitable monomers to be polymerized contain 4 to 12 carbon atoms: they may also contain halogen and/or alkoxy substituents. Lists of suitable styrene and vinyl naphthalene derivatives and vinyl-pyridine, -quinoline and -isoquinoline derivatives with which they may be copolymerized are given. They may also be copolymerized with acrylic and alkacrylic acid esters, nitriles and N,N-disubstituted amides. Polymerization is preferably carried out between -100 DEG  and + 150 DEG C. in the presence of a suitable diluent such as benzene, toluene, cyclohexane, methylcyclohexane, xylene, n-butane, n-hexane, n-heptane or isooctane. The terminal lithium atoms on the polymer chain may be carbonated and replaced by -COOH groups, or reacted with ethylene oxide giving terminal hydroxyethyl groups.  Specification 906,315 is referred to.