Patent GB-959542-A (GB)
Title: Process for the preparation of biphenylic compounds
IPC: B01J27/00
Filed: 1962-12-20
Abstract: A process for the preparation of biphenylic compounds comprises treating a compound containing at least one hydrogen atom attached to an aromatic carbon atom with a salt of a palladium or platinum group metal e.g. a chloride sulphate, sulphonate, nitrate or carboxylates in the presence of an acid-binding substance e.g. a salt or strong base in a weak acid such as salts of an alkali metal or alkaline earth metal and an organic acid. The starting material may have a polynuclear structure and contain one or more heterocyclic and/or naphthene rings which may or may not be fused. If desired, two or more aromatic nuclei, either fused or unfused, may be present in the molecule. In general a mononuclear compound is preferably used as starting material, e.g. toluene; cumene; biphenyl; naphthalene; anisole; diphenyl ether; m-xylene; chlorobenzene; phenyl acetate; methyl beta-phenyl-beta, beta-dimethylpropionate; and N,N-dimethylaniline. They yield 4,41-dimethyl-biphenyl, 4,41-diisopropylbiphenyl, p-quaterphenyl, 2,21-binaphthyl, 4,41-dimethoxybiphenyl, 4,41-diphenoxybiphenyl, 3,31,5,51-tetramethylbiphenyl, 4,41-dichlorobiphenyl, 4,41-diacetoxybiphenyl, 4,41-bis(1,1-dimethyl -2-methoxy-carbonylethyl)biphenyl, and 4,41-dis (dimethylamino)-biphenyl, respectively. Particularly preferred as starting materials are o-xylene and benzene, yielding 3,31, 4,41-tetramethyl-biphenyl and biphenyl, respectively.  In an example methyl beta-phenyl-beta, beta-di-methyl-propionate is mixed with palladium dichloride, sodium acetate and acetic acid and boiled under a reflux from which metallic palladium precipitates and is separated and the product 4,41-bis(1,1-dimethyl -2- methoxycarbonylmethyl) biphenyl is eventually separated from the filtrate. In another example the palladium dichloride, cumene, sodium acetate and anhydrous acetic acid are heated when metallic palladium is precipitated, and the product diisopropylbiphenyl is separated from the filtrate.ALSO:A process for the preparation of biphenylic compounds comprises treating a compound containing at least one hydrogen atom attached to an aromatic carbon atom with a salt of a palladium or platinum group metal, e.g. a chloride, sulphate, sulphonate, nitrate or carboxylates in the presence of an acid-binding substance, e.g. a salt of a strong base and a weak acid such as salts of an alkali metal or alkaline earth metal and an organic acid.  The starting material may have a polynuclear structure and contain one or more naphthene rings which may or may not be fused.  If desired, two or more aromatic nuclei, either fused or unfused, may be present in the molecule. In general, a mononuclear compound is preferably used as starting material, e.g. toluene, cumene, biphenyl, naphthalene and m-xylene. They yield 4,41-dimethylbiphenyl, 4,41-diisopropylbiphenyl, p - quaterphenyl, 2,21 - binaphthyl, 3,31,5,51 - tetramethylbiphenyl, respectively. Particularly preferred as starting materials are o-xylene and benzene, yielding 3,314,41 - tetramethylbiphenyl and biphenyl, respectively.  In an example, palladium dichloride, cumene, sodium acetate and anhydrous acetic acid are heated when metallic palladium is precipitated, and the product diisopropylbiphenyl is separated from the filtrate.