Patent GB-736438-A (GB)
Title: Improvements in or relating to copolymerization products
IPC: C07C51/567
Filed: 1953-02-20
Abstract: Mono-alkenyl succinic anhydrides or acids are made by reacting in the liquid phase at above 300 DEG , preferably 330-350 DEG  F., a propylene tetramer fraction of acyclic branched chain structure boiling within the range 350-480 DEG  F. with maleic anhydride in a weight ratio of 3 to 5, preferably 3.5-4.5, parts of tetramer to 1 part of anhydride and, if desired, hydrolysing the mono-alkenyl succinic anhydride thus obtained to the corresponding acid.  The reactants are preferably contacted for 18-28 hours.  The structure of the anhydride is stated to be of the form <FORM:0736438/IV (b)/1> The tetramer may be made by polymerizing propylene in the presence of a phosphoric acid catalyst, e.g. kieselguhr saturated with aqueous orthophosphoric acid preferably at 200-500 p.s.i. at 300-450 DEG  F. with a feed rate of 0.5-1.25 vols. of gas per vol. of catalyst per hour, and finally fractionating to separate the cut required. Alternatively propylene is polymerized under pressure in the presence of 5-15, preferably 10 per cent by weight of a BF3.H2O catalyst at 120-150 DEG  F. with final fractionation or in the preceding method. A weight ratio of about 4 : 1 of tetramer to maleic anhydride gives best yields. The product anhydride is isolated from reaction products by vacuum distillation, traces of maleic anhydride being removed by water washing at room temperatures or below before hydrolysis to the acid by heating with water at 100-210 DEG  F.  Separation after water washing is made easier by the addition to the anhydride product before washing of 10-25, preferably 15-20, per cent of a mineral lubricating oil and is of advantage when a concentrate of the products in such oils is to be obtained, c.f. Group III.  The reaction mixture, after water washing, may also be extracted with an aqueous alkali metal hydroxide solution at 60-150 DEG  F. to hydrolyse the anhydride and conversion to a water-soluble salt thereby results, the free acid being liberated on acidification, preferably with hydrochloric acid.  Sodium, lithium and potassium are specified hydroxides.  Examples are provided of the preparation of the above acids and anhydrides by methods given above.ALSO:Mono-alkenyl succinic acids made by hydrolysing an anhydride obtained by reacting in the liquid phase at above 300 DEG , preferably 330-350 DEG  F., a propylene tetramer fraction of acyclic branched strain structure boiling within the range 350-480 DEG  F. with maleic anhydride in a weight-ratio of 3 to 5, preferably 3.5-4.5, parts of tetramer to 1 part of maleic anhydride, are used in mineral lubricating-oil compositions.  Preferably the process is so arranged e.g. by the use of a lubricating oil as extracting solvent for the product, so that a concentrate containing about 25-60 per cent of active ingredient is obtained.  Generally 0.01-0.025 per cent of alkenyl succinic acid is added to the lubricating oil to serve as an anti-corrosion agent.  Other additives, e.g. 4-methyl-2,6-ditertiary butyl phenol and tetramethyl - diamino - diphenylmethane, may be present in the lubricating-oil composition. Examples are provided showing the preparation of oil concentrates and the comparative effect on rusting of mineral oil compositions containing 0.3 per cent of 4-methyl-2,6-ditertiary-butyl phenol, 0.0025 per cent of mixed mono- and di-lauryl acid orthophosphates, 0.005 per cent of phenol, 0.001 per cent of a dimethyl silicone polymer concentrate and either 0.015 per cent of an alkenyl succinic acid prepared according to the invention or similar quantities of alkenyl succinic acids made from C12 olefines obtained by dehydrogenating alcohols or cracking paraffin wax.