Patent GB-387335-A (GB)
Title: Process of making catalysts for polymerising vinyl compounds
IPC: C08F2/00
Filed: 1931-04-27
Abstract: Catalysts for accelerating the polymerization of vinyl compounds are manufactured by reacting together an organic acid anhydride and a true per salt (i.e. one which yields hydrogen peroxide on hydrolysis with water) in the presence of a solvent in which the catalytic reaction product is soluble and the non-catalytic reaction product is insoluble, and, if desired, separating the solution of catalyst from the undissolved bye-products.  The process is particularly described in respect of the reaction product of acetic anhydride and sodium perborate, obtained by adding these substances to about four or five times their combined weight of a solvent, such as toluene, ether, or vinyl acetate itself, allowing the mixture to stand with occasional stirring for about 20 hours and then separating the toluene solution from the solid residue.  The preferred proportions of the reagents are two or three molecules of anhydride per molecule of perborate, but equimolecular or other proportions may be employed.  The sodium perborate may be replaced by sodium percarbonate, and the acetic anhydride by propionic anhydride.  Examples describe the reaction of sodium perborate and acetic anhydride in the following solvents: (1) toluene; (2) vinyl acetate; (3) vinyl acetate containing acetaldehyde. Specifications 15271/14, 261,406, 280,246, 295,322, [all in Class 2 (iii), Dyes &c.], and 387,323 are referred to.  The Specification as open to inspection under Sect. 91 comprises also the reaction of organic acid anhydrides with hydrogen peroxide and with sodium peroxide.  This subject-matter does not appear in the Specification as accepted.ALSO:Catalysts for accelerating the polymerization of vinyl compounds are manufactured by reacting together an organic acid anhydride and a true per-salt (i.e. one which yields hydrogen peroxide on hydrolysis with water) in the presence of a solvent in which the catalytic reaction product is soluble and the non-catalytic reaction product is insoluble, and, if desired, separating the solution of catalyst from the undissolved bye-products.  The process is particularly described in respect of the reaction product of acetic anhydride and sodium perborate, obtained by adding these substances to about 4 or 5 times their combined weight of a solvent, such as toluene, ether or vinyl acetate itself, allowing the mixture to stand with occasional stirring for about 20 hours and then separating the toluene solution from the solid residue.  The preferred proportions of the reagents are 2 or 3 molecules of anhydride per molecule of perborate, but equimolecular or other proportions may be employed. The sodium perborate may be replaced by sodium percarbonate, and the acetic anhydride by propionic anhydride.  Examples describe the reaction of sodium percarbonate and acetic anhydride in the following solvents : (1) toluene; (2) vinyl acetate; (3) vinyl acetate containing acetaldehyde.  Specifications 15271/14, 261,406, 280,246, 295,322, [all in Class 2 (iii), Dyes &c.], and 387,323 are referred to.  The Specification as open to inspection under Sect. 91 comprises also the reaction of organic acid anhydrides with hydrogen peroxide and with sodium peroxide.  This subject-matter does not appear in the Specification as accepted.