Patent GB-1006786-A (GB)
Title: A process for the production of high molecular weight polyoxymethylenes
IPC: C08G2/00
Filed: 1963-10-10
Abstract: Formaldehyde is polymerized in the presence of a tin compound of formulae <FORM:1006786/C3/1> where R is an organic carboxylic acid radical, a dithiocarbarminic acid radical, a hydroxyl radical, a mercapto radical, a cyanide radical, a thio-cyanate radical or a cyanate radical, X is hydrogen or a methylene oxyalkyl radical, R1 is an alkyl, aryl, or a methyleneoxy alkyl radical, R2 is an alkyl radical, an aryl radical, a carbamide radical, or a thiocarbamide radical, or R1 and R2 together represent a hydrocarbon rin and x is a whole number from 1 to 10.  The polymerization may be carried out in an alkylating agent or in an acylating agent or in the gaseous phase in the presence of high molecular weight polyoxymethylene present in the form of a fluoridized bed. Specified catalysts include those having the formulae <FORM:1006786/C3/2> <FORM:1006786/C3/3> where R is phenyl and x is 4 to 10, <FORM:1006786/C3/4> where R is phenyl and x is 4 to 10, and <FORM:1006786/C3/5> The polymerization may take place in solution preferably in methylene chloride or ethyl orthoformate and may be continuous or not.  The formaldehyde and the catalyst may be added gradually to the polymerization medium.ALSO:Compounds of divalent tin of the formula <FORM:1006786/C2/1> where R is an organic carboxylic acid radical, a dithiocarbameric acid radical, a hydroxyl, mercapto, cyanide, thiocyanate or cyanate radical, or both R's together represent a sulphur atom, X is hydrogen or methylene oxyalkyl, R1 is alkyl aryl or methybeneoxyalkyl, R2 is alkyl, aryl, carbamide or thiocarbamide or R1 and R2 together represent a hydrocarbon ring and x is 1 to 10 are used as polymerization catalysts. Examples of such catalysts are complexes with diphenylamine, urea monomethylol-butyl ether and caprolactam-monomethylol-butyl ether. In examples:  (1) the compound <FORM:1006786/C2/2> is prepared by treating a concentrated solution in benzene of a divalent tin salt of 2-ethyl caproic acid with the N-methyl-stearyl-ammonium salt of N-methyl-stearyl-dithiocarbaminic acid (from N-methyl-stearylamine and carbon disulphide); (2) Sn=S.[NH(C6H5)2]x by treating tin-II-octate in diphenylamine and dioxane with excess water and then adding benzene while at the same time a powerful stream of hydrogen sulphide gas is passed through at 6 DEG  to 8 DEG  C.; (3) (a) <FORM:1006786/C2/3> R=phenyl by stirring silver cyanate with a divalent tin salt of 2-ethylcaproic acid in a solution of diphenylamine in benzene; (b) <FORM:1006786/C2/4> from divalent tin acetate and diphenylamine, dimethyl formamide and powdered potassium thiocyanate in benzene; (5) (a) Sn(OH)2 complexed with N : N1-dimethylol-tetramethylene-diurethane - N,N1\h - dimethylol - di - n - butyl ether by dissolving tin-II-octate in dioxane/ N,N1 - dimethylol - tetra - methylene diurethane - N,N1 - dimethylol - n - butyl ether and hydrolysing with water; replacing the water with hydrogen sulphide gives (b) Sn(SH2) complexed with caprolactam-monomethylol-n-butyl ether; and (6) (a) Sn-(SCH)2 solubilized by monomethylolthiourea-n-butyl ether form SnCl22H2O in water added to benzene and monomethylol - thiourea - n - butyl ether and azeotropically removing water while adding a conc., e.g. solution of potassium thiocyanate; (b) Sn(CH)2 complexed by N-methylol-urea-N1-methylol-n-butyl ether as in (a) but replacing the thiocyanate by potassium cyanide and using as complexer N-methylolurea-N1-methylol butyl ether and adding CO2.