Process for preparing polyvinylamine and salts thereof

Claim 1

A process for preparing poly(vinylamine) salt which comprises the steps of: A. reacting at a temperature of from 20° C. to 100° C. acetaldehyde with from two to four stoichiometric equivalents of acetamide in the presence of from 0.001 to 1.0 mole per mole of acetamide of an aqueous mineral acid catalyst to yield a vinylacetamide and ethylidene-bis-acetamide containing reaction product, B. neutralizing the aqueous mineral acid catalyst and heating the vinylacetamide and ethylidene-bis-acetamide containing reaction product to 150° C. to 250° C. for from 0.2 to 5 hours in the presence of an inorganic nonacidic silicious oxide surface catalyst to yield a decomposition product, said catalyst having a surface area of at least about 1 m 2 /g, C. separating vinylacetamide from said decomposition product by vacuum volatilization, D. contacting with vinylacetamide at a concentration of from 10% to 50% by weight in a reaction medium selected from polar hydrogen bonding liquids and nonpolar liquids with from 0.1 to 20 grams per 100 grams of vinylacetamide of a free radical initiator polymerization catalyst at a temperature of from 25° C. to 125° C. for from 4 to 8 hours to yield poly(vinylacetamide), E. hydrolyzing said poly(vinylacetamide) by contacting it with from 1.05 to 3 equivalents of a mineral acid per equivalent of poly(vinylacetamide) at a temperature of from .Badd..[.25° C. to 125° C. for from 4 to 8 hours.]..Baddend. .Iadd.60° C. to 175° C. for from 1 to 36 hours .Iaddend.to yield the poly(vinylamine) salt of said mineral acid, and F. precipitating and recovering said poly(vinylamine) salt.