GB1092657A - Improvements relating to the stabilization of aqueous formaldehyde solutions - Google Patents

Abstract

Formaldehyde condensates are prepared by reacting under alkaline or acidic conditions: (1) a guanamine of the formula <FORM:1092657/C3/1> in which R is an alkyl or aryl group, with an alkanol and formaldehyde; (2) a hydrocarbyl melamine of the formula <FORM:1092657/C3/2> in which R1 is an alkyl, cycloalkyl, aryl or aralkyl group, with a polyhydric alcohol and formaldehyde; and (3) a guanamine of the above formula, a polyhydric alcohol and formaldehyde. Examples relate to the condensation of formaldehyde, a guanamine or a melamine and methanol, glycerol, sorbitol, triethylene glycol, 1,1,1-trimethylolpropane, 1,2-propylene glycol, ethylene glycol, pentaerythritol, and polypropylene glycol. Example 8 describes the preparation of a condensate of polyvinyl alcohol, formaldehyde and benzoguanamine.ALSO:Aqueous formaldehyde solutions which contain at least 37% by weight formaldehyde are stabilized by dissolving therein less than 1000 p.p.m. by wt. of solution of one or more stabilizing agents selected from (1) alkoxymethylated guanamines obtained under alkaline or acid conditions from an alkanol formaldehyde and a guanamine of the formula <FORM:1092657/C2/1> wherein R is an alkyl or aryl group; (2) a condensation product, obtained under acid or alkaline conditions, of a polyhydric alcohol, formaldehyde and an hydrocarbyl melamine of the formula <FORM:1092657/C2/2> wherein R1 is an alkyl, cycloalkyl, aryl or aralkyl radical; (3) a product obtained by reacting under acid or alkaline conditions, a polyhydric alcohol and an alkoxymethylated hydrocarbyl melamine derived from the hydrocarbyl melamines of Formula II; (4) a product obtained by reacting under acid or alkaline conditions a polyhydric alcohol, formaldehyde or a guanamine of the Formula I; and (5) a product obtained by reacting under acid or alkaline conditions a polyhydric alcohol and an alkoxymethylated guanamine (the guanamine being the same as that stated in (1)). Preferred guanamines are aceto-, propio-, butyro- and benzo-guanamines, preferred hydrocarbyl melamines, methyl-, ethyl-, propyl-butyl-, cyclohexyl-, benzyl- and phenyl-melamines, preferred alkanols, methanol, ethanol, propanol, and butanol and preferred polyhydric alcohols, polyvinyl alcohol (see Division C3), ethylene glycol, 1,2-propylene glycol, polyethylene glycol, polypropylene glycol, glycerol, 1,1,1-trimethylol propane, pentaerythritol and sorbitol. The stabilizers may be prepared and added to the formaldehyde solution, which preferably also contains small amounts of methanol, without prior isolation of the reaction products. Examples are provided.