Patent GB-747093-A (GB)
Title: Water-soluble phenol-aldehyde condensation products
IPC: C14C3/18
Filed: 1952-05-30
Abstract: A water-soluble condensation product, suitable for use as a tanning agent, is made by condensing (a) 1 mol. of an alpha-beta unsaturated aldehyde, (b) about 2 mols. of resorcinol and (c) at most 1 mol. of a salt of sulphurous acid, or a polyhydric phenol, or a mixture of such a salt and such a phenol, or a salt of an aromatic amine.  Up to 1/3 molar proportion of the resorcinol may be replaced by an equimolecular amount of a monohydric phenol and up to 2/3 molar proportion of the resorcinol may be replaced by another polyhydric phenol.  The resorcinol, or mixture of resorcinol and another phenol may first be condensed in presence of water or an organic solvent (e.g. alcohols, ethers or esters) to give a water-insoluble product which is then condensed in presence of water with the salt of sulphurous acid, the polyhydric phenol or the salt of an aromatic amine.  Alternatively, all of the reactants may be condensed together in presence of water.  In examples: (1) A product obtained by condensing resorcinol and acrolein in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) resorcinol, catechol or pyrogallol and (c) the hydrochlorides of aniline, alpha-naphthylamine, pchloroaniline, as-m-xylidene or cumidene.  (2) A product obtained by condensing resorcinol, pyrogallol and acrolein in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) resorcinol and (c) o-toluidine hydrochloride.  (3) A product made by condensing resorcinol with crotonaldehyde in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) resorcinol, catechol or pyrogallol and (c) the hydrochlorides of aniline, alpha-naphthylamine, dimethyl-aniline or 2-chloro-4-toluidine.  (4) A product obtained by condensing resorcinol, acrolein and crotonaldehyde in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) catechol or (c) o- or p-chloroaniline.  (5) A product obtained by condensing resorcinol, "brenzoel" and crotonaldehyde in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) sodium bisulphite and catechol and (c) aniline hydrochloride.  "Brenzoel" is a phenolic oil which is recovered from waste liquors-formed in the low temperature carbonization process of lignites and pit-coals-by extraction with organic solvents.  It contains catechol and its homologues (e.g. homo-, isohomo- and ethyl-catechol), resorcinol and its homologues and substituted monohydric phenols.  (6) A product obtained by condensing resorcinol, catechol, acrolein and crotonaldehyde in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) pyrogallol and (c) o- or p-chloroaniline and concentrated HCl.  (7) A product obtained by condensing resorcinol, cresol and crotonaldehyde in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) resorcinol and catechol and (c) aniline-hydrochloride.  (8) A product obtained by condensing resorcinol and methyl- or ethyl-acrolein in presence of HCl is made water-soluble by reaction with (a) sodium bisulphite, (b) catechol or (c) aniline hydrochloride.  (9) A product obtained by condensing resorcinol and crotonaldehyde in presence of ethyl acetate and HCl is made water-soluble by reaction in presence of water with (a) sodium bisulphite, (b) a polyhydric phenol and (c) a salt of an aromatic amine.  (10) A product obtained by condensing resorcinol and cinnamaldehyde in presence of methanol and hydrochloric acid is made water-soluble by reaction in presence of water with (a) sodium bisulphite, (b) resorcinol or catechol and (c) aniline hydrochloride.  (11)-(13) Water-soluble products are made by condensing in presence of HCl, (a) resorcinol and acrolein, (b) and (c) resorcinol, catechol and acrolein, (d) resorcinol and crotonaldehyde, (e) and (f) resorcinol, catechol or pyrogallol and crotonaldehyde, (g) resorcinol and crotonaldehyde, (h) and (i) resorcinol, catechol and crotonaldehyde.  (14) A product obtained by condensing resorcinol and crotonaldehyde in presence of HCl is made water-soluble by reaction with aniline hydrochloride.  (15) A product obtained by condensing resorcinol or resorcinol and catechol with crotonaldehyde in presence of HCl is made water-soluble by reaction with a mixture of sodium bisulphite and sodium sulphite. Specification 747,092 is referred to.