Patent GB-635294-A (GB)
Title: Improvements in or relating to polyvinyl acetals
IPC: C08F8/30
Filed: 1947-07-04
Abstract: Polyvinyl acetals are made by condensing a vinyl alcohol polymer with a 5-acyloxy-pyrazole containing an amido-aldehyde group in the 1 or 3 position, or a lower acetal of such an aldehyde, the pyrazole compound being free from substituent groups which are reactive with aldehyde or ketone groups and having a hydrogen atom attached to the carbon atom in the 4 position.  Acyl covers radicles derived from both carboxylic and sulphonic acids. Lower acetal means an acetal formed with an alkanol of 1 to 4 carbon atoms or a 1 : 2 or 1 : 3 alkane diol.  The polyvinyl alcohol may be prepared by the partial or complete hydrolysis of polymers of vinyl acetate, vinylchloracetate, vinyl propionate, vinyl butyrate, or interpolymers of vinyl esters with vinyl chloride, alkyl acrylates, methacrylates, or ethylene. The pyrazoles may be prepared as described in Specification 631,269, [Group IV (b)].  The specified pyrazoles are m-[p-(5-ethylcarbonato-3-methyl-1-pyrazolyl) benzamido] benzaldehyde and the dimethyl acetal and ethylene glycol acetal of this aldehyde, m-[p-(5-benzoxy-3-methyl - 1 - pyrazolyl) benzenesulphonamido] benzaldehyde; m - [p - (5 - ethylcarbonato - 1 - methyl-3-pyrazolyl) benzamido] benzaldehyde; m-[p-(5-ethylcarbonato-3-phenyl-1-pyrazolyl) benzamido] benzaldehyde; m - [p - (5 - ethylcarbonato-1-phenyl-3-pyrazolyl) benzamido] benzaldehyde.  The condensation is preferably effected by heating in a solvent in the presence of acid.  Solvents specified are formamide, dimethyl formamide, methanol, ethanol, propanol, ethylene glycol, isopropanol, acetic acid, dioxane, acetone or mixtures of these with water.  The solubility and permeability of the polyvinyl acetals can be controlled by reacting hydroxyl groups not condensed with compounds free from dye intermediate groups such as acetic acid, benzaldehyde, benzyl chloride, dibasic acids, glycollic acid, o-sulphobenzaldehyde, chloroacetic acid or beta-chloro-ethanesulphonic acid.  The polyvinyl acetals may be coupled with diazonium salts to form azo dyes or oxidized p-phenylenediamine derivatives or with p-aminodiethylamine to produce a strong magenta azo-methine dye. The polyvinyl acetals alone or in admixture with a viscose dope may be made into films and fibres that can be locally or completely converted to colour by the above colour treatment.  The polyvinyl acetals are syitable for use in photography and may be mixed with gelatin, hydrolysed ethylene/vinyl acetate interpolymers, polyvinyl alcohol or hydrolysed cellulose esters. The acetals may be used in textile dyeing. Specifications 545,443, [Group XX], 600,023, 629,482, 24197/45 (as open to inspection under Sect. 91) are referred to.ALSO:5-Acyloxypyrazoles containing an amidoaldehyde group in the 1- or 3-position, or a "lower acetal" of such an aldehyde, are prepared as follows: (1) m-[p-(5-ethylcarbonato-3-methyl - 1 - pyrazolyl) - benzamido] - benzaldehyde dimethyl acetal by condensing 1-(41-chloroformylphenyl) - 3 - methyl - 5 - pyrazolyl ethyl carbonate, (prepared as described in Specification 631,269), with m-aminobenzaldehyde dimethyl acetal in the presence of dioxane and potassium carbonate.  Hydrolysis of the acetal gives the free aldehyde melting at 135-136 DEG  C.; (2) m-[p-(5-ethylcarbonato-1-methyl-3 pyrazolyl)-benzamido]-benzaldehyde is prepared by heating methylhydrazine sulphate and ethyl p-carbethoxybenzoylacetate in the presence of sodium acetate trihydrate, acetic acid and aqueous ethanol, from which after cooling and acidifying is separated 1-methyl-3-(p-carboxyphenyl)-5 pyrazolone which by treatment at 0 DEG  C. with ethyl chlorocarbonate after acidification is converted to 1-methyl-3-(p-carboxyphenyl)-5-pyrazolyl ethyl carbonate, which by heating with thionyl chloride in anhydrous benzene is converted to 1-methyl-3-(p-chloroformylphenyl)-5-pyrazolyl ethyl carbonate and the latter, by condensation with m-aminobenzaldehyde ethylene glycol acetal under conditions similar to (1) above, to m-[p-(5-ethylcarbonato - 1 - methyl-3-pyrazolyl)-benzamido] - benzaldehyde ethylene glycol acetal, which after hydrolysis yields the desired aldehyde of melting point 180-182 DEG  C.; (3) m-[p-(5-ethylcarbonato - 3 - phenyl - 1 - pyrazolyl) - benzamido] - benzaldehyde is prepared by condensing p-carboxyphenylhydrazine hydrochloride solution, after neutralization with sodium hydroxide, with ethyl benzoylacetate to yield, after acidification and purification, 1-(p-carboxyphenyl - 3 - phenyl - 5 - pyrazolone which in a manner similar to (2) is converted in 1-(p-carboxyphenyl)-3-phenyl-5-pyrazolyl ethyl carbonate, the latter by heating with thionyl chloride in anhydrous benzene gives on removal of the benzene 1-(p-chloroformylphenyl)-3-phenyl-5-pyrazolyl ethyl carbonate, which is converted as under (1) above by condensation with m-aminobenzaldehyde ethylene glycol acetal to m-[p-(5-ethylcarbonato-3-phenyl-1-pyrazolyl) -benzamido]-benzaldehyde ethylene glycol acetal, hydrolysis of which yields after purifying the required pyrazolyl aldehyde melting at 144-146 DEG C. Specifications 545,443, [Group XX], 600,023, [Group IV (a)], 629,482; and 24197/45 (as open to inspection under Sect. 91) also are referred to.ALSO:Polyvinyl acetals suitable for textile dyeing and colour formers are made by condensing a vinyl alcohol polymer with a 5-acyloxy-pyrazole containing an amido-aldehyde group in the 1- or 3-position, or a "lower acetal" of such an aldehyde, the pyrazole compound being free from substituent groups which are reactive with aldehyde or ketone groups and having a hydrogen atom attacked to the carbon atom in the four position.  The expression "acyl" covers radicles derived from both carboxylic and sulphonic acids.  The expression "lower acetal" means an acetal formed with an alkanol of 1 to 4 carbon atoms or a 1 : 2 or 1 : 3 alkane diol.  The polyvinyl alcohol may be prepared by the partial or complete hydrolysis of polymers of vinyl acetate, vinyl chloracetate, vinyl propionate, vinyl butyrate or interpolymers of vinyl esters with vinyl chloride, alkyl acrylates, methacrylates, or ethylene.  The pyrazoles may be prepared as described in Specification 631,269, (see also Group IV (b)).  The condensation of the alcohol and the pyrazole is preferably effected by heating a mixture of the materials in a solvent in the presence of a mineral acid such as phosphoric acid.  The solvents specified are formamide, dimethyl formamide, methanol, ethanol, propanol, ethylene glycol, isopropanol, acetic acid, dioxane, acetone, and mixtures of these with water.  The specified pyrazoles are m-[p-(5-ethylcarbonato-3-methyl-1-pyrazolyl)-benzamido] benzaldehyde and the dimethyl acetal and ethylene glycol acetal of this aldehyde; m-[p-(5-benzoxy-3-methyl-1-pyrazolyl - benzenesulphonamido] benzaldehyde; m - [p - (5 - ethylcarbonato - 1 - methyl-3 - pyrazolyl) - benzamido] benzaldehyde; m-[p - (5 - ethylcarbonato - 3 - phenyl - 1 - pyrazolyl) - benzamido] benzaldehyde; m - [p-(5 - ethylcarbonato - 1 - phenyl - 3 - pyrazolyl)-benzamido] benzaldehyde.  The solubility of the polyvinyl acetals can be controlled by reacting hydroxyl groups not condensed with compounds free from dye intermediate groups such as acetic acid, benzaldehyde, benzyl chloride, dibasic acids, glycollic acid, o-sulpho-benzaldehyde, chloroacetic acid or beta-chloro-ethanesulphonic acid.  The polyvinyl acetals may be coupled with diazonium salts to form azo dyes or with oxidized para-phenylenediamine derivatives or with p-aminodiethylaniline to produce a strong magenta azo-methine dye.  The polyvinyl acetals alone or in admixture with a viscose dope may be made into films and fibres that can be locally or completely converted to colour by the above dyeing treatment.  Specifications 545,443, [Group XX]; 600,023, [Group IV (a)]; 629,482 and 24197/45, (as open to inspection under Sect. 91), also are referred to.