Patent GB-586127-A (GB)
Title: Manufacture of new dyestuffs
IPC: C09B23/14
Filed: 1943-04-12
Abstract: Dyes of the general formula: <FORM:0586127/IV/1> wherein R1 represents H or alkyl (C1 to C6), R2 represents alkyl (C1 to C6) and R3 represents an aliphatic residue (C2 to C6) carrying at least one hydroxyl group, are obtained by reacting an acyl compound of general formula: <FORM:0586127/IV/2> with an aldehyde of general formula: <FORM:0586127/IV/3> or with an anil thereof.  The alkyl residues may be substituted, e.g. by hydroxyl, cyano, etherified or esterified hydroxyl, esterified or amidated carboxyl, amidated sulpho or sulphone groups, or halogen atoms.  Suitable cyanacetic esters are obtained from cyanacetic acid or its salts and ethylene chlorhydrin or bromhydrin, glycol; dioxypropanes, e.g. a  : g -dioxypropane; butylene glycols, e.g. b -butyleneglycol; 1 : 6-hexamethyleneglycol, glycerine, dioxyacetone; glycerine monoalkyl ethers, e.g. a -glycerine monomethyl ether; a -glycerine chlorhydrin; hexahydric alcohols, e.g. sorbitol; or alkylene oxides, such as ethylene oxide or spichlorhydrin.  Suitable N-alkyl derivatives of p-aminobenzaldehyde are, e.g. p-N-methyl-, p-N-ethyl-, p-N-methyl-N-ethyl-, p-N-dimethyl-, p-N-diethyl-, p-N-dipropyl-, p-N-methyl-N-b -hydroxyethyl-, p-N-ethyl-N-b -hydroxyethyl-, p-N-di-b -hydroxyethyl-, p - N - methyl - N - b  - methoxyethyl-, p - N - butyl - N - b  - hydroxyethyl -, p - N - ethyl - N - b  - chlorethyl-, p - N - methyl - N - b  - chlorethyl - and p - N - di - b  - chlorethylaminobenzaldehydes.  Such aldehydes are obtained by effecting a Sandmeyer reaction between a dialkylamine, e.g. N-dipropyl-, N-ethyl-N-b -hydroxyethyl-or N - ethyl - N - b  - chlorethyl - aniline, and formaldehyde, hydrochloric acid, meta-nitrobenzene sulphonic acid and iron, to produce anils of general formula:- <FORM:0586127/IV/4> wherein R1 and R2 have the meanings assigned above, and subsequently hydrolysing the anils with alkalis. Alternatively, the anils may be reacted directly with the acylated starting-materials.  The products are applied in suspension or solution in dyeing cellulose esters or ethers or artificial materials of other kinds, e.g. structures of superpolyamides or superpolyurethanes, or they may be incorporated with such products before their conversion into shaped structures.  In examples: (1) p-N-dimethylaminobenzaldehyde is condensed at 90-100 DEG  C. in piperidine or alcohol with cyanacetic acid-b -hydroxyethyl ester (obtainable from potassium cyanate and ethylene chlorhydrin); similar products are obtained by using other N-alkylated-p-aminobenzaldehydes, those which contain an hydroxyl substituent in the alkyl residue attached to the nitrogen atom being preferably used in the form of an anil obtained from an aromatic amine or a sulphonic acid there, e.g. metanilic acid; (2) p-N-dimethylaminobenzaldehyde is condensed with cyanacetic acid-b  : g  - dihydroxypropyl ester (obtainable from potassium cyanacetate and glycerin-g -chlorhydrin) in presence of piperidine, at 95-100 DEG  C. to furnish a product dyeing cellulose acetate artificial silk pure yellow; (3) the product of (1) is ground to a paste containing 20 per cent dyestuff with addition of a dispersion agent, e.g. Turkey red oil, sulphite-cellulose waste liquor or the sulphonation products of the residues from benzaldehyde-manufacture, and made up into a dye bath with water at 50 DEG  C. and soap solution, cellulose acetate artificial silk yarn being dyed greenish-yellow from the emulsion. Specification 396,893 is referred to.  The Specification as open to inspection under Sect. 91 comprises also the manufacture, from the appropriate starting-materials, of dyes in which R3 contains a salt-forming group, e.g. carboxyl sulphonic acid, or thiosulphonic acid groups, especially as acid esters, or which contain, in place of the ester group COOR3, an amide group CONR3R4, where R4 represents H or alkyl (C1 to C6).  Suitable starting-materials in the latter case are obtainable from cyanacetic acid and ethanolamine, diethanolamine, halogen-alkylamines, e.g. b -chlorethylamine, or by alkylating cyanacetic acid amide with alkylene oxides, e.g. ethylene oxide, or dihalogen alkyl compounds, e.g. symmetrical dibromethane. Alternatively, R3 may contain a substituent which is converted after the condensation into a hydroxy group or a salt-forming group, e.g. a halogen atom may be replaced by -SO3H or -S-SO2H.  Additional examples relate (a) to the use of cyanacetic acid hydroxyethylamides, e.g. cyanacetic acid-b -hydroxyethylamide or -di - (b  - hydroxyethyl) - amide, or acid esters thereof, as starting-materials, (b) to the fusion of the product of (1) above with maleic, succinic or phthalic anhydride, or with sulphocarboxylic acids, e.g. sulphobenzoic, sulphoacetic or chlorosulphoacetic acid, and (c) to the sulphonation of the product of (1) above, and its application as a dyestuff to cellulose acetate artificial silk yarn.  This subject-matter does not appear in the Specification as accepted.