Patent GB-653681-A (GB)
Title: Manufacture of new derivatives of di-imidazoles
Filed: 1948-03-18
Abstract: Di-imidazoles of the formula <FORM:0653681/IV (a)/1> where A is a benzene nucleus attached to two vicinal carbon atoms (which may be substituted, e.g. with alkyl or alkoxy groups or halogen atoms), R1 is an alkyl or aralkyl group which may be substituted, and R2 is an ethylene residue forming an uninterrupted series of double bonds with the imidazole rings, are incorporated in a spinning mass, the resulting threads thereby having an enhanced whiteness.  Examples show the addition of the di-imidazoles to viscose and acetyl-cellulose solutions, and the process is stated to be applicable also to linear synthetic polyamides.  Specification 611,510 is referred to.  The Specification as open to inspection under Sect. 91 refers to the use of compounds of the above formula where A is any aromatic nucleus, R1 is any substituent group (aryl being specified), and R2 is any divalent aliphatic residue which forms an uninterrupted series of double bonds with the two imidazole rings, preferably of the type -(CH = CH)n-, where n is a small integer.  This subject-matter does not appear in the Specification.ALSO:Di-imidazoles of the formula <FORM:0653681/IV (b)/1> where A is a benzene nucleus attached by two vicinal carbon atoms, R1 is an alkyl or aralkyl group which may be substituted, and R2 is an ethylene residue forming an uninterrupted series of double bonds with the imidazole rings, are prepared by (1) treating the parent compound (R1=H) with less than two mols. of an alkylating or aralkylating agent; (2) heating an o-phenylene diamine with a b -benzimidazylpropionic acid and dehydrogenating the product, or (3) heating an o-phenylene diamine with a b -benzimidazyl-acrylic acid; in methods (2) and (3), only one of the starting materials carries an alkyl or aralkyl group attached to a nitrogen atom; in method (1), a mixture is usually obtained, which may be separated by utilizing the different solubilities of the components in solvents.  The benzene rings may be substituted, e.g. with alkyl or alkoxy groups or halogen atoms.  In method (1), the group R1 may be introduced by heating the parent compound (preferably in the form of its alkali metal salt) with about 1.5 mols. of an alkyl halide, dialkyl sulphate or alkylene halohydrin, or with an aralkyl halide (which may contain a nuclear halogen atom).  The reaction is preferably carried out in the presence of a solvent and an acid-binding agent.  Suitable dehydrogenating agents for method (2) are mercuric oxide, mercuric acetate, potassium permanganate, manganese dioxide, copper oxide, copper sulphate, hydrogen perioxide, selenium dioxide, platinum oxide, potassium ferricyanide, ferric chloride, ferric sulphate and dehydrogenating catalysts such as finely divided nickel, copper, platinum or palladium.  A solvent such as glacial acetic acid or a dilute mineral acid is preferably used.  When a metal catalyst is employed, fused 2-methylbenzimidazole may be used as the solvent. Examples show the production of the following a ,b  - di - [benzimidazyl - (2)] - ethylenes: N-methyl-, N-(b -dimethylamino-ethyl)-, N-(b -oxy-ethyl)-, N-benzyl-, and N-ethylby method (1); N-methylby method (2), the N-methyl-a ,b -di-[benzimidazyl-(2)]-ethane being obtained by methylation of the parent compound; N-(b  - oxy - ethyl) - 6 - methyl - and N - (b -oxy-ethyl)-6-methoxyby method (3), the N-alkylation being effected after dehydrogenation; N-ethyl-6-methyl- and N-methylby method (3). The products form salts with acids and bases.  b -[Benzimidazyl-(2)]-acrylic acids are made by dehydrogenation of the corresponding propionic acids.  Specifications 600,696 and 611,510 are referred to.  The Specification as open to inspection under Sect. 91 refers to compounds of the above formula where A is any aromatic nucleus, R1 is any substituent group (aryl being specified), and R2 is any divalent aliphatic residue which forms an uninterrupted series of double bonds with the two imidazole rings, preferably of the type -(CH=CH)n-, where n is a small integer.  The compounds are made in the same way as given above, using the appropriate acids in methods (2) and (3).  The unsaturated acids required for method (3) may be obtained by dehydrogenation of the corresponding benzimidazyl-fatty acids. This subject-matter does not appear in the Specification as accepted.ALSO:Di-imidazoles of the formula <FORM:0653681/IV (c)/1> where A is a benzene nucleus attached by two vicinal carbon atoms (which may be substituted, e.g. with alkyl or alkoxy groups or halogen atoms), R1 is an alkyl or aralkyl group which may be substituted, and R2 is an ethylene residue forming an uninterrupted series of double bonds with the imidazole rings, exhibit a blue to violet fluorescence in daylight and ultra-violet light, and are applied to materials to improve the whiteness if undyed or to improve the purity of colour of dyed goods.  The materials are impregnated with (1) a solution of a metal salt of the di-imidazole, e.g. in ethanol; (2) an aqueous solution of an acid salt of the di-imidazole, or (3) a dispersion of the di-imidazole prepared with the aid of soaps, polyglycol ethers of fatty alcohols, sulphite cellulose liquor or condensation products of alkyl-naphthalene sulphonic acids with formaldehyde; after impregnation, the materials are centrifuged or squeezed and dried.  The compounds may be applied simultaneously with the usual washing and bleaching agents, e.g. soaps, salts of sulphonated 2-(higher alkyl)-benzimidazoles, monocarboxylic acid esters of 4-sulphophthalic acid with higher fatty alcohols, fatty alcohol sulphonates and condensation products of higher fatty acids with aliphatic oxy- or amino-sulphonic acids.  A typical preparation contains soap and 0.005-1 per cent of the di-imidazole.  The compounds are insensitive to moisture and do not colour specks of lime soaps which may be present.  The materials may be in the form of fibres or films and may be paper, textile materials of cotton, linen, regenerated cellulose (including staple fibres), wool, silk, synthetic polymers or polyamides.  In the examples: (1) the di-imidazole is stirred with fused soap and allowed to solidify, or with a fused fatty acid and then neutralized with alkali; alternatively, it may be dissolved in alcohol or other water-miscible solvent and then added to the soap.  Cellulosic or other textile material is washed with this preparation; (2) 2-heptadecyl-N-benzyl-benzidimazole disulphonic acid is added, in the form of its sodium salt, to the composition of (1).  Other higher alkyl radicals may replace heptadecyl, and mixtures of such compounds may be used; (3) cotton is treated with an aqueous solution of the di-imidazole formate; (4) a cellulose fabric dyed with a specified azo-dye is printed with a discharge paste containing the di-imidazole, alcohol and caustic soda, giving a white discharge; (5) cellulosic material is bleached with a sodium hypochlorite solution containing the di-imidazole; (6) cellulosic material (undyed) is washed with a solution containing the di-imidazole, soap, sodium perborate and sodium metasilicate. Specification 611,510 is referred to.  The Specification as open to inspection under Sect. 91 refers to the use of compounds of the above formula where A is any aromatic nucleus, R1 is any substituent group (aryl being specified), and R2 is any divalent aliphatic residue which forms an uninterrupted series of double bonds with the two imidazole rings, preferably of the type -(CH=CH)n-, where n is a small integer.  This subject-matter does not appear in the Specification as accepted.ALSO:Soap compositions contain a di-imidazole of the formula <FORM:0653681/III/1> where A is a benzene nucleus attached by two vicinal carbon atoms, R1 is an alkyl or aralkyl group which may be substituted, and R2 is an ethylene residue forming an uninterrupted series of double bonds with the imidazole rings.  The benzene rings may be substituted, e.g. with alkyl or alkoxy groups or halogen atoms.  Materials washed with such compositions have an enhanced whiteness if undyed or a greater brightness of colour if dyed.  The di-imidazoles may be present to the extent of 0.005 to 1 per cent.  They are insensitive to moisture, do not change colour during storage and do not colour specks of lime soaps that may be present.  The di-imidazoles may be incorporated in the soap by (1) adding them to fused soap and allowing the mass to cool; they are preferably first dissolved in alcohol or other water-miscible solvent to facilitate dispersion; (2) added to fused fatty acid and the mixture neutralized with alkali, or (3) added directly to a soap solution.  A combined bleaching and washing preparation is obtained by grinding soap to a powder with the di-imidazole, sodium perborate and sodium metasilicate. Specification 611,510 is referred to.  The Specification as open to inspection under Sect. 91 refers to the use of compounds of the above formula where A is any aromatic nucleus, R1 is any substituent group (aryl being specified), and R2 is any divalent aliphatic residue which forms an uninterrupted series of double bonds with the two imidazole rings, preferably of the type -(CH=CH)n-, where n is a small integer. This subject-matter does not appear in the Specification as accepted.