Patent GB-835898-A (GB)
Title: New ª:ª-di-[benzoxazolyl-(2)]-ethylenes
Filed: 1956-06-15
Abstract: Soap or detergent compositions contain as a brightening agent an a ,b -di-[benzoxazolyl-(2)]-ethylene of formula <FORM:0835898/III/1> in which R1 and R2 are benzene residues, at least one of which contains a single methyl group as substituent.  In an example, a composition comprising soap, anhydrous sodium carbonate, sodium pyrophosphate, sodium perborate, magnesium silicate, a ,b -di-[5-methylbenzoxazolyl-(2)]-ethylene, and water is used, and in another example, the same brightener is dispersed in a ethylene oxide condensate with saturated fatty alcohols containing 18 carbon atoms.ALSO:The invention comprises new a ,b -di-[benzoxazolyl -(2)]-ethylenes of general formula <FORM:0835898/IV (b)/1> in which R1 and R2 represent benzene residues at least one of which contains a single methyl substituent.  They may be prepared by the following methods: (a) by melting a methyl-o -hydroxy-aminobenzene with fumaric acid; or by melting it with succinic acid followed by dehydrogenation of the -CH2-CH2- group in the resulting a ,b -di-[benzoxazolyl-(2)]-ethane; alternatively the latter ethane compounds may be obtained by condensing succinic acid with an o-hydroxy-aminobenzene in the molecular ratio 1:1 and condensing the resulting compound of formula <FORM:0835898/IV (b)/2> with a further o-hydroxy-aminobenzene; (b) by treating an acylamino compound of the formula <FORM:0835898/IV (b)/3> with an agent capable of splitting off water, e.g. oleum or zinc chloride; if oleum is used sulphonation of the benzene rings may also take place; (c) treating an acylamino compound of formula <FORM:0835898/IV (b)/4> with an agent capable of splitting off water, e.g. zinc chloride, boric acid, propionic acid or glacial acetic acid, preferably at a temperature of 140-180 DEG C.; (d) by condensing an o-hydroxy-aminobenzene at raised temperature with fumaric acid, malic acid or aspartic acid or an alkyl mono- or di-ester of one of these acids in a molecular ratio of 2:1, and without separating the product, heating it with a catalyst capable of eliminating the elements of water; the reaction is preferably carried out in a highboiling solvent using sulphonic acids of the benzene series or boric acid as catalyst; and (e) heating a compound of formula <FORM:0835898/IV (b)/5> with an agent capable of splitting off water, e.g. zinc chloride, preferably at a raised temperature in an organic solvent. Examples are given of the preparation of <FORM:0835898/IV (b)/6> and its disulphonated derivative; <FORM:0835898/IV (b)/7> and (c) <FORM:0835898/IV (b)/8> The products are useful for brightening various materials, e.g. lacquers, such as alkyd resin lacquers or nitrocellulose lacquers, and particularly synthetic fibres such as those of cellulose esters, polyacrylonitrile, polyesters or polyvinyl chloride. Starting materials used in the examples are produced as follows: <FORM:0835898/IV (b)/9> by heating fumaric acid dichloride with 1-amino-2-hydroxy-5-methylbenzene; <FORM:0835898/IV (b)/10> by heating 1-amino-2-hydroxy-5-methylbenzene with malic acid; and (c) a -[5-methyl-benzoxazolyl - (2)] - b  - [benzoxazolyl - (2)] - ethane by heating succinic acid with o-hydroxy-aminobenzene to give <FORM:0835898/IV (b)/11> which is heated with 1-amino-2-hydroxy-5-methylbenzene.  Specifications 835,891, 835,892, 835,893, 835,894, 835,895, 835,896 and 835,897 are referred to.ALSO:The invention comprises new a .b -di[benzoxazolyl-(2)]-ethylenes of general formula <FORM:0835898/IV(c)/1> in which R1 and R2 represent benzene residues, at least one of which contains a single methyl substituent.  They may be prepared by the following methods: (a) by melting a methyl-o-hydroxy aminobenzene with fumaric acid, or by melting it with succinic acid followed by dehydrogenation of the -CH2-CH2- group in the resulting a .b -di-[benzoxazolyl-(2)]-ethane; alternatively the latter ethane compounds may be obtained by condensing succinic acid with an o-hydroxy-aminobenzene in the molecular ratio 1.1 and condensing the resulting compound of formula <FORM:0835898/IV(c)/2> with a further o-hydroxyaminobenzene; (b) by treating an acylamino compound of formula <FORM:0835898/IV(c)/3> with an agent capable of splitting off water, e.g. oleum or zinc chloride if oleum is used sulphonation of the benzene rings may also take place; (c) treating an acylamino compound of formula <FORM:0835898/IV(c)/4> with an agent capable of splitting off water, e.g. zinc chloride, boric acid, propionic acid or glacial acetic acid, preferably at a temperature of 140-180 DEG  C.; (d) by condensing an o-hydroxyaminobenzene at raised temperature with fumaric acid, malic acid or aspartic acid or an alkyl mono- or di-ester of one of these acids in a molecular ratio of 2 : 1, and, without separating the product, treating it with a catalyst capable of eliminating the elements of water; the reaction is preferably carried out in a high-boiling solvent using sulphonic acids of the benzene series or boric acid as catalyst; and (e) heating a compound of formula <FORM:0835898/IV(c)/5> with an agent capable of splitting off water, e.g. zinc chloride, preferably at a raised temperature in an organic solvent.  The products are active optical brightening agents which are suitable for brightening a wide range of materials, especially organic materials such as synthetic fibres.  In the examples: (a) paper or cardboard is brushed with a nitrocellulose lacquer containing 0.01% of a .b  - di[5 - methyl - benzoxazolyl-(2)] - ethylene; (b) a polyacrylonitrile fabric and a polyvinyl chloride yarn are treated in a bath containing water, formic acid, sodium chloride and a paste containing water, a .b -di-[5-methyl - benzoxazolyl - (2)] - ethylene and the addition product of ethylene oxide with a mixture of saturated fatty alcohols predominantly containing 18 carbon atoms; (c) polyester fibres are treated with a bath containing ammonia and a paste of a .b -di-[5-methyl-benzoxazolyl-(2)]-ethylene with water and the addition product of ethylene oxide with a mixture of saturated fatty alcohols containing preponderantly 18 carbon atoms; instead of the addition product referred to a condensation product of naphthalene sulphonic acid may be used and a .b -di-[6-methyl-benzoxazolyl-(2)]-ethylene may be used instead of the 5-methyl compound; (d) a polyester fabric is treated in a bath containing water, formic acid, sodium chlorite and the paste referred to in (b) above; peracetic acid may be used instead of formic acid and sodium chlorite; and (e) a polyester fabric is treated with a liquid containing water, potato starch, ammonia and the paste referred to in (b) above.  In all cases the products were brighter than the untreated materials.ALSO:a ,b  - di - [benzoxazolyl - (2)] - ethylenes of formula <FORM:0835898/IV (a)/1> in which R1 and R2 are benzene residues at least one of which contains a single methyl group, are used as brightening agents.  In an example 0.15 part of a ,b  - di - [5 - methyl - benzoxazolyl(2)]-ethylene dissolved in 2 parts of dimethylformamide is added to a solution of 150 parts of a polyacrylonitrile powder and 1000 parts of dimethyl-formamide; a film produced from the resulting mass has a brighter appearance than a film made in a similar manner without the addition of the oxazolyl compound.