DE1205941B - Optical brighteners - Google Patents

Description

Optical brightening agents It has been found that practically colorless compounds of the coumarin series of the general formula in which A stands for a phenylene or naphthylene radical, R for hydrogen or a lower alkyl radical, e.g. B. methyl, ethyl or propyl, and Y stands for 0 or NH, while R1 is an alkylene radical with preferably 2 to 4 carbon atoms and R2 and R3 are identical or different alkyl or aralkyl radicals, or their quaternization products have been very successful as optical brighteners can be used, especially for materials made of polyacrylonitrile or cellulose esters.

The phenylene radical is preferably substituted by Radicals - OH, - O-alkyl, - O-aralkyl, - NH2, - NH-alkyl, - N- (alkyl, - NHCO-alkyl, - NHCO-aryl, - NHCONH-alkyl or - NHCONH-aryl; but others can also Substituents may be present, such as e.g. B. alkyl groups or halogen; also the naphthylene residue can be substituted.

The compounds of the coumarin series proposed as lightening agents are accessible by using coumarin-3-carboxylic acid compounds of the general formula in which A and R have the meaning given above and in which X is a reactive radical, e.g. B. a free or esterified hydroxyl group or halogen, with amines of the general formula in the Y, R1. R2 and Rs have the meaning given above, are advantageously reacted with heating and the reaction products obtained are optionally quaternized.

As a representative of the coumarin required here as starting materials - 3 - carboxylic acid compounds are the methyl, ethyl, oxethyl, propyl, butyl, and phenyl esters of 7-oxycoumarin-3-carboxylic acid, of 7-methoxycoumarin-3-carboxylic acid, 7-dimethylaminocoumarin-3-carboxylic acid, 7-acetylaminocoumarin-3-carboxylic acid, the 5,6-benzocoumarin-3-carboxylic acid and the 7,8-benzocoumarin-3-carboxylic acid, for example called. As amines are z. B. the following compounds are listed: 2-dimethylaminoethanol, 2-diethylaminoethanol, 3-dimethylaminopropanol, 4-dimethylaminobutanol, 1-amino-2 - dimethylaminoethane, 1- amino - 2 - diethylaminoethane, 1-amino-3-dimethylaminopropane and 1-amino-3-diethylaminopropane.

Examples of quaternizing agents are dimethyl sulfate, diethyl sulfate, Methyl iodide, ethyl iodide, methyl 4-toluenesulfonate, ethyl 4-toluenesulfonate or called benzyl chloride.

The optical brightening agents can be used in the customary manner be, for example in the form of solutions in water or in organic solvents or in the form of aqueous dispersions; the lightening agents can also be used together use with detergents. Furthermore, they can also be added to spinning or casting compounds used for the production of artificial fibers, threads, foils or other structures to serve.

Coumarin compounds are already known as lightening agents, which has a tertiary amino group in the 7-position and hydrogen in the 3-position, an alkyl, aryl or aralkyl radical or the radical with an aliphatic alcohol contain esterified acetic acid. Compared to these connections, the Whitening agents of the present invention have a stronger effect.

The parts given in the following examples are parts by weight.

Example 1 Polyacrylonitrile fibers are used in a liquor ratio of 1:40 placed in an aqueous bath containing 0.05 g per liter of the one listed below Contains lightening agent and 1 g of oxalic acid and 1 g of sodium chlorite. The bathroom will then heated to boiling within 20 minutes and 45 to 60 minutes at this temperature held. The polyacrylonitrile fibers are then rinsed and dried. The fibers are lightened in an excellent way.

The lightening agent used was prepared in the following way: 268 parts of 5,6-benzocoumarin-3-carboxylic acid ethyl ester were mixed with 125 parts of 3-dimethylaminopropylamine added and heated on a boiling water bath for 6 hours. Then the melt triturated with 1500 parts of water; the resulting crystal slurry became 10,000 parts Given water and sucked off after stirring for 2 hours. The 5,6-benzocoumarin-3-carboxylic acid 3'-dimethylaminopropylamide thus obtained melted after recrystallization from cyclohexane at 122 to 124 "C. 110 parts of the 5,6-benzocoumarin-3-carboxylic acid-3'-dimethylaminopropylamide obtained were now heated with 600 parts of acetone and treated with 50 parts of dimethyl sulfate dropwise. After the reaction mixture is refluxed for a further 30 minutes was, the crystal slurry formed was filtered off with suction and recrystallized from alcohol. The quaternary salt obtained melted at 215 to 218 "C.

Instead of the above-mentioned Auffiellungsmittel one can use the same Success also use one of the lightening agents obtained by reacting 5,6-benzocoumarin-3-carboxylic acid ethyl ester with 3-dimethylaminopropylamine and quaternization with methyl iodide, ethyl iodide, diethyl sulfate, 4-Toluenesulfonsauremethylester or 4-Toluenesulfonsäureethylester were prepared.

Example 2 From 10 parts of one of the lightening agents listed in Example 1, A stock solution is prepared 10 parts of polyacrylonitrile and 80 parts of dimethylformamide; this is then added in such an amount to a conventional polyacrylonitrile spinning solution, that the concentration of the whitening agent in the spun polyacrylonitrile material Is 0.15 percent by weight. The spinning solution is then spun in the usual way, and the fiber material formed is bleached in a bath containing sodium chlorite. The whiteness effect thus obtained is excellent.

Example 3 Cellulose acetate fibers are made in a liquor ratio of 1:30 treated at 30 to 70 "C for 20 to 30 minutes in an aqueous bath that is im Liter contains 0.03 g of one of the lightening agents listed below. Afterward the fibers are rinsed and dried; they then show a very good lightening effect.

The lightening agent used was prepared in the following way: 5,6-Benzocoumarin-3-carboxylic acid ethyl ester was with 3 - dimethylaminopropanol 2 - dimethylaminoethanol or 2-diethylaminoethanol implemented and quaternized with dimethyl sulfate. The resulting crystalline reaction products were recrystallized from methanol.

Example 4 Polyacrylonitrile fibers are treated as in the example 1 with one of the two lightening agents listed below. The lightening effect achieved is excellent.

One of the lightening agents was prepared in the following manner: ethyl 5,6-benzocoumarin-3-carboxylate was reacted with 3-dimethylaminopropylamine and then with benzyl chloride quaternized. The quaternary salt recrystallized from alcohol melted at 229 to 230 "C.

The other lightening agent was made in the following way: 5,6-Benzocoumarin-3-carboxylic acid ethyl ester was reacted with 3-diethylaminopropylamine and then quaternized with dimethyl sulfate. The quaternary recrystallized from alcohol Salt melted at 134 to 140 "C.

EXAMPLE 5 Cellulose acetate fibers are treated according to that in the example 3 with one of the two lightening agents listed below. The fibers are then very well lightened.

One of the lightening agents was prepared in the following manner: ethyl 7-oxycoumarin-3-carboxylate was reacted with 3-dimethylaminopropylamine and quaternized with dimethyl sulfate. The quaternary salt recrystallized from aqueous methanol melted at 238 to 247 "C.

The other lightening agent was made in the following way: 7-Dimethylaminocoumarin-3-carboxylic acid ethyl ester was treated with 3-dimethylaminopropylamine implemented and quaternized with dimethyl sulfate. The recrystallized from methanol quaternary salt had a melting point of 265 to 267 "C.

Claims (1)

Claim: Use of practically colorless compounds of the coumarin series of the general formula in which A is a phenylene or naphthylene radical, R is hydrogen or a lower alkyl radical and Y is 0 or NH, while R1 is an alkylene radical with preferably 2 to 4 carbon atoms and R2 and R3 are identical or different alkyl or aralkyl radicals, or their quaternization products as optical brightening agents. Considered publications: German Patent Specifications No. 904 646, 937 822; U.S. Patent No. 2,683,720; Journal of the Am. Chem. Soc., 71, pp. 3602 to 3606.