Starch anthranilate

Starch anthranilates were proposed as optical brighteners. They improve the retention of inorganic fillers and fiber fines in paper processing.2535,2536... 

In a 2-1. beaker, set in a freezing mixture and provided with a stirrer and a thermometer for reading temperatures to o°, are placed 500 cc. of water, 137 g. (1 mole) of anthranilic acid and 200 cc. of concentrated hydrochloric acid the stirrer is started and the mixture cooled to about 6°. Meanwhile 69 g. (1 mole) of sodium nitrite is dissolved in 280 cc. of hot water and the solution cooled in ice portions are then placed in a separatory funnel of convenient size, supported in such a way that the lower end of the stem extends beneath the surface of the anthranilic acid solution. When the temperature has fallen to 50, the nitrite solution is run in, about 500 g. of cracked ice is added at such a rate as to keep the temperature below 50. This takes about ten minutes (Note 1). A drop of the solution should give an immediate blue color with starch-iodide paper. 

A. o-Hydrazinobenzoic acid hydrochloride. In a 2-1. beaker, provided with a stirrer and a low-temperature thermometer, and cooled in an ice-salt bath, are placed 42 g. (0.31 mole) of anthra-nilic acid and 300 ml. of water. The stirrer is started, and 340 ml. of concentrated hydrochloric acid (sp. gr. 1.18) is added in one portion the anthranilic acid dissolves, and its hydrochloride begins to separate almost immediately. After the mixture has been cooled to 0°, a solution of 21.6 g. (0.31 mole) of technical sodium nitrite in 210 ml. of water is added from a dropping funnel, the tip of which extends below the surface of the suspension, at such a rate that the temperature never rises above 3°. The addition requires about 30 minutes stirring is continued for 15 minutes longer, and at the end of this period a positive test with starch-iodide paper should be obtained (Note 1). The dear brown solution is then diluted with 150 ml. of ice water. 

Mason, J.R., M.L. Avery, J.F. Glahn, D.L. Otis, R.E. Matteson C.O. Nelms. 1991a. Evaluation of methyl anthranilate relative to starch-plated dimethyl anthranilate as a bird repellent livestock feed additive. J. Wildl. Manage. 55 182-187. 

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