Patent GB-327756-A (GB)
Title: A process for the manufacture and production of vat dyestuffs
IPC: C09B3/50
Filed: 1928-10-18
Abstract: 327,756. Johnson, J. Y., (I. G. Farbentndustrie Akt.-Ges.). Oct 18, 1928. Samples furnished. Halogenated 3.4.8.9-dibenzopyrene-5.10-quinones are prepared by treating the unsubstituted or substituted quinone in sulphuric acid or derivatives thereof, such as fuming sulphuric acid, chlorsulphonic acid, with chlorine, bromine, iodine or agents supplying these, in the presence or absence of catalysts. Two or more different halogens may be introduced into the molecule by simultaneous or successive halogenation with such halogens. In the presence of catalysts the working conditions are selected to prevent sulphonation &c. of the final product and to regulate the amount of halogen entering the molecule and the dyeing properties of the product. These working conditions are interdependent, the main considerations being as follows :-Temperature of halogenation: the working temperature is dependent on the halogen to be introduced, for chlorine temperatures about 50‹ C., for bromine about 60‹ C. and for iodine about 110‹ C. being required. Nature and quantity of catalyst: catalysts advantageously employed are iodine, mercury, selenium, sulphur, antimony and bismuth, the non-metallic catalysts being preferably used at the lower temperatures, for example for chlorination and the metals at the higher temperatures. When working at temperatures below 85‹ C. chlorination and bromination may be effected in presence of small quantities of catalyst, for example 0.1-0.5 per cent, but more desirable dyeing shades are obtained by the use of at least 1.5 per cent of catalyst. Above temperatures of 85‹ C. halogenation is carried out in the presence of up to 5 per cent or more of catalyst and may also be completed in a shorter time than at the lower temperatures to avoid sulphonation &c. of the product. To this end excess of halogenating agent may also be used and/or such agent rapidly introduced into the reacting mixture. The starting material : the halogen and nitro derivatives of 3.4.8.9-dibenzopyrene-5-10-quinone and the purified quinone itself may be subjected to more drastic reacting conditions than the crude material since they are more resistant to attack. The purification of the crude 3.4.8.9-dibenzopyrene-5-10-quinone may be effected by crystallization, sublimation, by treatment with oxidizing agents such as alkali hypochlorites, or by solution in concentrated sulphuric acid and precipitation of the oxonium sulphate by addition of water. The increased resistance of halogen derivatives to side-attack may be utilized by effecting the first stages of halogenation of the crude material at low temperatures prior to the more drastic treatment. The diluent : chlorsulphonic acid is particularly suitable since at temperatures of 85‹ C. and over it may function as a chlorinating agent itself. Further when used in conjunction with iodine as catalyst only a slight excess of halogen over the theoretical requirement for each halogen introduced into the molecule is required. When working in the absence of catalysts the halogenated products differ from those prepared with the aid of catalysts, presumably due to a different orientation of the halogen in the molecule. With oleum as diluent the halogen acid formed is oxidized to give free halogen so that almost theoretical proportions of the latter may be used. Halogenating temperatures are preferably kept below 90‹ C. These reacting conditions are exemplified by numerous examples which include the preparation of the following derivatives of 3.4.8.9-dibenzopyrene-5-10-quinone : mono-, di-, tri-, tetra- and hexa-bromo-; mono-, di-, tri-, tetra- and hexa-chloro-; a mixture of mono- and di-iodo; monobromomonochloro-, monobromodichloro; dibromomonochloro-, dibromodichloro-; tribromodichloro-; monobromomonoiodo-, dibromoiodo-; monobromomonomethoxyfrom the methoxydibenzopyrenequinone prepared by methylating the hydroxy derivative obtained from the diazotized reduction product of the mononitro derivative produced according to Specification 324,964. These products dye cotton in various shades of yellow and orange from red to violet vats, their colouring power and fastness being substantially greater than that of the halogen-free materials or of the known halogendibenzopyrenequinones. Specifications 205,502 and 249,147 also are referred to.