Патент USA US2405702код для вставки
Patented Aug. 13, 1946 2,405,702 UNITED STATES ATENT OFFICE. PROCESS FOR PREPARING PYRANTHRONE Henry R. Lee,w Pitman, andv Joseph Deinet and Hans B. Gottlieb, Glassboro, N. J., assignors to E. I. duPont de Nemours & Company, Wilming ton, DeL, a ‘corporation of Delaware - No‘ Drawing. Application May 23, 1944, Serial No. 536,986 _1. Claim. (01. zero-ease)‘ 1 25 This invention relates to an improvement in the. process for preparing pyranthrone, and more particularly to a process whereby crude 2,2’-di methyl-l,l’-dianthraquinonyl, which has been In‘ this‘ fusion, the dimethyldianthraquinonyl is prepared from a crude l-halogen-Z-methylan thraquinone, is converted to the 2'-phenoX'y-3‘ methylanthraquinone or isomeric products, which phenoxy derivatives are'readily removed from the thraquinone, is condenseddirectly to pyranthrone without. puri?cation of they intermediates. The 1-halogen-Z-methylanthraquinone, which is prepared by the halogenation of Z-methylan ring-closed to pyranthrone while the isomeric halogenmethylanthraquinone, which may be con sidered, in the main, the 2-ha1ogen-3-methylan pyranthrone by simple dilution of the reaction mass with ethyl alcohol or by extraction of the thraquinone as such oras it is ring-closed from 10 pyranthrone, after ?ltration, with other organic the methylorthobenzoyl benzoic acid,.is always solvents. As an alternative method of separating contaminated with large amounts of isomeric out the relatively pure pyranthrone, the reaction methyl-halogenanthraquinone compounds, . and, mass may be ?ltered after extraction with water and dissolved in concentrated sulfuric acid at more particularly, the 2-halogen-3~methylan thraquinone. In the preparation of the 2,2'-di room temperature, after which. it. is drowned in water, ?ltered, and. washed acid-free. This lat ter process appears: to sulfonate the phenoxy de anthraquinone prior to condensation, and, after rivative, rendering. it water-soluble, whereby it is condensation to the dianthraquinonyl, a further readily removed from the pyranthrone by ?ltra puri?cation of the \dianthraquinonyl was re tion and washing with water. 20 quired, for the methods heretofore employed for The following examples are given to illustrate effecting ring-closure of the 2,2’—dimethyl-1,1' the invention. The parts used: are by weight. dianthraquinonyl made it advisable to employ Erample 1 very pure dianthraquinonyl. Even after these. puri?cations, the overall yields of pyranthrone 25 _ One part’ ofwell powdered crude-2,2"-dimethyl 1,I’-dianthraquinonyl_, containing 25% of 3 were, not satisfactory, so that it has generally bromo-2-methylanthraquinone as an admixture,’ been. found more, advantageous to produce the pyranthrone starting. with the l-nitro-Z-methyl was gradually added‘ with agitation to a melt- of 1.8 parts of caustic potash» in 4.7 parts of phenol anthraquinone which is converted ?rst. to the ‘1 amino-2-anthraquinone._ then,v after 'diazotiza at 115“ C; during. the courseof 15 minutes. The methyl-1,1'-dianthraquinonyl, it has therefore been necessary to purify the 1-chloro-2-methyl tion,._ to the dianthraquinonyl compound. . It: isan object of the present invention to pro vide a process for preparing pyranthrone directly from the crude .1-halogen-2:-methylanithraqui none, which process will give the pyranthrone di rectly in good yields without requiring puri?ca tion of the dye intermediate employed-or pro duced in the reaction. It is a further object of the invention to provide a process for the prepa temperature of. the agitated masswas then. raised, kept ?rst» at, 125° C. for- 0:5 hour and later at 140° to 145°" C. for 3.5 hours. The mass Was drowned into 10 parts of, water» and aerated- at 90“ C. for the oxidation- of the: leuco pyranthrone for 3 hours. The product was collected, extracted. with'lO parts of 3%. caustic soda, washed free from phenol with. dilute caustic, then freed from alkali. with hotwater and dried. The resulting ration of pyranthrone starting from the crude powdered mixture Was extracted with 5 parts of dye intermediates by av process which does not 40 nitrobenzene at 130»u C. for 0.5 hour, was filtered involve‘ further puri?cation steps, and which pro duces the pyranthrone'of a quality equal to the at. 100i to’ 11b’?I C., washed. with ethanol to re move the nitrobenzene, and dried. All of the 3 phenoxy-Z-methylanthraquinone had been re commercial pyranthrone of today’s standards. We have found that pyranthrone of standard 45 moved by nitrobenzene. Pure pyranthrone was quality can be obtained directly from the crude obtained in 95% yield, based on the 2,2'-dimeth y1—1,1'-dianthraquinonyl contained in the orig l-halogen-Z-methylanthraquinone, where the inal crude quinonyl. crude 2,2’-dimethyl-1,1’-dianthraquinonyl con taining even as high as 50% of uncondensed iso Example 2 meric halogenmethylanthraquinones is used 50 One part of a Well powdered crude 2,2'-di with phenol and alkali metal hydroxide. With methyl-1,1’-dianthraquinonyl, containing 20% of crude 2,2'-dimethyl-1,1’-dianthraquinonyl con 3-bromo-2-methylanthraquinone as chief admix taining up to 25% of 3-halogeno-2-methylan thraquinone as impurity, our new fusion is more ture, was charged at 125° C. into an agitated melt economical than standard commercial methods. 65 of 2 parts of caustic potash and 4 parts of phenol. 2,405,702 3 4 The temperature of the fusion was raised and the mixture stirred for 4 hours at 145° to 150° C. After cooling to 110° 0., 4 parts of ethanol were added with agitation and the whole ?ltered at 70° C. The ?lter cake was washed with 8 parts of ethanol and ?nally with hot water until free from alkali and bromide. The yield of pure pyran throne amounted to 96%-99%, based on 2,2’-di methyl-1,1’-dianthraquinonyl contained in the tion, and that various modi?cations of the same are possible without departing from the spirit of this invention. The ratio of the phenol to the crude dimethyldianthraquinonyl and the ratio of ranthrone was isolated in good yield, based on same. the caustic to the phenol, or the duration of the fusion, may be varied within reasonable limits. The temperatures?ikewise, may be varied, it be ing understood, of course, that with too low a tem perature the reaction becomes too slow to be original crude quinonyl. 10 practical. Temperatures greatly in excess of those 3-phenoxy-2-methyl-anthraduinone is readily given in the examples, however, are not required. The phenoxymethylanthraquinone impurities isolated from the phenolic-alcoholic mother liquor. ' produced during the fusion, more particularly the Example 3 3-phenoxy-2-methylanthraquinone, may be re moved from the pyranthrone by using solvents 16 The starting material used in this instance was other than alcohol or nitrobenzene. Orthodi a crude quinonyl containing 40% of 3-chloro-2 chlorobenzene, or any other solvent in which this methylanthraquinone as the principal admixture. material is preferentially soluble, may of course This product was subjected to phenol-caustic be employed. potash fusion under the conditions described in It will be obvious that the phenol may be sub Example _2 for the crude quinonyl containing 20 stituted by other hydroxybenzenes, such as, for bromo product. The fusion was worked up in an instance, cresols or commercial mixtures of the identical manner with Example 2 and pure py 2,2'-dimethyl-1,l'-dianthraquinonyl contained in the original crude quinonyl. ' This process has a very important technical ad 25 vantage over the previously known processes in that the pyranthrone can be obtained directly and Example 4 without recrystallization from impure 2,2'-di methyl-1,1’-dianthraquinonyl, which, in turn, ' One part of a well powdered crude 2,2'-di- was obtained from the very impure l-halogen-2 of 3-bromo-2-methylanthraquinone, was charged 30 methylanthraquinone without isolation or puri? cation of the intermediates. If such impure di at 125° G‘. into an agitated melt of '2 parts of methyldianthraquinonyl is ring-closed directly by caustic soda and 4 parts of phenol. The temper the usual alcoholic caustic fusion methods, the ature of the agitated fusion was brought to 150° resulting pyranthrone gives dull and unsatisfac , C.'and kept at 150° to 152° C. for 4 hours. methyl-1,1’-dianthraquinonyl, containing 20% The melt was worked up as described in detail‘ 35 tory dyeings, and expensive and time-consuming recrystallization of such product is required to give a dye of satisfactory purity. On the other in Example 2. Pure pyranthrone was obtained in good yield, based on 2,2'-dimethyl-l,l’-dianthra quinonyl contained in the original crude quinonyl; hand, if the pyranthrone of satisfactory purity were to be obtained starting with impure l-halo Ewmple 5 ' ‘ gen-2-methylanthraquinone, the puri?cation of the resulting dimethyldianthraquinonyl requires large crystallization losses and materially reduces One part of a well powdered’ crude 2,2'-di methyl+l,1’-dianthraquinonyl, containing 5% ‘of -3—bromo-2-methylanthraquinone, was charged at 125° C. into an agitated mass of 2 parts of the yield of the resulting pyranthrone, based on the original starting material. By the present caustic potash and 4 parts of phenol. Thefusion - V invention, the pyranthrone is formed directly and was heated to 145° to 150° C. for 4 hours, allowed need only be washed from by-products, using suitable solvents, which simple operation involves to cool, and drowned into 15 parts of water. The mass was ?ltered, the cake extracted with'dilute' caustic, washed free from phenol and alkali, and no substantial loss of the 'pyranthrone itself. We claim: dried. This crude pyranthrone was puri?ed and "3 converted into dye paste in one step. The ?nely powdered crude was dissolved in 8 to 10 parts of concentrated sulfuric'acid and agitated at room‘ temperature-for 2 hours. In this treatment the admixed 3éphenoxy-Z-methylanthraquinone was -' completely sulfonated and remained dissolved, when the sulfuric acid solution was drowned into resulting pyranthrone was of excellent shade and > 7 It is of course understood that the above ex amples are given merely to illustrate the inven pyranthrone from an impure 2,2'-dimethyl-1,1' dianthraquinonyl containing substantial amounts of 2-ha1ogen-3-methylanthraquinones, which comprises fusing the crude 2,2'-dimethyl-1,l'-di anthraquinonyl with a phenol and an alkali metal hydroxide, diluting the fusion mass with ethyl alcohol, ?ltering o? the pyranthrone, and wash ing the resulting pyranthrone cake with alcohol water for the preparation of the dye paste. The strength. . The process for preparing a relatively pure and with water. 60 . > ’ HENRY R. LEE. JOSEPH DEINET. HANS B. GOTI'LIEB.