Abstract: This invention relates to the hydrogenation of halogen-substituted aromatic nitro compounds and in particular provides a novel catalyst for use in such processes.In more detail a catalyst suitable for use in the hydrogenation of halogen-substituted aromatic nitro compounds substantially without simultaneous dehalogenation comprises one or more metals from the group consisting of platinum, palladium, rhodium, iridium, ruthenium and osmium supported on or impregnated into a carrier material comprising carbon activated with phosphoric acid or a salt thereof.
Abstract: Selective reduction of compounds containing reducible nitro-, nitroso-, nitrilo-, oximes or double bonds is effected by the use of a metal macrocyclic compound in prereduced form, such as a metal phthalocyanine or a metal porphyrin.
Abstract: Polynitrated diaryl compounds of the formula given in the description are reduced with 1-2 mols of sulphides, or compounds which donate sulphide ions, per mol of nitro group in the presence of 0.5-10 mols of ammonia per mol of starting compound at 30.degree.-110.degree. C. to give nitroamino-diaryl compounds, for example 4,4'-dinitro-dibenzyl-2,2'-disulphonic acid is reduced to 4-nitro-4'-amino-stilbene-2,2'-disulphonic acid.
Type:
Grant
Filed:
April 14, 1980
Date of Patent:
September 7, 1982
Assignee:
Bayer Aktiengesellschaft
Inventors:
Karl Linhart, Dieter Pawellek, Harald Gleinig
Abstract: A process for the dechlorination of aromatic nitro or amino compounds consists in reacting anilines or nitrobenzenes which are polysubstituted by chlorine, with hydrogen, under the action of heat, in the presence of cations (Bi, Pb, Sn, Tl, Hg and Ag), in the liquid phase and at low pressure.The process makes it possible selectively to obtain anilines which are chlorine-substituted in the meta-position.
Abstract: Hydrogenation of mononitroaromatic compounds, particularly nitrobenzene, nitrotoluene and their monochloro and monohydroxy ring substitution products, using hydrogen sulfide as reducing agent and a titanium dioxide catalyst at 200.degree.-400.degree. C. and atmospheric pressure.
Type:
Grant
Filed:
February 23, 1981
Date of Patent:
April 20, 1982
Assignee:
Allied Corporation
Inventors:
Charles T. Ratcliffe, Stuart L. Soled, Anthony J. Signorelli, Irving L. Mador
Abstract: A process for the dechlorination of aromatic nitro or amino compounds comprising reacting anilines or nitrobenzenes, which are polysubstituted by chlorine, with hydrogen, under the action of heat, in the presence of an excess of chloride ions, in the liquid phase and at low pressure.The process makes it possible selectively to obtain anilines which are chlorine-substituted in the meta-position.
Abstract: A method of preparing 2,4-difluoroaniline by reacting 2,4,5-trichloronitrobenzene with a fluorinating agent to form 2,4-difluoro-5-chloronitrobenzene which is then hydrogenated with hydrogen in the presence of a catalyst to form 2,4-difluoroaniline.
Type:
Grant
Filed:
October 31, 1977
Date of Patent:
October 13, 1981
Assignee:
Merck & Co., Inc.
Inventors:
Roger J. Tull, Leonard M. Weinstock, Ichiro Shinkai