Abstract: This invention relates to an improved process for the recovery and regeneration of nitric acid from spent acid obtained from the mixed acid nitration of aromatic compounds. In that process a mixed acid of sulfuric acid and nitric acid is contacted with an aromatic composition at a temperature and pressure sufficient for producing a nitroaromatic composition and a spent acid containing unreacted nitric acid, sulfuric acid and solubilized nitroaromatic compounds in said spent acid. The improvement comprises initially heating the spent acid to a temperature of from about 120.degree. to 200.degree. C. for a time sufficient to convert said nitroaromatics in said spent acid to a nitroaromatic composition having a boiling point greater than 300.degree. C. at atmospheric pressure and then flash distilling the hot spent acid containing nitroaromatics compositions at a pressure from about 5 to 15 psia and temperature of 150.degree. to 200.degree. C.

Abstract: Nitrobenzenes are prepared by nitrating benzenes in a vapor phase with dilute or concentrated nitric acid wherein the following (A) or (B) is used as a catalyst:(A) acidic sheet clay minerals ion-exchanged with polyvalent metals, or(B) acidic composite oxides comprising oxides of metals belonging to Group IVA of the Mendeleefs' periodic table and tungsten oxide, molybdenum oxide, niobium oxide or zinc oxide.These catalysts have high catalyst activity and selectivity for vapor phase nitration reaction of benzenes with nitric acid and besides the activity is retained for a long time.

Abstract: Sulphuric and nitric acids present in dinitrotoluene are separated from the dinitrotoluene by adding up to 10 wt. % water (based on quantity of dinitrotoluene) to the mixture of dinitrotoluene, sulphuric acid and nitric acid, mixing and separating the aqueous phase containing nitric and sulphuric acids. The mixtures treated by this process generally contain up to 5 wt. % nitric acid and up to 6 wt. % sulphuric acid.

Abstract: A nonlinear optical element comprising 3-methyl-4-methoxy-4'-nitrostilbene useful for nonlinear optical and electro-optic effects.

Abstract: This invention relates to a novel process for preparing 3-amino-2-methylbenzotrifluoride from benzotrifluoride. The process comprises nitrating benzotrifluoride to form 3-nitrobenzotrifluoride, reacting this compound with trimethyl sulphoxonium halide to form 3-nitro-2-methylbenzotrifluoride and reducing the nitro group to an amino group.

Abstract: Nitration of benzene or toluene, and more specifically to such a reaction in a molten nitrate salt medium.

Abstract: In a method for denitrifying the nitric acid- and nitrous acid-containing spent acid phase from the nitration of an aromatic hydrocarbon by the mixed acid process which comprises forming a denitrification reaction medium by contacting the spent acid phase with an aromatic hydrocarbon under nitration reaction conditions to recover the nitric acid by the formation of a nitroaromatic hydrocarbon, the improvement which comprises(a) adding an amount of aromatic hydrocarbon which is slightly less than or equal to the stoichiometric amount necessary to deplete the spent acid phase of nitric acid,(b) photometrically monitoring the denitrification reaction medium for the appearance of a dark red to black color, and(c) upon detection of such color, adjusting the aromatic hydrocarbon:nitric acid molar ratio in the denitrification reaction medium to eliminate the color by reducing the aromatic hydrocarbon feed rate, or adding nitric acid to the denitrification reaction medium.

Abstract: The present invention relates to improvements in processes of preparing dinitrated aromatic compounds, particularly dinitrated aniline and dinitrated substituted aniline compounds, employing relatively dilute and then more concentrated nitric acid as the nitrating agent.

Abstract: Catalysts compositions useful to catalyze the nitration of aromatic compounds in the vapor phase to produce nitroaromatic compounds are represented by the empirical formula:(M.sup.1.sub.a M.sup.2.sub.b O.sub.c).sub.x (NO.sub.2).sub.ywherein M.sup.1 is at least one element selected from Group 4b of the Periodic Table of the Elements, M.sup.2 is at least one element selected from Group 3b of the Periodic Table of the Elements, a is 1, b is 0.050 to 20, c is a number taken to satisfy the average valences of M.sup.1 and M.sup.2 in the oxidation states in which they exist in the composition, x is 1, and y is 0 to c. The compositions are particularly effective to catalyze the vapor phase nitration of chlorobenzene and are characterized in such reaction by providing a para/ortho isomer distribution ratio of at least about 1.9/l.

Abstract: Benzene is efficiently nitrated in gaseous phase with NO.sub.2 or N.sub.2 O.sub.4 in the presence of a catalyst of acidic mixed oxide containing two or more sorts of metal oxides, for example, MoO.sub.3 --WO.sub.3, MoO.sub.3 --TiO.sub.2, WO.sub.3 --TiO.sub.2, TiO.sub.2 --ZnO or TiO.sub.2 --SiO.sub.2.

Abstract: A method is provided for denitrifying the aqueous spent acid of mononitration. The nitric acid in the aqueous spent acid is recovered by adiabatically reacting greater than a stoichiometric amount of a mononitroaromatic hydrocarbon with the aqueous spent acid which has been fortified to a nitric acid concentration of at least about 2 wt %. The denitrification method is useful in treating the aqueous spent acid phase from the mononitration stage of a dinitrotoluene process.

Abstract: An adsorptive separation process for separating the para-isomers of a di-substituted benzene from a feed mixture comprising the para-isomer and at least one other isomer. One substituted group is NO.sub.2 -- and the other group is a normal hydrocarbon having less than 6 carbon atoms per molecule, the halogens, NH.sub.2 --, NO.sub.2 -- or C.tbd.N--. The process comprises contacting the feed mixture with an adsorbent comprising crystalline silica having a silica/alumina mole ratio of at least 12, selectively adsorbing substantially all of the para-isomer to the substantial exclusion of the remaining isomers and thereafter recovering high-purity para-isomer by means of desorption with an appropriate desorbent material.

Abstract: In a process for nitrating aromatics using lower valent nitrating agents in trifluoroacetic acid, the product yield of nitroarenes can be significantly increased by maintaining an excess of nitrating agent over the stoichiometric amount during the reaction.

Abstract: Aromatic hydrocarbons are nitrated by reacting the aromatic hydrocarbon in a nitrogen tetroxide-containing liquid reaction medium, in the presence of a beta-dicarbonyl compound having a "W" configuration with a carbonyl group at each apex of the "W", preferably at a pressure and temperature sufficient to maintain the nitrogen tetroxide in the liquid state. Addition of an inert organic co-solvent to the liquid nitrogen tetroxide for the metal acetylacetonate promoted nitration of benzene essentially eliminates the production of dinitrobenzenes.

Abstract: Aromatic hydrocarbons selected from the group consisting of benzene and toluene are nitrated in the vapor phase at temperatures between about 80.degree. C. and about 190.degree. C. in the presence of a molecular sieve catalyst.

Abstract: Nitration of aromatics wherein gasified aromatic compounds and nitric acid are contacted with a silicon-aluminum catalyst.

Abstract: Aromatic compounds are nitrated in the vapor phase via a process comprising contacting the aromatic compound with a nitrating agent in the presence of a nitration promotion catalyst which comprises the adduct of:(a) an alumina-silica-metal oxide combination represented by the formula:(Al.sub.2 O.sub.3).sub.a (SiO.sub.2).sub.b (M.sub.2/n O).sub.cwherein M is a metal cation selected from the group consisting of the lanthanides or rare earths, Groups 1b, 2b, 5b, 6b, 7b, and 8 of the Periodic Table of the Elements, and mixtures thereof, and a, b, and c represent weight percent of the Al.sub.2 O.sub.3, SiO.sub.2, and M.sub.2/n O components, respectively, in the alumina-silica-metal oxide combination, with a being 0 to 100, b being 0 to 100, and c being 0 to 50, and n represents an integer from 1 to 7 of the valence of the metal cation, with the proviso that the sum of (a+b) must be greater than 0, and(b) a catalytically effective amount of sulfur trioxide.

Abstract: A method and reagent for the selective nitration of aromatic hydrocarbons which comprises contacting a complex of at least a catalytic amount of a polyether with a nitronium containing substance, e.g., NO.sub.2 BF.sub.4 with an aromatic hydrocarbon, e.g., toluene with at least one replaceable hydrogen. Nitration of toluene with these complexes at ambient temperature resulted in a reduction in meta substitution. In competitive studies, soluble crown ether complexes of NO.sub.2 BF.sub.4 in CH.sub.2 Cl.sub.2 nitrated toluene 45-59 times faster than they nitrated benzene.

Abstract: Fluoroalkoxysulfur fluorides of the formula ##STR1## wherein R is H, CH.sub.3, CF.sub.3, or C.sub.2 F.sub.5, and n is 1 or 2, used as fluorinating agents to replace OH groups in organic molecules with F and halocarbon solutions of lithium fluoroalkoxides.

Abstract: Aromatic compounds are nitrated in the vapor phase via a process comprising contacting the aromatic compound with a nitrating agent in the presence of a nitration promoting catalyst comprising a phosphorus-vanadium-oxygen complex.

Abstract: The invention relates to a process for the production of nitroaryl compounds which are at least monosubstituted, by nitration of aryl compounds which are at least monosubstituted, which process comprises carrying out the nitration in a two-phase system which consists of an inorganic phase consisting of sulfuric acid having a concentration of at least 80% and an organic phase consisting of an inert organic liquid in which the nitration product is almost insoluble in the presence of sulfuric acid, at a temperature in the range from -30.degree. to 100.degree. C., with nitric acid as nitrating agent.The novel process can be generally employed for aryl compounds which are at least monosubstituted. The corresponding nitroaryl compounds are obtained in high yield and isomeric purity.

Abstract: Fluoroalkoxysulfur fluorides of the formula ##STR1## wherein R is H, CH.sub.3, CF.sub.3, or C.sub.2 F.sub.5, and n is 1 or 2; their preparation by reaction of lithium fluoroalkoxides with sulfur tetrafluoride; their use as fluorinating agents to replace OH groups in organic molecules with F; and halocarbon solutions of lithium fluoroalkoxides.

Abstract: An adsorptive separation process for separating ortho or para-nitrotoluene from a feed mixture comprising the isomer to be separated and at least one other isomer of nitrotoluene, or for separating ortho and para-nitrotoluene from a mixture of all three isomers of nitrotoluene, which process comprises contacting the feed mixture with an adsorbent comprising a type X or type Y zeolite, whichever is appropriate, containing at the exchangeable cationic sites the appropriate cations, selectively adsorbing substantially all of the nitrotoluene to be separated to the substantial exclusion of the remaining isomers and thereafter recovering high-purity ortho, para or ortho and para isomers. A desorption step may be used to desorb the adsorbed isomers.

Abstract: The wash liquor resulting from the nitration of aromatic compounds is contacted with a quantity of the same aromatic compound being nitrated and the resultant solution is recycled to the nitration process.

Abstract: A process for the continuous catalytic vapor-phase mononitration of aromatic compounds, especially benzene, using as the catalyst an .alpha.-fluorosulfonic acid polymer admixed with a complement inert to the nitration reaction and dimensionally stable under the reaction conditions.

Abstract: The present invention relates to improvements in processes of preparing dinitrated .[.aromatic compounds, particularly dinitrated aniline and dinitrated substituted aniline compounds, employing relatively dilute and then more concentrated nitric acid as the nitrating agent.]. .Iadd.aniline and substituted phenol compounds in a two-step process, employing, in the first or mononitration step the spent nitric acid from the second of dinitration step. .Iaddend.