- Single step hydrogenation of nitrobenzene to p-aminophenol
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The present invention provides a single step process for the preparation of p-aminophenol by hydrogenation of nitrobenzene in presence of an aqueous acid over a mono or bimetallic nickel catalyst at a temperature in the range of 80-120° C. for a period of 1 to 4 hrs. The resulting reaction mixture is extracted with an organic solvent like ethyl acetate, cyclohexane or toluene to separate the aqueous layer containing PAP and neutralizing it with ammonia solution to recover the solid p-aminophenol.
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- Single step hydrogenation of nitrobenzene to p-aminophenol
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The present invention provides a single step process for the preparation of p-aminophenol by hydrogenation of nitrobenzene in presence of an aqueous acid over a mono or bimetallic catalyst at a temperature in the range of 80-120°C for a period of 1 to 4 hrs. The resulting reaction mixture is extracted with toluene to separate the aqueous layer containing PAP and neutralising it stepwise with ammonia solution to recover the solid p-aminophenol.
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- Single step process for the preparation of p-aminophenol
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The present invention provides a single step process for the preparation of p-aminophenol by contacting a mixture of nitrobenzene and water with hydrogen over a solid acid catalyst, terminating the reaction to obtain a reaction mixture containing the product, extracting the reaction mixture with an organic solvent, separating the aqueous layer containing the product, and then concentrating the aqueous layer by any conventional method to obtain the product.
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- Method for eliminating wrinkling in composite color-plus-clear coatings, and compositions for use therein
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The curable coating composition of the invention comprises a film forming component (A) and a wrinkle reducing catalyst (B) comprising a compound of the formula: EQU My (L)x PAL wherein M is a metal having an empty or full d orbital and wherein the pka of the aqua ion of M is less than or equal to 12; L is a ligand wherein the pka of the parent acid is -10 and is 4; and x is an integer which is a multiple of the charge of M, y is an interger which is a multiple of the charge of L, x and y selected so that ML is charge balanced. Film forming component (A) has first component (a) with a compound having appended thereto at least one carbamate or urea functional group, or a group convertible to a carbamate or urea group, and a second component (b) with a compound reactive with said carbamate or urea groups on component (a). The method of the invention requires applying a first coating to a substrate; applying a second coating to the first coating to provide a composite coating, the second coating comprising the composition of the invention, and curing the composite coating.
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- Para-aminophenol derivatives
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A process for the preparation of diaryl para-phenylenediamines from a crude para-aminophenol solution such as obtained by the catalytic hydrogenation of nitrobenzene in an aqueous acid reaction medium. The process comprises contacting the para-aminophenol containing acidic solution, after neutralization with ammonia, with an aromatic amine selected from the group consisting of aniline, mixed toluidines, ortho-toluidine, mixed xylidines, and mixtures thereof under conditions whereby the aromatic amine extracts the para-aminophenol from the crude feed solution and is separated therefrom. The separated solution comprised essentially of the aromatic amine extractant, para-aminophenol, and minor amounts of impurities is then contacted with an alkylation catalyst to produce the diaryl para-phenylenediamines.
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