Method for preparing aminostyrene through catalytic hydrogenation of nitrostyrene

Abstract

The invention relates to a method for preparing aminostyrene through catalytic hydrogenation of nitrostyrene. According to the method, in environment-friendly solvents H2O, ethanol, n-heptane, H2O-ethanol or H2O-n-heptane, nitrostyrene is catalyzed by Pt / SnO2-Sb2O3 serving as a catalyst to have hydrogenation reaction at 35-120 DEG C to prepare aminostyrene. Pt / SnO2-Sb2O3 has high selectivity in generation of aminostyrene; in H2O, ethanol and n-heptane, the selectivity for aminostyrene is respectively greater than 97%, greater than 95% and greater than 96%; the reaction rate in H2O is highest and the yield of aminostyrene is greater than 97%; no accumulation of harmful intermediates such as phenyl hydroxylamine is generated in the reaction process; since Pt / SnO2-Sb2O3 almost has no catalytic activity for hydrogenation of aminostyrene, the yield of aminostyrene does not decrease when time goes by after the reactants are completely converted.

Description

technical field [0001] The invention relates to a method for preparing aminostyrene by catalytic hydrogenation of nitrostyrene. Specifically related to Pt / SnO 2 -Sb 2 o 3 As a catalyst, in the green solvent H 2 O, ethanol, n-heptane, H 2 O-ethanol or H 2 In the O-n-heptane system, the method for preparing aminostyrene by catalyzing the selective hydrogenation of nitrostyrene. Background technique [0002] Aminostyrene is a kind of aromatic amine compounds, and it is an intermediate for the production of important chemical products such as medicines, stabilizers, fungicides, insecticides, and herbicides. [0003] Catalytic hydrogenation of nitrostyrene is an effective method for preparing aminostyrene. In nitrostyrene molecules, both nitro and vinyl groups are easily reduced by hydrogenation. The development of a catalyst with high activity for hydrogenation of nitrogroups and low activity for hydrogenation of vinyl groups is an important way to improve the efficiency ...

AI Technical Summary

Problems solved by technology

The disadvantage of this catalyst is that during the hydrogenation reaction, sulfur-containing by-products are produced, which reduces product quality and limits the reuse of solvents

[0004] At present, there are the following main problems in the preparation of aminostyrene by hydrogenation: (1) The reaction is mostly carried out in toxic, harmful and volatile organic solvents such as toluene and tetrahydrofuran

(2) The CoS mentioned above 3 、Co 3 o 4 , Fe 2 o 3 As well as catalysts such as Au and Ag, the activity is low, and the reaction requires a higher temperature (110-160°C) and a longer time

(3) The method disclosed in WO2009071727, which uses the strong interaction between the metal and the support produced by high-temperature reduction to modify the metal center, has the following disadvantages: after high-temperature reduction, the activity of the catalyst decreases significantly; in addition, the metal loading is low, if Increasing the metal loading will lead to a significant decrease in catalyst selectivity

(4) The above-mentioned catalysts such as Au and Ag are active for the hydrogenation of aminostyrene C=C bonds. Therefore, after the reactant is completely converted, the reaction time is continued to be extended, and the generated aminostyrene will be further hydrogenated, resulting in its The yield is reduced, which increases the difficulty of controlling the reaction in production ((Shimizu, Miyamoto et al., J. Catal., 2010), (Shimizu, Miyamoto et al., J. Phys. Chem. C, 2009))