Integrated member type methyl aromatic hydrocarbon selective oxidizing catalyst and its preparation and use

Abstract

The integrated member type catalyst for selective oxidation of methyl aromatic hydrocarbon includes carrier, adhesive and active component. The active component is attached via the adhesive onto the carrier, and the carrier is porous honeycomb ceramic material, metal screen or corrugated metal sheet. The active component has the general expression of V1PaXbAlcMdCreOn. The catalyst is superior to available one, which has environmental pollution caused by liquid phase oxidation, complete oxidation and catalyst deactivation of 'hot point' in the catalyst bed, and has high selectivity and excellent industrial application foreground.

Description

(1) Technical field [0001] The invention relates to an integral component type methyl aromatic hydrocarbon selective oxidation catalyst and its preparation and application, in particular to a catalyst for the oxidation and ammoxidation of toluene and picoline side chain methyl groups. (2) Background technology [0002] The selective oxidation of the side chains of methyl aromatic hydrocarbons is a very important step in the synthesis of fine chemical intermediates. The synthesized aromatic aldehydes, acids, nitriles, etc. can be used in textiles, pesticides, medicine, rubber, food and other fields. The industrially synthesized technical routes are mainly liquid-phase oxidation [Bo.HemantV, et al.Ind Eng Chem Prod Res Dev, 1984, 23(3): 455-458] and electrochemical oxidation [Zhu Xian et al., Journal of Shanghai University ( Natural Science Edition), 2001, 7(1): 73-76]. Although these synthetic routes are mature in technology, they will cause serious environmental problems, ...

AI Technical Summary

Problems solved by technology

But in the industrial application, there are also the following problems: ① the activity and selectivity of the catalyst need to be improved; ② the reaction is a strong exothermic reaction, the temperature of the catalyst bed is difficult to control, and the complete oxidation reaction is difficult to eliminate; ③ the catalyst is in Easy to deactivate and sinter under long-term high temperature environment

[0006] Although the fluidized bed reactor commonly used in industry [Chinese patent CN1214959] can solve the heat transfer problem of the catalyst bed, it requires higher mechanical strength of the catalyst, and the vanadium catalyst supported by the metal oxide carrier is Fragile in the bed, easy to lose active substances

When the granular catalyst undergoes a strong exothermic reaction in a fixed bed reactor, local "hot spots" will inevitably appear in the bed. Usually, the "hot spots" are sensitive to process parameters, and the most common is the local overheating of the entire catalyst bed. The axial and radial temperature difference of the bed increases, which leads to the rapid failure of the catalyst and the complete oxidation of the reaction material

In order to solve this problem, many researchers have improved the structure of the fixed-bed reactor, such as adding heat conducting sheets or other components in the catalyst bed [Chinese patent CN2415831]. Unable to solve the large temperature difference between the axial and radial directions; secondly, the catalyst is inertly diluted [such as patent US3801634, JP53-30688B, JP85485], and the catalyst is diluted with inert particles in the catalyst bed (using different dilution ratios), although this method is better The axial temperature uniformity of the catalyst bed is greatly improved, but the high temperature in the catalyst particles cannot be eliminated, and the production capacity of the device is reduced; the heat transfer of the molten salt outside the tube [patents US4256783, US3147084] is the current industry for strong exothermic The reaction technology is widely used. Although it can basically remove the heat from the part of the catalyst close to the tube wall, if the thermal conductivity of the catalyst particles themselves is not good, the particles are piled up on each other, and the high temperature inside the particles and the radial temperature gradient of the reactor cannot be eliminated.