Safe method for preparing nitropropane by vapor-phase nitration

Abstract

The invention relates to a safe method for preparing nitropropane by vapor-phase nitration, which comprises the following steps: carrying out reaction in a single-channel reactor, wherein after the reaction material propane enters a preheating pipe via a flowmeter and is mixed with pumped nitric acid in a mixing pipe, the mixed materials are sent into a reaction pipe, and the mol ratio of the propane to the nitric acid is controlled at (1-8):1; the mixed materials are subjected to nitration reaction by mass transfer and heat transfer in the reaction pipe, and the products enter a separator; and the reaction products stand in the separator until the reaction products stratify, the organic phase is separated from the water phase, and the organic phase is washed and dried to obtain the product. By using the invention, the propane and the nitric acid can be directly synthesized into various nitroparaffins under the condition of no catalyst, and the process is safe and continuous. The masstransfer and heat transfer are completed in the single channel without additional heat dissipation, thereby reducing the power consumption. The invention has the advantage of simple structure and is easy to operate. The conversion rate of the propane is higher than 20%, and the selectivity of the nitropropane is higher than 80%.

Description

technical field [0001] The invention relates to a technology for preparing nitroalkanes by gas-phase nitration of alkanes, in particular to a method for preparing nitropropane by safe gas-phase nitration in a single-channel reactor using propane and nitric acid as raw materials. Background technique [0002] Nitration of propane is an important reaction in the chemical industry, and its products include nitromethane, nitroethane, 1-nitropropane and 2-nitropropane. As important fine chemicals, nitroalkanes are the key raw materials for many high value-added pharmaceutical intermediates and chemical reagents. Nitropropane is the key raw material for the synthesis of 2-aminoisobutanol, Key raw materials for propanol, N-isopropylhydroxylamine and 4,4-dimethyloxazoline. The development of fine chemical industry is guaranteed by the progress of alkane nitration technology. [0003] Nitration of alkanes is the introduction of nitro groups to organic carbon atoms, which is a stron...

AI Technical Summary

Problems solved by technology

This process cancels the nitric acid recovery system and shortens the nitrification reaction process, but due to the need to introduce air, the reaction system may be on the edge of the explosion limit at any time, the safety is poor, and the conversion rate and selectivity of low-carbon alkanes and nitrogen oxides are low. nitric acid nitration process

[0004] The above published patents fail to completely solve the problem of nitrification safety, and the conversion rate of propane and the selectivity of nitropropane also need to be improved

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