Process for preparing nitroso sulfuric acid by recycling cyclopropylamine to produce tail gas sulfur dioxide

Abstract

The invention discloses a process for preparing nitroso sulfuric acid by recycling cyclopropylamine to produce tail gas sulfur dioxide. The steps of the process include: S01: obtaining sulfur dioxide gas from a cyclopropylamine production process; S02: sulfur dioxide gas enters a primary absorption kettle and is mixed with The primary absorption liquid in the primary absorption kettle reacts, the tail gas of the primary absorption kettle enters the secondary absorption kettle and reacts with the secondary absorption liquid in the secondary absorption kettle, and the tail gas of the secondary absorption kettle enters the tertiary absorption kettle and reacts with the secondary absorption liquid in the secondary absorption kettle. The tertiary absorption liquid reaction in the tertiary absorption kettle; wherein, the primary absorption liquid and / or the secondary absorption liquid is a mixed acid solution containing sulfuric acid, concentrated nitric acid and nitroso sulfuric acid; the tertiary absorption liquid is sulfuric acid; S03: a The crude product produced by the reaction in the first-stage absorption kettle is transferred to a thin-film evaporator for purification to obtain nitroso-sulfuric acid. It not only realizes the recovery and utilization of tail gas sulfur dioxide, but also separates tail gas absorption and crude product refining through multi-stage absorption kettles and thin film evaporators, which reduces the generation of waste gas in the production process of nitroso sulfuric acid and ensures the quality of nitroso sulfuric acid. .

Description

technical field [0001] The invention relates to a process for preparing nitroso sulfuric acid by recycling cyclopropylamine to produce tail gas sulfur dioxide, and belongs to the field of chemical production. Background technique [0002] At present, cyclopropylamine belongs to the intermediate of pharmaceutical synthesis and can be used to synthesize new antibacterial drug products, such as the synthesis of ciprofloxacin, enrofloxacin, spafloxacin and other drugs; Important intermediates of herbicides, such as cyprochlor, ciprofloxacin, etc. [0003] The general process method of domestic production of cyclopropylamine is to take γ-butyrolactone as the starting material, and finally obtain the cyclopropylamine product through the five-step reaction of ring opening, esterification, cyclization, amination and Hoffman degradation, wherein, γ- In the process of preparing 4-chlorobutyryl chloride by the first ring-opening reaction of butyrolactone, the reaction between γ-butyro...

AI Technical Summary

Problems solved by technology

In industry, a mixed solution of sulfuric acid and nitric acid is usually used to absorb sulfur dioxide gas to prepare nitrosyl sulfuric acid. The purpose is to increase the temperature to evaporate and remove the residual nitric acid and excess waste gas dissolved in the sulfuric acid solution of nitrosyl sulfuric acid, so that the temperature of the overall reaction kettle is too high, but the temperature is too high and it is easy to cause the decomposition of the nitrosyl sulfuric acid product , producing nitric acid mist, nitrogen monoxide, nitrogen dioxide, sulfur trioxide and other waste gases, not only need to carry out waste gas treatment, but also increase the cost of environmental protection, and the process is more cumbersome

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