Method for nitrifying paradichlorobenzene by using solid acid catalyst

Abstract

The invention relates to a method for nitrifying paradichlorobenzene by using a solid acid catalyst, which comprises the following steps: (1) preparing a 0.3 mol / L zirconium oxychloride solution with a teflon beaker in a fuming cupboard, adding a proper amount of HF, sufficiently stirring until the HF is completely dissolved, and transferring into a constant-pressure dropping funnel for later use; (2) preparing a 1.0 mol / L phenylphosphonic acid solution in the fuming cupboard; (3) slowly and dropwisely adding the zirconium oxychloride solution into the phenylphosphonic acid solution, and keeping the temperature; (4) after keeping the temperature, carrying out vacuum filtration, continuing carrying out water washing and vacuum filtration on the obtained solid until the Cl<-> concentration of the last filtrate is constant, and drying the finally obtained filter residue in a drying oven; (5) taking 1 mol of paradichlorobenzene, heating at 70 DEG C until the paradichlorobenzene is completely molten, and adding 1-3g of solid acid catalyst; and (6) slowly and dropwisely adding 1.1 mol of fuming nitric acid, and reacting. The method has the advantages of less liquid waste discharge and recyclable solid acid, and implements resource regeneration; and the conversion rate of chlorinated aromatics is up to 99% or above.

Description

technical field [0001] The invention relates to a method for catalyzing the nitration of chlorinated aromatic hydrocarbons with a solid acid, in particular to a method for catalyzing the nitration of p-dichlorobenzene with a solid acid. Background technique [0002] Solid superacids have many important catalytic properties due to their special crystal phase structure, surface characteristics and high specific surface area, and some metal oxides obtained by special treatment (such as ZrO 2 、TiO 2 , Fe 2 o 3 etc.) load SO 4 2- Afterwards, it can become a solid superacid. [0003] About SO 4 2- / ZrO 2 There are many research and application reports on the series of solid superacids, Xia Yongde et al reported (NH 4 ) 2 S 2 o 8 impregnated amorphous Zr(OH) 4 Can prepare super acidic and catalytic activity than SO 4 2- / ZrO 2 Stronger New Solid Superacid S 2 o 8 2- / ZrO 2 . [0004] At present, the production of 2,5-dichloronitrobenzene at home and abroad is t...

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Problems solved by technology

[0004] At present, the production of 2,5-dichloronitrobenzene at home and abroad is the use of nitric acid or the mixed acid method composed of nitric acid and sulfuric acid, but the reaction system is very corrosive to the equipment, and a large amount of waste acid and waste water containing organic compounds are produced, which pollutes the environment. Serious, high cost of treatment; In addition, the selectivity of this method is poor, there are many side reactions such as oxidation, hydrolysis, hydroxylation, etc., and it is difficult to recycle the waste acid, and the product purity is not high

[0005] The traditional reaction system adopts the mixed acid method composed of dropping concentrated sulfuric acid or nitric acid and sulfuric acid, and the stirring reaction time is long by using a stirred tank, the reaction is incomplete, and the yield is low

[0006] Aiming at the problems of serious equipment corrosion, environmental pollution and low selectivity of p-dichlorobenzene in the traditional mixed acid nitration method used in industry, the nitration of various solid acids and acidic ionic liquids for p-dichlorobenzene was discussed respectively. catalytic effect