89-58-7Relevant articles and documents
One-pot process for preparing acetic acid -2, 5 -dimethylphenyl ester and 2,5 -dimethylnitrobenzene (by machine translation)
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Paragraph 0021-0041; 0046, (2020/06/16)
The method comprises the following steps of: adding acetic anhydride in a single-mouth flask; adding additional p-xylene; adding the reaction solution obtained in Step III to a separatory funnel; stirring the reaction; cooling to room temperature; and quenching the reaction solution obtained in the step three steps: adding deionized water, stirring the reaction and cooling to room temperature; and quenching the reaction solution in step three steps: adding deionized water, stirring the reaction and cooling to room temperature; and thirdly, distilling the reaction solution obtained in the step three steps into dichloromethane to volatilize to obtain a product, namely acetic acid -2 -2, 5 - 5 -dimethylphenyl ester 2,5 - and 2,5 -dimethylnitrobenzene. To the method, nitrate is used as an oxidant and a nitrate agent, the price is low,2-dimethylnitrobenzene can be obtained while the acetic acid 5 - and 2,5 -dimethylphenyl ester are obtained, two products can be obtained through one-step reaction, and the utilization rate of the raw material is improved. (by machine translation)
Hydrophobic WO3/SiO2 catalyst for the nitration of aromatics in liquid phase
Kulal,Kasabe,Jadhav,Dongare,Umbarkar
, p. 105 - 113 (2019/02/15)
WO3/SiO2 solid acid catalyst synthesized using sol gel method has shown promising activity (up to 65% conversion) for aromatic nitration in liquid phase using commercial nitric acid (70%) as nitrating agent without using any sulfuric acid. The water formed during the reaction as well as water from dilute nitric acid (70%) was removed azeotropically, however due to the hydrophilic nature of the catalyst, some water gets strongly adsorbed on catalyst surface forming a barrier layer between catalyst and organics. This prevents effective adsorption of substrate on catalyst surface for its subsequent reaction. To improve the activity further, the hydrophilic/hydrophobic nature of the catalyst was altered by post modification by grafting with commercial short chain organosilane (Dynasylan 9896). The modified 20% WO3/SiO2 catalyst when used for o-xylene nitration in liquid phase, showed significant increase in the conversion from 65% to 80% under identical reaction conditions. Catalyst characterization revealed decrease in the surface area of 20% WO3/SiO2 from 356 m2/g to 302 m2/g after grafting with Dynasylan 9896. The fine dispersion of WO3 particles (2–5 nm) on silica support was not affected due to modification. NMR and FTIR study revealed the decrease in surface hydroxyl groups imparting hydrophobicity to the catalyst. Interestingly the total acidic sites of the catalyst remained almost unaltered (0.54 mmol NH3/g) even after modification. Even though, the acidity and other characteristics of the catalyst did not change appreciably, there was a considerable increase in the o-xylene conversion which can be ascribed to the hydrophobic nature of the catalyst.
HNO3/HFIP: A Nitrating System for Arenes with Direct Observation of π-Complex Intermediates
Lu, Le,Liu, Huixin,Hua, Ruimao
supporting information, p. 3197 - 3201 (2018/06/11)
This report describes an efficient nitrating system for the nitration of arenes at room temperature by using an equivalent of nitric acid in HFIP (1,1,1,3,3,3-hexafluoroisopropanol). The π-complex intermediate of an arene with a nitronium ion stabilized by HFIP can be directly observed by UV-vis spectra and is supported by theoretical calculations.
