Nitration Of Phenols Catalyzed By Mimetic Enzymatic And Green Synthesis Process Of 1,3,5-Trimethoxybenzene

Nitrophenols are important fine chemical intermediates. However, Chemical nitration of phenols can result in seeious pollution. With the increasingly serious global environment issues, development of green nitration technology has become more and more important. Enzymatic methods have become increasingly important in nitration of phenolic compounds, which were well known for their ability to catalytic chemical reactions with high efficiency and selectivity under mild reaction conditions. However, enzyme is sensitive to heat, poor lability, and few sources that limited its application. Herein, we have designed a class of stable and easy to synthesis of metalloporphyrins, which were used as mimetic enzymatic in nitration of phenolic compounds. A series of metalloporphyrins were designed and synthesized:Metal-tetrakis (p-carboxyphenyl) porphyrin (M-TCPP) and Metal-tetrakis (p-sulfophenyl) porphyrin (M-TSPP). The structural traits and spectral properties of metalloporphyrins have been discussed by Uv-vis, FT-IR and 1H NMR spectroscopic methods. The catalytic performance of metalloporphyrins to nitration of phenolic compounds were investigated under the H2O2/NO2- reagent system. Among the catalyst studied, iron porphyrins performed best catalytic in nitration of phenol. The results showed the optimal reaction temperature was room temperature, the optimal pH was 7, the optimal reaction time was 80 min, the optimal catalyst weight was 0.05?0.06g/mmol phenol, the optimal feeding mole ratio was H2O2:phenol= 50?60:3:1. Under these conditions, the yield of nitrophenol was 55%, the 2-nitrophenol/4-nitrophenol mole ratio wasl:1. The catalytic performance of iron porphyrin to nitration of p-cresol, resorcinol and phloroglucinol were investigated under the best reaction conditions, the results showed that the yield of nitrophenol could increase ten time, comparing with the reaction with out catalyst. Iron porphyrins has shown the best catalytic activity in the nitration of phenolic compounds as mimetic enzymatic.1,3,5-Trimethoxybenzene (TMB) are important fine chemical intermediates. At present, TMB was synthesized by phloroglucinol (PG) reacting highly toxic compounds with as methylating agent,such as dimethyl suifate and methyl iodide. Herein,1,3,5-Trimethoxybenzene (TMB) was synthesized by phloroglucinol (PG) reacting with dimethyl carbonate (DMC) as green methylating agent in this study. Among various catalyst systems tested, K2CO3/(Bu)4NBr was the most effective catalyst for the O-methylation of PG Some experiments of single factor test and orthogonal test were conducted to confirm the best reaction conditions by altering reaction temperature, DMC dosage, (Bu)4NBr dosage and K2CO3 dosage. The results showed that the influence degree was reaction temperature> DMC dosage>(Bu)4NBr dosage> KaCO3dosage.The optimal reaction temperature was 160? and the optimal feeding molar ratio was DMC:(Bu)4NBr:K2CO3:PG=12:0.15:1.5:1. Under these conditions, the yield of TMB was 76.0%. The process was environmentally friendly and easy to operate, easy to control the process, with good application prospect. The process has overcomed the traditional craft toxicity and environmental pollution.