Font Size: a A A

Research On The Direct Hydroxylation Of Benzene To Phenol

Posted on:2008-07-30Degree:MasterType:Thesis
Country:ChinaCandidate:G D YuanFull Text:PDF
GTID:2121360212499293Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
Phenol is important fine chemical intermediates with high economical value. Until now the phenol production is still growing. The traditional methods of producing them always have multi-step reactions, complicated process and many by-products such as acetone and other contaminations. It is inconsistent with the strategy for sustainable development. In recent years, as a more economical route, benzene direct synthesis of phenol hydroxylation reaction aroused extensive concerns. Directly benzene oxidation synthetic phenol hydroxylation, the only step chemical reaction from raw materials can be the final product. This accords with the view point of Green Chemistry. This reaction is directly connected to the activation of C-H bond on aromatic ring, preserves a challenging topic in chemistry and attracts much attention recently.Currently, many studies on the direct synthesis of phenol, but all methods have their own shortcomings. This paper mainly focused on the catalytic reaction, preparation of the catalysts and enhancing the presented catalysts to increase the reaction rate of and the product selectivity of phenol. Selected the oxidant H2O2, the catalyst containing Fe2+, in phase-transfer catalysis conditions, studied the hydroxylation of benzene to phenol synthesis.This paper designedβ-cyclodextrin as phase-transfer catalyst oxidizing benzene direct synthesis of phenol hydroxylation reaction.β-cyclodextrin had obviously catalysis and emulsification, the appropriate dosage was 0.1 mmol. The addition of acetic acid (HAc) in reaction enhanced phase-transfer performance and emulsifying effect ofβ-cyclodextrin, improved the conversion of benzene and phenol selectivity. When benzene : acetic acid = 2 : 1 (volume ratio), the reaction result was the most desired trajectory.Used FeSO4 as main catalyst, pyrogallic acid(1, 2, 3-trihydroxybenzene) as co-catalyst catalyzing benzene oxidation synthetic phenol. In this paper, the dosage of FeSO4 and pyrogallic acid was 6mmol, the ratio of FeSO4 and pyrogallic acid was 1:1.This paper designed the experiment of using ironic acetate as catalyst synthetic phenol. The optimal conditions were discovered through using ironic acetate as catalyst. When PH=3, benzene 5mL, hydrogen peroxide 12mL,β-cyclodextrin 0.1mmol, the optimal conditions were reaction time 1.5-2h, reaction temperature 50°C, the dosage of ironic acetate 3.2mmol. Ironic acetate had more reaction actively than FeSO4.
Keywords/Search Tags:Benzene, Hydroxylation, Phenol, yield of phenol, Selectivity of phenol, Phase-transfer catalysis
PDF Full Text Request
Related items