1988-89-2Relevant articles and documents
Phosphorous acid-catalyzed alkylation of phenols with alkenes
Wu, Shaofeng,Dong, Jianyu,Zhou, Dan,Wang, Wan,Liu, Long,Zhou, Yongbo
, p. 14307 - 14314 (2020/01/31)
A H3PO3-catalyzed alkylation of phenols with alkenes is achieved in a facile, efficient, and selective manner. The reaction shows a unique selectivity, i.e., excellent regioselectivity, thorough suppression of overalkylation, without alkylation of a simple phenyl ring, and can selectively provide ortho-, meta-, or para-alkylated phenol derivatives in good to excellent yields. This feature along with mild reaction conditions, sensitive functional group tolerance, and scale-up synthesis and late modification of phenolic bioactive compounds make it an ideal and practical alternative for the modification of phenols.
METHOD OF PREPARING FOR SELECTIVE DI-STYRENATED PHENOL USING ZIRCONIUM OXIDE SOLID ACID CATALYST MANUFACTURED BY BEING IMPREGNATED ZIRCONIUM HYDROXIDE IN SULFURIC ACID AQUEOUS SOLUTION
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Paragraph 0102; 0103; 0107; 0109; 0111; 0113; 0115; 0137, (2018/04/12)
The present invention relates to a selective preparation method of di-styrenated phenol represented by chemical formula 1 obtained by making a phenol compound represented by chemical formula 2 react with a styrene monomer in the presence of a zirconium oxide solid acid catalyst prepared by impregnating zirconium hydroxide with an aqueous sulfuric acid solution. In chemical formulas 1 and 2, R_1 and R_2 are each independently selected from hydrogen, a C_1-C_20 alkyl group, a C_1-C_20 alkoxyl group, a C_3-C_30 cycloalkyl group, and a C_6-C_30 aryl group. The selective preparation method according to the present invention can minimize the amount of an unreacted residual material and can dramatically increase selectivity of di-styrenated phenol by exhibiting a high reactivity in the presence of the zirconium oxide solid acid catalyst prepared by impregnating zirconium hydroxide with the aqueous sulfuric acid solution.COPYRIGHT KIPO 2018
Efficient catalyst for hydroarylation reaction of styrene with phenol to obtain high DSP selectivity in mild condition
Kim, Vicna,Ju Shin, Eun,Ahn, Hogeun,Chung, Minchul,Jung, Sunghun,Kwak, Wonbong
, p. 139 - 146 (2018/03/06)
Background: Technical mixture of styrenated phenols including mono-, di-, and tristyrenated phenol, has been commonly applied for industrial materials such as rubber or plastic stabilizer, antioxidant, and nonionic surfactant, etc. Among these styrenated phenols, di-styrenated phenol should be most effective as rubber and plastic stabilizers. Although a number of catalysts for the synthesis of styrenated phenols have been explored, researches on the synthesis of styrenated phenol generally have been focused on selective preparation of mono-styrenated phenol MSP, rather than distyrenated phenol DSP. In this paper, we have investigated the hydroarylation reaction of styrene with phenol to find the optimal catalyst, including single catalysts and mixed catalysts, to get high selectivity to DSP under mild reaction conditions. Method: Hydroarylation reactions of styrene with phenol using various single catalysts, such as inorganic acids, organic acids, Lewis acids, and metal salt catalysts, have been conducted. To optimize the reaction conditions, hydroarylation reactions of styrene with phenol employing InCl3 catalyst were carried out with a variety of styrene amount, catalyst amount, reaction time, and reaction temperature. Halogenpromoted hydroarylation reactions of styrene with phenol were investigated in the presence of NBS or I2 as a halogen source and a variety of metal halides as a Lewis acid catalyst. Br-promoted hydroarylation reactions of styrene with phenol were accomplished using InCl3 along with NBS under a variety of NBS amount and reaction temperature. To explore the scope of Br-promoted hydroarylation, the reactions of various styrene derivatives with phenol were carried out using NBS and InCl3. Results: Hydroarylation reactions of styrene with phenol using various single catalysts, such as inorganic acids, organic acids, Lewis acids, and metal salt catalysts, have been conducted. Among 19 catalysts used, best results in both high conversion of phenol and high DSP selectivity are obtained with InCl3 catalyst. Using InCl3, total yield of styrenated phenols is 98% and product selectivity MSP/DSP/ TSP is 20/65/13. When InCl3 as an optimal catalyst was applied for the hydroarylation reactions of styrene with phenol under various reaction conditions, the optimal reaction conditions for obtaining a high yield, high DSP, and low MSP are as follows: styrene/phenol = 2 molar ratio, catalyst/phenol = 0.1 molar ratio, reaction time 6 hours, reaction temperature 120°C. In the halogen-promoted hydroarylation reactions of styrene with phenol in the presence of NBS or I2 as a halogen source and various metal halides as a Lewis acid catalyst, best yield (99%) and DSP selectivity (MSP/DSP/ TSP=13/42/41) were obtained using NBS and InCl3. The optimal reaction condition for Br-promoted hydroarylation reaction was found to be phenol 1 eq., styrene 2 eq., InCl3 0.04 eq., NBS 1 eq., 4 hours reaction time, room temperature. For the reactions of various styrene derivatives with phenol using NBS and InCl3, the best DSP selectivity was observed for the CH3-substituted styrene derivative. Conclusion: We have developed hydroarylation reaction of styrene with phenol for obtaining a high yield and a high DSP selectivity even at room temperature. Using NBS as a Br source and InCl3 as a catalyst at room temperature, Br-promoted hydroarylation reaction of styrene with phenol yields good results with respect to both yield and DSP selectivity.
