Papers by Keyword: p-Cymene

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Authors: Liang Wu Bi, Qiu Ge Zhang, Zhen Dong Zhao, Da Wei Li
Abstract: The chemical oxidation of p-cymene was preliminarily studied by several oxidants. The conversion of p-cymene and selectivity of p-cymen-8-ol were both influenced by the factors such as dosage of oxidant, dosage of sulphuric acid, reaction time, reaction temperature and solvent variety. The reasonable oxidation conditions were molar ratio of p-cymene to potassium permanganate 1:3, molar ratio of sulphuric acid to potassium permanganate 0.13:1, mixture of water and acetic acid (1:1, v/v) as solvent, reaction temperature 80 °C and reaction time 9 h. The conversion of p-cymene and selectivity of p-cymen-8-ol were respectively 92.21 % and 69.65 % in the reasonable oxidation conditions. The by-products of p-cymene oxidation mainly included p-iso-propyl benzoic acid, p-isopropyl benzaldehyde and p-methyl acetophenone.
Authors: Jun He, Jing Zhang, Jun Hui Li, Zhi Rong Zhu
Abstract: The shape-selective alkylation of toluene with propylene to produce p-cymene (p-isopropyltoluene) was investigated over parent zeolites and modified zeolites. The catalytic performance was compared over ZSM-5, MOR, SAPO-11, MCM-22 and β zeolite. And, their selectivity was improved by loading of metallic oxides over zeolites, and modified β zeolite showed the highest conversion of toluene and the highest selectivity of p-cymene. Moreover, the reaction conditions were optimized over the modified β zeolite.
Authors: Liang Wu Bi, Qiu Ge Zhang, Peng Wang, Zhen Dong Zhao, Da Wei Li, Yu Xiang Chen, Dong Mei Li, Yan Gu, Jing Wang, Xian Zhang Liu
Abstract: Turpentine-based dipentene (TBDP) contains limonene 30.32 %, terpinolene 31.35 %, α-terpinene 7.55 %, γ-terpinene 6.40 % and p-cymene 12.87 %. Three Pd/C catalysts were characterized by BET, XRD, TG-DTG and atomic absorption spectrometry (AAS). The properties of the catalysts on TBDP conversion were compared. Difference of catalytic competitive reactions of TBDP by catalyst A with the change of reaction temperature was discussed in detail. The yield of p-cymene at 280-310°C was over 95.0 %. It was important to control the reaction temperature for TBDP dehydrogenation catalyzed by Pd/C catalysts. It is valuable to probe the catalytic behaviors of Pd/C catalyst on TBDP dehydrogenation for research and development of efficient preparation technology of p-cymene from TBDP.
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