Catalytic Oxidation of p-Cymene in the Liquid Phase

Abstract

HIS research on the liquidphase oxidations of various aromatic hydrocarbons, with no catalysts, Stephens (3) found that 100 grams of p-cymene heated to 85°C. for Í4 days with oxygen bubbling through it yielded 1.23 grams of cumie aldehyde and 0.81 gram of cumie acid. Also, he found that, when 50 grams were heated to 102-104°C ., other conditions remaining the same, 0.96 gram of p-tolylmethyl ketone as well as some cumie acid and aldehyde were formed; and finally that 50

Synthesis of Terephthalic Acid by p‐Cymene Oxidation using Oxygen: Toward a More Sustainable Production of Bio‐Polyethylene Terephthalate

“…An overview of existing studies on the heterogeneous oxidation of p ‐cymene reveals the existence of different catalyst formulations for such reactions. In 1932, Stubbs presented the aerobic liquid‐phase oxidation of p ‐cymene in the presence of a manganese dioxide catalyst to form 33 % p ‐methylacetophenone and 40 % p ‐toluic acid at 160 °C . Makgwane et al.…”

“…Although the first studies dealing with the selective oxidation of p ‐cymene began more than 80 years ago and several studies have been reported since then, no significant research progress has been achieved using heterogeneous catalysts, although many homogeneous methods have been reported . In a SABIC study, biobased TA was synthesized by first converting terpene to p ‐cymene and then oxidizing the latter by a two‐step process; a mineral acid was used in the first step, and a transition‐metal oxidant, such as a permanganate compound, was used in the second step .…”

“…The only study of the synthesis of p ‐toluic acid from p ‐cymene was reported 80 years ago, but there are no reports concerning the one‐step oxidation to TA . p ‐Cymene is classified as an alkylbenzene related to a monoterpene.…”

Liquid Phase Oxidation of p-cymene by (VO)2P2O7 and VO(PO3)2 Catalysts

“…The observed results in the present study are significantly better when compared to the previous reported by Senseman et al [31] and Serif et al [2] in the liquid phase oxidation of p-cymene. In particular, Serif et al [2] obtained the hydroperoxide content of about 19% (after 197 h) and 40% (after 35.5 h) at 60 and 80°C, respectively.…”

“…In particular, Serif et al [2] obtained the hydroperoxide content of about 19% (after 197 h) and 40% (after 35.5 h) at 60 and 80°C, respectively. More interestingly were the product distributions obtained by Senseman et al [31] where the main reaction products were found to be p-toluic acid (or p-methyl benzoic acid), formaldehyde, formic acid, terephthalic acid, CO 2 and water which was different to the products achieved in this work and by others [1,2]. Based on the results achieved in the present study of using the (VO) 2 P 2 O 7 as catalyst, a higher catalytic performance for the liquid phase oxidation of p-cymene to TCHP in terms of the process space time yield and product selectivity can be achieved by improving the kinetic rate determining step that are required for the C-H bond activation.…”