ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2025
·
IF 3.5
Hongrui Zhang,Feng Xu,Xiang Zhou,Zhiquan Chen,Juncheng Jiang,Gang Fu,Lei Ni
The oxidation of diphenyl sulfide (DPS) by hydrogen peroxide (H2O2) to synthesize diphenyl sulfoxide (DPSO) is extremely exothermic and has a high thermal risk. When thermal runaway happens, it may lead to equipment damage or even explosions. Therefore, in this work, a microreactor was adopted to reduce reaction thermal risk and process conditions were optimized. Phosphotungstic acid (PTA) was used as the catalyst, and the effects of process conditions, including reaction temperature, residence time, catalyst concentration, and molar ratio on the conversion and yield were systematically investigated. The results showed that the DPSO yield could reach up to 84.3% under the condition of 0.75% catalyst loading, 25 min residence time, 70 °C reaction temperature, and H2O2–DPS molar ratio of 2. Then, apparent reaction kinetics were studied, and a kinetic model was established and validated. By varying the initial concentrations of H2O2 and DPS, the reaction was determined to be of second-order, with an activation energy of 57.5 kJ·mol–1 and a pre-exponential factor of 2.96 × 107 mol–1·L·min–1. Furthermore, the temperature distribution along the microreactor was estimated by combining the thermal equilibrium with the reaction kinetics. The results indicated that in a 1/16 in. microreactor, the reaction was nearly isothermal. Temperature distributions were also predicted for microreactors with different diameters and materials. It was demonstrated that the reaction could be safely scaled up to a 3/8 in. microreactor at a reaction temperature of 55 °C, with the maximum temperature rise remaining below 5 °C and no decline in DPSO yield. This study provided a convenient method to guide the safe sizing-up of the reaction in flow reactors.
研究领域:
化学工程
·
反应动力学
✓ 已验证
产品关联
DOI
高影响因子
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
·
2016
·
IF 2.226
Xiaoji Cao,Chenlu Wang,Weimin Mo
Rationale Aryl thioethers are potentially useful precursors for constructing various biologically active sulfur-containing heterocycles. The detailed relationship between the losses of HS radical and CS with the spin multiplicity of positively charged diphenyl sulfide biradicals derived from 3-iodophenyl phenyl sulfides has not been obtained by tandem mass spectrometry combined with theoretical calculations. Methods Collision-induced dissociation mass spectrometry experiments were carried out using an ion trap mass spectrometer with APCI in positive mode. The MS/MS experiment for dibenzothiophene was performed by CI triple-quadrupole mass spectrometry in positive ion mode. The accurate masses of fragments were obtained by reflective TOFMS with an EI source. Theoretical calculations were achieved by the density functional theory method at the B3LYP level with the 6−31+G(d, p) basis set in the Gaussian 03 package of programs. Results In the fragmentation of positively charged diphenyl sulfide biradicals, losses of HS· and CS were observed, which were proposed to originate from spin multiplicity transformation from a triplet ground state to a singlet excited state and a phenyl radical shift in triplet ground state, respectively. Moreover, a protonated dibenzothiophene intermediate was confirmed to exist in the process of HS radical loss. A linear correlation was established between the product ion abundance from the two competitive losses and the Hammett constants (σ) of substituent groups on the benzene ring. Conclusions The eliminations of HS· and CS in the fragmentation of positively charged diphenyl sulfide biradicals were triggered by spin multiplicity transformation from a triplet ground state to a singlet excited state and a phenyl radical shift in a triplet ground state, respectively. Based on theoretical calculations, two competitive neutral losses are thermodynamically controlled. Copyright © 2016 John Wiley & Sons, Ltd.
研究领域:
分析化学
·
理论计算化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Jiali Ge,Xinghao Wang,Chenguang Li,Siyuan Wang,Lianhong Wang,Ruijuan Qu,Zunyao Wang
Polychlorinated diphenyl sulfides (PCDPSs) are a group of dioxin-like compounds that have been widely used in agricultural and industrial productions. Here, we systematically investigated the photochemical behaviors of 2,2′,3′,4,5-pentachlorodiphenyl sulfide (2,2′,3′,4,5-PCDPS) on the surface of silica gel (SG) in an aqueous environment. Under the simulated sunlight irradiation, 2,2′,3′,4,5-PCDPS adsorbed on SG (0.11 mg/g) was found to be degraded with time, giving a removal rate of 68.5% within 16 h at pH 7.0. Environmental factors like pH and humic acid can also affect the removal rate. Results showed that the removal rate of 2,2′,3′,4,5-PCDPS in alkaline conditions (75.6% at pH 11) was higher than that in acidic conditions (46.7% at pH 3). Moreover, the addition of (1–5 mg/L) humic acid can promote the degradation rate compared to control group. In our study, it was found that SG can act as photocatalyst to generate reactive oxygen species (ROS) for the degradation of PCDPSs, and UV light contributed much more than visible light (>420 nm). According to electron paramagnetic resonance (EPR) technology and radicals quenching experiments, hydroxyl radical ( OH), single oxygen ( 1 O 2 ), and superoxide radical ( O 2 − ) participated in the removal of the contaminant. Based on the identified intermediate products via LC–MS, two main pathways, i.e., the hydroxyl-substituted reaction of the benzene ring and the oxidation of the sulfur atom, were proposed for the photodegradation of 2,2′,3′,4,5-PCDPS. Then, the density functional theory (DFT) was employed to confirm these reaction pathways. This study would enhance the understanding of the photochemical transformation and environmental fate of PCDPSs on the surface of solids in natural waters.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）