INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Songyuan Sun,Haomiao Xu,Yurui Fan,Zhisong Liu,Qinyuan Hong,Wenjun Huang,Zan Qu,Naiqiang Yan
The polyvinylchloride industry is an important mercury emission source derived from the decomposition of commercial activated carbon-supported mercuric chloride (HgCl2/AC, with 12–15 wt % HgCl2) in acetylene hydrochlorination. Our results indicated that the loss of mercury was ascribed to the Hg–Cl bond breaking from the HgCl2 molecule at elevated temperatures that resulted in slip Hg0 in the exhausted gas. Herein, we employed a novel strategy that uses chalcogen bonding (ChB, e.g., S-, Se-, and Te-) interactions to anchor HgCl2 molecules, to improve the thermal stability and catalytic performances. The mercury desorption temperature reached approximately 300 °C, which is much higher than the optimum hydrochlorination reaction temperature. Notably, low-mercury catalysts (5 wt % HgCl2) guaranteed high catalytic performances, and Se–HgCl2/AC exhibited 83% acetylene conversion efficiency and near-perfect 100% selectivity. Moreover, the online mercury monitoring results showed that Se–ChB significantly inhibited the escape of mercury during the reaction. Density functional theory results confirmed that the reaction followed an Eley–Rideal (E–R) mechanism, which showed that the strong adsorption of HCl endowed the catalyst with superior durability and facilitated the reaction by reducing the energy barrier from 0.94 to 0.54 eV. Thus, the new strategy for highly stable low-mercury catalyst preparation can solve the problem of mercury contamination and enhance the productivity of PVC production.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Xianliang Qiao,Chaoyue Zhao,Zhiqiang Zhou,Qingxin Guan,Wei Li
N-doped carbon material is a promising alternative to mercury catalyst for acetylene hydrochlorination. Herein, we present an innovative strategy to synthesize pyridinic N-rich aromatic ladder structure material through controlling the self-assembly of polyacrylonitrile polymer chains. The prepared material gave ∼93% conversion of acetylene with >99% selectivity for vinyl chloride and exhibited a satisfying stability during 200 h lifetime test. Characterizations and density functional theory calculations demonstrated that the activity of the catalyst likely originates from three types of active pyridinic N sites in the ladder structure. Particularly, the pyridinic N sites with one H atom nearby are more active because the H atom can stabilize the transition state through H···Cl bond, thereby reducing the energy barrier. The energy barriers on these pyridinic N sites were calculated to be 29.8 and 47.4 kcal mol–1, much lower than 83.2 and 84.4 kcal mol–1 on those sites without H atom nearby. The facile and highly effective strategy for the synthesis of a specific N species with defined formation mechanism is expected to be helpful in the design of other green catalysts for acetylene hydrochlorination.
研究领域:
材料科学
·
催化化学
·
理论计算化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Xingzong Dong,Guangye Liu,Zhaoan Chen,Quan Zhang,Yunpeng Xu,Zhongmin Liu
An original nonmetallic mercury-free catalyst for the production of vinyl chloride monomer (VCM) by acetylene hydrochlorination was studied in this work. It was first found that a nitrogen-containing diheterocycle, 1,8-diazabicyclo[5.4.0]undec-7-ene hydrochloride ([DBU][Cl]), displayed excellent catalytic performance in acetylene hydrochlorination. The 20%[DBU][Cl]/AC catalyst exhibited an acetylene conversion of 86.7% and a selectivity to VCM of 99.2%, and the deactivation rate was only 0.033 %/h during the 200 h lifetime evaluation under the conditions of a bed temperature of 240 °C, GHSV(C 2 H 2 ) of 30 h −1 and V(HCl)/V(C 2 H 2 ) of 1.2. TPD characterizations and intermittent flow experiments revealed that the 20%[DBU][Cl]/AC catalyst has a larger HCl adsorption capacity and smaller VCM adsorption capacity, which may be one of the reasons for the good catalytic activity and stability. The catalytic mechanism over [DBU][Cl] was proposed based on DFT calculations.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 41
·19358-19363
·
IF 3.591
Xin Jin,Yalei Hao,Chengxiang Liu,Hongbin Feng,Xingyun Li,Yan Zhu,Yuxin Zhou,Yujiang Song,Jiapeng Hu
The development of advanced carbon materials as metal-free catalysts holds great importance for mercury catalyst replacement in acetylene hydrochlorination. In this paper, we transform discarded cigarette butts into a porous nitrogen-doped carbon material (N-CB-800), exhibiting characteristics of high specific surface area, large N doping amount, defective structure and strong C2H2 chemical adsorption ability. These unique features endow N-CB-800 with a high catalytic performance with an acetylene conversion of 71.8% at 220 °C and an acetylene space velocity of 100 h−1, making it one of the most active metal-free catalysts. This work will be of great value for the recycling of living waste and provide meaningful guidance for the development of non-mercury catalysts for acetylene hydrochlorination.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）