ACS Sustainable Chemistry & Engineering
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2024
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IF 7.1
Xiang Hui,Liguo Wang,Jianhui Shi,Tiping Wei,Fengqin Guo,Yan Cao,Peng He,Jiajun Zhang,Huiquan Li
The methoxycarbonylation of amines into carbamates via the construction of a C–N bond is an important reaction in pharmaceutical and fine chemical syntheses. However, the methoxycarbonylation of amines with dimethyl carbonate (DMC) without metal-based catalysts or other base catalysts has rarely been studied, and the reaction mechanisms remain underexplored. Herein, efficient methoxycarbonylation of biobased pentanediamine (PDA) with DMC promoted by water is proposed. The addition of water as a catalyst resulted in a 4-fold increase in yield. The conducted kinetic studies showed that proton transfer from PDA to methoxy occurs through the hydrogen bond between the zwitterionic intermediate and water. In situ analyses have shown that OH– and water form hydrogen bonds with the ether O atom of DMC and hydroxyl H atoms of PDA, synergistically promoting the elimination of the methoxy group. The addition of water reduced the energy barrier of the methoxy group elimination from 16.3 to 0.6 kcal/mol, confirming the results of theoretical computations. Furthermore, the methyl (5-aminophenyl)carbamate intermediate was recycled into dimethyl pentane-1,5-diyldicarbamate without the use of an additional catalyst, which was mediated by the hydrogen bond between PDA and methyl (5-aminophenyl)carbamate. The reported mild methoxycarbonylation of biobased PDA under metal-free conditions is a green and sustainable method of synthesizing biobased dicarbamate.
研究领域:
有机化学
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绿色化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2024
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IF 4.1
Jianqi Tang,Yunhan Bai,Yucong Song,Xiaoshu Ding,Guirong Wang,Yanji Wang
The solubilities of methyl furan-2,5-dimethylenedicarbamate (FDC) and methyl tetrahydrofuran-2,5-dimethylenedicarbamate (THFDC) in dimethyl carbonate (DMC), anhydrous ethanol (EtOH) and benzene were studied using the static equilibrium method combined with high-performance liquid chromatography under atmospheric pressure at temperatures ranging from 278.15 K to 318.15 K. The experimental results demonstrate that the solubility of FDC and THFDC exhibits an upward trend as temperature increases. Among the six correlation models used, all of them (modified Apelblat equation, Buchowski-ksiazczak (λh) model, simplified two-parameter equation, polynomial equation, NRTL model and Wilson model) can effectively correlate the solubility data. Notably, the Wilson model demonstrates superior correlation performance compared to others in FDC system and the NRTL model demonstrates superior correlation performance compared to others in THFDC system. Using the modified Van’t Hoff equation and Gibbs equation, we calculated the apparent standard dissolution enthalpy ( Δ H sol ), the standard dissolution entropy change ( Δ S sol ), and the standard dissolution Gibbs energy ( Δ G sol ) for FDC and THFDC in different solvents. The research resulted indicate that all these dissolution processes are non-spontaneous, entropy-increasing endothermic processes. This study provides valuable reference data for crystallization and purification in industrial production.
研究领域:
化学工程
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物理化学
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DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 9
·2282-2290
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IF 5.726
Dawei Zhou,Peixue Wang,Yan Long,Yuqing Fei,Youquan Deng
The thermal cracking behavior of diethyl hexamethylenedicarbamate (EHDC) was investigated in this work. The polymers formed under different conditions were analyzed by IR and TG, indicating that the polymers were mixtures of EHDC, polyureas, imines and others. The polymers could be converted to EHDC by a simple alcoholysis reaction for the first time over Fe–Ni/Al2O3 catalysts. Under the optimized reaction conditions, the yield of EHDC could reach up to 52% with 99% selectivity over 8% Fe–3% Ni/Al2O3 catalysts. The catalysts were extensively characterized by BET, XPS, XRD, SEM, TEM, H2-TPR and NH3-TPD, showing that the interaction effect between Fe species and Ni species may be attributed to high catalytic performance of the catalyst. Meanwhile, the loss of active components resulted in decreased catalytic activity.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
GREEN CHEMISTRY
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2024
·Vol. 26
·期 23
·11636-11649
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IF 9.3
Yunhan Bai,Dule Huhe,Xinyu Du,Yucong Song,Xiaoshu Ding,Dongsheng Zhang,Xinqiang Zhao,Yanji Wang
The synthesis of polyurethane from renewable biomass is crucial for pursuing a sustainable future and a bio-based economy. The traditional production process of hexamethylene-1,6-diisocyanate (HDI) involves highly toxic phosgene, environmental pollution, and unsustainable raw materials. This work proposes a new green and intrinsically safe method for synthesizing HDI. The biomass-based platform molecule 5-hydroxymethylfurfural (5-HMF) is used as the raw material to synthesize HDI through 2,5-bis(aminomethyl)furan (BAF), methyl furan-2,5-dimethylene dicarbamate (FDC), and hexamethylene-1,6-dicarbamate (HDC). This approach opens a new pathway for preparing HDI using sustainable raw materials. Among them, the efficient ring-opening and deoxidation of FDC while retaining methyl carbamate functional groups is attractive and extremely challenging. In this work, we report the process of selectively converting FDC to HDC and screen the active metals, supports, metal loadings of the catalyst, and solvents. In the H2O-ethanol system, the conversion of FDC over 7 wt% Pt/Nb2O5 was higher than 99.9%, and the yields of 2-hydroxy-hexamethylene-1,6-dicarbamate (HHDC) and HDC were 61.0% and 12.5%, respectively. The structure–activity relationship of supported platinum-based catalysts was studied. In addition, it was found that H2O can significantly promote the formation of HDC. The catalytic reaction path and mechanism of the reaction were proposed by combining experiments with DFT theoretical calculations.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2024
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IF 3.7
Yaqi Qu,Xiang Li,Hualiang An,Xinqiang Zhao,Yanji Wang
The selective hydrogenation of dimethyl toluene-2,4-dicarbamate (TDC) to methyl cyclohexyl-2,4-dicarbamate (also called hydrogenated TDC, HTDC) is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-diisocyanate. Herein, we prepared a series of supported Rh-based catalysts by the excessive impregnation method and investigated their catalytic performance for the selective hydrogenation of TDC. The emphasis was put on the influence of support properties on the catalytic performance. Among the prepared catalysts, Rh/γ-Al 2 O 3 performed the best: a HTDC yield of 88.4% was achieved with a 100% conversion of TDC under the conditions of 100 °C, 3 MPa and 1 h. Furthermore, Rh/γ-Al 2 O 3 could be repetitively used for 4 times without a significant loss of its catalytic activity. TEM, XRD, N 2 adsorption-desorption, H 2 -TPR, NH 3 /CO 2 -TPD, XPS and ICP characterizations were employed to distinguish the properties of the prepared catalysts and the results were correlated with their catalytic performance. It is indicated that the yield of HTDC shows a positive relevance with the percentage of moderate-to-strong acid sites and the content of Rh n + ( n ≥3) in the catalysts. High values of the percentage and the content can promote a strong interaction between Rh nanoparticles and the supports, facilitating both the transfer of electrons from Rh to the support and the formation of Rh n + species. This is conducive to activating the benzene ring of TDC and thereby improving the yield of HTDC.
研究领域:
催化
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化学工程
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材料科学
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产品关联
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
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2017
·Vol. 43
·期 12
·6951-6972
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IF 1.369
Ammar Muhammad,Cao Yan,Wang Liguo,He Peng,Li Huiquan
Synthesis of HDC by methoxycarbonylation of HDA with DMC was carried out over the bulk and hybrid heteropoly acid (HPA) catalyst. The catalysts were systematically characterized by XRD, FTIR, SEM and NH 3 -TPD techniques. The by-products produced in the reaction were identified and a possible reaction pathway was proposed based on the by-products analysis. The performances of bulk and hybrid HPA catalysts were evaluated. The H 4 [SiW 12 O 40 ] catalyst revealed high performance compared with other catalysts and its high performance was attributed to its acidic properties. Effects of reaction parameters and reusability of the H 4 [SiW 12 O 40 ] catalyst were also investigated. Under the optimized reaction conditions, HDA conversion reached 93.2% with 64.8% HDC selectivity and only 3.8% by-product selectivity. Moreover, a possible reaction mechanism was proposed for the synthesis of HDC over H 4 [SiW 12 O 40 ] catalyst.
研究领域:
化学工程
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2019
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IF 6.97
Kirill A. Alferov,Zhongwei Fu,Shuxian Ye,Dongmei Han,Shuanjin Wang,Min Xiao,Yuezhong Meng
A new one-pot synthesis method of dimethyl hexane-1,6-diyldicarbamate (HDC), a potential intermediate compound in the synthesis of polyurethanes, from CO2, methanol, and 1,6-hexanediamine (HDA) is disclosed. The starting materials are renewable, stable, easily available, and cheap. The process was implemented in 1-methyl-2-pyrrolidinone (NMP) solvent over CeO2 catalysts. Three different CeO2 catalysts (commercial nanospheres, CeO2(c) obtained by direct calcination of (NH4)2Ce(NO3)6, and CeO2 nanorods) were tested in this reaction and their micromorphology and physical–chemical properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and N2 adsorption. CeO2 nanorods proved to be the most active catalytic material. The influence of different parameters on reaction outcome was studied. The yield of HDC was about 80% under optimized reaction conditions. Experiments for better understanding of reaction mechanism were also performed.
研究领域:
化学工程
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催化
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材料科学
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有机化学
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可持续化学
✓ 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）