Preparation of propylene carbonate by alcoholysis of urea from the perspective of homogeneous reaction: Influence of dissolution and precipitation of metal oxide catalysts

Yang, Fei; Shen, Weihua; Fang, Yue

doi:10.1002/cjce.24680

Cited by 2 publications

(2 citation statements)

References 27 publications

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“…Thus, a relationship was established between the PC yield and the basicity. MgCa1CN was found to have the highest basicity, proving that basicity has a direct effect on the catalytic activity and, thus, on the yield of PC [ 38 ].…”

Section: Resultsmentioning

confidence: 99%

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

et al. 2023

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A series of calcium oxide–magnesium oxide (CaO–MgO) catalysts were prepared under the effects of different precipitating agents and using varied Mg/Ca ratios. The physiochemical characteristics of the prepared catalysts were analyzed using XRD, FE-SEM, BET, FTIR, and TG/DTA techniques. Quantification of basic active sites present on the surface of the CaO–MgO catalysts was carried out using the Hammett indicator method. The as-prepared mixed oxide samples were tested for propylene carbonate (PC) synthesis through the alcoholysis of urea with propylene glycol (PG). The effects of the catalyst composition, catalyst dose, reaction temperature, and contact time on the PC yield and selectivity were investigated. The maximum PC yield of 96%, with high PC selectivity of 99% and a urea conversion rate of 96%, was attained at 160 °C using CaO–MgO catalysts prepared using a Mg/Ca ratio of 1 and Na2CO3 as a precipitating agent. The best-performing catalysts also exhibited good reusability without any significant loss in PC selectivity. It is expected that the present study will provide useful information on the suitability of different precipitating agents with respect to the catalytic properties of the oxides of Ca and Mg and their application in the synthesis of organic carbonates.

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Section: Resultsmentioning

confidence: 99%

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

et al. 2023

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“…Recently, a few studies show that ZnO tends to form Zn(NCO) 2 (NH 3 ) 2 in the presence of urea at high temperature (see Scheme a) due to the release of isocyanic acid and ammonia during the composition of urea. [ 33–36 ] In the alcoholysis of BUs, similar reaction may take place (see Scheme 1b). The isocyanic acid releasing during BU degradation and the ammonia forming in the BU alcoholysis would result in the formation of Zn(NCO) 2 (NH 3 ) 2 , in the presence of ZnO.…”

Section: Introductionmentioning

confidence: 98%

Understanding of ZnO‐Catalyzed Polyurethane Synthesis from Bisurea for Further Exploration of One‐Pot Synthesis and Property Evaluation Thereof

Yang,

Zhang,

Meng

et al. 2024

Macro Chemistry & Physics

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ZnO is considered to be a good catalyst for the synthesis of polyurethanes (PUs) by alcoholysis of bisureas (BUs). ZnO tends to form Zn(NCO)2(NH3)2 in the presence of urea at high temperature, so does it in the alcoholysis of BUs. Therefore in this study, we attempt to understand the role of Zn(NCO)2(NH3)2 playing in the alcoholysis of BUs. A loading of Zn(NCO)2(NH3)2 at 5 mol% is found to be sufficient to catalyze the polymerization and the reaction time is greatly cut from 40 h (catalyzed by ZnO) to 26 h, with similar chemical structures and properties. The tensile strength, elongation at break and toughness for PU‐Zn‐5 can reach 43.8 MPa, 330%, and 94.0 J/cm3, respectively. One‐pot synthetic strategy is then further introduced to improve the efficiency of the polymerization. Zn(NCO)2(NH3)2, BU and PU can be synthesized in one pot, by adding ZnO, urea, diamine, LiBr and diol sequentially. The feasibility of this one‐pot method is verified, indicated by the similar reaction time, chemical structures, molecular weight, thermal and mechanical properties. This one‐pot synthetic strategy offers an efficient way to synthesize PUs directly and simply from urea, diamines and diols, which is beneficial for improving the molecular diversity of PUs.This article is protected by copyright. All rights reserved

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Preparation of propylene carbonate by alcoholysis of urea from the perspective of homogeneous reaction: Influence of dissolution and precipitation of metal oxide catalysts

Cited by 2 publications

References 27 publications

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

Understanding of ZnO‐Catalyzed Polyurethane Synthesis from Bisurea for Further Exploration of One‐Pot Synthesis and Property Evaluation Thereof

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