Zn–Ca–Al mixed oxide as efficient catalyst for synthesis of propylene carbonate from urea and 1,2-propylene glycol

2017 ◽  
Vol 25 (5) ◽  
pp. 609-616 ◽  
Author(s):  
Sen Liu ◽  
Suhong Sun ◽  
Xuehui Tian ◽  
Peiyong Sun ◽  
Shenghong Zhang ◽  
...  
2011 ◽  
Vol 17 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Jiancheng Zhou ◽  
Wu Dongfang ◽  
Birong Zhang ◽  
Yali Guo

A series of single-metal carbonates and Pb-Zn mixed-metal carbonates were prepared as catalysts for alcoholysis of urea with 1,2-propylene glycol (PG) for the synthesis of propylene carbonate (PC). The mixed carbonates all show much better catalytic activities than the single carbonates, arising from a strong synergistic effect between the two crystalline phases, hydrozincite and lead carbonate. The mixed carbonate with Pb/Zn=1:2 gives the highest yield of PC, followed by the mixed carbonate with Pb/Zn=1:3. Furthermore, Taguchi method was used to optimize the synthetic process for improving the yield of PC. It is shown that the reaction temperature is the most significant factor affecting the yield of PC, followed by the reaction time, and that the optimal reaction conditions are the reaction time at 5 hours, the reaction temperature at 180 oC and the catalyst amount at 1.8 wt%, resulting in the highest PC yield of 96.3%.


Author(s):  
A. V. Sulimov ◽  
A. V. Ovcharova ◽  
G. M. Kravchenko ◽  
Yu. K. Sulimova

Objectives. Cyclic carbonates are important products of organic synthesis, which are widely used as solvents, catalysts, and reagents for the production of various compounds (in particular, urethane-containing polymers) by the non-isocyanate method. The process of carbamide alcoholysis with polybasic alcohols is a promising method for the synthesis of cyclic carbonates. The purpose of this study is to determine the reaction conditions for the interaction of propylene glycol with carbamide in the presence of zinc acetate as a catalyst.Methods. We conducted experiments to study the synthesis of propylene carbonate in a batch laboratory apparatus. Moreover, we analyzed the starting reagents and final products using gas–liquid chromatography.Results. We studied the synthesis of propylene carbonate by carbamide alcoholysis with propylene glycol in the presence of a catalyst (zinc acetate) by varying the following parameters: initial molar ratio of propylene glycol/carbamide = (0.5–5):1, synthesis temperature 130–190°С, reagent residence time in the reactor 0.5–4 h, and the catalyst amount in the reaction mixture 0–1.5 wt %.Conclusions. We determined the technological parameters of propylene carbonate synthesis in a batch reactor. Moreover, we showed that the process allowed the production of propylene carbonate with a sufficiently high yield of 80%—at the initial molar ratio of propylene glycol/ carbamide = 3:1, temperature 170°C, and residence time 2 h.


2017 ◽  
Vol 68 (5) ◽  
pp. 1118-1121
Author(s):  
Vasile Georgescu ◽  
Casen Panaitescu ◽  
Mihaela Bombos ◽  
Dorin Bombos

Hydrogenolysis of glycerol was conducted on catalyst of the type mixed oxide of Cu-Cr doped with NiO on g-Al2O3. The prepared catalyst was analyzed by XRD, IR and TPR. Catalytic tests were carried out on a laboratory plant in continuous flow system on a reactor equipped with heating mantle, at molar ratio of glycerol / hydrogen of 1/300, glycerol volume hourly space velocities 1000s-1, temperatures 200-220oC and pressures 3-5 bar. The main reaction products identified were propylene glycol and hydroxyacetone. Glycerol conversion increases with temperature and pressure on ranges of parameters studied. Selectivity to propylene glycol increases with increasing of temperature and pressure and the selectivity to hydroxyacetone decreases with increasing of temperature and pressure on the variation range of the parameters studied.


2021 ◽  
Vol 1020 ◽  
pp. 219-223
Author(s):  
Richard S. Horng ◽  
Wei Cheng Hung ◽  
Ju Wei Kuo

Ionic liquid with a single hydroxyl group, 1-(2-hydroxyl-ethyl)-3-methylimidazolium bromide (HEMIMB), was prepared. It was found that HEMIMB could be an efficient catalyst for CO2 cycloaddition to propylene oxide to produce propylene carbonate (PC). An ionic liquid polymer with multi-hydroxyl groups poly(1-2-hydroxyl-ethyl)-3-vinylimidazolium bromide (PHEVIMB) was also prepared. In this study, both catalytic reaction performances of HEMIMB and PHEVIMB were investigated. Results showed that product separation and catalyst recycles in the process of PHEVIMB catalytic reaction system was much more efficient with a yield of 55.5%, even after three consecutive catalyst reuses. Meanwhile, the separation was less time-efficient for homogeneous catalytic system of HEMIMB molecules with a single hydroxyl group despite of a yield of 92.4%. When it comes to practical industrial process design, the single component with multifunctional ionic liquid polymer, as catalyst, may be considered effective and friendly process.


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