scholarly journals Investigation of propylene carbonate synthesis regularities by the interaction of propylene glycol with carbamide

2020 ◽  
Vol 15 (1) ◽  
pp. 55-61
Author(s):  
A. V. Sulimov ◽  
A. V. Ovcharova ◽  
G. M. Kravchenko ◽  
Yu. K. Sulimova
Keyword(s):  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Residence Time ◽  
Zinc Acetate ◽  
Batch Reactor ◽  
Molar Ratio ◽  
High Yield ◽  
Gas Liquid Chromatography ◽  
Cyclic Carbonates ◽  
Initial Molar Ratio

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.

Methanol Synthesis in a Slurry Phase Reactor over Cu/ZnO/Al2O3 Catalyst

2014 ◽  
Vol 931-932 ◽  
pp. 27-31 ◽  
Author(s):  
Kuntima Krekkeitsakul ◽  
Thanes Utistham ◽  
Unalome Wetwatana Hartley
Keyword(s):  
Surface Area ◽  
Residence Time ◽  
Methanol Synthesis ◽  
Batch Reactor ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Mixed Gas ◽  
Reactor Model ◽  
Co Conversion ◽  
Bet Analysis

Methanol synthesis from synthesis gas (syngas, a mixture of hydrogen (H2) and carbon monoxide (CO)) in the presence of copper/zinc oxide/alumina catalyst (Cu/ZnO/Al2O3) was investigated using semi-batch reactor. The process was operated at 280 °C under pressure 40 bar in a slurry reactor (Parr reactor model 4848). The catalyst weight, syngas molar ratio and residence time were optimized for methanol synthesis. Cu/ZnO/Al2O3catalyst was prepared by a two-step surfactant assisted precipitation method using polyethylene glycol (PEG 6000). The catalysts surface area, crystallinity, reducibility and morphology were characterized by BET, XRD, H2-TPR and SEM-EDS, respectively. The BET analysis indicated that the catalyst calcined at 300 °C gave the highest surface area (99.67 m2/g). The crystallite size of Cu in Cu/ZnO/Al2O3catalyst was estimated to be 14.14 nm., after adding the surfactants. The maximum methanol yield (607.53) was achieved after 24 hours of residence time using 5 g of the catalyst under a stream of 2 to 1 molar ratio of H2and CO reactive mixed gas. Under these conditions, 38.26% of CO conversion and 93.11% of selectivity to methanol were achieved. When the residence time was decreased to 12 hours with molar ratio of 0.5 H2to 1 CO, the yield of methanol was 388.11, with a CO conversion of 38.53% and selectivity to methanol of 90.77%.

Synthesis of Propylene Carbonate from Carbon Dioxide and 1,2-Propylene Glycol over Zinc Acetate Catalyst

2008 ◽  
Vol 47 (5) ◽  
pp. 1365-1369 ◽  
Author(s):  
Xinqiang Zhao ◽  
Na Sun ◽  
Shufang Wang ◽  
Fang Li ◽  
Yanji Wang
Keyword(s):  
Carbon Dioxide ◽  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Zinc Acetate

scholarly journals Promising Immobilization of Industrial-Class Phospholipase A1 to Attain High-Yield Phospholipids Hydrolysis and Repeated Use with Optimal Water Content in Water-in-Oil Microemulsion Phase

2021 ◽  
Vol 11 (4) ◽  
pp. 1456
Author(s):  
Yusuke Hayakawa ◽  
Ryoichi Nakayama ◽  
Norikazu Namiki ◽  
Masanao Imai
Keyword(s):  
Water Content ◽  
Reaction Rate ◽  
Enzyme Reaction ◽  
Initial Reaction Rate ◽  
Industrial Applications ◽  
Molar Ratio ◽  
High Yield ◽  
Initial Reaction ◽  
Phospholipase A1 ◽  
Repeated Use

In this study, we maximized the reactivity of phospholipids hydrolysis with immobilized industrial-class phospholipase A1 (PLA1) at the desired water content in the water-in-oil (W/O) microemulsion phase. The optimal hydrophobic-hydrophilic condition of the reaction media in a hydrophobic enzyme reaction is critical to realize the maximum yields of enzyme activity of phospholipase A1. It was attributed to enzymes disliking hydrophobic surroundings as a special molecular structure for reactivity. Immobilization of PLA1 was successfully achieved with the aid of a hydrophobic carrier (Accurel MP100) combination with the treatment using glutaraldehyde. The immobilized yield was over 90% based on simple adsorption. The hydrolysis reaction was kinetically investigated through the effect of glutaraldehyde treatment of carrier and water content in the W/O microemulsion phase. The initial reaction rate increased linearly with an increasing glutaraldehyde concentration and then leveled off over a 6% glutaraldehyde concentration. The initial reaction rate, which was predominantly driven by the water content in the organic phase, changed according to a typical bell-shaped curve with respect to the molar ratio of water to phospholipid. It behaved in a similar way with different glutaraldehyde concentrations. After 10 cycles of repeated use, the reactivity was well sustained at 40% of the initial reaction rate and the creation of the final product. Accumulated yield after 10 times repetition was sufficient for industrial applications. Immobilized PLA1 has demonstrated potential as a biocatalyst for the production of phospholipid biochemicals.

scholarly journals Synthesis of propylene carbonate from urea and 1,2-propylene glycol over metal carbonates

2011 ◽  
Vol 17 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Jiancheng Zhou ◽  
Wu Dongfang ◽  
Birong Zhang ◽  
Yali Guo
Keyword(s):  
Reaction Time ◽  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Reaction Temperature ◽  
Reaction Conditions ◽  
Lead Carbonate ◽  
Synthetic Process ◽  
Metal Carbonates ◽  
Optimal Reaction ◽  
Mixed Carbonate

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%.

Degradation of an Azo Dye by Fenton Type Processes Assisted with UV Irradiation

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Natalija Koprivanac ◽  
Dinko Vujevic
Keyword(s):  
Uv Irradiation ◽  
Azo Dye ◽  
Dye Degradation ◽  
Degradation Products ◽  
Batch Reactor ◽  
Process Efficiency ◽  
Molar Ratio ◽  
Synthetic Dyes ◽  
Ambient Conditions ◽  
Treatment Methods

Organic synthetic dyes are widely produced and used today. Significant losses of organic and inorganic content occurs during the manufacturing and application of dyes and its discharge in the effluent presents a threat to the eco-systems due to general toxicity and resistance to destruction by biological treatment methods. Particularly azo dyes are of special environmental concern due to their degradation products such as aromatic amines, which are considered highly carcinogenic. So, dyes have to be removed from coloured wastewater before discharge. However, traditional treatment methods (adsorption, coagulation/flocculation) mainly transfer the contaminants from wastewater to secondary waste. Therefore, advanced oxidation processes seem to be sustainable and clean technology to decolorize and minimize organic dyes content from wastewater. In this paper, degradation of an azo dye C.I. Direct Orange 39 (DO39) using Fenton type processes (Fe2+/H2O2, Fe3+/H2O2and Fe0/H2O2) has been performed. The molar ratio of Fenton’s type reagents has been varied in the range of 1 : 5 up to 1 : 50 at 0.5 and 1.0 mM concentrations of iron salts and iron powder. Experiments have been conducted for two hours in a batch reactor with magnetic stirring, ambient conditions and pH 3. The process efficiency and formation of degradation by-products have been determined on the basis of results obtained by UV/VIS spectrophotometric, total organic carbon (TOC) and high performance liquid chromatography (HPLC) analyses. The optimal Fenton and Fenton ``like" processes parameters have been applied in the photo reactor, too. It has been observed that simultaneous utilization of UV irradiation with Fenton's and Fenton ``like" reagents increases the degradation of DO39 dye. Degradation of the dye in dilute aqueous solution follows pseudo-first order kinetics. The maximal decolourization of 20 mg L-1 DO39 in water of 93.2% and TOC degradation of 76.9% were obtained using Fe3+/H2O2= 1 : 5 molar ratio. The results indicate that the treatment of DO39 dye wastewater with UV/Fe3 +/H2O2 system was found to be the most efficient.

Vapor-phase oxidation of propylene glycol-methanol mixture to methyl lactate on CeO2/Al2O3 catalyst

2021 ◽  
pp. 92-97
Author(s):  
M.E. Sharanda ◽  
◽  
A.M. Mylin ◽  
O.Yu. Zinchenko ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Propylene Glycol ◽  
Vapor Phase ◽  
Flow Reactor ◽  
Aldol Condensation ◽  
Ethyl Lactate ◽  
Molar Ratio ◽  
Methyl Lactate ◽  
Reactor Inlet ◽  
Phase Oxidation ◽  
Al2o3 Catalyst

The vapor-phase oxidation of mixtures of propylene glycol with methanol and ethanol to methyl and ethyl lactate, respectively, on supported CeO2/Al2O3 catalyst with 10 wt.% CeO2 content was studied. The steel flow reactor with a fixed catalyst bed (4 cm3) was used. 20 wt.% solution of propylene glycol in alcohol was fed to the reactor inlet by Waters 950 pump at LHSV= 0.5-0.8 h-1. Reaction temperature and pressure were varied in the interval of 190-250 0C and 1.3-1.8 bars respectively. Compressed air was given to the reactor inlet at the molar ratio of propylene glycol/O2 = 1. The reaction products were analyzed using gas chromatography (Agilent 7820A) and 3C NMR (Bruker Avance 400) methods. Studied oxidation of propylene glycol in the presence of methanol describes by total reaction CH3CHOHCH2OH +O2 + СН3OH = CH3CHOHCOOСН3 +2H2O At first, hydroxyacetone is formed that is further oxidized to pyruvic aldehyde, which attaches alcohol to form hemiacetal. Then, hemiacetal of methyl glyoxal rearranges into methyl lactate by Cannizzaro. At 220 0C and load on a catalyst of < 2 mmol PG/gcat/h, the selectivity towards methyl lactate reaches 70 wt.% at 100 % propylene glycol conversion. The main by-products are formed as the result of acetaldehyde transformation. Acetaldehyde could be formed at hydroxyacetone aldol decondensation. In the presence of ethanol, the formation of a significant amount of acetaldehyde and its aldol condensation products as well as the formation of diethoxyethane are observed. Therefore, ethyl lactate selectivity at 100 % propylene glycol conversion does not exceed 45 %. Supported CeO2/SiO2 contact was tested in this oxidation reaction also. However, CeO2/SiO2 provides the low, up to 25%, selectivity towards methyl lactate at full propylene glycol conversion. It was shown that at the same conditions methyl lactate is formed with higher selectivity then ethyl lactate. The high methyl lactate yield up to 70 wt.% could be obtained via vapor-phase oxidation of 20% mixture of propylene glycol with methanol by air oxygen on supported CeO2/Al2O3 catalyst at 210 - 220°С and at time contact of 3-4 seconds.

Optimization and statistical analysis of sono-Fenton treated wastewater of food industry using reactor by response surface method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod
Keyword(s):  
Reaction Time ◽  
Response Surface ◽  
Food Industry ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Experimental Result ◽  
Molar Ratio

Abstract The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).

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