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.

Conversion of fructose into methyl lactate over SnO2/Al2O3 catalystin flow regime

2020 ◽  
pp. 43-47
Author(s):  
S.V. Prudius ◽  
◽  
N.L. Hes ◽  
A.M. Mylin ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Practical Interest ◽  
Dimethyl Acetal ◽  
Racemic Mixture ◽  
Process Conditions ◽  
Impregnation Method ◽  
Aqueous Methanol ◽  
Methyl Lactate ◽  
Al2o3 Catalyst ◽  
Target Reaction

In recent years, numerous researchers have focused on the development of catalytic methods for processing of biomass-derived sugars into alkyl lactates, which are widely used as non-toxic solvents and are the starting material for obtaining monomeric lactide. In this work, the transformation of fructose into methyl lactate on Sn-containing catalyst in the flow reactor that may be of practical interest was studied. The supported Sn-containing catalyst was ob-tained by a simple impregnation method of granular γ-Al2O3. The catalytic ex-periments were performed in a flow reactor at temperatures of 160-190 °C and pressure of 3.0 MPa. The 1.6-9.5 wt.% fructose solutions in 80% aqueous methanol were used as a reaction mixture. It was found that addition to a reac-tion mixture of 0.03 wt.% potassium carbonate leads to the increase in selec-tivity towards methyl lactate on 15% at 100% conversion of fructose. Prod-ucts of the target reaction С6Н12О6 + 2СН3ОН = 2С4Н8О3 + 2Н2О were ana-lyzed using 13C NMR method. The following process conditions for obtaining of 65 mol% methyl lactate yield at 100% fructose conversion were found: use of 4.8 wt.% fructose solution in 80% methanol, 180 °С, 3.0 МПа and a load on catalyst 1.5 mmol C6H12O6/mlcat/h at contact time of 11 minutes. The cata-lyst productivity is 2.0 mmol C4H8O3/mlcat/h and the by-productі are 1,3-dihydroxyacetone dimethyl acetal (20%) and 5-hydroxymethylfurfural (10%). It should be noted that a racemic mixture of L- and D-methyl lactates has been obtained by conversion of D-fructose on the SnO2/Al2O3 catalyst. The SnO2/Al2O3 catalyst was found to be stable for 6 h while maintaining full fruc-tose conversion at 55–70% methyl lactate selectivity. After regeneration the catalyst completely restores the initial activity.

scholarly journals VAPOR-PHASE SYNTHESIS OF LACTIDE FROM ETHYL LACTATE OVER TiO2/SiO2 CATALYST

2019 ◽  
Vol 85 (7) ◽  
pp. 31-37 ◽  
Author(s):  
Volodymyr Brei ◽  
A Varvarin ◽  
Svetlana Levytska ◽  
Ya Glushchuk
Keyword(s):  
Lactic Acid ◽  
Vapor Phase ◽  
Flow Reactor ◽  
Diffuse Reflectance Spectroscopy ◽  
Industrial Process ◽  
Ethyl Lactate ◽  
Phase Method ◽  
Two Stage ◽  
Solid Catalysts ◽  
Steel Flow

The lactide is monomer for production of polylac- tide – biodegradable polymer that use as an ecological packagingmaterial. In an industry the two-stage lactide synthesis is applied. At first, lactic acid condenses into the oligomer using Sn-octanoate catalyst, then oligo- mer depolymerizes to lactide. The drawbacks of this liquid-phase method are a significant amount of by- products — dimers and trimers of lactic acid and low lactide yield.Now a direct vapor-phase condensation of lactic acid and its esters to lactide is considered as alternative to the industrial process. One-stage lactide obtaining and use of solid catalysts are advantages of such method. In this work, the vapor-phase transfor- mation of ethyl lactate over supported TiO2/SiO2 and TiO2/Al2O3 oxides in nitrogen flow at 200–300 °С was studied. The oxide samples were obtained by impregnating silica gel and γ -alumina with an approp- riate amount of titanium tetrabutoxide solution in iso- propanol, then dried at 80 oC, and finally calcined at 500 oC in air for 4 h. The catalysts were characterized by BET method, X-ray diffraction and UV-Vis diffuse reflectance spectroscopy. Catalytic experi- ments were carried out in a steel flow reactor at 200 –270 °С and atmospheric pressure. The load on a ca-talyst was varied in the interval of 8.2–36.4 mmol ethyllactate/(gcat⋅ h) that corresponds gas hourly space velo- city of the mixture of ethyl lactate and nitrogen of 1230–1490 h–1. It was shown that TiO2/SiO2 with5 wt.% content of titanium dioxide provides 48 % conversion of ethyl lactate with selectivity and pro- ductivity towards lactide 74 % and 7.0 mmol/(gcat⋅ h)at 270 °C, respectively. It was found thatTiO2/SiO2 is more efficiently for lactide producing (STY = 6.2 mmol/(gcat⋅ h) compared to TiO2/Al2O3catalyst (STY =1.8 mmol/(gcat⋅ h). It was shown that spent TiO2/ SiO2 catalyst fully restores activity after regenerati- on in air at 500 °С for 2 h. The two-stage scheme of ethyl lactate condensation with the participation of coordina- tion-unsaturated titanium ions is discussed.

The vapor-phase oxidation of n-butane in a flow reactor

1970 ◽  
Vol 15 (3) ◽  
pp. 275-287 ◽  
Author(s):  
C.A. Euker ◽  
J.P. Leinroth
Keyword(s):  
Vapor Phase ◽  
Flow Reactor ◽  
Phase Oxidation

ChemInform Abstract: Vapor-Phase Oxidation of Ethyl Lactate to Pyruvate over Various Oxide Catalysts.

ChemInform ◽  
2010 ◽  
Vol 24 (38) ◽  
pp. no-no
Author(s):  
S. SUGIYAMA ◽  
N. SHIGEMOTO ◽  
N. MASAOKA ◽  
S. SUETOH ◽  
H. KAWAMI ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Oxide Catalysts ◽  
Ethyl Lactate ◽  
Phase Oxidation

Vapor-Phase Oxidation of Ethyl Lactate to Pyruvate over Various Oxide Catalysts

1993 ◽  
Vol 66 (5) ◽  
pp. 1542-1547 ◽  
Author(s):  
Shigeru Sugiyama ◽  
Naoya Shigemoto ◽  
Naoki Masaoka ◽  
Souichi Suetoh ◽  
Hideaki Kawami ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Oxide Catalysts ◽  
Ethyl Lactate ◽  
Phase Oxidation

scholarly journals Vapor phase aldol condensation of methyl acetate with formaldehyde over a Ba–La/Al2O3 catalyst: the stabilizing role of La and effect of acid–base properties

RSC Advances ◽  
2017 ◽  
Vol 7 (82) ◽  
pp. 52304-52311 ◽  
Author(s):  
Qiang Bao ◽  
Wanchun Zhu ◽  
Jianbiao Yan ◽  
Chunlei Zhang ◽  
Chunli Ning ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Methyl Acetate ◽  
Aldol Condensation ◽  
Acid Base ◽  
Al2o3 Catalyst ◽  
Base Properties

Vapor phase aldol condensation of methyl acetate with formaldehyde was studied over Ba–La/Al2O3 with different amounts of lanthanum catalysts.

Hydrogenolysis of glucose and fructose in glycol solutions over CuO-MgO-ZrO2 catalyst

2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  
Keyword(s):  
Ethylene Glycol ◽  
Propylene Glycol ◽  
Flow Reactor ◽  
General Trend ◽  
Raw Materials ◽  
Reaction Products ◽  
Renewable Raw Materials ◽  
High Partial Pressure ◽  
Zro2 Catalyst ◽  
Phase Process

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

2017 ◽  
Vol 68 (7) ◽  
pp. 1496-1500
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ancuta Trifoi ◽  
Minodora Pasare ◽  
Ionut Banu ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Fixed Bed ◽  
Continuous System ◽  
Space Velocity ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Liquid Hourly Space Velocity ◽  
Hydrodesulfurization Process ◽  
Al2o3 Catalyst ◽  
Simplified Kinetic Model

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

scholarly journals Vapor Phase Modification for Selective Enrichment of Grafted Styrene/Acrylonitrile onto Carbon Nanotubes Via ATRP

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 459
Author(s):  
Maryam Azadbakht ◽  
Elnaz Esmizadeh ◽  
Ali Vahidifar ◽  
Tizazu H. Mekonnen ◽  
Mehdi Salami-Kalajahi
Keyword(s):  
Carbon Nanotubes ◽  
1H Nmr ◽  
Vapor Phase ◽  
Proton Nuclear Magnetic Resonance ◽  
Acid Vapor ◽  
Selective Enrichment ◽  
Pristine Mwcnts ◽  
Morphological Studies ◽  
Phase Oxidation ◽  
Multi Walled Carbon Nanotubes

Nitric acid vapor phase oxidation of multi-walled carbon nanotubes (MWCNTs) was proposed as a promising technique to fabricate poly styrene-co-acrylonitrile (SAN)-grafted-CNTs via atom transfer radical polymerization (ATRP). The in-situ ATRP grafting approach was successfully employed to graft polystyrene (PS), SAN and polyacrylonitrile (PAN), onto the convex surfaces of pristine MWCNTs (PCNT) and acid-functionalized MWCNTs (FCNT). Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA) confirmed the effectiveness of the modification via the ATRP grafting approach. The molar composition of acrylonitrile in the synthesized copolymer on the surface of CNTs for an FCNTs was calculated to be about 80% and 67.5% by 1H-NMR and TGA respectively, whereas the value is lower for PCNTs. Morphological studies showed that SAN-grafted FCNTs exhibit rougher surface morphology compared to the SAN-grafted PCNTs. Moreover, the higher diameter of the FCNTs indicated the higher polymer content, which was coated onto CNTs functionalized by vapor-phase oxidation. Therefore, the vapor phase oxidation strategy employed in this study could be utilized as a general method to prepare CNTs which can serve as an ATRP macroinitiator for the fabrication of various polymer grafted CNTs.

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