scholarly journals Formation of Acrylaldehyde by Vapor-Phase Aldol Condensation I. Basic Oxide Catalysts

1991 ◽  
Vol 64 (4) ◽  
pp. 1342-1345 ◽  
Author(s):  
Mamoru Ai
Keyword(s):  
Vapor Phase ◽  
Aldol Condensation ◽  
Oxide Catalysts ◽  
Basic Oxide

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.

Vapor-phase Oxidation of Cyclohexane over Supported Fe-Mn Catalysts: In-Situ DRIFTS studies

2021 ◽  
Author(s):  
Vijendra Kumar Yadav ◽  
Taraknath Das
Keyword(s):  
Surface Area ◽  
Raman Spectra ◽  
Vapor Phase ◽  
Oxide Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Mn Oxide ◽  
Phase Oxidation

Alumina-supported Fe-Mn oxide catalysts were synthesized by the incipient wetness impregnation method. The catalysts were characterized by using various characterization techniques such as surface area, XRD, H2-TPR, and Raman spectra...

scholarly journals Vapor phase hydrogenation of furfural over nickel mixed metal oxide catalysts derived from layered double hydroxides

2016 ◽  
Vol 517 ◽  
pp. 187-195 ◽  
Author(s):  
Taylor P. Sulmonetti ◽  
Simon H. Pang ◽  
Micaela Taborga Claure ◽  
Sungsik Lee ◽  
David A. Cullen ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Vapor Phase ◽  
Layered Double Hydroxides ◽  
Oxide Catalysts ◽  
Mixed Metal Oxide ◽  
Metal Oxide Catalysts ◽  
Mixed Metal ◽  
Mixed Metal Oxide Catalysts ◽  
Double Hydroxides

Vapor-phase intramolecular aldol condensation of 2,5-hexanedione to 3-methylcyclopent-2-enone over ZrO2-supported Li2O catalyst

2017 ◽  
Vol 92 ◽  
pp. 105-108 ◽  
Author(s):  
Daolai Sun ◽  
Shigenori Chiba ◽  
Yasuhiro Yamada ◽  
Satoshi Sato
Keyword(s):  
Vapor Phase ◽  
Aldol Condensation
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