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

How to Cite

Sharanda, M., Mylin, A., Зінченко, О., & Brei, V. (2021). Vapor-phase oxidation of propylene glycol-methanol mixture to methyl lactate on CeO2/Al2O3 catalyst. Catalysis and Petrochemistry, (31), 92-97.


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
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 70wt.% 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.
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Pat. № 145097 Ukraine, MPK C07C69/75, C08G63/08. Patent for Utility Model «Method of obtaining lactid from polyols» / V.V. Brei, I.V. Schutsky, M.I. Sharanda, A.M. Varvarin, S.I. Levytska, A.M. Mylin, S.V. Prudius, O.Yu. Zinchenko; customer LLC Production Group "Techinservice". - № u 2020 02764; app. 07.05.2020; pub. 25.11.2020. [in Ukrainian]

Hamad K., Kaseem M., Yang H.W., Deri F., Ko Y.G. Properties and medical applications of polylactic acid: A review. eXPRESS Polymer Letters. 2015. 9(5). 435-455.

Mylin A. M., Brei V. V. Selective conversion of glycerol-ethanol mixture into ethyl lactate over СеO2/Al2O3 catalyst. Ukrainian Chemistry Journal. 2016. 82 (2): 79. [in Ukrainian].

Purushothaman R., Haveren J., Es D. et al. Appl. Catal. B. 2014. 147. pp. 92-100.

Montini T., Melchionna M., Monai M., Fornasiero P. Fundamentals and catalytic applications of CeO2-based materials. Chem. Rev. 2016. 116: 5987.

Romanova I.V. Catalytic Activity of Copper and Cerium Oxides in Ethanol Oxidation.Chemistry, physics and technology of surface. 2010. V. 1. № 4. pp. 436-440. [in Russian]

Brei V.V., Mylin A.M. Oxidation of alcohols over cerium-oxide catalyst: correlation between the activation energy of the reaction and the chemical shift δ (R13СОH). Ukrainian Chemistry Journal. 2019. 85 (8): 66. [in Ukrainian].