Oxidation of Primary Alcohols to Carboxylic Acids

Tojo, Gabriel; Fernández, M.

doi:10.1007/0-387-35432-8

Cited by 93 publications

(23 citation statements)

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“…Although, basic pH values accelerate the reaction rate, it can be caused the sugar decomposition especially above the pH 11.0 value. The reaction pH range is suggested between 8.0-10.0 for the 2-KLG production [30].…”

Section: Phmentioning

confidence: 99%

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Optimisation of Catalytic Oxidation Conditions for the 2-Keto-L-Gulonic Acid Production Using Response Surface Methodology

Mutlu

Erbaş

2023

Preprint

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L-Ascorbic acid, also known as vitamin C, is a very important antioxidant ingredient and used in many industries. 2-keto-L-gulonic acid (2-KLG) is the main precursor of L-ascorbic acid production and it can be produced from L-sorbose via microbial fermentation or chemical (catalytic) oxidation. While some special strains are used in microbial fermentation, some catalysts are used in chemical oxidation. The aim of this research is to determine the optimum conditions by using the reaction temperature, pH value and time as the variable factors for the production of maximum 2-KLG content with the catalytic oxidation of L-sorbose in the presence of Pt/Al2O3 catalyst with response surface methodology approach. The limit values of variable factors were applied as 40, 50 and 60°C for the temperature; 7, 8 and 9 for the pH value and 3, 6 and 9 h for the time. According to the analyses results, the increasing time and temperature effected the conversion of L-sorbose into the 2-KLG negatively. The optimum conditions as regards the central composite design were determined as 41.30°C for the temperature, 8.23 for the pH and 3.25 h for the reaction time. Under these conditions L-sorbose was converted into 2-KLG with an average yield of 43.70%.

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Section: Phmentioning

confidence: 99%

“…Additionally, the formed some oxidation by-products can be absorbed on catalyst surface stronger than the L-sorbose and that causes the catalyst poisoning. In this case, it is not recommended to extend the reaction time for avoiding this situation, since conversion of L-sorbose to 2-KLG is not possible with the poisoned catalyst [30].…”

Section: Timementioning

confidence: 99%

Optimisation of Catalytic Oxidation Conditions for the 2-Keto-L-Gulonic Acid Production Using Response Surface Methodology

Mutlu

Erbaş

2023

Preprint

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“…Perhaps alcohol oxidation was considered as a mature technology far from the forefront of organic synthesis, it remains challenging to select productive conditions for unseen alcohols, especially those with complex structures or oxidation‐sensitive functional groups. [ 27 ]…”

Section: Background and Originality Contentmentioning

confidence: 99%

Auto Machine Learning Assisted Preparation of Carboxylic Acid by TEMPO‐Catalyzed Primary Alcohol Oxidation

Qiu

et al. 2022

Chin. J. Chem.

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Comprehensive Summary Though alcohol oxidations were considered as well‐established reactions, selecting productive conditions or predicting reaction yields for unseen alcohols remained as major challenges. Herein, an auto machine learning (ML) model for TEMPO‐catalyzed oxidation of primary alcohols to the corresponding carboxylic acids is disclosed. A dataset of 3444 data, consisting of 282 primary alcohols and 45 conditions, were generated using high‐throughput experimentation (HTE). With the HTE data and 105 descriptors, a multi‐label prediction was performed with AutoGluon (an open‐source auto machine learning framework) and KNIME (an open‐source data analytics platform). For the independent test of 240 reactions (a full matrix of 20 unseen alcohols and 12 conditions), AutoGluon with multi‐label prediction for yield prediction (AGMP) gave excellent performance. For external test of 1308 reactions (consisting of 84 alcohols and 45 conditions), AGMP still afforded good results with R2 as 0.767 and MAE as 4.9%. The model also revealed that the newly generated descriptor (Y/N, classification of the reaction reactivity) was the most relevant descriptor for yield prediction, offering a new perspective to integrate HTE and ML in organic synthesis.

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“…10 The use of 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) in combination with a wide variety of co-oxidants allows for the regioselective oxidation of primary over secondary alcohols and has therefore found wide spread application. 11,12 Initially, TEMPO was combined with hypochlorite as the co-oxidant in a biphasic reaction mixture but nowadays the most frequently used co-oxidant is bis-acetoxy iodobenzene (BAIB). 13,14 Two step oxidation protocols, in which the alcohol is first oxidized to the corresponding aldehyde and subsequently further oxidized to the carboxylate have also been developed.…”

Section: General Strategiesmentioning

confidence: 99%