“…The mechanism of this reaction has been studied previously. 25,26 And the apparent reaction steps are illustrated in Scheme 2.Scheme 2.Synthesis reaction of glyoxylic acid and the side-reaction.…”
Section: Methodsmentioning
confidence: 99%
“…The mechanism of this reaction has been studied previously. 25,26 And the apparent reaction steps are illustrated in Scheme 2.…”
In-situ Fourier-transform infrared (FTIR) spectroscopy has been recognized as an important technology for online monitoring of chemical reactions. However, analysis of the real-time IR data for identification and quantification of uncertain reactants or intermediates is often ambiguous and difficult. Here we propose an analysis algorithm based on reaction kinetic modeling and the chemometric method of partial least squares (PLS) to comprehensively and quantitatively study reaction processes. Concentration profiles and apparent kinetic parameters can be simultaneously calculated from the spectral data, without the demand of complicated analysis on characteristic absorbance peaks or tedious sampling efforts for multivariate modeling. Paal-Knorr reactions and glyoxylic acid synthesis reactions were selected as typical reactions to validate the algorithm. The quantitative results were verified by measurements and demonstrated great credibility of this method. Moreover, the reaction kinetic models extracted from FTIR data were used to simulate reaction processes and optimize the conditions in order to maximize product yields. This analysis method based on kinetic modeling and the PLS method has been proven as a useful tool to quantitatively study the chemical reaction and has the ability for reaction monitoring and process optimization.
“…The mechanism of this reaction has been studied previously. 25,26 And the apparent reaction steps are illustrated in Scheme 2.Scheme 2.Synthesis reaction of glyoxylic acid and the side-reaction.…”
Section: Methodsmentioning
confidence: 99%
“…The mechanism of this reaction has been studied previously. 25,26 And the apparent reaction steps are illustrated in Scheme 2.…”
In-situ Fourier-transform infrared (FTIR) spectroscopy has been recognized as an important technology for online monitoring of chemical reactions. However, analysis of the real-time IR data for identification and quantification of uncertain reactants or intermediates is often ambiguous and difficult. Here we propose an analysis algorithm based on reaction kinetic modeling and the chemometric method of partial least squares (PLS) to comprehensively and quantitatively study reaction processes. Concentration profiles and apparent kinetic parameters can be simultaneously calculated from the spectral data, without the demand of complicated analysis on characteristic absorbance peaks or tedious sampling efforts for multivariate modeling. Paal-Knorr reactions and glyoxylic acid synthesis reactions were selected as typical reactions to validate the algorithm. The quantitative results were verified by measurements and demonstrated great credibility of this method. Moreover, the reaction kinetic models extracted from FTIR data were used to simulate reaction processes and optimize the conditions in order to maximize product yields. This analysis method based on kinetic modeling and the PLS method has been proven as a useful tool to quantitatively study the chemical reaction and has the ability for reaction monitoring and process optimization.
“…The catalytic conversion of organic compounds to high-valued chemicals has been a major challenge in human society. Glyoxylic acid (GA) as one of the widely used chemical intermediate plays an essential role in developing many kinds of commercialized downstream products, such as vanillin, penicillin, and allantoin used in food additives, cosmetic, and pharmaceutical fields. , At present, chemical oxidation of glyoxal using nitric acid as the oxidizing agent and electrochemical reduction of oxalic acid are the main production methods. − Nevertheless, nitric acid oxidation for GA production causes uncontrolled over-oxidation to generate oxalic acid as a byproduct and environmental problem of NO x emission. Meanwhile, the electrochemical reduction method still has not been commercialized on a large scale, due to high energy consumption.…”
Transforming glyoxal to value-added glyoxylic acid (GA) is highly desirable but challenging due to the uncontrollable overoxidation. In this work, we report on a first demonstration of semioxidation of glyoxal with high selectivity (86.5%) and activity on WO 3 nanoplate photoanode through the photoelectrochemical strategy. The optimization of reactivity was achieved via crystal facet regulation, showing a satisfactory GA production rate of 308.4 mmol m −2 h −2 , 84.0% faradaic efficiency, and 4.3% total solar-to-glyoxylic acid efficiency on WO 3 with enriched {200} facets at 1.6 V versus RHE. WO 3 with a high {200} facet ratio exhibits more efficient electron−hole transfer kinetics, resulting in the facilitated formation of hydroxyl radicals ( • OH) and glyoxal radicals. Meanwhile, the theoretical calculation results indicate that the high selectivity and activity come from the strong adsorption ability for glyoxal and the low reaction energy for glyoxal radical generation on the (200) facets of WO 3 . Moreover, the high energy demand toward oxalic acid production on WO 3 leads to the exciting semi-oxidation process.
“…Glyoxylic acid (GA), containing both aldehyde (‐CHO) and carboxyl group (‐COOH), has been widely applied in the synthesis of fine organic chemicals, such as pharmaceutical, pesticide, fragrance, cosmetic industry, etc [1–3] . At present, the most widely employed methods to synthesize GA are the nitric acid oxidation of glyoxal, maleic anhydride oxidation, dichloroacetic acid method, and electrochemical reduction of oxalic acid (OA) [4–7] . Among these methods, currently, the most common technique to prepare GA is oxidation of glyoxal by nitric acid, in which one of the aldehyde groups in glyoxal is oxidized to carboxyl group by concentrated nitric acid.…”
Section: Introductionmentioning
confidence: 99%
“…[1][2][3] At present, the most widely employed methods to synthesize GA are the nitric acid oxidation of glyoxal, maleic anhydride oxidation, dichloroacetic acid method, and electrochemical reduction of oxalic acid (OA). [4][5][6][7] Among these methods, currently, the most common technique to prepare GA is oxidation of glyoxal by nitric acid, in which one of the aldehyde groups in glyoxal is oxidized to carboxyl group by concentrated nitric acid. There are still many shortcomings of this method.…”
Electroreduction of oxalic acid (OA) is an effective process to produce glyoxylic acid (GA). However, electrochemically generated GA solution is yellow, which lowers the quality of GA and affects the application in producing the downstream products. It is urgent to investigate the composition of chromogenic substances (CSs) and separate them from the GA solution. In this work, the presence of tartaric acid, glyceric acid, and pyruvic acid in the electrochemically generated GA solution is successfully confirmed by high‐performance liquid chromatography‐electrospray‐mass spectrometry. Tartaric acid is originally generated from GA and glycolic acid, and then further reduced to obtain chromogenic glyceric acid and pyruvic acid. 92.97 % of CSs could be successfully removed from the GA solution by electrodialysis at 240.64 A/m2 and 25 °C. A separation of OA and GA is also achieved by electrodialysis. This study makes a significant contribution to the industrialization of electroreduction process to prepare GA.
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