488-31-3Relevant academic research and scientific papers
PROCESSES FOR PREPARING ALDARIC, ALDONIC, AND URONIC ACIDS
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Paragraph 00108-00109, (2021/05/29)
Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C2-C7 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C2-C7 aldonic acid and/or lactone(s) thereof and/or a C2-C7 aldose are described.
Electrochemical oxidation of diclofenac on CNT and M/CNT modified electrodes
Ferreira, M.,Figueiredo, J. L.,Fonseca, A. M.,Güney, S.,Ku?niarska-Biernacka, I.,Neves, I. C.,Parpot, P.,Pereira, M. F. R.,Soares, O. S. G. P.
, p. 12622 - 12633 (2021/07/25)
The electrochemical oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug considered as an emerging pollutant (frequently detected in wastewater), was investigated on CNT, Pt/CNT and Ru/CNT modified electrodes based on Carbon Toray in aqueous media. The electroreactivity of DCF on these modified electrodes was studied using cyclic voltammetry and the kinetic parameters were calculated from the scan rate study. Cyclic voltammograms show several oxidation processes, which confirm the interaction between DCF and the catalyst surface necessary for direct oxidation processes. Constant potential electrolysis of DCF was carried out on carbon nanotubes (CNT) and metal supported CNT (M/CNT) modified electrodes, in 0.1 M NaOH and 0.1 M Na2CO3/NaHCO3buffer media. The highest DCF conversion (88% after 8 h of electrolysis) was found in carbonate buffer medium, for Ru/CNT, while the best carbon mineralization efficiency (corresponding to 48% of the oxidized DCF) was obtained on Pt/CNT modified electrode in 0.1 M NaOH medium. The products of the electrolyses were identified and quantified by HPLC-MS, GC-MS, HPLC-UV-RID and IC. The results show the presence of some low molecular weight carboxylic acids, confirming the cleavage of the aromatic rings during the oxidation process.
Bimetallic AuPt/TiO2Catalysts for Direct Oxidation of Glucose and Gluconic Acid to Tartaric Acid in the Presence of Molecular O2
Ding, Jie,Jin, Xin,Lai, Linyi,Liu, Mengyuan,Sun, Yu,Wang, Jinyao,Xia, Qi,Yan, Hao,Yang, Chaohe,Zhang, Guangyu,Zhang, Wenxiang
, p. 10932 - 10945 (2020/11/23)
Tartaric acid is an important industrial building block in the food and polymer industry. However, green manufacture of tartaric acid remains a grand challenge in this area. To date, chemical synthesis from nitric acid-facilitated glucose oxidation leads to only a one-pot aqueous-phase oxidation of glucose and gluconic acid using bimetallic AuPt/TiO2 catalysts in the presence of molecular O2, with ～50% yield toward tartaric acid at 110 °C and 2 MPa. Structural characterization and density functional theory (DFT) calculation reveal that the lattice mismatch between fcc Pt and bcc Au induces the formation of twinned boundaries in nanoclusters and Jahn-Teller distortion in an electronic field. Such structural and electronic reconfiguration leads to enhanced σ-activation of the C-H bond competing with π-πelectronic sharing of the C═O bond on the catalyst surface. As a result, both C-H (oxidation) and C-C (decarboxylation) bond cleavage reactions synergistically occur on the surface of bimetallic AuPt/TiO2 catalysts. Therefore, glucose and gluconic acid can be efficiently transformed into tartaric acid in a base-free medium. Lattice distortion-enhanced reconfiguration of the electronic field in Pt-based bimetallic nanocatalysts can be utilized in many other energy and environmental fields for catalyzing synergistic oxidation reactions.
Aerobic oxidation of xylose to xylaric acid in water over pt catalysts
Sadula, Sunitha,Saha, Basudeb
, p. 2124 - 2129 (2018/10/20)
Energy-efficient catalytic conversion of biomass intermediates to functional chemicals can make bio-products viable. Herein, we report an efficient and low temperature aerobic oxidation of xylose to xylaric acid, a promising bio-based chemical for the production of glutaric acid, over commercial catalysts in water. Among several heterogeneous catalysts investigated, Pt/ C exhibits the best activity. Systematic variation of reaction parameters in the pH range of 2.5 to 10 suggests that the reaction is fast at higher temperatures but high C C scission of intermediate C5-oxidized products to low carbon carboxylic acids undermines xylaric acid selectivity. The C C cleavage is also high in basic solution. The oxidation at neutral pH and 60 8C achieves the highest xylaric acid yield (64 %). O2 pressure and Pt amount have significant influence on the reactivity. Decar-boxylation of short chain carboxylic acids results in formation of CO2, causing some carbon loss; however, such decarboxyla-tion is slow in the presence of xylose. The catalyst retained comparable activity, in terms of product selectivity, after five cycles with no sign of Pt leaching.
Rate-limiting steps in bromide-free TEMPO-mediated oxidation of cellulose - Quantification of the N-Oxoammonium cation by iodometric titration and UV-vis spectroscopy
P??kk?nen, Timo,Bertinetto, Carlo,P?nni, Raili,Tummala, Gopi Krishna,Nuopponen, Markus,Vuorinen, Tapani
, p. 532 - 538 (2015/10/28)
A iodometric titration method was introduced to study the conversion of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) to the corresponding N-oxoammonium cation (TEMPO+) by hypochlorite in the absence and presence of bromide ion. The validity of the titration was verified with UV-vis spectroscopy combined with a multivariate curve resolution (MCR) algorithm to calculate the concentrations and spectral signatures of the pure components (i.e., TEMPO, Cl(+1) and TEMPO+). The formation of the oxoammonium cation was successfully followed during the activation of TEMPO by HOCl and HOBr. It was found that HOBr is a more effective activator for TEMPO than HOCl is. Moreover, the importance of a separate activation step for TEMPO with bromide-free TEMPO oxidations could be identified with this titration method. The content of TEMPO+ was also monitored during the TEMPO-mediated oxidation of a cellulosic pulp by hypochlorite in the absence and presence of bromide. It was found that the oxidation of the alcoholic groups by TEMPO+ was generally the rate-determining step and much slower than the regeneration of TEMPO+ through oxidation of the hydroxylamine by HOCl and HOBr. However, at high pH the latter reaction became rate-limiting.
Efficient chiral resolution of (±)-cyclohexane-1,2-diamine
Gao, Chuan-Zhu,Wang, Tian-Shuai,Chen, Jia,Fei, Fan,Zhang, Yan,Yang, Bo
, p. 490 - 492 (2014/11/08)
A novel and efficient method has been developed for the chiral resolution and separation from cis-cyclohexane-1,2-diamine of (±)-cyclohexane-1,2- diamine, which reacts with xylaric acid, a substitute for tartaric acid. This method provides (1R,2R)-cyclohexane-1,2-diamine, and (1S,2S)-cyclohexane-1,2- diamine and cis-cyclohexane-1,2-diamine in good yield with high optical purity.
Pentaric acids and derivatives from nitric acid-oxidized pentoses
Hinton, Michael R.,Manley-Harris, Merilyn,Hardcastle, Kenneth I.,Kiely, Donald E.
, p. 68 - 85 (2013/03/28)
This report describes the preparation of the four stereoisomeric pentaric acids by nitric acid oxidation of d-xylose, d-arabinose, l-arabinose, and d-ribose, with xylaric, d-arabinaric, and l-arabinaric acids being made in a reactor under computer control. The pentaric acids were converted to their crystalline N,N′-dimethylpentaramides, derivatives that proved useful for isolation of the arabinaric acids from their respective oxidation mixtures. The N,N′-dimethylpentaramides were readily convertible to the corresponding pentaric acid disodium salts in aqueous sodium chloride. The 2,3,4-O-triacetyl-N,N′-dimethylpentaramides of xylaric, l-arabinaric, and ribaric acid were also prepared. Ribaric acid was isolated as crystalline 1,4(5,2)-ribarolactone and further characterized by x-ray crystallography.
Identification of low molecular weight organic acids by ion chromatography/hybrid quadrupole time-of-flight mass spectrometry during Uniblu-A ozonation
Amorisco, Apollonia,Locaputo, Vito,Pastore, Carlo,Mascolo, Giuseppe
, p. 187 - 199 (2013/02/23)
RATIONALE: The balance of organic nitrogen and sulfur during ozonation of organic pollutants often shows a lack of complete mineralization. It follows that polar and ionic byproducts are likely to be present that are difficult to identify by liquid chromatography/mass spectrometry (LC/MS). METHODS: The structural elucidation of low molecular weight organic acids arising from Uniblu-OH ozonation has been investigated by ion chromatography/electrospray tandem mass spectrometry (IC/ESIMS/MS) employing a quadrupole timeofflight mass spectrometer. Unequivocal elemental composition of the byproducts was determined by a combination of mass accuracy and high spectral accuracy. RESULTS: The employed identification strategy was demonstrated to be a powerful method of unequivocally assigning a single chemical composition to each identified compound. The exact mass measurements of [M-H]- ions allowed the elemental formulae and related structures of eighteen byproducts to be determined confidently. The main degradation pathways were found to be decarboxylation and oxidation. The experimental procedure allowed the identification of both nitrogen- and sulfur-containing organic acid by-products arising from Uniblu-OH ozonation. CONCLUSIONS: The obtained results are of environmental relevance for the balance of organic nitrogen and sulfur during the ozonation of organic pollutants due to the lack of complete mineralization of the compounds containing these atoms. Copyright 2012 John Wiley & Sons, Ltd. Copyright
The use of N,N′-diallylaldardiamides as cross-linkers in xylan derivatives-based hydrogels
Pohjanlehto, Helin,Set?l?, Harri,Kammiovirta, Kari,Harlin, Ali
body text, p. 2736 - 2745 (2012/01/05)
N,N′-Diallylaldardiamides (DA) were synthesized from galactaric, xylaric, and arabinaric acids, and used as cross-linkers together with xylan (X) derivatives to create new bio-based hydrogels. Birch pulp extracted xylan was derivatized to different degrees of substitution of 1-allyloxy-2-hydroxy-propyl (A) groups combined with 1-butyloxy-2-hydroxy-propyl (B) and/or hydroxypropyl (HP) groups. The hydrogels were prepared in water solution by UV induced free-radical cross-linking polymerization of derivatized xylan polymers without DA cross-linker (xylan derivative hydrogel) or in the presence of 1 or 5 wt % of DA cross-linker (DA hydrogel). Commercially available cross-linker (+)-N,N′-diallyltartardiamide (DAT) was also used. The degree of substitution (DS) of A, B, and HP groups in xylan derivatives was analyzed according to 1H NMR spectra. The DS values for the cross-linkable A groups of the derivatized xylans were 0.4 (HPX-A), 0.2 (HPX-BA), and 0.4 (X-BA). The hydrogels were examined with FT-IR and elemental analysis which proved the cross-linking successful. Water absorption of the hydrogels was examined in deionized water. Swelling degrees up to 350% were observed. The swollen morphology of the hydrogels was assessed by scanning electron microscopy (SEM). The presence of cross-linkers in DA hydrogels had only a small impact on the water absorbency when compared to xylan derivative hydrogels but a more uniform pore structure was achieved.
Reaction pathways of glucose oxidation by ozone under acidic conditions
Marcq, Olivier,Barbe, Jean-Michel,Trichet, Alain,Guilard, Roger
experimental part, p. 1303 - 1310 (2009/12/01)
The ozonation of d-glucose-1-13C, 2-13C, and 6-13C was carried out at pH 2.5 in a semi-batch reactor at room temperature. The products present in the liquid phase were analyzed by GC-MS, HPAEC-PAD, and 13C NMR s
