scholarly journals Continuous-flow hydrogenation over resin supported palladium catalyst for the synthesis of industrially relevant chemicals

2021 ◽  
Vol 132 (2) ◽  
pp. 717-728
Author(s):  
Emil Kowalewski ◽  
Bartosz Zawadzki ◽  
Krzysztof Matus ◽  
Kostiantyn Nikiforow ◽  
Anna Śrębowata
Keyword(s):  
Continuous Flow ◽  
Catalytic Performance ◽  
Cyclohexanone Oxime ◽  
Reaction Conditions ◽  
Liquid Phase Hydrogenation ◽  
Oxime Formation ◽  
Supported Palladium ◽  
Average Size ◽  
High Flexibility ◽  
Optimal Reaction

AbstractHerein, the catalytic performance of palladium nanoparticles grafted on the polymeric TSNH2 (Tentagel-S-NH2) resin was investigated for continuous-flow liquid-phase hydrogenation of two industrially relevant chemicals: 2-methyl-3-butyn-2-ol and nitrocyclohexane. We investigated the effect of process parameters such as temperature and pressure on PdTSNH2 activity and selectivity. Depending on the reaction conditions, well-dispersed PdNPs with average size of about 2 nm have shown very high flexibility in terms selectivity toward the desired products: 2-methyl-3-buten-2-ol or 2-methyl-2-butanol in the case of 2-methyl-3-butyn-2-ol hydrogenation and cyclohexanone oxime or cyclohexylamine as the main product in the case of nitrocyclohexane conversion. The optimal reaction conditions for 2-methyl-3-buten-2-ol formation were estimated at 25 °C and 5 bar, and in the case of cyclohexanone oxime formation at 40 °C and 10 bar. We demonstrated the general trend in the catalytic performance of 2.2 wt% Pd grafted on Tentagel-S-NH2. Independently of the hydrogenated substrate, the increase in conversion leads to decreased selectivity to 2-methyl-3-buten-2-ol and cyclohexanone oxime at the expense of increasing the selectivity to 2-methyl-2-butanol or cyclohexylamine. Graphic abstract

Study on Catalytic Performance of Supported HPW/C Catalyst for Diethyl Adipate Synthesis

2012 ◽  
Vol 468-471 ◽  
pp. 1371-1374
Author(s):  
Ke Nian Wei ◽  
Bin Zhou ◽  
Jiang Quan Ma ◽  
Yan Wang
Keyword(s):  
Physical Chemistry ◽  
Reaction Time ◽  
Adipic Acid ◽  
Acid Content ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Reaction Conditions ◽  
Catalyst Amount ◽  
Reaction Performance ◽  
Optimal Reaction

HPW/C catalysts were prepared using impregnation method. The physical chemistry properties of the catalysts were characterized employing XRD and NH3-TPD.The effects of HPW loading, catalyst amount and reaction time on the catalyst performances were investigated. The results more acid content and active center contribute to the reaction performance. Under the optimal reaction conditions of 0.8g 29%(w) HPW/C as the catalyst, n(adipic acid): n(ethanol):n(toluene)=1:6:1,5h,the etherification rate was 97.3%.

Study on Catalytic Oxidatio Benzaldehyde to Benzoic Acid with Keggin Polyoxometalate [(CH2)5NH2]4SiW12O40

2012 ◽  
Vol 161 ◽  
pp. 185-189 ◽  
Author(s):  
Yuan Sheng Ding ◽  
Fei Lu ◽  
Xin Bao Han
Keyword(s):  
Benzoic Acid ◽  
Organic Ligand ◽  
Sodium Molybdate ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Composition And Structure ◽  
The Matrix ◽  
Ft Ir ◽  
Keggin Polyoxometalate ◽  
Optimal Reaction

The organic–inorganic hybrid catalyst [(CH2)5NH2]4SiW12O40 was prepared by matrix acid and piperidine. The matrix acid was synthesized by sodium molybdate and sodium silicate, and the piperidine was organic ligand. The proposed composition and structure of the catalyst were evidenced by XPS, FT-IR, XRD, TG-DTA and elemental analysis. The results indicated that the heteropoly anions still reserved their Keggin structure in the compound. Its catalytic performance was evaluated in the oxidation of benzaldehyde to benzoic acid. Various reaction parameters were changed to attain the optimal conditions. The optimal reaction conditions were found to be: n(catalyst): n(benzaldehyde)=3.1×10-3:1; n(H2O2)： n(benzaldehyde)=4.5：1; reaction temperature was 80°C; reaction time was 4h. The yield of benzoic acid achieved above 85%.

scholarly journals Efficient Catalytic Production of Biodiesel with Acid-Base Bifunctional Rod-Like Ca-B Oxides by the Sol-Gel Approach

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 83 ◽  
Author(s):  
Anping Wang ◽  
Hu Li ◽  
Heng Zhang ◽  
Hu Pan ◽  
Song Yang
Keyword(s):  
Renewable Resources ◽  
Sol Gel ◽  
Acid Value ◽  
Catalytic Performance ◽  
Acid Base ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalytic Material ◽  
Acid And Base ◽  
Optimal Reaction

The search for acid-base bifunctional catalysts has become a hot topic in the preparation of biofuels from renewable resources. In the present work, a series of novel acid-base bifunctional metal-boron catalysts were successfully prepared by a sol-gel method and characterized by XRD, IR, SEM, TEM, TGA, BET, and TPD. Among those bifunctional solid materials, the Ca-B(700) catalyst had the highest density of both acid and base sites and showed excellent catalytic performance in the production of biodiesel from nonedible oils with high acid value. Under the optimal reaction conditions of 20/1 methanol/oil mole ratio and 4 wt % catalyst dosage at 105 °C for 2 h, a high biodiesel yield of 96.0% could be obtained from Jatropha curcas oil in one-pot. In addition, Ca-B(700) was also applicable to producing biodiesel from Firmiana platanifolia L.f. oil in a relatively low acid value, with an almost quantitative yield (98.5%) at 65 °C after 2 h. The Ca-B(700) catalyst had good stability and reusability, which is a promising acid-base bifunctional catalytic material for the preparation of biodiesel.

scholarly journals Synthesis and process optimization of Boscalid by catalyst Pd-PEPPSI-IPrDtBu-An

2021 ◽  
pp. 3-3
Author(s):  
Jian Xu ◽  
Xiao-Bing Lan ◽  
Lin-Jian Xia ◽  
Yi Yang ◽  
Gao Cao
Keyword(s):  
Raw Materials ◽  
Condensation Reaction ◽  
Suzuki Reaction ◽  
Coupling Reaction ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
Synthesis Process ◽  
Reaction Conditions ◽  
Cross Coupling Reaction ◽  
Optimal Reaction

The purpose of this research was to reduce the amount of noble metal palladium catalyst and improve the catalytic performance in the Suzuki-Miyaura cross-coupling reaction, which is the key step in the synthesis of Boscalid. Taking o-bromonitrobenzene and p-chlorophenylboronic acid as raw materials, three kinds of Pd-PEPPSI-IPr catalysts were synthesized and employed in the Suzuki reaction, and then the biaryl product was subjected to reduction and condensation reaction to prepare Boscalid. Under optimal reaction conditions, the result showed that the catalytic system exhibits highest catalytic efficiency under aerobic conditions, giving the 2-(4-chlorophenyl)nitrobenzene over 99 % yield. Moreover, the Pd-PEPPSI-IPrDtBu-An catalyst was minimized to 0.01mol%. The synthesis process was mild, the post-treatment was simple, and the production cost was reduced which makes it suitable for industrial production.

Solvent-Free Oxidation of Benzyl Alcohol by 30% H2O2 over LDH Hosted Chromium Complex

2014 ◽  
Vol 1015 ◽  
pp. 497-500 ◽  
Author(s):  
Xiao Li Wang ◽  
Gong De Wu ◽  
Zhi Li Zhai ◽  
Yu Wei Dai
Keyword(s):  
Benzyl Alcohol ◽  
Phase Transfer ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Chromium Complex ◽  
Solvent Phase ◽  
Oxidation Of Benzyl Alcohol ◽  
Double Hydroxide ◽  
Optimal Reaction ◽  
Free Oxidation

A Mg–Al layered-double hydroxide (LDH) intercalated by sulphonato-salhen-chromium (III) complex was prepared and then used to the selective oxidation of benzyl alcohol by 30% H2O2. without any organic solvent, phase transfer catalyst or additive. The results revealed that the LDH hosted chromium complex exhibited much higher catalytic performance than its homogeneous analogue. Under the optimal reaction conditions, the highest conversion of benzyl alcohol reached 52.1%, with 100% of the selectivity to benzyldehyde.

Synthesis of Phosphonates via Michaelis-Arbuzov Reaction

2017 ◽  
Vol 14 (6) ◽  
pp. 883-903 ◽  
Author(s):  
Boppudi Hari Babu ◽  
Gandavaram Syam Prasad ◽  
Chamarthi Naga Raju ◽  
Mandava Venkata Basaveswara Rao
Keyword(s):  
Reaction Times ◽  
Biologically Active ◽  
Fine Tuning ◽  
Arbuzov Reaction ◽  
Reaction Conditions ◽  
Solvent Type ◽  
Potential Applications ◽  
Synthetic Methodologies ◽  
Optimal Reaction ◽  
The Arbuzov Reaction

Background: Michaelis–Arbuzov reaction has played a key role for the synthesis of dialkyl or diaryl phosphonates by reacting various alkyl or aryl halides with trialkyl or triaryl phosphite. This reaction is very versatile in the formation of P-C bond from the reaction of aliphatic halides with phosphinites or phosphites to yield phosphonates, phosphinates, phosphine oxides. The Arbuzov reaction developed some methodologies, possible mechanistic pathways, selectivity, potential applications and biologically active various phosphonates. Objective: The synthesis of phosphonates via Michaelis–Arbuzov reaction with many new and fascinating methodologies were developed and disclosed in the literature, and these are explored in this review. Conclusion: This review has discussed past developments and vast potential applications of Arbuzov reaction in the synthesis of organophosphonates. As presented in this review, various synthetic methodologies were developed to prepare a large variety of phosphonates. Improvements in the reaction conditions of Lewis-acid mediated Arbuzov rearrangement as well as the development of MW-assisted Arbuzov rearrangement were discussed. Finally, to achieve high selectivities and yields, fine-tuning of reaction conditions including solvent type, temperature, and optimal reaction times to be considered.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

scholarly journals A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Zhanzhi Liu ◽  
Ying Li ◽  
Jing Wu ◽  
Sheng Chen
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Optimal Temperature ◽  
Reaction Conditions ◽  
Enzymatic Production ◽  
Physiological Properties ◽  
Potential Applications ◽  
Kinetics Of ◽  
Optimal Reaction ◽  
Gene Age

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.

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