56-81-5Relevant academic research and scientific papers
Functional investigation and applications of the acetylesterase activity of the Citrus sinensis (L.) Osbeck peel
Fontana, Gianfranco,Bruno, Maurizio,Maggio, Antonella,Rosselli, Sergio
supporting information, p. 4502 - 4507 (2020/03/16)
The hydrolysis of acetyl moieties on a set of commercially relevant substrates was performed by employing the whole tissue of Citrus sinensis (L.) Osbeck peel as an efficient biocatalyst in mild reaction conditions with high degree of regioselectivity. The reaction is done in aqueous media and the product is easily recovered. Optimal reaction conditions were deduced and two practical applications were investigated: the elaboration of acetylglicerols and the preparation of vitamin K1 precursor. Peel waste (flavedo and albedo) from orange juice manufacturing was successfully employed as a biocatalyst.
Biochemical characterization of a recombinant acid phosphatase from Acinetobacter baumannii
Smiley-Moreno, Elizabeth,Smith, Douglas,Yu, Jieh-Juen,Cao, Phuong,Arulanandam, Bernard P.,Chambers, James P.
, (2021/06/09)
Genomic sequence analysis of Acinetobacter baumannii revealed the presence of a putative Acid Phosphatase (AcpA; EC 3.1.3.2). A plasmid construct was made, and recombinant protein (rAcpA) was expressed in E. coli. PAGE analysis (carried out under denaturing/ reducing conditions) of nickel-affinity purified protein revealed the presence of a nearhomogeneous band of approximately 37 kDa. The identity of the 37 kDa species was verified as rAcpA by proteomic analysis with a molecular mass of 34.6 kDa from the deduced sequence. The dependence of substrate hydrolysis on pH was broad with an optimum observed at 6.0. Kinetic analysis revealed relatively high affinity for PNPP (Km = 90 μM) with Vmax, kcat, and Kcat/Km values of 19.2 pmoles s-1, 4.80 s-1(calculated on the basis of 37 kDa), and 5.30 × 104 M-1s-1, respectively. Sensitivity to a variety of reagents, i.e., detergents, reducing, and chelating agents as well as classic acid phosphatase inhibitors was examined in addition to assessment of hydrolysis of a number of phosphorylated compounds. Removal of phosphate from different phosphorylated compounds is supportive of broad, i.e., 'nonspecific' substrate specificity; although, the enzyme appears to prefer phosphotyrosine and/or peptides containing phosphotyrosine in comparison to serine and threonine. Examination of the primary sequence indicated the absence of signature sequences characteristic of Type A, B, and C nonspecific bacterial acid phosphatases.
Well-defined Cp*Co(III)-catalyzed Hydrogenation of Carbonates and Polycarbonates
Dahiya, Pardeep,Gangwar, Manoj Kumar,Sundararaju, Basker
, p. 934 - 939 (2020/12/15)
We herein report the catalytic hydrogenation of carbonates and polycarbonates into their corresponding diols/alcohols using well-defined, air-stable, high-valent cobalt complexes. Several novel Cp*Co(III) complexes bearing N,O-chelation were isolated for the first time and structurally characterized by various spectroscopic techniques including single crystal X-ray crystallography. These novel Co(III) complexes have shown excellent catalytic activity to produce value added diols/alcohols from carbonate and polycarbonates through hydrogenation using molecular hydrogen as sole reductant or iPrOH as transfer hydrogenation source. To demonstrate the developed methodology's practical applicability, we have recycled the bisphenol A monomer from compact disc (CD) through hydrogenation under the established reaction conditions using phosphine-free, earth-abundant, air- and moisture-stable high-valent cobalt catalysts.
Product Control and Insight into Conversion of C6 Aldose Toward C2, C4 and C6 Alditols in One-Pot Retro-Aldol Condensation and Hydrogenation Processes
Gao, Lou,Hou, Wenrong,Hui, Yingshuang,Tang, Yi,Zhan, Yulu,Zhang, Yahong
, p. 560 - 566 (2021/06/25)
Alcohols have a wide range of applicability, and their functions vary with the carbon numbers. C6 and C4 alditols are alternative of sweetener, as well as significant pharmaceutical and chemical intermediates, which are mainly obtained through the fermentation of microorganism currently. Similarly, as a bulk chemical, C2 alditol plays a decisive role in chemical synthesis. However, among them, few works have been focused on the chemical production of C4 alditol yet due to its difficult accumulation. In this paper, under a static and semi-flowing procedure, we have achieved the product control during the conversion of C6 aldose toward C6 alditol, C4 alditol and C2 alditol, respectively. About C4 alditol yield of 20 % and C4 plus C6 alditols yield of 60 % are acquired in the one-pot conversion via a cascade retro-aldol condensation and hydrogenation process. Furthermore, in the semi-flowing condition, the yield of ethylene glycol is up to 73 % thanks to its low instantaneous concentration.
Broadband laser-based mid-IR spectroscopy for analysis of proteins and monitoring of enzyme activity
Schwaighofer, Andreas,Akhgar, Christopher K.,Lendl, Bernhard
, (2021/02/26)
Laser-based infrared (IR) spectroscopy is an emerging key technology for the analysis of solutes and for real-time reaction monitoring in liquids. Larger applicable pathlengths compared to the traditional gold standard Fourier transform IR (FTIR) spectroscopy enable robust measurements of analytes in a strongly absorbing matrix such as water. Recent advancements in laser development also provide large accessible spectral coverage thus overcoming an inherent drawback of laser-based IR spectroscopy. In this work, we benchmark a commercial room temperature operated broadband external cavity-quantum cascade laser (EC-QCL)-IR spectrometer with a spectral coverage of 400 cm?1 against FTIR spectroscopy and showcase its application for measuring the secondary structure of proteins in water, and for monitoring the lipase-catalyzed saponification of triacetin. Regarding the obtained limit of detection (LOD), the laser-based spectrometer compared well to a research-grade FTIR spectrometer employing a liquid nitrogen cooled detector. With respect to a routine FTIR spectrometer equipped with a room temperature operated pyroelectric detector, a 15-fold increase in LOD was obtained in the spectral range of 1600–1700 cm?1. Characteristic spectral features in the amide I and amide II region of three representative proteins with different secondary structures could be measured at concentrations as low as 0.25 mg mL?1. Enzymatic hydrolysis of triacetin by lipase was monitored, demonstrating the advantage of a broad spectral coverage for following complex chemical reactions. The obtained results in combination with the portability and small footprint of the employed spectrometer opens a wide range of future applications in protein analysis and industrial process control, which cannot be readily met by FTIR spectroscopy without recurring to liquid nitrogen cooled detectors.
The structure and prebiotic activity of arabinogalactan from Ferula Kuhistаnica
Rakhmanberdyeva,Shashkov,Bobakulov, Kh.M.,Azizov,Malikova, M.Kh.,Ogay
, (2021/05/31)
Acidic arabinogalactan with molecular weight 36 kDa was isolated from the aerial part of Ferula kuhistаnica, the monosaccharide composition of which is represented by galactose and arabinose in a ratio of 3.6:1. The chemical and spectral methods revealed a main polymer chain consisting of (1 → 6) β-galactopyranose residues, where in position of C-3 were the residues of α-arabinofuranose and its 1,5-linked oligomers, as well as β-GlcpA-4-OMe-(1 → 6)-β-Galp-(1→ fragments. In addition, a small part of the main chain carries monosaccharide residues of β-Galp-(1→ in position C-2. The effect of arabinogalactan on the growth of an associative culture of bifidobacteria and some mono-strains of lactobacilli was studied and it was shown that it exhibits more effective prebiotic activity.
Novel method for producing 2-amino-1, 3-propylene glycol by JIT method
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Paragraph 0052-0054, (2021/11/26)
The invention belongs to the field of fine chemical engineering, and relates to a novel method for producing 2-amino-1, 3-propylene glycol by a JIT method, the novel method is composed of a catalytic chlorination reaction and a catalytic amination reaction, glycerol is chlorinated by hydrogen chloride under the catalysis of zinc chloride to obtain 2-chloro-1, 3-propylene glycol, and the 2-chloro-1, 3-propylene glycol is subjected to a catalytic reaction by urotropin to obtain 2-chloro-1, 3-propylene glycol.
A mild and convenient approach for selective acetonide cleavage involved in carbohydrate synthesis using PPA-SiO2
Nikam, Rahul R.,Gore, Kiran R.
, p. 63 - 74 (2020/01/28)
Here, we report a highly selective, efficient and rapid method for the selective cleavage of primary acetonide using silica supported polyphosphoric acid (PPA-SiO2) for various carbohydrate substrates. Corresponding diols were obtained in good to excellent yields within 30 min using PPA-SiO2. Overall, PPA-SiO2 was found to be a useful catalyst for selective acetonide cleavage in carbohydrate substrates which may expand its utility in organic synthesis.
Selective hydrogenolysis of biomass-derived sorbitol to propylene glycol and ethylene glycol on in-situ formed PdZn alloy catalysts
Jia, Yuqing,Liu, Haichao,Sun, Qianhui
, (2020/08/13)
Sorbitol hydrogenolysis to industrially important propylene glycol and ethylene glycol receives increasing attention, recently. Here, we developed an efficient and stable PdZn alloy catalyst, in-situ formed from a physical mixture of Pd/ZrO2 and ZnO, for the sorbitol hydrogenolysis with Mg3AlOx as a solid base, and obtained a 54.6% yield of the two target glycols (493 K and 5.0 MPa H2). The amounts of ZnO and Mg3AlOx strongly influenced the activity and selectivity, due to their effects on the formation of the PdZn alloys and the competitive metal-catalyzed dehydrogenation/hydrogenation and base-catalyzed retro-aldol condensation steps. The kinetic isotope effects, combined with the inhibiting effects of H2 pressure on the activity in a broad range (3.0–8.0 MPa), confirm that the sorbitol dehydrogenation to hexose intermediates is the kinetically-relevant step in the sorbitol hydrogenolysis. This study provides insights into the catalytic functions and reaction parameters for the hydrogenolysis of polyols to the target glycols.
Catalytic Hydrogenolysis of Solketal on Bifunctional Catalysts with Production of High Octane Components of Motor Fuels
Goncharova, A. V.,Knyazeva, M. I.,Maksimov, A. L.,Ni, D. S.,Ramazanov, D. N.,Samoilov, V. O.
, p. 108 - 117 (2020/03/27)
The possibility of implementing the concept of converting bioglycerin into a blend of oxygenates, potentially applicable as components of gasoline by ketalization with acetone (T = 30°C–40°C, atmospheric pressure), accompanied by mild hydrogenolysis of ketal [T = 100°C–140°C, p(H2) = 2 MPa] to obtain a mixture of of glycerol and solketal isopropyl ethers was demonstrated. Results showed that the preferred method of conversion was the separate performing of ketalization and hydrogenolysis, since when these stages are combined, the side reaction of the formation of free isopropyl alcohol was highly selective. The regularities in the influence of the composition of the catalytic system (Pd/C + para-toluenesulfonic acid) on its activity were observed in the reaction of catalytic hydrogenation of solketal to a mixture of glycerol and solketal isopropyl ethers (optimal ratio of Pd/para-toluenesulfonic acid = 0.811 mol). The addition of 4%–5% glycerol to raw materials increased the yield of target hydrogenation products from 25% to 36%. Using a flow unit, the catalytic hydrogenation of solketal was optimized. In the optimal mode [T = 170°C, p(H2) = 4 MPa, v = 0.5 h?1, H2/feedstock = 660 nL L?1], the conversion of solketal to a mixture of target products (glycerol monoisopropyl ether, glycerol diisopropyl ethers, and solketal isopropyl ether) reached 98%. The possibility of carrying out the reaction on heterogeneous bifunctional catalysts of the Pd/sulfonated coal type was shown.
