Yield Of Target Product Research Articles

Acrylic acid synthesis by oxidative condensation of methanol and acetic acid on B–P–V–W–Ox/SiO2 catalyst

The process of oxidative condensation of methanol with acetic acid to acrylic acid on B–P–V–W–Ox/SiO 2 catalyst modified by hydrothermal method has been studied. Modification of the catalyst by hydrothermal treatment of the carrier changes its physical and chemical properties, and therefore its catalytic properties. The influence of the main technological parameters – temperature, contact time and ratio of reagents on the selectivity and yield of the reaction products and on the conversion of acetic acid has been studied when hydrothermally treated catalyst was used. The best time of contact was 8 sec. which allows to reach the highest selectivity and yield of acrylic acid and methyl acrylate. The highest catalytic activity of the designed catalyst is observed at the reaction temperature of 673 K, however, it is impossible to increase temperature over this value due to the limited thermal stability of the catalyst and the sharp increase in the formation of complete oxidation products. With an increase of methanol part in the ratio of reagents (methanol: acetic acid) to 1,2:1, the selectivity of acrylic acid and methyl acrylate increases, and the selectivity of by-products is significantly reduced. The highest yield of the target products in the reaction of oxidative condensation of methanol with acetic acid is observed at a ratio of oxygen: acetic acid 1,5:1. The growth of the oxygen: acetic acid ratio promotes reduce of acetone and methyl acetate selectivity but does not change the selectivity of methyl acrylate and significantly increases the selectivity and yield of acrylic acid. At the best conditions of the reaction it was possible to achieve 54.7 % total yield of acrylic acid and methyl acrylate. Due to the wide availability and relatively low cost of the initial reagents (methanol and acetic acid), the synthesis of acrylic acid by the oxidative condensation of methanol with acetic acid in the presence of the developed catalyst is very promising

Kinetic Studies of Hydrodeoxygenation of Ethyl Ester of Decane Acid over a Ni-Cu-Mo/Al2O3 Catalyst

Nickel-based catalysts for hydrodeoxygenation of vegetable oils are an alternative to the systems based on noble metals and sulfide catalysts for hydrotreatment. Modification of the nickel catalysts with molybdenum and copper allows the yield of target products to be increased and the corrosion resistance of the catalytic system to be improved. The studies were aimed at establishing relationships between temperature, contact time and activity of the modified nickel-containing catalyst to hydroxygenation of esters of fatty carboxylic acids, as well as at determining effective kinetic parameters of the reactant consumption. A flow reactor with the fixed catalyst bed was used for experimental studies at РН2 = 0.25 MPa, temperatures 270, 285, 300 and 315 °C, contact time varied from 600 to 1800 s. It was shown that the selectivity to the main reaction products – nonane and decane – did not change upon varying the reaction temperature and contact time. The experimental data were used for determining the effective rate constants and activation energy of the reaction.

Modeling of Catalytic Reforming: Effect of Kinetic Parameters on the Expected Composition of Products

The sensitivity of the kinetic model of reforming developed earlier to variations of the rate constants of 27 individual reactions is studied. The model adequately describes the operation of the factory unit for gasoline reforming 85−140°С on the Pt−Sn catalyst. In the computational experiments, reactions were determined that have the greatest effect on the yield of target products. The concentrations of target products (benzene, toluene, and the sum of xylenes) are predicted without significant errors if variations in the rate constants are within 10% of their reference values.

Дослідження кінетичних можливостей одержання метил-1,3,4-триметилциклогекс-3-енкарбоксилату за реакцією Дільса-Альдера

Kinetics of the reaction of the cycloaddition of 2,3-dimethylbuta-1,3-diene (DMB) and methylmethacrylate (MMA) by the Diels-Alder reaction was studied. Reaction rate constants k = 4.4∙10-6 l/(mol∙s) at T = 403 K; k = 10.0∙10-6 l/(mol∙s) at T = 413 K; k = 15.8∙10-6 l/(mol∙s) at T = 423 K; k = 19.4∙10-6 l/(mol∙s) at T = 433 K and the activation parameters of the reaction Eakt = 75.2 kJ/mol, ΔS = -146.8 J/(mol∙K), ΔH = 73.9 kJ/mol were determined. Influence of temperature, molar ratio of reagents on the yield of the target product was investigated. At temperature increase from 403 to 433 K, methyl-1,3,4-trimethylcyclohex-3-encarboxylate (MTMCHC) yield increases from 78 % to 92 %. With further increase in temperature, DMB boils and MMA remains in a liquid state, accordingly it is not expected that the target product yield will materially increase. An increase in the excess of DMB: МMA from 1:1 to 2.5:1 makes it possible to increase yield of MTMCHC from 65 % to 92 %. The production of methyl-1,3,4-trimethylcyclohex-3-encarboxylate at the optimal conditions was established: temperature of 423−433 K and molar ratio of reagents DMB:MMA = 1.5:1, the yield of MTMCHC reaches 89−92 % at productivity of 101−105 g/(l·h). Based on the obtained reaction rate constants and the activation parameters of the [4+2]-cyclic addition of 2,3-dimethylbuta-1,3-diene and methylmethacrylate, it was found that the reaction under study is subject to the kinetic law of the second order.

COMPLEXES OF IZOTHIADIAZOLE-CONTAINING BROMONITROSUBSTITUTED THREE UNITS PRODUCT WITH D-METALS (NI, CO, ZN)

This work is continuation of synthesis researches of substituted macroheterocyclic compounds with 1,2,4-thiadiazole fragments. Data of synthesis of complexes with divalent d-metals (Ni, Co, Zn) on the basis of received earlier brominenitrosubstituted isothiadiazole three-unit product are presented. Complexes of BAB-type product consisting 1,2,4-thiadiazole and bromine-nitro-isoindole fragments were received by interaction 3,5-bis-[5(6)-bromine-6(5)-nitro-3-iminoizoindolin-1-ilidenamiino]-1,2,4-thiadiazol with acetates of d-metals in 2-ethoxyethanol at 100 ºC for 2 h. After the reaction the mixture was poured into water and precipitate was filtered and washed with 5 % ammonia, water and hot organic solvents (acetone, methanol, dimethylformamide, pyridine). Yield of target products was 18 – 28 %. The resulting complexes are dark brown powders with high solubility in alcohols, DMF, insoluble in water, dichloromethane and hexane. The structures of products were established by data of mass spectrometry, elemental analysis, UV-vis and IR spectroscopy. Data of MALDI-TOF mass spectrometry showed that complexes with metal of three-unit product with 1,2,4-thiadiazole fragment were isolated as monohydrate by analogy with literary for 1,3,4-thiadiazole. Data of atomic absorption analysis with good convergence of the experimental and calculated values confirmed monohydrate structure these products. These complexes of three-unit products will be used for synthesis of new various substituted macroheterocycles with 1,2,4-thiadiazole fragments.
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Sulfonic acid functionalized hydrophobic mesoporous biochar: Design, preparation and acid-catalytic properties

Sulfonic acid functional strong acidic catalysts are largely used in various chemical reactions. However, in many reactions with water as product, the catalytic activity and selectivity are unsatisfactory, because hydrophilic acid sites of SO3H would suffer from acidity decreasing and some hydrolysis side reactions would occur via water adsorption. Herein, a novel hydrophobic arenesulfonic acid functionalized biochar was successfully prepared for the first time by one-pot diazo reduction method of biochar with amino-arenesulfonic acid (such as, 4-aminbenzenesulfonic acid, 4-amino-1-naphthalenesulfonic acid, 8-amino-1-naphthalenesulfonic acid, 4-amino-3-hydroxy-1-naphthalenesulphonic acid). It has a large specific surface area of 200–400 m2/g, a hydrophobic network with water contact angle higher than 120° and a higher concentration of sulfonic acid over 1.0 mmol/g. Moreover, the hydrophobicity-oleophilicity and acidity are increased with the arene length and grafting amount of arenesulfonic acid. In the esterification reaction of fatty acid with methanol as well as the transesterification reaction of glycerol trioleate with methanol for the production of biodiesel, the sulfonated biochar shows a higher conversion of 96.7% for esterification and 86.3% for transesterification compared with amberlyst-15 (86.7%, 39.9%) and traditional sulfonation biochar-SO3H (27.4%, 32.6%). In the alkylation reaction of 2-methylfuran with cyclopentanone for the production of high-density biofuel, its catalytic efficiency with target product yield of 76.1% is higher than that of amberlyst-15 (50.2%) and traditional sulfonation biochar-SO3H (13.2%), because of its hydrophobicity and strong acidity. Furthermore, the catalyst is stable and shows an excellent cycle performance after 6 runs. The successful preparation of hydrophobic biochar-based acidic catalysts not only provides a new way for high-value utilization of biochar, but also eliminates the negative effect of water on many catalytic reactions.

Basic ionic liquids promoted chemical transformation of CO2 to organic carbonates

Ionic liquids (ILs), especially basic ILs with unique physicochemical properties, have wide application in catalysis. Using basic ILs as catalysts for the conversion of cheap, abundant, nontoxic, and renewable CO2 into value-added organic carbonates is highly significant in view of environmental and economic issues. This review aims at giving a detailed overview on the recent advances on basic ILs promoted chemical transformation of CO2 to cyclic and linear carbonates. The structures of various basic ILs, as well as the basic ILs promoted reactions for the transformation of CO2 to organic carbonates are discussed in detail, including the reaction conditions, the yields of target products, the catalytic activities of basic ILs and the reaction mechanism.

Effect of Antigens Obtained from the Recombinant Strain Bacillus anthracis 55ΔTPA-1Spo– on Organs and Tissues of Immunized Animals

The recombinant B. anthracis strain 55ΔTPA-1Spo– was used for the development and trial of a method for the simultaneous production of immunogenic anthrax antigens, a protective antigen, and the EA1 protein of the S layer, which are components of a prototype anthrax vaccine. The proposed method includes inoculum preparation, cultivation in liquid medium without antibiotics, sterilizing filtration, concentration, diafiltration, and chromatographic purification on various carriers. This method provides for a high yield of both target products. The purified antigens (alone or in combination with each other) were shown to have no toxic effect on organs and tissues of vaccinated laboratory animals in amounts that were several times higher than immunizing doses. The minor changes revealed by histological examination reflect the adaptation-compensatory reactions of the macroorganism and tend to normalize. The response of immune-competent organs corresponded to moderate development of immunogenesis. The addition of EA1 protein to the recombinant protective antigen resulted in an increase in the expression of the genes determining TLR of innate immunity. Immunization of laboratory animals with the combined preparation caused more pronounced immunobiological alterations in lymphoid organs than the use of only the protective antigen.

New Methods for the Synthesis of Alkoxy Derivatives of the closo-Decaborate Anion [2-B10H9(OR)]2–, Where R = C2H5, iso-C3H7, С4H9

A two-stage scheme was proposed for the synthesis of alkoxy derivatives of the closo-decaborate anion [B10H9(OR)]2–, where R = C2H5, iso-C3H7, C4H9. At the first stage, the oxonium derivatives with the general formula [B10H9(OR2)]– were synthesized by the reaction between the [B10H11]–anion and acyclic ethers. At the second stage, the synthesized oxonium derivatives reacted with hydrazine hydrate to form the alkoxy derivatives with the general formula [B10H9(OR)]2–, where R = C2H5, iso-C3H7, C4H9. This approach appreciably increased the yield of target products and simplified their separation. The alkoxy derivatives were separated and characterized by IR and 1H, 11B, and 13C NMR spectroscopy.

A transcriptome analysis of the ameliorate effect of Cyclocarya paliurus triterpenoids on ethanol stress in Saccharomyces cerevisiae.

Saccharomyces cerevisiae (S. cerevisiae) plays a critical role in ethanol fermentation. However, during the fermentation, yeast cells are exposed to the accumulation of ethanol, which significantly affect the cell growth and the target product yield. In the present work, we employed RNA-sequence (RNA-seq) to investigate the ameliorate effect of Cyclocarya paliurus (C. paliurus) triterpenoids on S. cerevisiae under the ethanol stress. After C. paliurus triterpenoids intervention (0.3% v/v), 84 differentially expressed genes (DEGs) were identified, including 39 up-regulated and 45 down-regulated genes. The addition of triterpenoids decreased the filamentous and invasive growth of cells, and benefit to the redox balance and glycolysis. This study offers a global view through transcriptome analysis to understand the molecular response to ethanol in Sc131 by the treatment of C. paliurus triterpenoids, which may be helpful to enhance ethanol tolerance of S. cerevisiae in the fermentation of Chinese fruit wine.

Altering the sensitivity of Escherichia coli pyruvate dehydrogenase complex to NADH inhibition by structure-guided design

A sufficient supply of reducing equivalents is essential for obtaining the maximum yield of target products in anaerobic fermentation. The pyruvate dehydrogenase (PDH) complex controls the critical step in pyruvate conversion to acetyl-CoA and NADH. However, in anaerobic Escherichia coli, PDH residing in the dihydrolipoamide dehydrogenase (LPD) component is normally inactive due to inhibition by NADH. In this study, the protein engineering of LPD by structural analysis was explored to eliminate this inhibition. A novel IAA350/351/358VVV triple mutant was successfully verified to be more effective than other LPD mutants reported till date. Notably, PDH activity with the triple mutant at an [NADH]/[NAD+] ratio of 0.15 was still higher than that of the wild-type without NADH addition. The altered enzyme of the PDH complex was also active in the presence of such high NADH levels. This is the first study concerning protein engineering of PDH by structure-guided design. The presence and functional activity of such an NADH-insensitive PDH complex provides a useful metabolic element for fermentation products and has potential for biotechnological application.

Influence of Molecular Weight of Chitosan on Interaction with Casein

The process of complex formation of casein from skimmed milk and purified casein with chitosan of different molecular weights was studied. It was shown that at pH 6.3 casein micelles and parts of whey proteins coagulated with positively charged chitosan molecules with molecular weights of 45.3, 25.4, 7.7 and 1.5 kDa. As a result of ionic interaction of chitosan with skimmed milk proteins the yield of target product reached 90–92%. It consisted of all forms of casein: α-casein, β-casein, κ-casein and small amount of whey proteins.

Creation of New Analogues of Natural Phytogormons for Increasing the Yield of Agricultural Crops

Synthesis of new potential plant growth regulators (analogues of natural phytohormones) is accomplished by mixing an equimolar mixture of aryloxypropin and 1-methylpiperidin-4-one under the conditions of Favorsky's reactions. New derivatives of acetylene aminoalcohols - the ZhOT series - have been obtained. The structure of the synthesized compounds was established by IR and NMR 1H spectroscopy. Screening of their water-soluble forms, on wheat and barley seeds, two preparations (ZhOT-4 and ZhOT-7) were selected, which exceed both the control and standards of known phytohormones, such as heteroauxin (indolyl-3-acetic acid), 6-BAP (6-benzylaminopurine) for further testing. Conducted in-depth laboratory and demonstration field tests on cereals (wheat and barley) showed high efficiency of ZhOT-4 and ZhOT-7, the indicators of which exceeded the well-known reference preparation - Agrostimulin (Ukraine). The growth regulating activity of synthesized compounds was determined. Processing of wheat seeds ZhOT-4 and ZhOT-7 increased the field germination of seeds, plant height, leaf area, the mass of the aerial part and the total area. The conducted studies showed that the biological activity of the tested compounds largely depends on the concentration and the best growth regulator is ZhOT-4. The activity of the synthesized growth regulatory compounds has been determined. Treatment of seeds of with ZhOT-4 and ZhOT-7 increased seed germination, height of plants, leave areas, weight of an elevated part and the total area, weight of an elevated part and the total area. Studies have shown that the biological activity of tested compounds is largely dependent on the concentration and the best growth regulator is ZhОТ-4. Thus, the advanced laboratory and demonstration (small-scale) comparative tests of ZhOT-4 and ZhOT-7 and the well-known reference preparation "Agrostimulin" (Ukraine) for cereals (wheat and barley) showed high efficiency of new synthesized preparations. The use of ZhOT preparations increases the germination and germination energy, the number of spikelets, the mass of grains, the bushiness and the yield of wheat and barley, leads to the accumulation of dry mass in both the ground and underground parts of plants. The advantages of ZhOT-4 and ZhOT-7 are: high efficiency, a wide range of cultures, good solubility in water, low application dose of 0.0001% by active ingredient (1g per 1t of water) or 13-50 mg per hectare, comparable to natural phytohormones, long shelf life, safety, high yield of target products, sequential 3-stage reaction in one reactor.

Copper‐Catalyzed Esterification of N‐Heteroaryl Methanes by Oxidative Dehydrogenation

AbstractCopper‐catalyzed cross‐dehydrogenative esterification of readily available N‐heteroaryl methanes with acids has been realized in good to excellent yields of target products. Through simple regulation of acid loading, it is possible to achieve mono‐ or di‐esterification of the methyl group with high chemoselectivity. The protocol is suitable for a wide scope of substrates and exhibits high step efficiency and atom economy. It is envisaged that this radical‐promoted one‐pot dual functionalization of C(sp3)−H bond is a general and facile strategy that would enrich the applications of N‐heteroaryl methanes.

Enhancement of aromatics production from catalytic pyrolysis of biomass over HZSM-5 modified by chemical liquid deposition

The catalytic pyrolysis of biomass is a promising technology for producing high-quality fuels and value-added chemicals. However, the development of this technology has been hindered by high coke formation and low target product yield. In this study, chemical liquid deposition (CLD) was adopted to improve the catalytic performance of HZSM-5 in the catalytic pyrolysis of biomass. The changes of the characteristics, including crystallographic structure, porosity and acidity, of the HZSM-5 zeolite after modification were analyzed by XRD, N2 adsorption-desorption, FTIR and NH3-TPD. The results showed that CLD modification reduced the mesopore volume, pore opening size and the number of external acid sites without changing the micropore structure. Py-GC/MS (a pyrolyzer equipped with a gas chromatography-mass spectrometer) and kinetic analysis were used to analyze the catalytic performance of the parent and CLD-modified zeolites. It was found that the production of aromatics increased first and later decreased, reaching optimal levels at a 4% deposition of SiO2, while the selectivity of monoaromatics increased continuously. Additionally, CLD modification raised the energy barriers for the char/coke formation reactions and could inhibit its production. The deposition amount of 4% showed the best char/coke inhibitory effects for catalytic pyrolysis of cellulose, while the char/coke formation decreased continuously with the increase of the deposited amount of SiO2 for catalytic pyrolysis of lignin.

Microwave and enzyme co-assisted aqueous two-phase extraction of polyphenol and lutein from marigold (Tagetes erecta L.) flower

In this study, a novel method of simultaneous extraction and enrichment of total polyphenol (TP) and lutein from marigold flower was developed by microwave and enzyme co-assisted aqueous two-phase extraction (ATPE) (MEAATPE). In this study, ethanol/ammonium sulfate was chosen to construct aqueous two-phase system (ATPS) due to its fine partition and recycling behaviors. The optimal MEAATPE condition was obtained, that is, 28% (w/w), ethanol/20% (w/w) ammonium sulfate, 0.45 U/g enzyme concentration, enzymolysis time of 150 min, enzymolysis temperature of 45 °C, microwave time of 120 s, and microwave power of 270 W, by investigating the effects of ATPS composition and other factors on the yield of target products. Under this optimal condition, the yields of TP and lutein reached 84.61 and 7.32 mg/g with the corresponding recovery rates of 95.35% and 99.85%, respectively. Compared with enzyme-assisted ATPE, microwave-assisted ATPE, ATPE, and Soxhlet extraction (SE), the extraction yield of TP by MEAATPE was the highest, which is 71.14% higher than that of SE. Scanning electron microscopy analysis further showed an optative pretreatment effect of marigold flower powders. Thus, MEAATPE was an efficient, rapid, and environmental-friendly method used for the extraction of natural products.

The influence of modified EK2010 catalyst to the decarboxylation of oleic acid

It is known that the zeolite type catalytic system is the main catalyst of decarboxylation process. However, the influence of modification of acid–base properties of this type of catalyst to the decarboxylation reaction of organic acids is not investigated widely. Therefore, the modification of the bifunctional “EK2010” catalyst with MgO is conducted in the submitted paper. The influence of this modification to the route of decarboxylation process of organic acids and yield of target products have been investigated in the example of oleic acid. It is found out that, when the basicity is increasing, the modification occurs on the surface of catalyst and the activity of the catalyst is rising and decarboxylation reaction of oleic acid is going very well. The catalysts was investigated with XRD, XRF, TGA and IR techniques.

Thiol Treatment Creates Selective Palladium Catalysts for Semihydrogenation of Internal Alkynes

Summary Surface and interfacial engineering of heterogeneous metal catalysts is effective and critical for optimizing selective hydrogenation for fine chemicals. By using thiol-treated ultrathin Pd nanosheets as a model catalyst, we demonstrate the development of stable, efficient, and selective Pd catalysts for semihydrogenation of internal alkynes. In the hydrogenation of 1-phenyl-1-propyne, the thiol-treated Pd nanosheets exhibited excellent catalytic selectivity (>97%) toward the semihydrogenation product (1-phenyl-1-propene). The catalyst was highly stable and showed no obvious decay in either activity or selectivity for over ten cycles. Systematic studies demonstrated that a unique Pd-sulfide/thiolate interface created by the thiol treatment was crucial to the semihydrogenation. The high catalytic selectivity and activity benefited from the combined steric and electronic effects that inhibited the deeper hydrogenation of C=C bonds. More importantly, this thiol treatment strategy is applicable to creating highly active and selective practical catalysts from commercial Pd/C catalysts for semihydrogenation of internal alkynes.

Simulation of the high-octane alkylates manufacturing considering the process unsteadiness

ABSTRACTThe aim of this paper work is to study the model of the process of sulphuric-acid alkylation of isobutane using a mathematical model. The model of the object was developed considering the physicochemical regularities of the process. The paper analyzes the main processes occurring at the installation and performs the results of model verification. In addition, the technological scheme of one of the sulphuric-acid alkylation existing installations were considered. The developed program is able to calculate the composition of the obtained alkylate, to determine the yield of target products and by-products, to select optimal technological process conditions for a given raw material composition. It was noted, that the consumption of sulfuric acid increases as a result of the accumulation of high-molecular organic compounds in it, as well as its dilution with water, which enters the reactor along with the raw material and forms during the side reactions of the process.

Kinetic Simulation of Initiated Cracking of Tar

A kinetic model of the isothermal initiated cracking of tar has been developed, and parameters of the reactions have been found. A computer model of isothermal thermo-oxidative cracking of tar is implemented to determine kinetic constants, and a criterion for mismatching the calculated and experimental data is minimized. The kinetic simulation of the process has been carried out in isothermal regime so that the parameters that allow for increase in yield of target products have been determined.