Acetylene Method Research Articles

Effect of water content on the homogeneous catalytic process of N-vinyl pyrrolidone synthesis from acetylene

The mechanism of how water content influences the reaction process is clarified and a one-step synthesis of NVP without water removal is implemented.

Levels, Distributions, and Potential Risks of Hexachlorobutadiene from Two Tetrachloroethylene Factories in China

A systematic investigation was conducted on the emission of hexachlorobutadiene (HCBD) from two tetrachloroethylene factories that used the acetylene method (F1) and the tetrachloride transformation method (F2). The levels of HCBD in the air for F1 were found to be in the range of 1.46-1170 µg/m3, whereas F2 had levels in the range of 1.96-5530 µg/m3. Similarly, the levels of HCBD in the soil for F1 were found to be in the range from 42.2 to 140 µg/kg, whereas F2 had levels in the range from 4.13 to 2180 µg/kg. Samples obtained from the air, soil, and sludge in the reaction area of the tetrachloroethylene factories in China showed high levels of HCBD. The F1 method unintentionally produced more HCBD than the F2 method during tetrachloroethylene production, leading to greater harm. The results of the risk assessment suggested the presence of harmful health effects on workers in the workplace. The investigation findings highlight the need for improved management systems to ensure the safe production of tetrachloroethylene.

Molecular insights into the effects of N-doping on synthesis of vinyl acetate over carbon-supported zinc acetate

This work provides a mechanistic insight into the effects of different type of N-doped carbon-supported catalysts on the synthesis of VAc by the acetylene method. The introduction of N-doping can enhance the adsorption of acetylene and acetic acid molecules onto the catalyst supports. The N6–3 surface which with three pyridinic-N shows the most adsorption stability for both acetylene and acetic acid molecules, and facilitates the synthesis of VAc efficiently. While the N6 surface which with the pyridinic-N is obstructive to the VAc formation.

Efficiency of using new Rhizobium strains on legume crops

During significant time, the use of bean-rhizobial systems and development of effective, competitive microbial preparations have been an integral part of organic farming. Also, in intensive technologies, only due to such ones, it is possible without reducing the achieved level of agricultural production to reduce its cost, harmful effects on the environment and at the same time to achieve ecological purity of products selection of highly effective strains that have adapted to local soil and climatic conditions and acquired resistance to nutrients and plant protection is the most promising strategy to increase the effectiveness of microbial inoculants. The aim of this work was to select highly effective strains that have adapted to local soil and climatic conditions and have become resistant to nutrients and plant protection and are the most promising for improving the effectiveness of microbial inoculants. Field researches were conducted in the research fields of the Skvyra Research Station of Organic Production of the Institute of Agroecology and Environmental Management of NAAS (Ukraine, Kyiv region, Skvyra) during 2020–2021. Nitrogen-fixing activity of root nodules was determined by acetylene method. The gas mixture was analyzed on an «Agilent 6850 chromatograph». The paper presents the results of research to establish the effectiveness of new strains of inoculants on crops of legumes: soybean of Moravia variety and peas of Starter variety in the Kyiv region, Skvyra Research Station of Organic Production of the Institute of Agroecology and Environmental Management of NAAS. The significant effect of new rhizobia strains for inoculation of legumes on phenological indicators and yield of these crops in the conditions of intensive technologies was shown. The competitiveness of strains is controlled by both internal determinants — genotype of the microorganism, and external factors such as symbiont plant physiology, exposure to abiotic factors, tolerance to pesticides and agrochemicals used in crop production technologies. It has been shown that the use for inoculation of soybean strain B. japonicum EL 35 and for inoculation of peas strain R. leguminosarum bv. viciae PS 12 stimulate the development of plants during their growing season and allow to obtain symbiotic systems with a high level of nitrogen fixation, as a result of which we can increase the yield of legumes from 16 to 20%.

Performance Study of Zn-Co-Ni/AC Catalyst in Acetylene Acetylation

Zinc acetate (Zn(OAc)2) loaded on activated carbon (AC) is the most commonly used catalyst for the industrial synthesis of vinyl acetate (VAc) using the acetylene method. The aim of this study is to optimize the Zn(OAc)2/AC catalyst by adding co-catalysts to improve its activity and stability. Ternary catalysts were synthesized by adding Co and Ni to the Zn(OAc)2/AC catalyst (Zn-Co-Ni/AC). Due to the strong synergistic effect among promoter Co, Ni, and the active component of Zn(OAc)2, the resulting catalyst is capable to absorb more acetic acid and less acetylene. The stability and activity of Zn-Co-Ni/AC catalyst have been improved through electron transfer to alter the electron cloud density around the Zn element. Under the same reaction conditions, the activity of Zn-Co-Ni/AC catalyst was enhanced by 83% compared to that of Zn(OAc)2/AC, and the activity was still as high as 30.1% after 120 h of testing.

Progress in Vinyl Acetate

Vinyl acetate is an organic chemical raw material of great industrial value. It is widely used in synthetic film, adhesive, coating and textile slurry. The production route of vinyl acetate is introduced, and the advantages and disadvantages of synthesis methods of vinyl acetate method, acetylene method, EDA cracking method, base synthesis method and Halcon method are compared. The method of carbide acetylene has high economic efficiency, low energy consumption and good environmental protection, proposing the development direction of ethylene acetate production technology.

Design of metal-organic frameworks for selective adsorption of benzene from vinyl acetate

Vinyl acetate is an important organic chemical raw material, which can be used to synthesize a variety of polymer products. However, vinyl acetate products synthesized by the acetylene method contain about 100 ppm benzene impurities, which seriously restricts the synthesis of downstream high-end products. In this work, we screen and design high performance MOF materials for the separation of trace benzene in vinyl acetate using molecular simulation method. Based on the properties of benzene, 152 MOFs are selected from CoRE MOF database for high-throughput calculation. It is revealed that the MOFs with unsaturated metal sites and electron-withdrawing groups on organic ligands are favorable for the adsorption of benzene molecules. 5 top-performing MOFs selected are ECOLEP, FUTDII, EYOQAL, DUFGOB and FEWTUY. We modify ECOLEP, which has the highest adsorption selectivity for benzene, to design a series of MOFs to obtain better adsorbents. Four ECOLEP-M (M = Ni, Cu, Zn, Mg) materials are designed by changing the type of the metal sites, and ECOLEP-Cu performs best with the selectivity of 180300.2. Furthermore, in order to determine the effect of organic ligands, –CF3 group is introduced into ECOLEP-Cu. Finally, ECOLEP-Cu is selected as the most promising material for the removal of trace benzene from vinyl acetate.

HETEROGENEO-CATALYTIC SYNTHESIS OF VINYL CHLORIDE AND CHLOROPRENE FROM ACETYLENE

For the catalytic hydro chlorination of acetylene in the vapor phase based on local raw materials for the Zola-gel technology, we selected an active and high-performance catalyst (ZnCl2)x*(FeCl3)y*(CuCl2)z and also under the influence of various factors (partial pressure, temperature, ratio of reagent properties, contact time, catalyst concentration) the yield and reaction rate were studied with the participation of the selected catalyst. Based on the results obtained, a kinetic equation was proposed that satisfies the reaction, its adequacy is estimated, and a scheme of the reaction mechanism and the basis on the kinetic model are proposed. Because of studying the influence of the mass transfer coefficient on the process productivity and the influence of other factors, the technological parameters of the catalytic flocculants of vinyl chloride and the chloroprene extraction reactor of acetylene were calculated and the main indicators of the compatibility of technological capabilities of environmental and economic factors were substantiated. The successful development of the production of VC from ethylene was associated with the search for a cheaper hydrocarbon feed than acetylene. Analysis of the structure of the cost price of VC obtained by various methods shows that the acetylene method gives the highest cost, with acetylene accounting for about 90%. However, the world hydrocarbon price environment is constantly changing. In the future, it is possible to increase prices for oil and gas raw materials, the convergence of prices for acetylene and ethylene, and the latter may lose its main advantage in this regard.

A Novel Scheme for the Synthesis of 21-Acetoxypregna-1,4,9(11)-triene- 17α,21-diol-3,20-dione from 9α-Hydroxyandrostenedione

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.

Microbial Biomass, Respiratory Activity and Nitrogen Fixation in Soddy-Podzolic Soils of the Pre-Urals Area under Various Agricultural Uses

Indicators of the microbiological activity of virgin (mixed forest and forb–grassy meadow) and arable (permanent black fallow, permanent barley crop, field crop rotation, perennial legume crops) soddy-podzolic soils (Eutric Albic Retisols (Abruptic, Loamic, Cutanic)) of Perm oblast were studied. Depending on the type of land use, the content of organic carbon (bichromate oxidation method) in the soil varied from 0.78 to 1.57%; the carbon of microbial biomass (substrate-induced respiration method), from 366 to 1236 μg/g; basal respiration rate, from 1.62 to 3.13 µg C–CO2/(g h); and nitrogen-fixing capacity (acetylene method), from 11.53 to 77.18 µg C2H4/(kg h). The maximum values of the studied parameters were noted in the soil under the mixed forest, and the minimum values were in the soil of the permanent (42 yr) fallow. In the soil under forest, a low specific respiration of microbial biomass—2.5 µg C–CO2/(mg Cmic h)—was determined, which indicates the stability and maturity of this ecosystem. The most stable functioning of the microbial community among the arable soils under consideration was observed in the soil of the plot with the long-term (30 yr) cultivation of perennial legume crop (eastern galega, Galega orientalis). The contents of the soil organic matter and the microbial biomass carbon and the specific microbial respiration under galega were close to those of the soil of the forest ecosystem. The content of microbial biomass carbon and basal respiration displayed strong and moderate correlation dependences with the total content of soil organic carbon and its labile fraction.

Trace Benzene Separation from Vinyl Acetate: A Multiscale Simulation Study

Vinyl acetate (VAc) is a kind of widely used organic raw material which is mainly synthesized by the carbide acetylene method in China. However, trace amounts of benzene impurities in the VAc product has seriously limited its application in fine chemical industry. In this work, multiscale simulation method including molecular level and process simulation are used to screen an effective metal–organic frameworks (MOFs) which could be employed in the pressure swing adsorption (PSA) process. Grand canonical Monte Carlo (GCMC) and configure bias Monte Carlo (CBMC) are combined to investigate the adsorption behavior in different MOFs: Cu-BTC, Zn-BDC, IRMOFs, and M-DOBDC. Special interactions between exposed metal sites in Cu-BTC result in greater benzene adsorption capacity than VAc. Special square channels in Zn-BDC which is close to benzene molecule also favors the adsorption of benzene. The organic chain length and adding functional groups in IRMOFs have no influence on separation selectivity of benzene over...

Nitrogen transformation rates and N2O producing pathways in two pasture soils

Better understanding of N transformations and the regulation of N2O-related N transformation processes in pasture soil contributes significantly to N fertilizer management and development of targeted mitigation strategies. 15N tracer technique combined with acetylene (C2H2) method was used to measure gross N transformation rates and to distinguish pathways of N2O production in two Australian pasture soils. The soils were collected from Glenormiston (GN) and Terang (TR), Victoria, Australia, and incubated at a soil moisture content of 60% water-filled pore space (WFPS) and at temperature of 20 °C. Two tested pasture soils were characterized by high mineralization and immobilization turnover. The average gross N nitrification rate (ntot) was 7.28 mg N kg−1 day−1 in TR soil () and 5.79 mg N kg−1 day−1 in GN soil. Heterotrophic nitrification rates (nh), which accounting for 50.8 and 41.9% of ntot, and 23.4 and 30.1% of N2O emissions in GN and TR soils, respectively, played a role similar with autotrophic nitrification in total nitrification and N2O emission. Denitrification rates in two pasture soils were as low as 0.003–0.004 mg N kg−1 day−1 under selected conditions but contributed more than 30% of N2O emissions. Results demonstrated that two tested pasture soils were characterized by fast N transformation rates of mineralization, immobilization, and nitrification. Heterotrophic nitrification could be an important NO3−–N production transformation process in studied pasture soils. Except for autotrophic nitrification, roles of heterotrophic nitrification and denitrification in N2O emission in two pasture soils should be considered when developing mitigation strategies.

Activated carbon supported VN, Mo 2 N, and W 2 N as catalysts for acetylene hydrochlorination

Abstract The development of green catalysts for the calcium carbide acetylene method synthesis of vinyl chloride monomer (VCM), is essential material to industrial polyvinyl chloride production. The original catalyst HgCl2 easy to volatile during the reaction lead to environmental pollution. Here we present three different transition metal nitride load into activated carbon (AC): VN/AC, Mo2N/AC, and W2N/AC as novel catalysts. W2N/AC and Mo2N/AC was a relatively stable catalyst to compared with VN/AC. All of them VCM selectivity can maintain 98%. More HCl ratio for Mo2N/AC lead its acetylene conversion reach 80%. The former two catalysts are promising candidates for acetylene hydrochlorination.

Noninvasive assessment of cardiac output by brachial occlusion-cuff technique: comparison with the open-circuit acetylene washin method.

Cardiac output (CO) assessment as a basic hemodynamic parameter has been of interest in exercise physiology, cardiology, and anesthesiology. Noninvasive techniques available are technically challenging, and thus difficult to use outside of a clinical or laboratory setting. We propose a novel method of noninvasive CO assessment using a single, upper-arm cuff. The method uses the arterial pressure pulse wave signal acquired from the brachial artery during 20-s intervals of suprasystolic occlusion. This method was evaluated in a cohort of 12 healthy individuals (age, 27.7 ± 5.4 yr, 50% men) and compared with an established method for noninvasive CO assessment, the open-circuit acetylene method (OpCirc) at rest, and during low- to moderate-intensity exercise. CO increased from rest to exercise (rest, 7.4 ± 0.8 vs. 7.2 ± 0.8; low, 9.8 ± 1.8 vs. 9.9 ± 2.0; moderate, 14.1 ± 2.8 vs. 14.8 ± 3.2 l/min) as assessed by the cuff-occlusion and OpCirc techniques, respectively. The average error of experimental technique compared with OpCirc was -0.25 ± 1.02 l/min, Pearson's correlation coefficient of 0.96 (rest + exercise), and 0.21 ± 0.42 l/min with Pearson's correlation coefficient of 0.87 (rest only). Bland-Altman analysis demonstrated good agreement between methods (within 95% boundaries); the reproducibility coefficient (RPC) = 0.84 l/min with R2 = 0.75 at rest and RPC = 2 l/min with R2 = 0.92 at rest and during exercise, respectively. In comparison with an established method to quantify CO, the cuff-occlusion method provides similar measures at rest and with light to moderate exercise. Thus, we believe this method has the potential to be used as a new, noninvasive method for assessing CO during exercise.

BIOLOGICAL ACTIVITY OF RH IZOSPHERE SOIL SPRING WHEAT IN ASSOCIATION WITH BACTERIA AZOTOBACTER CHROOCOCCUMKZT79. MODIFIED N-ACETYL-D-GLUCOSAMINE

Aim. The study of the biological activity of rhizosphere soil of the plants of spring wheat in association with bacteria Azotobacter chroococcum T79, modified N-acetyl-D-glucosamine. Methods. The biological activity of the rhizosphere soil such as the growth-activating ability (method of phytotest), number (by quantitative dilutions of the soil suspension, plating on selective medium growth Eshbi, and counting bacterial colonies) and nitrogenase activity (acetylene method) of nitrogen-fixing microorganisms in the functioning of the association of spring wheat with bacteria Azotobacter chroococcum T79 in combination with N-acetyl-D-glucosamine (0.1 M) in the greenhouse experiments were study. Results. It was shown the significant increase of the number (in 1.4–3.9 times) and nitrogenase activity (in 2.1–5.6 times) of nitrogen-fixing microorganisms during the vegetation of wheat plants as well as the growth-activating ability of the soil (in 1.2 times) in the early stage of formation phytobacteriology association. Conclusion. The treatment of wheat seeds by Azotobacter chroococcum T79, modified N-acetyl-D-glucosamine vs. azotobacter monoinoculant was promoted activation of the functioning of the bacterial nitrogenase (by 10–38 %) and increasing populations of nitrogen-fixing microorganisms (in 1.2–2.2 times) more than their ability to accumulate biologically active substances in the rhizosphere soil of plants.

The study of symbiotic traits – nodulation and activity of nitrogen fixation – in different cultivars of spring vetch (Vicia sativa L.)

Common vetch Vicia sativa L. is one of the major annual fodder legume crops in Russia. Like other legumes, it can enter into symbiosis with nodule bacteria of the genus Rhizobium and to fix molecular nitrogen from the air. This ability contributes to the enrichment of soils with nitrogen and the possibility of growing crops on poor soils. Vetch symbiotic genes have not yet been identified, so the breeding of this crop is confined to the assessment of breeding material with regard to nodulation and very rarely to the activity of nitrogen fixation measured by the acetylene method. This paper presents the results of studies of nodulation and nitrogen-fixing activity that we conducted with four spring vetch cultivars raised at the Siberian Research Institute for Plant Industry and Breeding. Two varieties of forage pea, namely Druzhnaya and traditional cv. Falenskaya 42, were taken as references. The activity of nitrogen fixation was assessed from nitrogenase activity, assayed by the acetylene method. The study revealed significant varietal differences in nodulation and nitrogen fixation, determined on a gas chromatograph Tsvet 500, Russia. The nitrogenase activity rates in vetch cultivars under study varied from 2811 to 6890 С2Н4 nmol/ plant/h. Two of them, Lena and Priobskaya 25, were prominent in high nodulation nitrogen fixation rates. Nodulation in the two reference pea cultivars was weaker than in vetch. However, their nitrogen fixation activities were higher.

Preparation and Study of Polyvinyl Alcohol Fiber

The preparation of polyvinyl alcohol fibers mainly consists of three steps: 1. The polymerization of vinyl acetate. Need the preparation of vinyl acetate and polymerization of vinyl acetate. The polymerization of vinyl acetate uses acetylene method and ethylene method.2. Preparation of PVA. Mainly to let the polyvinyl acetate taking alcoholysis reaction to the effect of methanol or sodium hydroxide. 3. Preparation of polyvinyl alcohol fiber. Complete dope preparation through washing and dehydration, dissolving, mixing, filtering and deaeration, and uses the dry, wet two methods to form the spinning. Finally, through the follow-up processing, to accomplish the preparation of polyvinyl alcohol fiber. Water soluble and high concentration polyvinyl alcohol fiber ‘s performances are fine and is application widely.

Zinc Acetate Immobilized on Mesoporous Materials by Acetate Ionic Liquids as Catalysts for Vinyl Acetate Synthesis

Ionic liquid containing active ingredient Zn(CH3COO)2was loaded in mesoporous silica gel to form supported ionic liquids catalyst (SILC) which was used to synthesize vinyl acetate monomer (VAM). SILC was characterized by1HNMR, FT-IR, TGA, BET, and N2adsorption/desorption and the acetylene method was used to evaluate SILC catalytic activity and stability in fixed reactor. The result shows that 1-allyl-3-acetic ether imidazole acetate ionic liquid is successfully fixed within mesoporous channel of silica gel. The average thickness of ionic liquid catalyst layer is about 1.05 nm. When the catalytic temperature is 195°C, the acetic acid (HAc) conversion is 10.9% with 1.1 g vinyl acetate yield and 98% vinyl acetate (VAc) selectivity. The HAc conversion is increased by rise of catalytic temperature and molar ratio of C2H2 : HAc and decreased by mass space velocity (WHSV). The catalyst activity is not significantly reduced within 7 days and VAc selectivity has a slight decrease.

Daily dynamics of the number and activity of nitrogen-fixing bacteria in fallow and intensely cultivated soils

The daily dynamics (during 33 days) of the number (colony-forming units (CFU)) of nitrogen-fixing bacteria and of the nitrogen-fixing activity (the acetylene method) were determined in a gray forest soil under a fallow land and under an intensely cultivated field. The daily dynamics of the CFUs determined on the nitrogen-free medium in the samples from both plots had wavelike patterns. The daily values of the actual and potential activities of nitrogen fixation in the samples from the fallow land plot and of the actual activity of nitrogen fixation in the samples from the intensely cultivated soil were low and close to the detection limit. The potential activity of nitrogen fixation in the intensely cultivated soil was significant and also had a wavelike pattern. The harmonic analysis of the daily dynamics of the CFUs and nitrogen fixation showed the statistically significant harmonics of these biological characteristics pointing to the objective and regular character of the wavelike dynamics. The revealed dynamics of the biological characteristics of the soils and the methods of their analysis are important in terms of the comparative study of the biological properties of different soils.

Computer Simulation on Reaction Condition when Vinyl Acetate is Compound by Acetic Acid and Acetylene in Fixed Bed Reactor

The macro-dynamics for synthesis of vinyl acetate on Zn(Ac)2—acticarbon catalyst was studied. Consulting actual plant conditions by means of computer simulation, the parameters and reaction conditions for a fixed bed reactor used to produce vinyl acetate in acetylene method were calculated. The result shows that total heat transfer coefficient between catalyst bed and heat conductive oil could be affected by variety of conditions: catalyst diameter, airspeed, temperature and speed of heat conductive oil, and tube diameter in reactor. Analyzing the principles about how the factors affect the heat conduction, a laboratory reactor was made according to the analogue data. The actual temperature distribution of catalyst bed could inosculate with the analogue results roughly.