Separation Of Reaction Products Research Articles

Hydrodynamic studies of innovative membrane reactor for enzymatic hydrolysis of lignocellulosic waste.

This paper presents the study concerning the impact of the basic operational parameters on the performance of an innovative microfiltration membrane reactor applied for enzymatic hydrolysis of lignocellulosic biomass. The concept and basic hydrodynamics of the reactor with tubular ceramic membranes and a propeller agitator were shown. Besides, the efficiency of enzymatic hydrolysis of corn straw was studied to check reactor functionality. It has been proven that the proposed reactor construction can improve the microfiltration of lignocellulosic suspension by reducing the cake layer on the membrane surface. Increasing the rotational speed of the propeller agitator also improved the filtration efficiency. The permeate flux during the microfiltration experiments was lower for smaller lignocellulose biomass fraction (D<425 μm) when compared to the less fragmented corn straw (425<D<900 μm). For larger solid fractions, a stirring speed increase enhanced the separation efficiency regardless of the differences in biomass concentration. In contrast, this trend for the finer biomass fraction was only noticeable for the highest used biomass concentration (C=2.0%). Considering the enzymatic hydrolysis of corn straw, membrane separation of reaction products positively influenced the process yield, and the results depended on the applied operational parameters.

Oxygenated bio-fuel synthesis in reactive distillation: A technological reform under process intensification

Chemical Engineering processes demands separation of reaction products to obtain them in purest form. Reactive Distillation facilitates this feature by incorporating a reactive zone for reaction between conventional rectifying and stripping zone for distillation. It also aid for solid catalyst incorporation of amphoteric nature to avoid repetitive addition of catalyst for different experimental run and will also improve the product yield. The other beneficial features of Reactive Distillation include reduced synthesis cost, reduced utility space required and higher selectivity. This technique is introduced in this paper for synthesis of oxygenated bio-fuel. For this, fuel additive of ether family namely Tert Amyl Ethyl Ether (TAEE) is synthesized using ethanol. Similarly, Biodiesel synthesis is done using transesterification of waste cooking oil with methanol. Both fuel-oxygenate (TAEE) and biodiesel are then blended in varying proportion to improve ignition quality of biodiesel fuel. The study is done experimentally and analyzed under object oriented modeling mode in simulation. Optimization of synthesis process is done using revamping in experimental mode corresponding to sensitivity analysis in simulation. The congruence results show that purity of 95 % and 65 % for biodiesel and TAEE respectively is obtained in reactive distillation corresponding to reboiler duty of 2 kW and reflux ratio 4.

Principles of creating a digital twin prototype for the process of alkylation of benzene with propylene based on a neural network

Objectives. To identify the principles of creating digital twins of an operating technological unit along the example of the process of liquid-phase alkylation of benzene with propylene, and to establish the sequence of stages of formation of a digital twin, which can be applied to optimize oil and gas chemical production.Methods. The chemical and technological system consisting of reactor, mixer, heat exchangers, separator, rectification columns, and pump is considered as a complex high-level system. Data was acquired in order to describe the functioning of the isopropylbenzene production unit. The main parameters of the process were calculated by simulation modeling using UniSim® Design software. A neural network model was developed and trained. The influence of various factors of the reaction process of alkylation, separation of reaction products, and evaluation of economic factors providing market interest of the industrial process was also considered. The adequacy of calculations was determined by statistics methods. A microcontroller prototype of the process was created.Results. A predictive neural network model and its creation algorithm for the process of benzene alkylation was developed. This model can be loaded into a microcontroller to allow for real-time determination of the economic efficiency of plant operation and automated optimization depending on the following factors: composition of incoming raw materials; the technological mode of the plant; the temperature mode of the process; and the pressure in the reactor.Conclusions. The model of a complex chemicotechnological system of cumene production, created and calibrated on the basis of long-term industrial data and the results of calculations of the output parameters, enables the parameters of the technological process of alkylation to be calculated (yield of reaction products, energy costs, conditional profit at the output of finished products). During the development of a hardware-software prototype, adapted to the operation of the real plant, the principles and stages of creating a digital twin of the operating systems of chemical technology industries were identified and formulated.

Influence of Tween 80 on enzymatic hydrolysis of corn straw integrated with membrane separation

This study aimed to investigate the influence of Tween 80 on the enzymatic hydrolysis of corn straw integrated with two-step membrane separation of reaction products and recovery of enzymes. Supplementation of the reaction mixture with 0.6% (w/v) Tween 80 resulted in an increased yield of hydrolysis carried out with Cellic® CTec2, both in batch and membrane bioreactor, compared to the enzymatic process conducted without surfactant. In the microfiltration membrane bioreactor, the glucan and xylan saccharification yields were, on average 31.2% and 25.5%, respectively, higher than without using Tween 80. Besides, the addition of Tween 80 significantly enhanced membrane permeability during hydrolysis without impacting its retention coefficients toward catalytic proteins. The ultrafiltration enables partial enzyme recovery and supply enzymes for a new hydrolysis process. Results obtained in this study proved the benefits of using Tween 80 in enzymatic hydrolysis of lignocellulosic biomass. Reduction of membrane fouling by surfactant during hydrolysis increases the filtration efficiency and extends the membrane lifetime.

AWAGS: A single ASIC to identify fast ions from protons to uranium

New tracking detectors are necessary for beam diagnostics and event-by-event particle identification for the Super-FRS, a next generation reaction product separation being constructed at GSI/FAIR in Germany. Novel detectors and electronics are currently being developed to meet the stringent requirements of this forefront fragment separator due to high radiation levels, long term electronic stability and the required homogeneity of materials in the beam, while maintaining very high tracking efficiency. The present contribution focuses on the electronics for a new Gas Electron Multiplier (GEM)-based Time Projection Chamber (TPC) to provide the position information, which are needed to reconstruct the A/q of the fragment from protons to uranium ions. The most recent Front End Electronics (FEE) developed at GSI with a novel Amplifier With Adaptive Gain Settings (AWAGS) ASIC are being tested. This FEE has a low noise level (sub fC), a large dynamic range (up to ∼71pC) with excellent timing properties. The AWAGS uses a switched capacitance technique instead of fixed feedback capacitors to provide the large dynamic range. Results from the ASIC characterisation studies and the outlook for a new, updated chip for the full read out chain of the GEM TPC are presented.

Separation of reaction products from ex-situ mineral carbonation and utilization as a substitute in cement, paper, and rubber applications

Ex-situ mineral carbonation, a CCU process, is one possible approach for the decarbonisation of emission-intensive industry with hard-to-abate process emissions like the cement industry. The chemical reaction ensures long-term binding of carbon dioxide in minerals with the effect of storing otherwise emitted CO2 long term. As a major hurdle for CCU processes is often their economic viability, to create incentives for the usage of this process, these carbonated mineral products must become marketable. A separation approach for the reaction products of this process and possible utilization paths are presented. The separation results in three different fractions, each enriched in either the reaction products amorphous silica or magnesium/calcium silicate or unreacted peridotite. The fractions enriched with reaction products are tested as supplementary cementitious material in cement or as a filler in rubber and paper. The application tests show promising results, comparable or even better than the conventional product. Additionally, based on the laboratory explorations, we present initial economic and environmental investigations showing potential carbon footprint reductions of up to 27% for blended cement with a total global reduction potential of 681 MtCO2e/a. Also, potential carbon footprint reductions of 52% can be achieved by using carbonation products as fillers in rubber and 197% in paper, respectively. While the costs for the utilization of carbonated minerals have been calculated to be higher than for the conventional products, CO2 emission certificates could ensure the same price for cement and even lower costs for the substitution of fillers in paper and rubber.

Enzymatic membrane reactor in xylose bioconversion with simultaneous cofactor regeneration

In this study, we present the concept of co-immobilization of xylose dehydrogenase and alcohol dehydrogenase from Saccharomyces cerevisiae on an XN45 nanofiltration membrane for application in the process of xylose bioconversion to xylonic acid with simultaneous cofactor regeneration and membrane separation of reaction products. During the research, the effectiveness of the co-immobilization of enzymes was confirmed, and changes in the properties of the membrane after the processes were determined. Using the obtained biocatalytic system it was possible to obtain 99% xylonic acid production efficiency under optimal conditions, which were 5 mM xylose, 5 mM formaldehyde, ratio of NAD+:NADH 1:1, and 60 min of reaction. Additionally, the co-immobilization of enzymes made it possible to improve stability of the co-immobilized enzymes and to carry out xylose conversion in six consecutive cycles and after 7 days of storage at 4 °C with over 90% efficiency. The presented data confirm the effectiveness of the co-immobilization, improvement of the stability and reusability of the biocatalysts, and show that the obtained enzymatic system is promising for use in xylose bioconversion and simultaneous regeneration of nicotinamide cofactor.

LDAmy, an α-amylase from Colorado potato beetle (Leptinotarsa decemlineata) with transglycosylation activity

Potential of α-amylase from the gut of Leptinotarsa decemlineata (LDAmy) to catalyse transfer reactions was investigated. LDAmy as a component of insect gut extract showed significant transfer activity on reducing-end- and both-end-protected maltoheptamer substrates. Transfer reaction was examined using purified enzyme, 2-chloro-4-nitrophenyl β-d-glucopyranoside as acceptor and starch and maltooligosaccharides as donors. In addition to suitability of various donors, effect of pH and acetonitrile (MeCN) concentration were also studied. The reactions were followed using separation of reaction products by a reversed phase HPLC method. LDAmy catalysed the hydrolysis and transglycosylation of the both-end-protected substrate 4,6-O-benzylidene-4-nitrophenyl β-maltoheptaoside in parallel reactions. Shorter and longer both-end-protected products with degree of polymerization 4–10 were formed. Identification of products was carried out based on HPLC retention time, UV and mass spectra. Ratio of transglycosylation to hydrolysis reached 0.5 in presence of 20% MeCN as organic solvent. Aromatic protecting group at the non-reducing end was favourable for transfer reaction. Lack of the mobile loop and presence of more nonpolar aromatic moieties near to the active site may be the reason for the enhanced transfer activity of LDAmy based on the comparison of the sequence and structure of mammalian and insect-derived α-amylases. Highlights Transferase activity of Colorado potato beetle derived α-amylase LDAmy is presented. Effect of pH and organic co-solvent on transfer reaction of LDAmy were studied. Shorter and longer products were formed from a both-end protected maltoheptamer. The unusual transfer ability was explained by sequence differences of α-amylases.

Separation of Reaction Products from Ex-Situ Mineral Carbonation And Utilization as a Substitute in Cement, Paper, and Rubber Applications

Separation of Reaction Products from Ex-Situ Mineral Carbonation And Utilization as a Substitute in Cement, Paper, and Rubber Applications

Artemisinin DNA Base Interaction Studies in Presence of Fe(II): LC/TOF MS Separation of Reaction Products

Artemisinin (ART) is a sesquiterpene lactone and a popular malaria drug with potential anticancer properties. In this work, LC/TOF/MS, was used to investigate the reaction of ART with DNA bases. ART-deoxyadenosine and ART-deoxycytidine interactions, were studied in the presence of iron II ions. ART-deoxyadenosine and ART-deoxycytidine reaction mixtures gave chromatographic signatures that remained fairly unchanged at room temperature but grew after incubation at 37 °C. The change in temperature from room temperature to 37 °C was the main driver of adduct formation in these reactions. ART was found to react with Fe(II) ions as observed from several new chromatographic peaks. ART-deoxyadenosine as well as ART-deoxycytidine in the presence of Fe(II) ions resulted in formation of new chromatographic signatures of adducts consisting of DNA bases and ART. It was clear that addition of iron (II) to DNA base-ART mixtures gave rise to new reaction products mediated by a different reaction mechanism. Studies of ART reactions with DNA in vitro is key in elucidating elusive mechanism of this drug.

Enriched Co-Treatment of Pharmaceutical and Acidic Metal-Containing Wastewater with Nano Zero-Valent Iron

Among traditional hazardous waste sources, pharmaceutical-containing wastewater and acidic mine drainage need treatment to preserve the expected water supply quality. A nano zero-valent iron (nZVI)-enriched treatment of these two streams is evaluated for simultaneous removal of various heavy metal ions, organic pollutants, sulfates, the efficiency of the treatment system, and separation of reaction products in the fluidized-bed reactor. The reactor packed with silica sand was inoculated with sludge from an anaerobic digester, then 1–3 g/L of nZVI slurry added to cotreat a hospital feed and acid mine wastewater at 5:2 v/v. The biotreatment process is monitored through an oxidation–reduction potential (Eh) for 90 days. The removal pathway for the nZVI used co-precipitation, sorption, and reduction. The removal load for Zn and Mn was approximately 198 mg Zn/g Fe and 207 mg Mn/g Fe, correspondingly; achieving sulfate (removal efficiency of 94% and organic matter i.e., chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved organic carbon (DOC), total dissolved nitrogen (TDN) reduced significantly, but ibuprofen and naproxen achieved 31% and 27% removal, respectively. This enriched cotreatment system exhibited a high reducing condition in the reactor, as confirmed by Eh; hence, the nZVI was dosed only a few times in biotreatment duration, demonstrating a cost-effective system.

Nucleophilic degradation of diazinon in thermoreversible polymer-polymer aqueous biphasic systems.

Although aqueous biphasic systems have been largely investigated in the separation and/or purification of biocompounds, their potential as reaction media to design integrated reaction-separation processes has been less explored. In this work aqueous biphasic systems (ABSs) composed of polypropylene glycol of molecular weight 400 g mol-1 (PPG 400) and different polyethylene glycols (PEGs) were characterized, and investigated for integrated reaction-separation processes, i.e. in the nucleophilic degradation of diazinon and further separation of reaction products by taking advantage of the lower-critical solution temperature (LCST) behaviour of these ABSs. The nucleophilic degradation of diazinon was carried out in the monophasic regime at 298 K, after which an increase in temperature (up to 313 K) allowed the product separation by two-phase formation (thermoreversible systems). The reaction kinetics and reaction pathways have been determined. The reaction kinetic increases as the PEG molecular weight decreases, with the half-life values obtained being competitive to those previously reported using volatile organic solvents as solvent media and significantly higher than under alkaline hydrolysis. One reaction pathway occurs in ABSs comprising PEGs of higher molecular weights, whereas in the ABS composed of PEG 600 two reaction pathways have been identified, meaning that the reaction pathways can be tailored by changing the PEG nature. ABSs formed by PEGs of lower molecular weights were identified as the most promising option to separate the pesticide degradation products by simply applying changes in temperature.

Effect of Phosphorus Impurities in Precursors on Characteristics of Magnesiothermic Tungsten Powders

We have studied tungsten powders prepared by reducing the MgWO4 and Ca3WO6 tungstates containing 0.05–1.5 wt % phosphorus at temperatures from 700 to 800°C. The reduction of MgWO4 containing less than 0.3 wt % phosphorus was accompanied by separation of reaction products. Most of the magnesium oxide formed was located beyond the reaction zone. The tungsten powders prepared by reducing MgWO4 consisted of α-W. The powders prepared by reducing Ca3WO6 at a temperature below 740°C consisted of a mixture of the α- and β-phases. Raising the percentage of phosphorus in the starting tungstate led to an increase in the percentage of the β-phase. The highest β-W content of the powder was 60 wt %.

Enzyme synthesis of cephalexin in continuous-flow microfluidic device in ATPS environment

We present an experimental study dealing with the transfer of the enzyme synthesis of cephalexin from a batch arrangement to a continuous-flow microfluidic system with integrated reaction product separation and enzyme recovery. Cephalexin is synthesized by penicillin acylase in a kinetic regime that is characterized by the appearance of a concentration maximum during the enzyme reaction. We determine proper reaction conditions providing a high cephalexin yield and relatively short reaction time by performing a set of batch experiments. Once the residence/reaction time was found, the reaction process is transferred into a continuous mode. We employ an aqueous two-phase system (ATPS) forming two-phase slug flow in a microfluidic capillary as the reaction-separation environment. Such a flow arrangement guarantees a uniform residence time of the reaction mixture in the reaction microcapillary, and it provides in situ extraction of cephalexin. ATPS also offers an easy way for enzyme recycling and addition of fresh reactants as a benefit. We optimized the composition of the ATPS based on phosphates, polyethylene glycol and water so that cephalexin showed a high affinity to one phase and a soluble enzyme to the other phase. Due to the low level of utilization of a soluble catalyst in the continuous flow arrangement, we recycled the reaction phase containing the dissolved enzyme. The recycling loop also contained microdialysis unit for removal of phenylglycine that tends to cause system clogging. We show that the final design of the microfluidic system with recycle can operate continuously for at least 5 h. Our integrated microfluidic platform represents a general solution for enzymatic reactions performed with simultaneous reaction product separation and enzyme recycle.

Phenotypic and genetic study of seedlessness in grape varieties

The phenomenon of seedlessness in grapes is a special form of sterility and it is characterized by the complete absence of seeds in the berry or the presence of their primordia. A phenotypic and genetic studies of 20 varieties of seedless grape growing at the Anapa ampelographic collection were carried out. The manifestation of the degree of seedlessness may depend on growing conditions and climatic peculiarities during crop formation. In the weather and climate conditions of 2019, which were characterized by an increased temperature regime, the degree of seedless berries of the studied varieties was determined. Genetic studies were performed on the basis of polymerase chain reaction (PCR) with the separation of reaction products by capillary electrophoresis using the automatic genetic analyzer ABI Prism 3130. The DNA-marker p3-VvAGL11, closely linked to the VvAGL11 locus, which influences to the formation of seedlessness in grapes, was used in the work. The mass of rudiments was determined by extracting seed primordia from berries and their dehydration in a drying cabinet to final unchanged mass of rudiments. In the varieties Kishmish Sogdiana, Remaily Seedless and Kishmish Kruglyi rudiments were practically absent. The greatest mass of rudiments in the berry (over 14.1 mg) was observed in the varieties Pamyati Smirnova, Yangi Yer, Vanessa Seedless, Kishmish Luchistyi. In addition to the degree of development of seed rudiments, in seedless table grape varieties, an important indicator is the size of the berry, which generally affects the consumer choice of a particular variety. By the average weight of the berry, Kishmish Luchistyi variety (5.05 g) was distinguished. The smallest mass of berries observed in varieties Rozovyi Biser, Kishmish Siyekh, Kishmish Kruglyi, Kishmish Krupnyi, Bessemyannyi Ranniy (less than 1.5 g). DNA analysis using the p3-VvAGL11 marker revealed in all genotypes the presence of a PCR-product with a size of 198 nucleotide pairs, which corresponds to published data on the correlation of this size of the PCR-product with seedless berries.

DNA-fi ngerprinting of local Аbkhazian grape variety Kachich

The study of the indigenous gene pool of Vitis vinifera L. of diff erent zones of viticulture with the involvement of molecular genetic methods is an urgent due to the wide diversity of grape varieties. The territory of Abkhazia is a unique zone, one of the hotbeds of the emergence of cultural grapes. «Kachich» is the oldest Abkhazian grape variety, known for the quality of wines obtained from its harvest. The variety is more resistant to fungal diseases compared to popular European varieties cultivated in modern Abkhazia, and is particularly resistant to rot of berries. However, often the local population calls old bushes by the name «Kachich», which give grapes of good quality for making of red wines and not always these forms correspond to the morphological description of the variety. The aim of the research is DNA fi ngerprinting of the «Kachich» grape variety based on the analysis of polymorphism of microsatellite loci. The object of the study was the plants corresponding to the variety description, growing in the collection of the agricultural company “Wines and waters of Abkhazia” (Sukhum, Abkhazia). DNA was isolated from the young leaves of the top of the shoot of typical plants of the variety by the CTAB-method. Genotyping was carried out by polymerase chain reaction (PCR) with separation of reaction products by capillary electrophoresis. Highly polymorphic SSR-markers recommended for grapes varieties identifi cation were used for study (VVS2, VVMD5, VVMD7, VVMD25, VVMD27, VVMD28, VVMD32, VrZAG62, VrZAG79). The size of amplifi ed fragments was estimated using the automatic genetic analyzer ABI Prism 3130 and special software GeneMapper and PeakScanner. To clarify the size of amplifi ed fragments, the DNA of reference varieties was used. According to the results of microsatellite analysis, the DNA-certifi cate of the genotype of the «Kachich» grape variety was compiled: VVS2153 155 VVMD5234 240 VVMD7239 249 VVMD25239 267 VVMD27186 193 VVMD28234 248 VVMD32262 272 VrZAG62194 196 VrZAG79236 236. The resulting DNA-profi le was checked for matches in the Vitis International Variety Catalogue VIVC. No matches of the obtained DNA-profi le with any other DNA-profi le presented in the Database were found. DNA-certifi cate of genotype «Kachich» can be successfully used for varieties identifi cation of grape plants if necessary to clarify their varietals affi liation.

Titanium production by magnesium thermal reduction in the electroslag process

Titanium is widely used in specific applications due to its high strength, low density and good chemical stability. Despite it is one of the most abundant elements in the earth’s crust, it is very expensive, because production of pure metallic titanium is very complex. Kroll process is the way how most of the titanium is produced nowadays. Shortages of this process are that it is batch process and it is very energy exhaustive, because titanium sponge material after reduction reaction needs complex post processing to isolate pure titanium. In this work we describe and experimentally investigate technology for Ti production from titanium tetrachloride using combined Kroll and electroslag process. Such process allows to achieve better reaction product separation by molten slag and process can potentially be continuous, thus technological process to produce metallic titanium can be significantly shortened.

Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization

Large amounts of residual 1-methylnaphthalene are generated when 2-methylnaphthalene is extracted from alkyl naphthalene. In order to transform waste into assets, this study proposes a feasible process for preparing 2-methylnaphthalene from 1-methylnaphthalene through isomerization and crystallization. The 1-methylnaphthalene isomerization was carried out in a fixed-bed reactor over mixed acids-treated HBEA zeolite. The results showed that acidic properties of catalysts and reaction temperature were associated with the 2-methylnaphthalene selectivity, yield and catalytic stability. At a high reaction temperature of 623 K, the 2-methylnaphthalene yield was 65.84 %, and the deactivation rate was much lower. The separation of reaction products was then investigated by two consecutive crystallization processes. Under optimal conditions, the 2-methylnaphthalene purity attained 96.67 % in the product, while the yield was 87.48 % in the refining process.

Experimental Investigation on the Separation Time in Compacted Thermite Using a Combustion Front Quenching Technique as Validation of a Phase Field Model

A combustion front quenching technique is used to investigate the separation of reaction products during a fast self-propagating high-temperature synthesis (SHS) thermite reaction, which is applied to the aluminothermic welding of rails. Quenching of the reaction zone with a melt temperature at approximately 2400 K enables the possibility of analyzing intermediate stages during exothermic SHS type reactions and the prediction of a time duration for a complete separation of the products Fe, Al2O3, and intermetallics. An average separation time is then used to validate a 3D phase field solver phaseFieldFoam and solution parameters through application of the diffusive Cahn–Hilliard equation, also known as model B.

Metal Nanoparticles Stabilized in Ionic Liquids for Catalytic Multiphase Reactions

Metal nanoparticles (MNPs) have attracted widespread interest as catalytic materials due to their small size and high surface to volume ratio, which lead to a greater catalytic activity. To preserve such features however, agglomeration of MPNs must be prevented by the use of stabilizing agents of which ionic liquids (ILs) are probably the best ever reported compounds. ILs offer unique environments suitable for both the synthesis, the stabilization, and the segregration of highly dispersed MNPs. Such dispersions have been successfully tested for catalysis in a number of different processes mostly including hydrogenations, hydroformylations, and C-C bond forming reactions (Heck, Suzuki, Sonogashira, and Ullman couplings). In this review, an introductory section is focused on major aspects accounting for the stabilizing effects of ILs on MNPs. Then, model examples of catalytic applications are given for Pd-, Rh-, and Ru- NPs in multiphase systems composed of binary and ternary immiscible liquid phases which are able not only to improve the catalytic performance of NPs, but to allow also the recycling of nanocatalysts and the easy separation of reaction products. Keywords: Metal nanoparticles, multiphase organic reactions, catalysis, ionic liquids, catalyst recycling, products separation.