Production Of Acetone Research Articles

Boosting photocatalytic synchronous production of H2 coupled with acetone over Co doped Cu3P quantum dots/ZnIn2S4 nanosheets p-n nanojunction

Photocatalysis provides a new way for synchronous H2 production and organic synthesis at normal temperature and pressure, usually, water and organic substrate function as sources of hydrogen protons and organic products, which are complex and limited by two half-reactions. Employing alcohols as reaction substrates to simultaneously produce H2 and valuable organics in a redox cycle is worthy studying, to which catalyst design at atomic level holds the key. In this paper, Co elements doped Cu3P (CoCuP) quantum dots (QDs) are prepared and coupled with ZnIn2S4 (ZIS) nanosheets to form a 0D/2D p-n nanojunction which can effectively boost aliphatic and aromatic alcohols activation to simultaneously produce H2 and corresponding ketones (or aldehydes). The optimal CoCuP/ZIS composite demonstrated the highest activity for dehydrogenation of isopropanol to acetone (17.77 mmol⋅g−1⋅h−1) and H2 (26.8 mmol⋅g−1⋅h−1), which was 2.40 and 1.63 times higher than that of Cu3P/ZIS composite, respectively. Mechanistic investigations revealed that such high-performance originated from the accelerated electron transfer of the formed p-n junction and the thermodynamic optimization caused by the Co dopant which was the active site of oxydehydrogenation as a prerequisite step for isopropanol oxidation over the surface of the CoCuP/ZIS composite. Besides that, coupling of the CoCuP QDs can lower the dehydrogenation activation energy of isopropanol to form a key radical intermediate of (CH3)2CHO* for improving the activity of simultaneous production of H2 and acetone. This strategy provides an overall reaction strategy to obtain two meaningful products (H2 and ketones (or aldehydes)) and deeply explores the integrated redox reaction of alcohol as substrate for high solar-chemical energy conversion.

Enhancing acetone production from H2 and CO2 using supplemental electron acceptors in an engineered Moorella thermoacetica

Acetogens grow autotrophically and use hydrogen (H2) as the energy source to fix carbon dioxide (CO2). This feature can be applied to gas fermentation, contributing to a circular economy. A challenge is the gain of cellular energy from H2 oxidation, which is substantially low, especially when acetate formation coupled with ATP production is diverted to other chemicals in engineered strains. Indeed, an engineered strain of the thermophilic acetogen Moorella thermoacetica that produces acetone lost autotrophic growth on H2 and CO2. We aimed to recover autotrophic growth and enhance acetone production, in which ATP production was assumed to be a limiting factor, by supplementing with electron acceptors. Among the four selected electron acceptors, thiosulfate and dimethyl sulfoxide (DMSO) enhanced both bacterial growth and acetone titers. DMSO was the most effective and was further analyzed. We showed that DMSO supplementation enhanced intracellular ATP levels, leading to increased acetone production. Although DMSO is an organic compound, it functions as an electron acceptor, not a carbon source. Thus, supplying electron acceptors is a potential strategy to complement the low ATP production caused by metabolic engineering and to improve chemical production from H2 and CO2.

Environmental assessment of acetylene production process via calcium carbide: A case study in Sancti Spíritus

Currently, the generation of resources and the problems associated with them are considered to be concern issues for mankind. Acetylene is an essential resource for industrial activities in the Cuban economy and lacks an environmental assessment that establishes the potential impacts of the activities involved in the process. The present study carried out an environmental evaluation of impacts associated with the acetylene process via calcium carbide (CaC2) at the Sancti Spíritus Industrial Gases Company, Cuba. For this purpose, the Life Cycle Assessment (LCA) methodology was applied, considering a cradle-to-gate perspective. The results showed that the activity with the greatest impact was related to CaC2 (impacts up to 99.31%), followed by acetonation (impacts up to 48.84%). This behavior is due to the contribution of CaC2 and acetone production processes respectively. In the Ecosystem Quality damage category was found the highest impact. In addition, a sensitivity analysis was performed to evaluate the impact of the purity variation in the environmental profile on the damage categories, showing that electricity consumption is considered a hotspot in the process and should be controlled more effectively. The present study reports valuable information for the identification of possible environmental improvements to reduce the potential impacts of obtaining acetylene in the Cuban scenario.

Production of acetone, butanol, and ethanol by electro-fermentation with Clostridium saccharoperbutylacetonicum N1-4

This manuscript describes the effect of altering the extracellular redox potential during the production of acetone, butanol, and ethanol on a dual chamber H-type microbial fuel cell by fermenting glucose with Clostridium saccharoperbutylacetonicum N1-4. Extracellular redox potential modification was achieved by either supplementing the microbial broth with the redox agent NADH or by poising the cathode potential at −600 mV vs. Ag/AgCl. The addition of NADH was found to foment the production of acetone via fermentation of glucose. The addition of 200 mM of NADH to the catholyte rendered the highest production of acetone (2.4 g L-1), thus outperforming the production of acetone by conventional fermentation means (control treatment) by a factor of 2.2. The experimental evidence gathered here, indicates that cathodic electro-fermentation of glucose favors the production of butanol. When poising the cathode potential at −600 mV vs Ag/AgCl (electro-fermentation), the largest production of butanol was achieved (5.8 g L-1), outperforming the control treatment by a factor of 1.5. The production of ABE solvents and the electrochemical measurements demonstrate the electroactive properties of C. saccharoperbutylacetonicum N1-4 and illustrates the usefulness of bio-electrochemical systems to improve conventional fermentative processes.

Developing a genetic engineering method for Acetobacterium wieringae to expand one-carbon valorization pathways

BackgroundDeveloping new bioprocesses to produce chemicals and fuels with reduced production costs will greatly facilitate the replacement of fossil-based raw materials. In most fermentation bioprocesses, the feedstock usually represents the highest cost, which becomes the target for cost reduction. Additionally, the biorefinery concept advocates revenue growth from the production of several compounds using the same feedstock. Taken together, the production of bio commodities from low-cost gas streams containing CO, CO2, and H2, obtained from the gasification of any carbon-containing waste streams or off-gases from heavy industry (steel mills, processing plants, or refineries), embodies an opportunity for affordable and renewable chemical production. To achieve this, by studying non-model autotrophic acetogens, current limitations concerning low growth rates, toxicity by gas streams, and low productivity may be overcome. The Acetobacterium wieringae strain JM is a novel autotrophic acetogen that is capable of producing acetate and ethanol. It exhibits faster growth rates on various gaseous compounds, including carbon monoxide, compared to other Acetobacterium species, making it potentially useful for industrial applications. The species A. wieringae has not been genetically modified, therefore developing a genetic engineering method is important for expanding its product portfolio from gas fermentation and overall improving the characteristics of this acetogen for industrial demands.ResultsThis work reports the development and optimization of an electrotransformation protocol for A. wieringae strain JM, which can also be used in A. wieringae DSM 1911, and A. woodii DSM 1030. We also show the functionality of the thiamphenicol resistance marker, catP, and the functionality of the origins of replication pBP1, pCB102, pCD6, and pIM13 in all tested Acetobacterium strains, with transformation efficiencies of up to 2.0 × 103 CFU/μgDNA. Key factors affecting electrotransformation efficiency include OD600 of cell harvesting, pH of resuspension buffer, the field strength of the electric pulse, and plasmid amount. Using this method, the acetone production operon from Clostridium acetobutylicum was efficiently introduced in all tested Acetobacterium spp., leading to non-native biochemical acetone production via plasmid-based expression.ConclusionsA. wieringae can be electrotransformed at high efficiency using different plasmids with different replication origins. The electrotransformation procedure and tools reported here unlock the genetic and metabolic manipulation of the biotechnologically relevant A.wieringae strains. For the first time, non-native acetone production is shown in A. wieringae.

Control of side-stream pressure-swing distillation and extractive distillation for separating azeotropic mixture of cyclohexane and acetone

Dynamic controls of a side-stream pressure swing distillation (PSD) and extractive distillation (ED) process for cyclohexane and acetone separation are investigated. The processes operating parameters are optimized with a sequential iterative procedure based on the total annual cost (TAC). The dynamic result shows that for the side-stream PSD process, a modified control structure 2 (CS2) with the composition controller (CC) cascaded with the temperature controller 2 (TC2) can efficiently handle the feed disturbances, with the output signal being the ratio of reboiler duty to feed flow rate (QR/F). For the ED process, a modified control structure 4 (CS4) with the acetone product composition controller as the characteristic control loop can efficiently handle the disturbances which is controlled by the ratio of solvent flow to feed flow rate (S/F). A comparison of the side-stream PSD process and the ED process shows the former has decent dynamic performance.

Production of acetone by catalytic hydration of acetylene

Among the known processes for the production of acetone, the most promising is the synthesis by hydration of acetylene in the presence of catalysts. The advantage of this method is the possibility of carrying out the process in existing acetaldehyde production plants. On the other hand, the process of simultaneous production of acetaldehyde and acetone under the action of polyfunctional catalysts and the implementation of the process using flexible technology is promising. To study the influence of various factors on the process of obtaining acetone by the catalytic hydration of acetylene and to create a technology for producing acetone. The specific surface area, crushing strength, total pore volume, and ash content of the samples were determined. Acetylene was saturated with water at a temperature of 70-80 ℃ and a ratio of water: and acetylene = (1:3)-(1:5), mol was passed through the catalyst bed at 360 ℃ with a space velocity of 180-200h-1. The gas-vapour mixture leaving the reactor was cooled in a refrigerator. The reaction products were collected with water. The catalyst contains acetaldehyde, acetone, crotonaldehyde, etc. To maintain the degree of acetylene conversion not lower than 80%, the reaction temperature was raised by 10 ℃ every 20 hours. After 96-120 hours, the degree of acetylene conversion decreases to 75-70%. The reactions of catalytic hydration of acetylene to acetaldehyde and acetone were carried out on the selection of polyfunctional mixed catalysts. As a result, a catalyst with cadmium fluoride and chromium(III) oxide dissolved in alumina promoted with aluminium fluoride was chosen to produce acetaldehyde. Acetaldehyde is formed by the interaction of acetylene: water =1:3–1:5 at 360-440 ℃ in the presence of a catalyst based on cadmium fluoride with a composition of 18% CdF2, 2,0% AlF3, 5% Cr2O3, 75% Al2O3. The addition of zinc oxide or fluoride to the cadmium-chromium-aluminium catalyst (Catalysts No.5) ensures the selectivity of the catalyst and directs the acetylene hydration reaction towards the formation of acetone. As the temperature rises above 450 ℃, the yield of acetone formation and the selectivity of the process decrease due to the transformation of the formed acetone into other substances. In the temperature range of 360-500 ℃, the relationship between the reaction yield and temperature is extreme, and at 450 ℃ the yield was considered to be maximum. Based on the obtained results, a technological scheme for the production of acetone by the catalytic hydration of acetylene was proposed.

Greener approach to the comprehensive utilization of algal biomass and oil using novel Clostridial fusants and bio-based solvents

A greener method has been tested to utilize algal biomass as a feedstock to produce bio-oil in addition to acetone, butanol, and ethanol (ABE) products. Various hydrolysis treatments were used prior to fermentation including combination of thermal, chemical, and enzymatic, which resulted in maximum sugar release of 27.78 g/L. Bio-based terpenes was used instead of common toxic chemicals together with Clostridial fustants to produce bio-alcoholic fuels. Protoplast fusion technique were used to produce the novel Clostridia fusants (C. beijernickii + C. thermocellum and C. acetobutylicum + C. thermocellocum). Fused strains were then subjected to UV radiation for strain enhancement. Final fusansts showed clear improvement in thermal stability and resistance to biobutanol toxicity. Fermentation experiments showed maximum biobutanol final production of 7.98 g/L using CbCt versus 7.39 g/L using CaCt. Oil extraction from virgin algae was tested using a green, bio-based approach using terpenes with ultrasonication and green Bligh and Dyer method, separately. In preliminary study on algal biomass, the combinations of ultrasonication followed by the green Bligh and Dyer have resulted in oil yield of 46.27% (d-limonene) and 39.85% (p-cymene). Oil extraction from an algae sample following fermentation using the combined extraction method resulted in significantly higher oil yield of 65.04%.

Kinetic and thermodynamic aspects of the process of thermal inactivition of kluyveromyces marxianus inulinase

Background: Inulinase is widely found in microorganisms and higher plants. It catalyzes the reaction of the hydrolysis of inulin, which is present in the tubers and roots of many plants, to fructose and a small amount of glucose.
 Inulin is one of several plant-based polysaccharides that contain glucose or fructose. It is used as a substrate in industrial fermentation processes and in the food industry due to its relatively cheap and abundant source for the microbiological production of high fructose juices, ethanol, acetone and butanol. Inulin-derived oligosaccharides are also used in the medical and food sectors. Inulinase which produced from the yeast K. marxianus at levels close to commercial use. This indicates that inulinase can be used in the production of fructose and fructose syrups. So our main object is to study the effect of different temperatures on the conformation of the Kluyveromyces marxianus inulinase macromolecule, to provide optimal conditions for aniline hydrolysis by inulinase.
 Materials and method: Method of isolation and purification of the inulinase enzyme from Kluyveromyces marxianus, as well as the determination of the protein content and enzyme activity as mentioned in the context of the research. Experiments were carried out to study the thermal stability of enzyme. For this, an enzyme solution at a concentration of 5•10-5 mol / l was incubated in a time interval of 10-60 min at different temperatures, followed by determination of the catalytic activity.
 It is known that different types of bonds and interactions participate in the formation of the molecular structure of enzymes, which are covalent bonds, hydrogen bonds, salt bridges, hydrophobic interactions, so our main goal is to study the effect of different temperatures on the formation of the enzyme molecule in order to provide optimal conditions for aniline hydrolysis. by enzyme.
 Results: of this study revealed that the residual activity of the enzyme after 60 minutes of incubation at 50 °C was 10% of the initial activity at 60 °C 7%. As for the Rate Constants of thermal inactivation of Inulinase at 70 °C were 3.45.
 Conclusions: Results of this study were important and useful in determining parameters of inulinase enzyme. Based on the shape of the curves of the dependence of the catalytic activity of Kluyveromyces marxianus inulinase on the time of thermal inactivation in the temperature range of 20-80 ° C.

Exploration of algal biorefinery frameworks: Optimization, quantification of environmental impacts and economics

The integrated algal biorefinery (IABR) was considered as a feasible alternative to fossil fuels. After the processes of algae cultivation and pretreatment, the algae biomass with different carbohydrate/lipid contents is split into the carbohydrate process for producing fuel/chemicals and the oil process for producing fuel/energy. Four frameworks of IABR are presented: (i) Scenario 1 (SC1) is designed to produce lactic acid/biodiesel, (ii) Scenario 2 (SC2) is an extension of SC1 by increasing the production of biooil, (iii) Scenario 3 (SC3) is an extension of SC2 by adding the combined heat and power (CHP) process, and (iv) Scenario 4 (SC4) is an extension of SC3 by increasing the production of acetone, butanol, and ethanol (ABE). Through sensitivity analysis of environmental impacts and economics to assess the influences of parameters of four scenarios, it shows that (i) SC1 ensures the lower total eCO2 emission than other scenarios, (ii) SC3 with the low carbohydrate content and the low percentage of carbohydrate process could suppress eCO2 emission, (iii) SC3 with the high lipid content and the low percentage of carbohydrate process has the higher total profit than SC2 due to the extra green electricity from CHP for sale. To address an IABR with high economic potential and low environmental impact, the process optimization of SC4 under prescribed algae carbohydrate/lipid contents shows that (i) the total profit of SC4 is higher than SC3 by 81.8 % and (ii) the eCO2 emission of SC4 is lower than SC3 by 51.9 %.

Design and fabrication of a multi-tubular fixed bed reactor for acetone production as a pilot plant model for chemical engineering training in developing nations

In this work, the design and fabrication of a pilot-scale multi-tubular fixed bed reactor have been carried out with the aid of computational software (MATLAB R2010b), aiming to process 6.5 L/h of isopropanol to acetone using non-adiabatic thermal conditions. The reactor fabricated would serve as a demonstration rig to enhance research practice, teaching, and learning processes in Advanced Reactor Analysis. The acetone production studied involves four stages, which are simultaneous vaporization and dehydrogenation, condensation, and storage. In the simultaneous vaporization and dehydrogenation, isopropanol is heated to 473 K indirectly to change the phase of raw material from liquid to vapor. In comparison, isopropanol is dehydrogenated to be acetone and hydrogen with 50 % conversion using Cu/SiO2 composite as a catalyst in the multi-tubular fixed bed reactor at 473 K and 1 bar. Condensation occurs when an ice bath cools down the vapor product to liquid. Hence, the condensed product is tested for acetone, and the overall cost analysis for the whole process iscalculated. The design can be a model for other chemical engineering schools to fabricate a locally made reactorfor the training and re-training of chemical engineers, especially in developing nations.

Mixed effects of moderate exercise and subsequent various food ingestion on breath acetone

Acetone, which is exhaled with breath, is a by-product of lipolysis and could be used as a simple, useful indicator of lipolysis in the body because, unlike blood sampling, it can be measured non-invasively and repeatedly. Breath acetone concentration, however, is known to be affected by several factors such as exercise and food. We designed the experiments to evaluate the mixed effect on breath acetone of exercise and food ingestion in order to enhance the usefulness of breath acetone for monitoring fat loss. Seven healthy males performed moderate exercise for twice of 45 min with an interval of 15 min then rested for 4 h. Exhaled air was sampled every 15 min throughout the experiment. The subjects took one of four types, sugar-rich, balanced, protein-rich and fat-rich, of food for lunch one hour after the exercises or kept fasting. In the case of fasting, breath acetone kept increasing significantly (p < 0.05) compared with the rest value after the exercises until the end of the experiment. In contrast, in the case of taking any type of food, the change in breath acetone varied according to the food type. In the case of taking sugar-rich food, breath acetone significantly decreased (p < 0.05) compared with the fasting case. This decrease might be due to a suppression of acetone production when carbohydrates such as sugar are supplied to a body in the fasting condition. In contrast, in the case of taking fat-rich food, breath acetone showed the higher level than the fasting case. This additional increase might be attributable to the promotion of ketone bodies production, including acetone, due to the ingestion of medium chain triglycerides contained in the fat-rich food. We should therefore consider exercise and food ingestion in using breath acetone as a non-invasive indicator of lipolysis.

A kinetic investigation on low-temperature ignition of propane with ozone addition in an RCM

To extend the temperature for propane ignition to a lower region (< 680 K), ozone (O3) was used as an ignition promoter to investigate the low-temperature chemistry of propane. Ignition delay times for propane containing varying concentrations of O3 (0, 100, and 1000 ppm) were measured at 25 bar, 654–882 K, and equivalence ratios of 0.5 and 1.0 in a rapid compression machine (RCM). Species profiles during propane ignition with varying O3 concentrations were recorded using a fast sampling system combined with a gas chromatograph (GC). A kinetic model for propane ignition with O3 was developed. O3 shortened ignition delay times of propane significantly, and the NTC behavior was weakened. O atoms released from O3 reacted with propane through hydrogen abstraction reactions, which led to the fast production of OH radicals. The following oxidation of fuel radicals generated additional OH radicals. Consequently, the inhibition caused by the slow chemistry of hydrogen peroxide (H2O2) in the NTC region was weakened in the presence of O3. Experimental results with O3 addition can provide extra constraints on the low-temperature chemistry of propane. Species profiles during propane ignition at 730 K with 1000 ppm O3 addition showed the production of propanal (C2H5CHO), acetone (CH3COCH3), and acetaldehyde (CH3CHO) was promoted significantly. Model analyses indicated that O3 shifted the oxidation temperature of propane to a lower region, in which reactions of ROO radicals (NC3H7O2 and IC3H7O2) tend to generate RO radicals (NC3H7O and IC3H7O). The promotion of RO radicals led to the fast production of C2H5CHO, CH3COCH3, and CH3CHO. The corresponding species profile highlighted the reaction relevant to ROO and RO radicals (NC3H7O + O2 = C2H5CHO + HO2 and 2 IC3H7O2 = 2 IC3H7O + O2). Rate constants of these reactions were updated, which can potentially improve the performance of the core mechanism under lower temperatures and provide references for model development of larger hydrocarbons.

Low temperature catalytic conversion of CH4, CO2, and C2H4 to value-added C3 oxygenates and olefins via C1-C2 coupling on Pd-Au/CeO2

The catalytic conversion of CH4 and CO2 in the presence of more reactive co-reactants C2H4 and O2 on Pd-Au/CeO2 is achieved at 200 °C and elevated pressures. Propene and acetone were produced from the catalyzed reaction of CH4 +C2H4 +O2; addition of CO2 to the reactant stream produced methyl acetate (MAc) but it significantly reduced the C-selectivities of propene and acetone. DRIFTS experiments confirmed the formation of methoxy species from CH4 +CO2 at 200 °C, which is an intermediate in the formation of MAc. Control experiments with blanks, and with CeO2 did not show any propene, acetone, or MAc products. The complete oxidation of C2H4 was avoided; the catalyst is stable, and reactant conversions and product yields were sustained for the observed 1200 min time-on-stream, indicating that there is little or no carbon deposition and sintering. This direct coupling of CH4 and C2H4 intermediates to higher carbon-number products at 200 °C is significant.

Electro-oxidation of propylene by palladium functionalized titanium hollow fibre electrodes

The performance of Pd functionalized titanium hollow fibre electrodes (Pd@Ti-HFEs) in the electro-oxidation of propylene was investigated at pH 1 and pH 4 and at applied potentials ranging from 0.7 to 1.2 V vs RHE. Larger quantities of products were obtained at pH 1 in comparison to pH 4, mainly due to extensive dissolution of Pd to Pd2+ in the range of 0.9–1.1 V, initiating a homogeneous chemical reaction of propylene and water to form acetone and Pd nanoparticles. At the lower end of the applied potentials (0.7–0.9 V), allyl alcohol and acrolein are formed, likely heterogeneously by the Pd surface. At the most oxidative potential investigated (1.2 V), acetone production decreases, while propylene glycol and CO2 emerge as reaction products. PdO2 likely forms at these potentials, limiting dissolution and inducing the shift in product selectivity. At pH 4, allyl alcohol and acrolein were detected in the electrolyte up to 1.1 V, while quantities of acetone were significantly smaller than observed at pH 1 at this potential. SEM images show extensive dissolution of Pd does not occur at pH 4, and formation of PdO is favored, as confirmed by post-analysis by XPS. At 1.2 V, quantities of propylene glycol again increase. Varying the flow rate of propylene through the HFE did not affect the product distribution, indicating that mass transfer limitations are likely absent. By taking results of cyclic voltammetry, and SEM and XPS of used electrodes into consideration, we provide an illustration of the correlation between electrode morphology and composition, and the product selectivity.

Microscopic pyrolysis mechanism of tert-butyl hydroperoxide via ReaxFF molecular dynamics

Tert-butyl hydroperoxide (TBHP) is a common curing agent and free radical initiator in petrochemical industries, but may trigger fires and explosions once it decomposes. Therefore, it is imperative to elucidate the pyrolysis mechanism. Herein, the pyrolysis behaviors of TBHP are investigated via ReaxFF molecular dynamics simulations with a reliable force field validated by the density functional theory (DFT) method. The main pyrolysis products of water, acetone, methanol, oxygen, isobutene, methane, tert-butyl alcohol, formaldehyde, and propene, are all detected in the reported experiments. It is found that the peroxy bond scission and the hydrogen abstraction of TBHP by the radicals are two main initial reactions. In the subsequent reactions, the decomposition pathways of two main large radicals of (CH3)3CO· and (CH3)3COO· are tracked, followed by the main consumption and generation channels of the small reactive species of ·OH, ·CH3, and O2. A detailed reaction scheme of the TBHP pyrolysis is thus proposed. In addition, the apparent activation energy is calculated as 20.8 kcal/mol, which reasonably agrees with the experimental value. This work will provide scientific guidance for the process safety of organic peroxides and the development of suppression technologies.

Catalytic Dehydration of Isopropanol to Propylene

Catalytic dehydration of isopropanol to propylene is a common reaction in laboratories to characterize the acid–base properties of catalysts. When acetone is produced, it is the sign of the presence of basic active sites, while propylene is produced on the acid sites. About 2/3rd of the world production of isopropanol is made from propylene, and the other third is made from acetone hydrogenation. Since the surplus acetone available on the market is mainly a coproduct of phenol synthesis, variations in the demand for phenol affect the supply position of acetone and vice versa. High propylene price and low demand for acetone should revive the industrial interest in acetone conversion. In addition, there is an increasing interest in the production of acetone and isopropanol from CO/CO2 via expected more environmentally friendly biochemical conversion routes. To preserve phenol process economics, surplus acetone should be recycled to propylene via the acetone hydrogenation and isopropanol dehydration routes. Some critical impurities present in petrochemical propylene are avoided in the recycling process. In this review, the selection criteria for the isopropanol dehydration catalysts at commercial scale are derived from the patent literature and analyzed with academic literature. The choice of the process conditions, such as pressure, temperature and gas velocity, and the catalysts’ properties such as pore size and acid–base behavior, are critical factors influencing the purity of propylene. Dehydration of isopropanol under pressure facilitates the downstream separation of products and the isolation of propylene to yield a high-purity “polymer grade”. However, it requires to operate at a higher temperature, which is a challenge for the catalyst’s lifetime; whereas operation at near atmospheric pressure, and eventually in a diluted stream, is relevant for applications that would tolerate a lower propylene purity (chemical grade).

Comparative study of different modelling strategies for the dynamic design of cumene reactor in cumene production process

Cumene production is an important intermediate process for the production of phenol and acetone. This paper discusses different modelling strategies to solve the mathematical model of cumene reactor. Five different strategies have been utilised for solving the Partial Differential Equations obtained during the reduction of mathematical model. The schemes include dynamic modelling using Finite Difference Method in OpenModelica, pde solver, FDM in Simulink, MATmol and Orthogonal Collocation Method. A comparative study of the schemes with plant data has been done and it is observed that Orthogonal Collocation Method gives a good agreement with plant data compared to other strategies.

Formation of Organic Acids and Carbonyl Compounds in n-Butane Oxidation via γ-Ketohydroperoxide Decomposition.

A crucial chain-branching step in autoignition is the decomposition of ketohydroperoxides (KHP) to form an oxy radical and OH. Other pathways compete with chain-branching, such as "Korcek" dissociation of γ-KHP to a carbonyl and an acid. Here we characterize the formation of a γ-KHP and its decomposition to formic acid+acetone products from observations of n-butane oxidation in two complementary experiments. In jet-stirred reactor measurements, KHP is observed above 590 K. The KHP concentration decreases with increasing temperature, whereas formic acid and acetone products increase. Observation of characteristic isotopologs acetone-d3 and formic acid-d0 in the oxidation of CH3 CD2 CD2 CH3 is consistent with a Korcek mechanism. In laser-initiated oxidation experiments of n-butane, formic acid and acetone are produced on the timescale of KHP removal. Modelling the time-resolved production of formic acid provides an estimated upper limit of 2 s-1 for the rate coefficient of KHP decomposition to formic acid+acetone.

Formation of Organic Acids and Carbonyl Compounds in n‐Butane Oxidation via γ‐Ketohydroperoxide Decomposition

AbstractA crucial chain‐branching step in autoignition is the decomposition of ketohydroperoxides (KHP) to form an oxy radical and OH. Other pathways compete with chain‐branching, such as “Korcek” dissociation of γ‐KHP to a carbonyl and an acid. Here we characterize the formation of a γ‐KHP and its decomposition to formic acid+acetone products from observations of n‐butane oxidation in two complementary experiments. In jet‐stirred reactor measurements, KHP is observed above 590 K. The KHP concentration decreases with increasing temperature, whereas formic acid and acetone products increase. Observation of characteristic isotopologs acetone‐d3 and formic acid‐d0 in the oxidation of CH3CD2CD2CH3 is consistent with a Korcek mechanism. In laser‐initiated oxidation experiments of n‐butane, formic acid and acetone are produced on the timescale of KHP removal. Modelling the time‐resolved production of formic acid provides an estimated upper limit of 2 s−1 for the rate coefficient of KHP decomposition to formic acid+acetone.