Tert-butanol System Research Articles

An Effective Strategy for the Production of Lauric Acid-Enriched Monoacylglycerol via Enzymatic Glycerolysis from Black Soldier Fly (Hermetia illucens) Larvae (BSFL) Oil.

Here, we developed an efficient strategy for the production of lauric acid-enriched monoacylglycerol (MAG) via enzymatic glycerolysis using black soldier fly (Hermetia illucens) larvae (BSFL) oil. The effects of the substrate molar ratio, reaction temperature, type of immobilized lipase, and organic solvent on the MAG content and conversion degree of BSFL oil were optimized. The maximum substrate conversion rate (97.88%) and MAG content (70.84%) were obtained in a tert-butanol system at 50 °C with a glycerol/BSFL oil molar ratio of 4:1 by using immobilized MAS1 lipase as a catalyst. The MAG content in the purified product reached 97.7%, with lauric acid accounting for 50.2%. Improved oxidation stability was observed after glycerolysis. Overall, this study provides a new strategy for the preparation of lauric acid-enriched MAG from BSFL oil.

Investigation of energy-saving thermally coupled extractive distillation alternatives with different liquid side-stream for a quaternary azeotropic system

The acetone/methanol/butanone/tert-butanol system is a quaternary organic compound with multi-azeotropes and often appears in the chemical and petrochemical industries. In view of achieving its energy efficient separation, this article establishes seven alternative thermally coupled extractive distillation configurations by introducing one or more liquid side-streams into one regular four-column configuration with chlorobenzene as an entrainer. Furthermore, the intensified configurations having multiple side-streams, multiple recycling-streams, and multiple solvent recovery sections features are optimized by a simulated annealing based systematic optimization method with the minimum total annual cost (TAC) as the target. Finally, a comprehensive assessment is made among all the configurations in terms of several metrics such as TAC, energy-saving, exergy loss and CO2 emissions. The results demonstrate that these intensified configurations can respectively reduce 5.32–14.38% energy consumption, 3.91–10.11% TAC and 5.65–18.05% CO2 emissions as compared with the regular configuration. One of double-side-stream configurations is the optimal option while the only triple-side-stream configuration is the suboptimal one. Besides, the proposed optimization method for side-stream extractive distillation configurations shows high computational efficiency and good applicability and flexibility.

Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity

Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents.

Kinetics of lipase recovery from the aqueous phase of biodiesel production by macroporous resin adsorption and reuse of the adsorbed lipase for biodiesel preparation

A commercial macroporous resin (D3520) was screened for lipase recovery by adsorption from the aqueous phase of biodiesel production. The influences of several factors on the adsorption kinetics were investigated. It was found that the kinetic behavior of lipase adsorption by macroporous resin could be well described by pseudo-first-order model. Temperature had no significant effects on lipase adsorption, while resin-to-protein ratio (R) significantly affected both rate constant (k1) and equilibrium adsorption capacity (Qe). No lipase was adsorbed when mixing (shaking) was not performed; however, protein recovery reached 98% after the adsorption was conducted at 200rpm for 5h in a shaker. The presence of methanol and glycerol showed significant negative influence on lipase adsorption kinetics. Particularly, increasing glycerol concentration could dramatically decrease k1 but not impact Qe. Biodiesel was found to dramatically decrease Qe even present at a concentration as low as 0.02%, while k1 was found to increase with biodiesel concentration. The adsorbed lipase showed a relatively stable catalytic activity in tert-butanol system, but poor stability in solvent-free system when used for biodiesel preparation. Oil and biodiesel were also found to adsorb onto resin during transesterification in solvent-free system. Therefore, the resin had to be washed by anhydrous methanol before re-used for lipase recovery.

Biodiesel synthesis directly catalyzed by the fermented solid of Burkholderia cenocepacia via solid state fermentation

The objectives of this work were to evaluate the production of Burkholderia cenocepacia lipase via solid state fermentation (SSF) and its applications in atransesterification reactions through the direct addition of the lyophilized fermented solid to tert-butanol system. The maximal olive oil-hydrolyzing activity of fermented solid was 72.3 units per gram of dried fermented solid at 96h through adding 8% (v/w) olive oil as inducer during SSF. After lyophilization and delipidation, the whole fermented solid was directly employed to catalyze the ethanolysis of soybean oil for biodiesel production in tert-butanol. The highest biodiesel yield was 86% after 96h under the optimized conditions of 45°C, speed rate 200rpm, alcohol/oil molar ratio 4:1, fermented solid amount 1.5wt.% (based on oil weight, g), tert-butanol amount 40% ((based on oil volume, v/v) and moisture content 5wt.% (based on oil weight, g). This strategy of biodiesel production in this work shows potential alternative to lower down the lipase cost for enzyme-catalyzed transesterification reactions.

Effects of some inhibitors on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides and preparation of biodiesel by enzymatic transesterification of the lipid

Microbial lipid produced using yeast fermentation with inexpensive carbon sources such as lignocellulosic hydrolyzate can be an alternative feedstock for biodiesel production. Several inhibitors that can be generated during acid hydrolysis of lignocellulose were added solely or together into the culture medium to study their individual inhibitory actions and their synergistic effects on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides. When the inhibitors were present in isolation in the medium, to obtain a high cell biomass accumulation, the concentrations of formic acid, acetic acid, furfural and vanillin should be lower than 2, 5, 0.5 and 1.5 g/L, respectively. However, the synergistic effects of these compounds could dramatically decrease the minimum critical inhibitory concentrations leading to significant growth and lipid production inhibitions. Unlike the above-cited inhibitors, sodium lignosulphonate had no negative influence on biomass accumulation when its concentration was in the range of 0.5-2.0 g/L; in effect, it was found to facilitate cell growth and sugar-to-lipid conversion. The fatty acid compositional profile of the yeast lipid was in the compositional range of various plant oils and animal tallow. Finally, the crude yeast lipid from bagasse hydrolyzate could be well converted into fatty acid methyl ester (FAME, biodiesel) by enzymatic transesterification in a tert-butanol system with biodiesel yield of 67.2% and lipid-to-biodiesel conversion of 88.4%.

Biocatalytic synthesis and antioxidant capacities of ascorbyl esters by Novozym 435 in tert-butanol system using different acyl donors

Biocatalytic synthesis and antioxidant capacities of ascorbyl esters by Novozym 435 in tert-butanol system using different acyl donors

Enzymatic synthesis of ascorbyl palmitate in ultrasound-assisted system: Process optimization and kinetic evaluation

This work is focused on the optimization of reaction parameters for the synthesis of ascorbyl palmitate catalyzed by Candida antarctica lipase in different organic solvents under ultrasound irradiation. The sequential strategy of experimental design proved to be useful in determining the optimal conditions for reaction conversion in tert-butanol system using Novozym 435 as catalyst. The optimum production was achieved at 70 °C, ascorbic acid to palmitic acid molar ratio of 1:9, enzyme concentration of 5 wt% at 3 h of reaction, resulting in an ascorbyl palmitate conversion of about 27%. Reaction kinetics for ascorbyl palmitate production in ultrasound device showed that satisfactory reaction conversions (∼26%) could be achieved in short reaction times (2 h). The empirical kinetic model proposed is able to satisfactorily represent and predict the experimental data.

Enzymatic Synthesis of Ascorbyl Palmitate in Organic Solvents: Process Optimization and Kinetic Evaluation

This work is focused on the optimization of reaction parameters for the synthesis of ascorbyl palmitate catalyzed by Candida antarctica lipase in different organic solvents. The sequential strategy of experimental designs proved to be useful in maximizing the conditions for product conversion in tert-butanol system using Novozym 435 as catalyst. The optimum production were achieved at ascorbic acid to palmitic acid mole ratio of 1:9, stirring rate of 150 rpm, 70 °C, enzyme concentration of 5 wt.% at 17 h of reaction, resulting in an ascorbyl palmitate conversion of about 67%. Reaction kinetics for ascorbyl palmitate production showed that very satisfactory reaction conversions (∼56%) could be achieved in short reaction times (6 h). The kinetic empirical model proposed showed ability to satisfactory represents and predict the experimental data.

Physicochemical properties of stillingia oil: Feasibility for biodiesel production by enzyme transesterification

The physicochemical properties, fatty acids profile and triglyceride compositions of the stillingia oil were analyzed. The stillingia oil was found to contain 98.79% neutral lipids, 0.22% phospholipids and 0.99% glycolipids, which exhibited varying contents of fatty acids. The major triglyceride was double linoleic acid linolenic acid triglyceride, which accounted for approximately 79.49% of the total triglycerides. Preparation of biodiesel from stillingia oil was investigated by enzyme transesterification with methanol as the acyl acceptor. The results showed that lipase type (Novozym 435, Lipozyme TLIM and Lipozyme RMIM), reaction systems (in solvent-free and tert-butanol system) and operational parameters (lipase loading, reaction time, temperature, and molar ratio of alcohol to oil) influenced the biodiesel yield. Fuel properties of biodiesel from stillingia oil were evaluated and all were in acceptable range for use as biodiesel in diesel engines, and had remarkable flash point and satisfactory cold flow properties. It was concluded that stillingia oil was an alternative potential feedstock oil for biodiesel production.

Catalytic studies of lipase on FAME production from waste cooking palm oil in a tert-butanol system

In this present work, fatty acid methyl ester (FAME) was produced from waste cooking palm oil (WCPO) by lipase-catalyzed reaction. The catalytic activities of several commercial lipases and different organic solvent were screened. Novozyme 435 was found to be more effective in catalyzing the transesterification of WCPO with methanol. tert-Butanol was used as the reaction medium, which eliminated both negative effect caused by excessive methanol and glycerol as the byproduct. Several variables such as effect of methanol/oil molar ratio, effect of lipase quantity and effect of agitation speed (rpm) were examined in a batch system. Transesterification of WCPO can reach up to 88% FAME yield under optimum condition (methanol/oil molar ratio 4:1, 4% Novozyme 435 based on oil weight, 200 rpm and 12 h reaction time). Kinetics of lipase-catalyzed transesterification of WCPO in tert-butanol system was also investigated. A model based on Ping Pong Bi Bi with only inhibition by methanol was found to fit the initial rate data and the kinetics parameters were evaluated by non-linear regression analysis.

Study on factors influencing stability of whole cell during biodiesel production in solvent-free and tert-butanol system

Utilizing whole cell biocatalyst for biodiesel production has some advantages since it can avoid the complex procedures of isolation, purification and immobilization of extracellular lipase. However, during repeated use of Rhizopus oryzae ( R. oryzae) IFO4697 whole cell for biodiesel production in solvent-free system, the whole cell exhibited very poor stability; while the whole cell stability has been found to be significantly improved in tert-butanol system compared to that in solvent-free system. The difference in whole cell stability was found to be due to the difference of product accumulation between solvent-free and tert-butanol system. After 144 h reaction, glycerol and methyl ester accumulated in the cell in solvent-free system came up to about 1000 mg/g and 350 mg/g dry biomass, respectively, while in tert-butanol system, glycerol and methyl ester accumulation was kept at a relatively low level, approximately 100 mg/g and 2 mg/g dry biomass, respectively. The accumulated glycerol influenced whole cell stability through mass transfer limitation only, while the accumulated methyl ester influenced whole cell stability through both mass transfer limitation and product inhibition. Further study showed that a slight loss in enzymatic activity in tert-butanol system was caused by protein leakage.

Rhizopus oryzae Whole-Cell-Catalyzed Biodiesel Production from Oleic Acid in tert-Butanol Medium

During the usage of Rhizopus oryzae whole cell instead of immobilized enzyme for biodiesel production, the intracellular lipase was found to have 1,3-positional specificity when used to catalyze methanolysis of triglycerides. Thus, the application of R. oryzae whole cell in biodiesel production from triglycerides is restrained to some extent. However, it might be a promising catalyst for biodiesel production from free fatty acids (FFAs). In this paper, R. oryzae IFO4697 whole cell [immobilized within biomass support particles (BSPs)] catalyzed biodiesel production from oleic acid was studied systematically. It has been demonstrated that, in a tert-butanol system, R. oryzae whole cell exhibited both better methanol endurance and better stability than that in a solvent-free system. Molecular sieves (3 A) were added into the reaction mixture to online remove the produced water, and a much higher biodiesel yield could be achieved (biodiesel yield reached 90% at 48 h).

Mechanism Exploration during Lipase-Mediated Methanolysis of Renewable Oils for Biodiesel Production in a tert-Butanol System

tert-Butanol has been developed as a novel reaction medium for lipase-mediated methanolysis of renewable oils for biodiesel production, in which lipase could maintain high catalytic activity, although the log P value of tert-butanol was just about 0.35. The related mechanism exploration has been carried out, and it has been proposed first in this manuscript that in the biodiesel production system, log P(environment) (log P(environment) = x(methanol) log P(methanol) + x(oils) log P(oils) + x(solvent) log P(solvent)) including reactants and organic solvent should be taken into account to consider the effect of the whole environment on lipase activity instead of just considering the effect of the organic solvent itself. Further study showed that the operational stability of the lipase could be improved significantly in this system and there was no loss in lipase activity even after its being continuously used for 200 batches. The phase diagrams of the ternary-components tert-butanol/methanol/rapeseed oils were plotted further, and it was found that the methanol tolerance was the saturated methanol concentration in the system. It was demonstrated first here that the improved stability of the lipase was due to the elimination of negative effects caused by methanol and byproduct glycerol in the tert-butanol system.

Rhizopus oryzae IFO 4697 whole cell catalyzed methanolysis of crude and acidified rapeseed oils for biodiesel production in tert-butanol system

Whole cell Rhizopus oryzae ( R. oryzae) IFO4697 immobilized within biomass support particles (BSPs) was used as catalyst for biodiesel production in tert-butanol, in which the stability of the catalyst could be enhanced significantly. Different feedstocks (refined, crude and acidified rapeseed oils) were adopted further for biodiesel production in tert-butanol system and it was found that when acidified rapeseed oil was used as feedstocks, the reaction rate and final methyl ester (ME) yield were significantly higher than that of refined and crude rapeseed oil. Major differences among the aforementioned oils were found to be the contents of free fatty acid (FFA), water and phospholipids, which showed varied influences on whole cell mediated methanolysis for biodiesel production. The reaction rate increased with the increase of free fatty acid content in oils; water content had varied influence on reaction rate and biodiesel yield; using adsorbent to remove excessive water could increase biodiesel yield significantly (from 73 to 84%); it was also found interestingly that phospholipids contained in oils could increase the reaction rate to a certain extent.

Lipase-catalyzed biodiesel production from soybean oil deodorizer distillate with absorbent present in tert-butanol system

Lipase-catalyzed alcoholysis of soybean oil deodorizer distillate (SODD) for biodiesel production was studied. During this system both free fatty acids and glycerides could be converted to biodiesel simultaneously. tert-Butanol has been adopted as the reaction medium, in which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated completely. There was no obvious loss in lipase activity even after being repeatedly used for 120 cycles. Fine-pored silica gel and 3 Å molecular were found to be effective to control by-product water concentration and much higher biodiesel yield could be achieved with those adsorbents present in the reaction system. The highest biodiesel yield of 97% could be achieved with 3 Å molecular sieve as the adsorbent.

Influence of unequal component efficiencies on trajectories during distillation of a homogeneous azeotropic mixture

The overall objective of this work is to examine the influence of interphase mass transfer on the composition trajectories in homogeneous azeotropic distillation. A total of 38 experiments were carried out in a bubble cap distillation column operated at total reflux with the system: water–ethanol– tert-butanol. The experiments were carried out in the two regions on either side of the distillation boundary connecting the ethanol–water and t-butanol–water azeotropes. In order to model the composition trajectories, a rigorous nonequilibrium (NEQ) stage model is developed. The NEQ model incorporates the Maxwell–Stefan diffusion equations to describe the intraphase transfers in the vapor and liquid phases. The only adjustable parameter in the NEQ model is the size of the vapor bubbles on trays. A choice of a bubble diameter of 4 mm in the developed NEQ model gave the best agreement with the experimental results for all of the 38 experimental runs. The Murphree efficiencies of the constituents in the ternary mixture were found to be significantly different from one another for all the runs. In order to ascertain the influence of unequal component efficiencies on the column composition trajectories, the experimental results were also simulated with an equilibrium (EQ) stage model assuming a uniform, constant efficiency for all components on all the trays. The value of this constant efficiency for any experimental run was obtained by averaging the individual component efficiencies for all the three components on all the trays, calculated by the rigorous NEQ model. The predictions of the EQ model leads to significantly worse predictions of the column composition trajectories for each of the runs, when compared to the NEQ model. It is found that the column composition trajectories are significantly altered due to differences in the component efficiencies. From a design view point, it is shown that for the water–ethanol– tert-butanol system, the attainment of a desired ethanol purity in the top product may require significantly larger number of stages than that anticipated by the EQ model incorporating constant component efficiencies.

The photolysis of potassium peroxodisulphate in aqueous solution in the presence of tert-butanol: a simple actinometer for 254 nm radiation

Aqueous potassium peroxodisulphate (0.01 mol dm −3) together with tert-butanol (0.1 mol dm −3) was photolysed with 254 nm light at 20 °C. The peroxodisulphate ion is cleaved, giving rise to sulphate radicals SO 4 − . These attack the tert-butanol under hydrogen abstraction and hydrogen sulphate formation. In deoxygenated solutions, Φ(H +) = 1.4, Φ(SO 4 2−) = 1.4 and Φ((HOC(CH 3) 2CH 2) 2) is approximately 0.7; in the presence of oxygen, Φ(H +) = 1.8. The enhancement of Φ(H +) by oxygen comes about through the production of superoxide via one of the bimolecular decay channels of the tert-butanol-derived peroxyl radical. The superoxide radical reduces S 2O 8 2− under liberation of further SO 4 − . The oxygenated peroxodisulphate- tert-butanol system is shown to constitute a straightforward actinometer for 254 nm light. Some data and observations regarding the tert-butanol-free peroxodisulphate system are also presented.