Molecular Distillation Research Articles

Research on optimization algorithm of molecular distillation process parameters based on ELM-ADHDP

In the traditional molecular distillation process, there are also large differences in the process parameters of different extracts in the process of separation and purification, and there are equipment aging and site condition changes in the project of equipment operation, and the setting of process parameters is only based on the experience of the operator, which greatly reduces the effect of separation and purification. In this paper, ELM-ADHDP is used to optimize the process parameters of the molecular distillation system, determine the best process parameters, achieve accurate and optimized control of the equipment, improve the efficiency of separation and purification, and reduce the energy consumption and the dependence on manual experience.

Preparation of High-Purity Docosahexaenoic Acid Ethyl Ester from Algal Oil through Enzymatic Ethanolysis.

Docosahexaenoic acid plays a crucial role in infant brain function, and the market demand of high-purity docosahexaenoic acid is continuously increasing. The availability of docosahexaenoic acid in natural fish oil is limited, prompting the exploration of alternative sources like microalgae. For algal oil, enzymatic ethanolysis is preferred to chemical methods because the former is milder and can avoid docosahexaenoic acid oxidation. However, enzymatic methods have generally low yield due to the poor substrate-specificity of lipase to long-chain polyunsaturated fatty acids, affecting the yield and purity of docosahexaenoic acid. Therefore, we developed an efficient process to produce high-purity docosahexaenoic acid ethyl ester from algal oil, by screening lipases, optimizing enzymatic ethanolysis and applying molecular distillation. Lipase UM1 was the best lipase to produce ethyl ester from algal oil with the highest ethyl ester yield (95.41%). Meanwhile, it was a catalyst for the reaction of long-chain polyunsaturated fatty acids with ethanol. The fatty acid docosahexaenoic acid conversion rates exceeded 90%. After molecular distillation, a final product containing 96.52% ethyl ester was obtained with a docosahexaenoic acid content up to 80.11%. Our findings provide an highly effective enzymatic method for the production of high-purity docosahexaenoic acid ethyl esters, with potential commercial applications.

Research on the influence of fluid viscosity on the inlet flow parameters of wiped film molecular distillation

Wiped film molecular distillation is a kind of evaporation device with rotating scraping film structure, which is used to separate and purify viscous materials at molecular level. The feed pump of a wiped film molecular distillation is a centrifugal pump driven by a brushless DC motor. The fluid flow at the outlet has an important effect on the evaporation process. Based on the geometric model of the test pump generated by Gambit, the unsteady flow and head in the pump under optimal, low flow and shut off conditions were calculated, and the influence of liquid viscosity on the flow parameter pulsation behind the impeller, that is, inside the volute was investigated. The head calculated by unsteady flow model and steady flow model is compared with the experimental values. In addition, the calculated liquid velocity distribution during water transport is compared with the measured results of LDV in detail. The results show that the increase of fluid viscosity weakens the flow parameter pulsation behind the impeller of the feed pump and the flow separation tendency near the blade face.

Enzymatic synthesis of branched chain fatty acid-enriched structured triacylglycerols via esterification with glycerol.

While branched-chain fatty acids (BCFA)-enriched triacylglycerols (TAG) has various health benefits, its preparation has not been reported. This study aimed to synthesize high-purity BCFA-enriched structured TAG. First, BCFA was enriched from lanolin through saponification, calcification, and urea complexation. Next, BCFA-enriched TAG was synthesized by enzymatic esterification of BCFA and glycerol. Then, lipases were screened by molecular docking and practical experiments, which suggested that Lipozyme 435 was the best lipase for esterification since it had the lowest binding energy. Structured TAG containing 92.23% BCFA was synthesized under conditions optimized by single-factor experiments. Furthermore, molecular distillation was adapted to remove excess fatty acids and small molecule impurities. Finally, high-purity BCFA-enriched structured lipid containing 70.26% TAG was obtained. Overall, this study successfully developed a method for synthesizing BCFA-enriched structured TAG, which holds great promise for applications in value-added foods.

Esterification effect on the recovery of vitamin E from palm oil refining residues by molecular distillation

AbstractWaste edible oils are an alternative source of high‐value natural compounds. Vitamin E can be recovered from palm oil refining residues by molecular distillation. However, the presence of other lipophilic molecules compromises the selective separation of vitamin E. Esterification of the free fatty acids can enhance the selective separation of vitamin E by molecular distillation, but the conditions for carrying out the reaction need to be investigated to simultaneously ensure the conversion of free fatty acids and the reduction of vitamin E losses. Thus, this study investigated the effect of the esterification of the industrial waste on the recovery of vitamin E by molecular distillation. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and analysis for fats and oils preconized by the American Oil Chemists' Society (AOCS) were used in the characterization of the industrial waste. Determination of the best condition to carry out the reaction was obtained by a central composite rotational design (CCRD) using the response surface methodology (RSM) and the desirability profile. The results showed that the best condition for the esterification was at 64°C, 213 min, 2 wt.% sulphuric acid, and a 10/1 methanol/free fatty acids molar ratio. This reaction condition achieved 97.9% conversion of free fatty acids and less than 3% of vitamin E loss. The esterification promoted concentration of vitamin E in the residue stream (145.4%) and reduction in the distillate stream (87.8%). Therefore, the obtained results presented a suitable route to obtaining vitamin E concentrate and adding value to an industrial residue.

Catalytic hydrotreating of crude bio-oil from straw and its distillates obtained by molecular distillation: A comparative study

In this study, the crude bio-oil (CBO) obtained from hydrothermal liquefaction of peanut straw was separated into light oil (LO) and heavy oil (HO) by molecular distillation at 130 ℃ and different pressures (0.5, 1 and 3 kPa). With process variables fixed, the CBO and its distillates were subjected to catalytic hydrotreating to probe the behavior characteristics of CBO from straws during this process. The LO yield fluctuated between 29.8 and 34.8 wt% with the change of distillation pressure. LO presented lower C content and higher H and O content than the corresponding HO. The LO obtained at 1 kPa showed a significant content difference between ketones (34.50%) and phenolic compounds (5.84%), indicating the differential distribution of these chemical components in CBO and the possibility of component separation by molecular distillation. Hydrotreating of LO gained obviously higher yield of upgraded oil (82.1–89.7 wt%) and lower yield of solid (6.1–9.1 wt%) than the corresponding HO (61.2–69.4 wt% and 21.3–24.6 wt%, respectively). The addition of n-hexane in the hydrotreating of HO led to an increase in hydrocarbon content and a decrease in content of phenolic compounds in the upgraded oil, although it did not contribute to increasing the upgraded oil yield.

Application of integrated molecular distillation-adsorption process for deacidification and recovery of vitamin E and carotenoids from palm oil

Palm oil is a natural source of phytonutrients such as vitamin E and carotenoids. However, these high-value compounds are lost during conventional refining. These phytonutrients can be separated and recovered from crude palm oil (CPO) through methods which prevents the degradation of these compounds. This study evaluated the integrated approach of molecular distillation and adsorption, with the aim of deacidifying and separating vitamin E and carotenoids from CPO, allowing their recovery. Wiped-film molecular distillation (WFMD) was used for deacidification and vitamin E enrichment, the best results were obtained at 200 °C and 21 mL/min. The distillate stream was enriched 937.8% in vitamin E, and the residue stream (named deacidified palm oil - DAPO), enriched in carotenoids, reached 0.1% free fatty acids (FFA). Integration with the adsorption process achieved a carotenoids removal of 79.4% from the DAPO stream. Moreover, the kinetic constant (k2) of adsorption increased by around 87% for DAPO, a result attributed to the absence of fat crystals on the adsorbent surface verified by scanning electron microscopy. Notably, the integrated process approach used is an innovative methodology for the vegetable oil industry presenting an alternative route that allows the preservation and recovery of phytonutrients, and the oil deacidification.

Application of pilot‐scale molecular distillation for enrichment of phytonutrients from a novel deodorizer distillate of the margarine and shortenings industry

AbstractBackgroundA wiped‐film molecular distillation (WFMD) pilot plant was used to evaluate process conditions for enriching phytonutrients (PN) from a novel vegetable oil deodorizer distillate (VODD) of the margarine and shortenings industry. This byproduct results from the incorporation of new blends of vegetable oils, such as soybean and palm oil, making it of interest due to its distinct chemical composition and matrix, which differ from those of deodorizer distillates studied previously. The significance of the present investigation is related to the properties of the oil blend, requiring the establishment of new process conditions for this specific VODD. Experimental design was used to evaluate the WFMD process variables, with the aim of removing free fatty acids and enabling eight PN to be concentrated in the reprocessing stages.ResultsThe product obtained after three WFMD stages presented a fivefold increase in the total PN concentration, compared to the raw material. Notably, the procedure provided enrichment ratios of 7.2‐fold for total tocopherols (including α‐, β‐, λ‐ and δ‐tocopherols), 4.5‐fold for total phytosterols (including campesterol, stigmasterol and β‐sitosterol) and 1.2‐fold for squalene, together with a deacidification efficiency of 78.93%.ConclusionThe proposed process provided significant concentration gains for all eight PN evaluated, resulting in a value‐added product. These excellent results were achieved using only three WFMD stages, without any need for additional processing steps. The data obtained at the pilot scale provide valuable insights for predicting the scalability of the process and facilitating potential industrial implementation. © 2023 Society of Chemical Industry.

Physical, textural and crystallization properties of ground nut oil-based diacylglycerols in W/O margarine system

Enzymatic glycerolysis produced ground nut oil-based diacylglycerols (GNO-DAG) with a purity of 43.28 ± 0.89% (GNO-DAG40). GNO-DAG80 (with a DAG purity of 87.33 ± 0.61%) was obtained after purification using molecular distillation. Traditional palm oil was mixed with the “liquid” DAG as margarine base oils. Subsequent evaluations of palm oil-DAG-based fats (PO-GNO DAG) as a margarine replacement in a W/O model system showed that the material was an ideal functional base oil with improved aeration properties and plasticity during application. The binary system physical, textural and crystallization property were determined, and the compatibility of the binary mixed system was analyzed by constructing a phase diagrams. The PO-GNO DAG showed decent compatibility between the two phases and had better texture and rheological properties. In addition, PO-GNO DAG40 showed better apparent viscosity and aeration characteristics than PO-GNO DAG80, with potential application in the food specialty fats industry.

Route optimization on selectivity and kilogram-scale synthesis of Vilanterol Trifenatate

The development of an improved manufacturing process for the active ingredient vilanterol trifenatate, a potent drug for the treatment of chronic obstructive pulmonary disease (COPD), has been described with high yield and purity. The robust process was demonstrated on a multi kilogram scale. Wiped Film Molecular Distillation was applied to purify intermediates that were easily decomposed at high temperature, improving the yield by 10–15%. Meanwhile, the corresponding impurity was studied in detail and well resolved. Finally, vilanterol trifenatate was obtained pure in a very competitive total of 6 steps with a yield of 57.9%, and it was crystallized with greater than 99.9% purity, 99.9% chiral purity and no single major impurity >0.1%.

Pre‐deacidification of hazelnut oil by short‐path distillation: Changes in 3‐chloropropane‐1,2‐diol esters, glycidyl esters, free fatty acids, tocopherols, and diglycerides

AbstractPerforming pre‐deacidification using short‐path distillation at high temperatures and vacuum levels is a general application for fats and oils with high free fatty acids (FFA) to reduce their FFA contents to reasonable levels before steam distillation or neutralization. This study aims to determine the changes in 3‐chloropropane‐1,2‐diol esters (3‐MCPDE), glycidyl esters (GE), and diglyceride (DG) as well as the losses in tocopherols during this process. A bleached hazelnut oil having 12.10% FFA content was distilled using a molecular distillation unit at 200 °C, 220 °C, and 240°C temperatures and 0.25, 0.5, 1, and 2 mbar absolute pressures. The target was to reduce FFA content to less than 2% with minimum tocopherol loss. The results showed that considerable removals in FFA and GE contents were achieved by increasing the temperature and vacuum, while fewer decreases were detected in 3‐MCPDE and DG concentrations. Tocopherols were dramatically decreased by temperature rising, therefore, the lowest temperature (200°C) and absolute pressures (0.25–0.5 mbar) might be suitable for pre‐deacidification of hazelnut oil, where the distilled oil contained 1.78%–1.90% FFA, 243.11–286.76 mg kg–1 tocopherol, 0.50–0.55 mg kg–1 3‐MCPDE, 0.03–0.05 mg kg–1 GE and 4.00–4.22 mg kg–1 DG.Practical Application: Vegetable oils with high free fatty acid (FFA) contents are generally subjected to physical refining to avoid considerable refining loss. However, high temperatures applied to vegetable oils during physical refining result in the formation of 3‐MCPDE&GE, and the loss of some nutrients, such as tocopherols. These adverse effects can be reduced through application of lower temperatures and shorter time during physical refining. This can be applied after the FFA contents of the oils are decreased to reasonable levels (less than 2%) by distillation (pre‐deacidification) before the deodorization. Although this technique has been implemented in many plants, there is almost no information on the effects of applied conditions on 3‐MCPDE and GE and some other minor constituents. This manuscript explains the changes in these compounds during the pre‐deacidification of hazelnut oil by molecular distillation. Suitable distillation conditions were also suggested, which would be very useful for industrial refining plants.

Synthesis of polyglycerol fatty acid esters catalyzed by lipase and evaluation of its emulsification properties

The present study investigated the physicochemical properties of the newly synthesized polyglycerol fatty acid esters (PGFEs) and their potential application as food emulsifiers. It turned out that the complete removal of glycerol from crude polyglycerol was achieved by optimizing the molecular distillation temperature (120 °C). Moreover, novozym 435 was used to catalyze the synthesis of PGFEs with different aliphatic chain lengths, and the esterification rate of the obtained products was 93%∼98%. The characteristic absorption peak of the ester carbonyl group was displayed at 1738 cm−1, and that of C–O–C on the ether bond was at 1100 cm−1 and 1048 cm−1. Therefore, the synthesis can be determined to be PGFEs. Their hydrophilic lipophilic balance (HLB) values are >7, which can be used as oil-in-water emulsifiers. When curcumin nanoemulsions were constructed by PGFEs with various aliphatic chains as emulsifiers, it was found that all PGFEs in C10∼C18 can form stable curcumin nanoemulsions (encapsulation rate was >95%). PGFEs with longer aliphatic chains can stabilize nanoemulsions more efficiently (larger droplet sizes and lower ζ-electric potential), and showed better storage and UV stability. Whereas, medium-chain PGFEs emulsions, especially PGC, showed the best curcumin release efficiency, which theoretically supported the application of PGFEs to functional emulsion products.

Effect of molecular distillation on the anti-inflammatory activity and neurotoxicity of Asarum essential oil.

Asarum essential oil (AEO) has been shown to have good pharmacological activities for the anti-inflammatory and analgesic effects, but increasing the dose may cause toxicity. Therefore, we studied the toxic and pharmacodynamic components of AEO by molecular distillation (MD). Anti-inflammatory activity was assessed using RAW264.7 cells. Neurotoxicity was assessed in PC12 cells and the overall toxicity of AEO was evaluated in the mouse acute toxicity assay. The results showed that AEO is primarily composed of safrole, methyl eugenol, and 3,5-dimethoxytoluene. After MD, three fractions were obtained and contained different proportions of volatile compounds relative to the original oil. The heavy fraction had high concentrations of safrole and methyl eugenol, while the light fraction contained high concentrations of α-pinene and β- pinene. The original oil and all three fractions exhibited anti-inflammatory effects, but the light fraction demonstrated more excellent anti-inflammatory activity than the other fractions. Asarum virgin oil and MD products are all neurotoxic. The exposure of PC12 cells to high concentrations of AEO resulted in abnormal nuclei, an increased number of apoptotic cells, increased ROS formation, and decreased SOD levels. Moreover, the results of acute toxicity tests in mice revealed that the light fractions were less toxic than virgin oils and other fractions. In summary, the data suggest that the MD technology enables the enrichment and separation of essential oil components and contributes to the selection of safe concentrations of AEO.

Fatty acid, triglyceride, and kinetic properties of milk fat fractions made by the combination of dry fractionation and short-path molecular distillation

In this study, we aimed to detect the physicochemical properties of distilled products (residue and distillate) obtained from anhydrous milk fat (AMF) and its dry fractionation products (liquid and solid fractions at 25°C (25 L and 25 S)). The results showed that the saturated fatty acids and low- and medium-molecular-weight triglycerides were easily accumulated in the distillate, and the percentage of unsaturated fatty acid and high-molecular-weight triglycerides in the residue were higher, and these components in 25 S and 25 L were influenced more significantly than those in the AMF. In addition, the distillate had larger melting ranges in comparison with the distilled substrate, while the melting ranges of residue was smaller. The triglycerides were presented as the mixture crystal forms (α, β', and β crystal) in 25 S, AMF, and their distilling products, and it was transformed gradually to a single form as the increasing of distilling temperature. Moreover, the accumulated pattern of triglycerides was double chain length in 25 S, AMF, and their distilling products. These results provide a new approach to obtain the MF fractions with different properties, and the findings of this study enrich the theoretical basis of MF separation in practical production.

Fatty acid and triglyceride molecular species of milk fat fractionated by short‐path molecular distillation

SummaryFractionation is important for the application of milk fat (MF). In this study, the contents of fatty acid (FA) and triglyceride (TAG) of MF and its fractions distilled by short‐path molecular distillation (SPMD) were detected. The results showed that a total of 19 FAs and 109 TAG molecular species were detected. Moreover, the short‐chain saturated FA, medium‐chain saturated FA, low‐molecular‐weight TAG, medium‐molecular‐weight TAG, S3 (TAG molecular species with three saturated FAs) and L2S (TAG molecular species with two long‐chain FAs and one short‐chain FA) were easily accumulated in the distillate, and the percentage of these components all increased first and then decreased during the whole distilling process. Compared with the distillate, polyunsaturated FA (PUFA) and high‐molecular‐weight TAG (HMW‐TAG, with the carbon numbers: 41–54 and molecular weight: 704–888) were enriched in the residue, and the increasing ratio of PUFA and HMW‐TAG was 393.75% and 8.58% respectively. Further analysis showed that the 16:0/4:0/16:0, 16:0/4:0/14:0, 16:0/12:0/4:0, etc. were the discrepant TAG molecular species during SPMD. Therefore, these results demonstrated that different fractions of MF could be obtained by adjusting the fractionation temperature, and it also would provide more important theoretical guidance for regulating MF fractionation, enriching the nutritional information of MF fractions.

792 Tea oil concentrate from camellia oleifera, obtained by molecular distillation, to improve skin comfort and well-being

792 Tea oil concentrate from camellia oleifera, obtained by molecular distillation, to improve skin comfort and well-being

Ab initio molecular dynamics calculation and vacuum distillation experimental study on the interaction mechanism of PbS–FeS

An important way to obtain PbS and FeS is the thermal decomposition of Jamesonite. However, the mechanism of PbS–FeS interaction is unknown. In order to explore the separation effect of PbS and FeS, thermodynamic calculation, dynamic simulation and vacuum distillation experiments were used to explore the interaction mechanism of PbS and FeS. The decomposition and volatilization temperatures of PbS and FeS were obtained by thermodynamic calculation. The difference of saturated vapor pressure indicates that there is a tendency of separation between them. The ab initio molecular dynamics method was used to calculate the density of states of PbS and FeS at different temperatures, indicating that the FeS(114) structure is more stable than the PbS(200) structure, and the Pb–S bond is easier to break than the Fe–S bond at the same temperature. The experimental results of vacuum distillation show that the volatilization temperature of PbS is much lower than that of FeS, and FeS can only volatilize into the gas phase at a higher temperature. The theoretical calculation method is consistent with the experimental results, which shows that the thermodynamic calculation and dynamic simulation methods are reliable in predicting the volatilization and separation of crystal structures. The interaction mechanism between PbS and FeS was explored from the theoretical point of view to provide theoretical guidance for vacuum distillation experiment.

Separation of D-Limonene and Other Oxygenated Compounds from Orange Essential Oil by Molecular Distillation and Fractional Distillation with a Wiped Film Evaporator

Orange essential oil (OEO) is mainly composed of D-Limonene and other oxygenated compounds that contribute to the orange flavor and aroma. However, D-Limonene is unstable in the presence of heat, light, and water, affecting the quality of the OEO. Therefore, the objective of this study was to fractionate OEO by distillation, both molecular and fractionated (hybrid), producing a D-Limonene-rich fraction. The OEO was characterized by physicochemical tests and gas chromatography combined with mass spectrometry (GC–MS). The fractionation of the OEO was carried out by molecular distillation and fractional distillation following, in both cases, a factorial design (23) with central points, considering the D-Limonene percentage in the distillate and the residue as a response variable. According to the physicochemical characterization, the predominant optical isomer was dextrorotatory, where D-Limonene is the main component of OEO (92.584%). For molecular distillation, the D-Limonene content was reduced to 47.964% in the residue or deterpenated fraction, while for fractional distillation, it was 86.779%. For this study, molecular distillation was considered a non-thermal process (use of low temperatures) that promoted the efficient recovery of oxygenated compounds. In contrast, fractional distillation favored the recovery of D-Limonene in the light fraction.

Application of molecular distillation in the recovery of high-value bioactive compounds present in wastes of vegetable oil processing: effect of esterification

Refining vegetable oils generate residues that can be reused to obtain high-value compounds. Tocopherols, phytosterols, and squalene can be recovered from deodorizer distillates using molecular distillation. However, treatment of the deodorizer distillates is required to obtain better separation results. Thus, this work aimed to evaluate the effect of the esterification of a residue composed of mixtures of different types of deodorizer distillates on the efficiency of phytonutrient recovery by molecular distillation. The results showed the best conditions for the esterification were 74 °C, 214 min, 3% H2SO4, and 2:1 molar methanol/free fatty acids ratio. These reaction conditions maintained 97% of total phytonutrients and reduced 90.5% of free fatty acids. Concentration gains for tocopherols (331%), phytosterols (232%), and squalene (300%) were obtained for the esterified residue. Therefore, this work presents an alternative route to obtaining a phytonutrient concentrate by combining steps of esterification and molecular distillation for mixtures of deodorizer distillates.

Enrichment of high‐purity nervonic acid ethyl ester from Acer truncatumBunge seed oil by combination method of urea inclusion and molecular distillation

AbstractAcer truncatum Bunge is a type of maple that is unique to China. Its fruit setting rate and seed oil content are both high. The oil is mainly composed of C16–C24 fatty acids and contains 5%–7% nervonic acid (NA). NA and its derivatives can delay ageing and prevent and treat disorders such as senile dementia and Alzheimer's disease. The content of NA ethyl ester prepared by the seed oil of A. truncatum Bunge is 5.84%. We report a new process for the enrichment of NA ethyl ester by urea inclusion (UI) and molecular distillation (MD), with the aim of obtaining highly pure NA ethyl ester. First, based on the difference in fatty acid ethyl ester saturation and carbon chain length, unwanted compounds such as oleic acid ethyl ester, linoleic acid ethyl ester, and sterol were removed by one‐stage UI, the content of NA ethyl ester was increased to 18.69%. The oil in the UI compound was used as a feed, and differences in the mean molecular free paths between the components were exploited to separate the C16–C20 fatty acid ethyl esters (FAEEs) by two‐stage MD. The total content of C16–C20 FAEEs decreased to 3.69% and the purity of NA ethyl ester increased to 47.47%. A new purification process of UI‐MD‐UI was established and NA ethyl ester could be purified to 91.8%. The combination of MD and UI has an important reference value for the industrialization of producing high‐purity NA ethyl ester.