Molecular Distillation Research Articles

Optimization of wiped-film short path molecular distillation for recovery of cannabinoids from cannabis oil using response surface methodology

Few studies have explored the molecular distillation techniques that can improve the recovery of cannabinoids from crude cannabis oil with scale-up potential. Wiped-film short path molecular distillation is commonly employed in the cannabis industry for separating cannabinoids from terpenes and heavy compounds. It is a two-cut process, where the distillation of terpenes and cannabinoids occurs at the first and second cuts, respectively. In this experiment, the effects of the distillation parameters in the second cut, including feed flow rate (35–55 Hz) (41.6–71.3 mL min−1) and internal condensation temperature (60–90 °C), were examined and optimized using a central composite rotatable design towards maximizing cannabinoid mass and recovery efficiency in the distillate and minimizing cannabinoid mass in the residue. Results show that irrespective of internal condensation temperature, reducing feed flow rate increased the cannabinoid's yield and recovery. Although long distillation time was observed at low feed flow rates, the quality of cannabinoids remained unaffected. Response surface methodology was used to optimize the wiped-film short path molecular distillation of cannabis oil. The predicted optimal conditions were a feed flow rate of 35 Hz (41.6 mL min−1) and an internal condensation temperature of 75 °C. At these optimized conditions, the recovery efficiency of tetrahydrocannabinol was 93.4% in the distillate. To this end, this study provides distillation conditions to be considered by the cannabis industry if aiming for a cannabinoid-rich distillate from the molecular distillation process without affecting cannabinoid quality.

Preparation of γ‐linolenic acid rich triacylglycerol from borage oil via a two‐step lipase‐catalyzed reaction

Abstractγ‐Linolenic acid (GLA) rich triacylglycerol (TAG) was successfully synthesized from glyceride, instead of glycerol, and fatty acid (FA) via Lipozyme TL IM‐catalyzed esterification as a novel strategy. In the first step, GLA was enriched into glyceride fraction from borage oil by Candida rugosa lipase‐catalyzed hydrolysis. The glyceride was separated from the reaction mixture by molecular distillation. GLA was enriched from 20.64% in borage oil to 45.94% in the glyceride fraction under optimum conditions. In the second step, the Lipozyme TL IM‐catalyzed synthesis of TAG was carried out with the glyceride, and the FA obtained by saponification of a portion of the glyceride. The optimum conditions were the temperature of 50°C, the enzyme loading of 10%, and the vacuum level of 20 mmHg, respectively. The maximum TAG content of approximately 92% was achieved after 12 h under the optimum conditions.

Synthesis and characterization of medium- and long-chain structural lipid rich in α-linolenic acid and lauric acid

Medium- and long-chain triglycerides (MLCT) have been widely concerned. In this study, lauric acid (La) was incorporated into flaxseed (Linum usitatissimum L.) oil (FO, aLna-riched) by lipase-catalyzed acidolysis. The synthesis efficiency of four immobilized lipases (Lipozyme RM IM, TL IM, AOAB8 and Novozym 435) was compared, while Lipozyme AOAB8 reaction for 2 h was the best scheme. Further, the optimal conditions for synthesizing structural lipids (aLSLs, rich in aLna and La) were obtained by response surface methodology: the reaction temperature was 44.6 °C, substrate molar ratio was 12 (La/FO), and enzyme loading was 9.11%. After purification by molecular distillation, the triglycerides (TAGs) of aLSLs contained 75.35% of TAGs with α-linolenic acid (aLna), 40.82% of MLCTs with La, and 26.75% (65.53% of the total MLCTs) of TAGs with both aLna and La (ɑ-MLCT). Meanwhile, the content of La and aLna in aLSLs were 22.38% and 39.78%, respectively. The chemical structure and microstructure of aLSLs were similar to FO. In addition, the thermo-oxidative decomposition behavior of aLSLs was significantly improved compared with physical mixture oil. This improvement might be related to the insertion of La and the structure of TAG. In all, this study firstly developed a novel thermo-oxidatively stable MLCT with high levels of aLna and La.

Fatty acids methyl esters from soybean oil for biobased surfactants industry: Obtention C16 / C18 concentrate for use as feedstock

Soybean fatty acid methyl esters (FAMEs) are used as biodiesel, a co-fuel according to current consumption figures. In addition, FAMEs are becoming increasingly important as biodegradable substitutes for mineral oils, such as oil for chainsaws, gearboxes, hydraulics, and lubricants for crude oil production. Therefore, the possibility of producing a wide spectrum of value-added products in oleochemical industry will guarantee the competitiveness of biodiesel plants in the market. In this way, soybean FAMEs of local production were modified to obtain the desired characteristics to produce biobased surfactants as methyl ester sulfonated (MES). In order to incorporate soybean FAMEs into the conventional MES manufacturing process, their lipid profile must be similar to that of the traditionally used raw material, that is, palm oil. This oil is composed of acids with a length between C12 and C18 and 44–50 % of unsaturated acids, a higher concentration of unsaturated acids is not convenient because generated impurities could affect the final color of the product. Thus, the objective of this work is to achieve a ratio between soybean C16/C18 FAMEs of 60/40, the maximum possible ratio from the initial C16/C18 of 11.0/87.6. In this study, molecular distillation and urea complexation were used as individual and combined techniques to obtain C16/C18 concentrate. In the molecular distillation a ratio of 16.2 / 83.1 was obtained with a yield of 23.2 % (evaporation temperature of 70 °C) while by urea complexation a ratio of 35.4/ 60.8 was obtained with a yield of 32.0 % (urea: FAMEs mass ratio of 1: 1). The most suitable combination of both techniques was a urea complexation stage followed by a molecular distillation stage. The obtained product had a ratio of 56.7 / 43.3 and a yield of 41.8 %. The results of this study could be applied to other vegetable sources to obtain an appropriate profile of FAMEs. Also, the developed process in this work could be used in the industry of green surfactants to produce the segmentation of biodiesel industry. • FAMEs from soybean oil could be used in the biobased surfactants industry. • Urea Complexation and Molecular Distillation combined could join to biodiesel industry. • This method of purification allows a greater productive diversification of biodiesel. • The combination of two techniques allows modifying the FAMEs profile of soybean oil.

Molecular distillation of copaiba oleoresin—A clean process for diterpenes enrichment

AbstractCopaiba oleoresin has sesquiterpenes and diterpenes with significant medicinal properties, including being antimicrobial, antiparasitic, and wound healing, among others. Thus, the objective of this work was to study the diterpene enrichment of the copaiba oleoresin from Copaifera officinalis via molecular distillation. Evaporator temperature (EVT) and feed flow rate (Q) were evaluated using an experimental design (22 with central point) considering the ratio of distillate and residue streams (DTR) as the response to optimize the residue recovery. EVT and Q were the main effects for diterpenes recovery, with the best experimental condition at 100°C (EVT) and 15 ml/min (Q) under 0.001 mbar, of which the residue stream had a diterpenes content of 99.25%. With the molecular distillation process, it was possible to add value to the copaiba streams, separating and purifying diterpenes with applicability in the biomedical and pharmaceutical industries since no solvent is used in this process (clean).

Mineral saturated hydrocarbons and mineral aromatic hydrocarbons in tropical plant oils and their removal by molecular distillation

AbstractNowadays, tropical plant oils (e.g., palm oil and coconut oil) are extensively used in consumer products, especially in infant formulas. However, there is a lack of statistical data on the levels of mineral oil in these oils, including mineral saturated hydrocarbons (MOSH) and mineral aromatic hydrocarbons (MOAH). In this study, we reported a survey of MOSH/MOAH in tropical oils, and in addition, we provided an effective strategy (i.e., molecular distillation) to reduce their contents. A total of 686 tropical plant oils were collected from five tropical countries for this survey. The highest quantifiable MOSH and MOAH concentrations were up to 456.0 and 78.9 mg kg−1, respectively. Interestingly, MOSH was ubiquitous in almost all the tested samples. The distribution of sub‐fractions for MOSH centered at C25–C35 and C35–C40 in most crude and refined oils. After distillation, the MOH sub‐fraction ≤40 was effectively removed, but >40 was unaltered.

Enrichment of nervonic acid in Acer truncatum Bunge oil by combination of two-stage molecular distillation, one-stage urea complexation and five-stage solvent crystallization

Nervonic acid is the world's first and only potent substance that can repair damaged nerve fibers and promote nerve cell regeneration with high nutritional value. The wide variety of fatty acids in plant oils and fats with similar structures makes the large-scale separation and purification of high-purity nervonic acid very difficult. A new combined process of molecular distillation, urea inclusion and solvent crystallization was established to prepare high-purity nervonic acid with the mixed fatty acids obtained after saponification and acidification of Acer truncatum Bunge oil as raw materials. First, according to the difference in the mean free path of fatty acids, molecular distillation was used to separate and remove C16 saturated fatty acid of palmitic acid and four C18–C20 fatty acids of stearic, oleic, linoleic, and linolenic acids. The content of C16–C20 fatty acids decreased from 72.92% to 19.22% after two-stage molecular distillation processes, in which the contents of saturated fatty acid of palmitic acid decreased to about 0.5%. Then, according to the difference in carbon chain length and saturation of fatty acid, the contents of C22–C24 saturated fatty acids of tetracosanoic and docosanoic acids decreased to 0.21% and 0.07% by urea inclusion with urea/free fatty acid preparation by saponification (SPOMFs) ratio as 0.6. In addition, all saturated fatty acids were basically separated. Finally, according to the difference in the solubility of fatty acids in solvents, the C18–C20 unsaturated fatty acids of oleic, linoleic, and linolenic acids and C22 unsaturated fatty acid of erucic acid were removed by solvent crystallization. The content of C18–C20 unsaturated fatty acids decreased to less than 5% with pentanol as the solvent after the first stage solvent crystallization. The content of erucic acid decreased to 3.47% with anhydrous ethanol as the solvent after the second to fifth stage solvent crystallization. The combined process of molecular distillation, urea inclusion and low temperature crystallization innovatively adopted an efficient, simple and easy-to-industrial solvent crystallization method to separate erucic and nervonic acids, obtaining nervonic acid with purity of 96.53% and final yield of 47.99%.

Phase separation and critical size in molecular sorting.

Molecular sorting is a fundamental process that allows eukaryotic cells to distill and concentrate specific chemical factors in appropriate cell membrane subregions, thus endowing them with different chemical identities and functional properties. A phenomenological theory of this molecular distillation process has recently been proposed [M. Zamparo, D. Valdembri, G. Serini, I.V. Kolokolov, V.V. Lebedev, L. Dall'Asta, and A. Gamba, Phys. Rev. Lett. 126, 088101 (2021)0031-900710.1103/PhysRevLett.126.088101], based on the idea that molecular sorting emerges from the combination of (a) phase separation driven formation of sorting domains and (b) domain-induced membrane bending, leading to the production of submicrometric lipid vesicles enriched in the sorted molecules. In this framework, a natural parameter controlling the efficiency of molecular distillation is the critical size of phase separated domains. In the experiments, sorting domains appear to fall into two classes: unproductive domains, characterized by short lifetimes and low probability of extraction, and productive domains, that evolve into vesicles that ultimately detach from the membrane system. It is tempting to link these two classes to the different fates predicted by classical phase separation theory for subcritical and supercritical phase separated domains. Here, we discuss the implication of this picture in the framework of the previously introduced phenomenological theory of molecular sorting. Several predictions of the theory are verified by numerical simulations of a lattice-gas model. Sorting is observed to be most efficient when the number of sorting domains is close to a minimum. To help in the analysis of experimental data, an operational definition of the critical size of sorting domains is proposed. Comparison with experimental results shows that the statistical properties of productive and unproductive domains inferred from experimental data are in agreement with those predicted from numerical simulations of the model, compatibly with the hypothesis that molecular sorting is driven by a phase separation process.

Separation of Free Fatty Acid and Triglycerides by Molecular Distillation–Experimental and Simulation Approaches

Separation of free fatty acids and triglycerides is important in the edible oil industry. In this study, both experimental and simulation approaches were conducted using falling film molecular distillation. A binary mixture of oleic acid as free fatty acid with refined soybean oil as triglyceride was used. Evaporation temperature range tested was from 110 to 160 °C, while other parameters such as condensation temperature, feeding rate, and vacuum pressure were fixed. The free fatty acid content of retentate was gradually decreased as evaporation temperature increased, while the free fatty acid content of distillate was approximately 100 wt.%, regardless of temperature. Triglycerides had an extremely low vapor pressure compared to oleic acid; therefore, their fraction in distillate was negligible. The mass conservation and transport equations were selected to explain the evaporation mechanism, and analytical solutions were simply introduced under the conditions of low mass fraction of volatile compound in the feeding mixture. Some experimental data are re-quired to determine the coefficient of molecular distillation in the governing equation. Using this obtained parameter, the proposed model could simulate all mass amounts and fractions of each component in retentate and distillate with a good agreement between experimental and simulation data, indicating the reasonable accuracy of the model proposed.

Green extraction and separation of Dendranthema indicum essential oil by supercritical carbon dioxide extraction combined with molecular distillation

The optimal extraction parameters of Dendranthema indicum extract using supercritical carbon dioxide extraction were organized by response surface methodology (RSM) with Box - Behnken design (BBD). The peak extraction yield (9.37%) was obtained in the condition of 750 W of microwave power, 40 °C of extraction temperature, 26 MPa of extraction pressure, and 105 min of extraction time. Subsequently, molecular distillation was applied to separate essential oil from D. indicum extract. The separation yield of D. indicum essential oil obtained at 80 (DIEO80) and 90 °C (DIEO90) were 0.21 g/100 g and 0.44 g/100 g, respectively, which was lower than those of 100, 110 and 120 °C, while they presented transparent with no precipitate. DIEO90 possessed the strongest antioxidant activities (16.08 μmol TE/g for 1,1-diphenyl-2-picrylhydrazyl scavenging activity, 46.05 μmol TE/g for ferric reducing antioxidant power, respectively). Furthermore, alkenes, alcohols and esters were identified the main volatile flavor components for D. indicum extract and essential oils. The proportions of major contributing components such as 1,8-cineol (6.45%–15.04%), isopinocarveol (6.02%–11.78%), (E)-α-bergamotene (3.02%–5.62%), (E)-β-famesene (2.80%–12.92%), germacrene D (2.83%–8.23%), 6-ethenyl-2,2,6-trimethyloxan-3-ol (5.86%–6.88%), (6-Ethenyl-2,2,6-trimethyl-oxa- n-3-yl) acetate (9.11%–10.51%) and β-elemene (4.16%–6.44%). Though molecular distillation, compounds with low boiling points were enriched in DIEO80 and DIEO90, and compounds with high boiling points were in other oils. Overall, the sequential green process based on supercritical carbon dioxide extraction with molecular distillation is an efficient method for extraction and separation of essential oil.

Enzyme-catalyzed preparation of polyol ester lubricants and performance research-based on pelargonic acid, oleic acid and trimethylolpropane

Chemical oil esters synthesized by polyols and fatty acids are biodegradable and have ideal physicochemical and lubricating properties as compared to mineral lubricants. Using sulfuric acid and lipases as catalysts, a polyester lubricant was synthesized from pelargonic acid (PA) and trimethylolpropane (TMP). Lipase-catalyzed goods are superior and more in accordance with green production requirements. The optimized reaction conditions of lipase catalytic were 50 °C, 15%wt enzyme content, PA: TMP= 3.3:1 %, and 15 % water content. When the time reached 96 h, the accumulation of trimethylolpropane (TMPTP) reached 82% under these conditions. The TMPTP purified by molecular distillation has a flashpoint of 276 °C, a pour point of − 57 °C, and a viscosity index of 145, making it more suitable for extreme environments. On this basis, to improve the viscosity-temperature performance of the substrate, a certain proportion of oleic acid (OA) is added. Low viscosity (kinematic viscosity of 4.86–9.54 mm2/s at 100 °C), high viscosity index (VI > 160), low pour point (−50 °C), and low friction coefficient (COF) of 0.09 ∼ 0.11 is among the properties of a series of synthetic hetero-chain mixed esters, which can meet the needs of a variety of extremely low temperatures and complex working conditions.

Antimicrobial, Antioxidant, Anti-Inflammatory Activities of Eight Essential Oils Obtained from Traditional Chinese Medicines Using Supercritical Fluid Extraction Coupled Molecular Distillation

Atractylodes chinensis (DC.) Koidz., Magnolia officinalis Rehd. et Wils., Citrus reticulata Blanco, Amomum villosum Lour., Pogostemon cablin (Blanco) Benth., Mosla chinensis Maxim., Zingiber officinale Rosc., and Artemisia argyi Lévl. et Vant are eight of the extensively used herbs among Traditional Chinese Medicines (TCM) with a long history. The essential oil (EO) extracts of the eight TCMs were obtained using supercritical fluid extraction coupled with molecular distillation to investigate the chemical composition, antimicrobial, antioxidant activities, and anti-inflammatory activity for further exploration of the underlying mechanism of the various biological activities. The chemical components of the EO were analyzed by GC-MS. The antimicrobial activity was evaluated by the agar-well diffusion assay and the minimum inhibitory concentration assay. The antioxidant activity of the EO was evaluated by 1, 1-diphenyl-2-picrylhydrazyl radical and 2, 2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid ammonium salt assays. The anti-inflammatory activity of a recipe named “Shenshusan” was evaluated by the xylene-induce ear vasodilatation assay and the acetic acid-induce capillary permeability enhancement assay. Chemical constituents of the EO varied markedly among the eight species of TCMs. The EOs from Mosla chinensis and Artemisia argyi exhibited strong antimicrobial activity while the EOs from Magnolia officinalis, Mosla chinensis and Zingiber officinale exhibited strong antioxidant activity. The recipe “Shenshusan” showed significant anti-inflammatory activity (340 mg/kg for mice). This study contributes to what is known about the eight kinds of TCM possesses the potent antimicrobial, antioxidant, and anti-inflammatory activity which held great potential and can help guide future recommendations and interventions for food, medicine, and cosmetics application.

Analysis and optimization of feed liquid flow characteristics of distributor in scraping film molecular distillation equipment

Abstract The initial liquid film is the basis of material evaporation during distillation, so it is of great significance to study the distribution of the initial liquid film of distributor in the process of scraping film molecular distillation. In this paper, CFD is used to study the distribution of distributor liquid film, and the mathematical model of the triangular tooth distributor and its peripheral cylinder is established, and the effects of the triangular tooth distributor’s speed, feed rate, and feed position on initial liquid film uniformity are investigated. And the reliability of the numerical simulation model is verified by experiments. In this paper, a new feed structure that includes an intermediate feed device and inclined tooth distributor is proposed and researched by numerical simulation. And compared with the previous structure, the liquid film distribution is more uniform. This has important guiding significance to the optimization of equipment in production.

Fractions of laurel essential oil obtained by molecular distillation with greater antioxidant and antimicrobial activities

This study aimed to analyze the chemical composition and the antioxidant and antimicrobial activities of Laurus nobilis L. essential oil (LEO) and its fractions obtained by short-path molecular distillation. According to the chemical composition, it can be said that LEO and its fractions proved to have antioxidant activity sinceboth have a high content of total phenolic content (TPC). Short-path molecular distillation was used to separate essential oil fractions with superiorantioxidant activity. Laurel residue (LR) exhibited the greatest antioxidant activity, with higher values of trolox equivalent antioxidant capacity with ABTS radical cation (TEAC-ABTS) assay and TPC. In addition, LR had the lowest value of IC50-DPPH. For antimicrobial activity, all natural products tested had an effect on all foodborne pathogenic microorganisms. LEO, as well as its fractions, showed antimicrobial, bacteriostatic, or bactericidal activity against Gram-positive and Gram-negative bacteria. The LEO and its fractions obtained by molecular distillation can be used as antimicrobials and as food preservatives to prevent oxidation. Also, consumers considered the addition of LEO or its fractions in food products as positive.

Potential valorization of waste cooking oils into sustainable bio-lubricants

This work explores the feasibility of using waste cooking oils (WCO) as eco-lubricants. Five WCO from different food facilities were studied. Three of them were fractionated into both lighter and heavier fractions by molecular distillation. A comprehensive chemical characterization (fatty acids distribution, polar compounds and acidity) was carried out on all WCOs and their fractions, which led to set relationships with the oils’ properties (such as viscosity index, low temperature viscous flow behavior, oxidation resistance, etc.). It is worth mentioning the high viscosity index values found in waste cooking oils with both low total polar compounds and acidity level, as well as the benefit which acidity had on their fluidity at low temperature and their lubricity. Moreover, it was also noteworthy that the lighter fractions, merely constituted by free fatty acids (FFA), presented an improved oxidative resistance. The largest OOT enhancement, 12.4%, was found for the light fraction of a non-segregated oil. Moreover, a better thermal stability was shown by the heavier fractions. Finally, both fractions exhibited enhanced friction-reducing capability as compared to their parent WCO. The light fractions from a non-segregated oil, a fast food restaurant oil and a deep-fried food establishment oil yielded wear reductions of 11.7%, 44.3% and 36.8%, respectively. Therefore, molecular distillation has been proved to be a key strategy to obtain more efficient liquid eco-lubricants.

Molecular Distillation of Lavender Supercritical Extracts: Physicochemical and Antimicrobial Characterization of Feedstocks and Assessment of Distillates Enriched with Oxygenated Fragrance Components.

Lavandula angustifolia is one of the most widely cultivated non-food crops used in the production of essential oil; it is used in perfumery, aromatherapy, pharmaceutical preparations, and food ingredients. In this study, supercritical fluid extraction (SFE) and molecular distillation (MD) were combined, primarily to enrich scCO2 extracts with lavender oxygenated monoterpenes, avoiding thermal degradation, hydrolysis, and solvent contamination, and maintaining the natural characteristics of the obtained oils. Molecular distillation was developed for the first time for the extraction of crucial lavender fragrance ingredients, i.e., from two scCO2 extracts obtained from dry flower stems of lavender cultivated in Poland and Bulgaria. The best results for high-quality distillates were obtained at 85 °C (EVT) and confirmed that linalyl acetate content increased from 51.54 mg/g (initial Bulgarian lavender extract, L-Bg-E) and 89.53 mg/g (initial Polish lavender extract, L-Pl-E) to 118.41 and 185.42 mg/g, respectively, corresponding to increases of 2.3 and 2.1 times in both distillate streams, respectively. The distillates, light oils, and extracts from lavender were also evaluated for their antimicrobial properties by determining the minimum inhibitory concentration (MIC) by the broth microdilution method. Generally, Gram-positive bacteria and Candida spp. were more sensitive to all distilled fractions and extracts than Escherichia coli (Gram-negative bacteria).

Experimental and computer simulation of a molecular distillation process for the dehydration of tetramethylammonium hydroxide solution

Tetramethylammonium hydroxide pentahydrate (TMAH·5H2O) is easily decomposed when heated, which results in the difficulty of dehydration. In this study, a new process for dehydration of a TMAH propylene glycol solution using wiped-film molecular distillation was developed. The experiments were carried out to evaluate the effect of operating conditions on the performance of the dehydration with the operating temperature ranging from 65 °C to 90 °C, the operating pressure from 100 Pa to 2000 Pa and the mass flow rate from 36 to 162 g/min. The experimental results indicated that molecular distillation was capable of dehydrating TMAH solution to a water content of 0.65% from 5.82%. Then a modified Flash module in Aspen plus, which used the fitting factor and linear correlation between the simulated and experimental temperatures, was developed to simulate the dehydration process. The relative error between the modified simulated and experimental data is less than 5%, and the response surface methodology analysis was conducted to optimize the operating conditions. The optimal dehydration conditions were 85 °C, 100 Pa and 54 g/min feed flow rate, where the minimum water content in distilled solution is 0.43%. The results show that the process developed realizes a high efficiency of dehydration and prevents TMAH from thermal decomposition.

Industrially concentrated tocopherols from soybean oil deodorizer distillate

Although the tocopherol concentration in Soybean Oil Deodorizer Distillate (SODD) regarding molecular distillation (MD) has been studied in the last 20 years, no scientific studies were published yet in international journals about the results of this technology when applied in an industrial scale. This research aimed to evaluate the tocopherols concentration through industrial patented MD technology in a vegetable oil refinery, using a phospholipase A2 enzymatic physical degumming process, packed dual temperature column deodorizer coupled to a double washer and a Tocoboost® patented technology. The results of the refinery production process from July 2019 to February 2020 could totalize over 81 days, comprising 243 samples and more than 1900 laboratory analysis. The input and output SODD samples were analysed by Gas Chromatography (GC), in which graphics of the automation system and mass balance of the refinery production ranges were also verified. The results showed that it is possible to achieve over five times Vitamin E concentration from non-modified soybean oil deodorizer distillate in a physic enzymatic phospholipase degumming process plant using a combination of advanced technology in order to separate high value-added molecules gained through studied hypotheses regarding vacuum, temperature, distiller models, backset flows, multiple stages of distillation, degradation and product recovery.

Development status and future research direction of molecular distillation technology

Molecular distillation is a new separation technology. Compared with the traditional separation technology, the operating temperature is far lower than the boiling point of liquid, the distillation pressure is under extremely high vacuum, the heating time is short, the system is basically oxygen-free, and the effective components in the system can be guaranteed to the maximum extent. The basic principle, technical characteristics and equipment of molecular distillation technology are reviewed, and its advantages and disadvantages are analyzed and evaluated. The application of molecular distillation technology in industrial production, existing problems and solutions are introduced, which shows a broad application prospect. The advantages and disadvantages of the application of molecular distillation technology in various fields are discussed. In this paper, the molecular distillation technology is comprehensively reviewed from the aspects of its principle, structure type, industrial application and research status. Finally, on this basis, the key problems to be solved urgently in the future of molecular distillation technology are put forward, and the prospect of promoting the industrialization process of molecular distillation technology is put forward.

Synthesis of partial glycerides rich in α-linolenic acid efficiently from silkworm pupa oil with immobilized lipase MAS1-H108A

In this paper the ability of immobilized lipase MAS1-H108A to prepare α-linolenic acid-rich partial glycerides was studied. The effects of different reaction conditions on the yield of Diacylglycerol (DAG) and Monoglyceride (MAG) were investigated, including substrate molar ratio, substrate concentration, temperature and lipase dosage. The highest yield (63.92% of MAG and 30.61% of DAG) was obtained when silkworm pupa oil/glycerol ratio of 1:3, lipase dosage was 50 U/g, substrate concentration was 40% (w/v), at 40 °C. Under the optimal conditions, the scale-up (50 times) and single-stage molecular distillation were carried out to separate DAG and MAG, the yield of MAG in the light phase was 99.18%, and the concentration of DAG in the heavy phase was 89.47%, α-linolenic acid in MAG and DAG accounted for 28.96% and 28.23%, respectively. The results can be shown that the immobilized lipase MAS1-H108A has excellent potential for enzymatic glycerolysis to prepare functional partial glycerides.