Lauric Ester Research Articles

Preparation and Charcterisation of Acetate Cellulose Laurate Ester in Sodium Acetate/Zinc Chloride Systems

The objective of this study was to explore the preparation and characterisation of acetate cellulose laurate ester in sodium acetate/zinc chloride systems. The cellulose used in the study was obtained from oil palm empty fruit bunch and oil palm frond. The characterization of both the isolated cellulose and the acetate cellulose laurate ester was carried out using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Differential thermogravimetric (DTG), and Thermogravimetric analysis (TGA). The FT-IR analysis of the acetate cellulose laurate ester revealed the presence of C=O, confirming its modification. The crystallinity of the isolated cellulose and the acetate cellulose laurate ester was found to be 67-72% and 51-54%, respectively. The thermal stability of the isolated and modified cellulose esters was found to be 360-340 ℃ and 380-365 ℃, respectively. The solubility test showed that the prepared acetate cellulose laurate esters were soluble in different solvents. However, this study found that the synthesis of acetate cellulose laurate ester in an aqueous medium is not feasible. The improved hydrophobic character, good thermal stability, water retention value, and excellent solubility in different solvents of the acetate cellulose laurate ester reported in this study make it a potential material for applications in bioplastics, and packaging materials.

Formulation of Body Lotion with Sucrose Ester Emulsifier

Abstract Sucrose ester is synthesized from palm fatty acid methyl ester and sucrose using a base catalyst. Emulsifiers that replace palm oil with sucrose esters are biodegradable and potentially non-toxic to the skin. The efficiency of sucrose ester production was obtained by using water as a solvent for sucrose, with a mass ratio of 3:5 for water and sucrose. Dilution of sucrose with water reduces caramelization during reaction. Based on laboratory research, sucrose ester has good emulsion stability from sucrose myristate ester, sucrose palmitate ester, and sucrose laurate ester. The design used a random block design with three levels of variation in sucrose ester concentration, namely 2%, 6%, and 10%. Based on ANOVA, there is a very significant effect between variations in concentration on specific gravity, pH, viscosity and surface tension. Verification tests were carried out on consumer references in the form of organoleptic tests on 35 respondents. Then, microbial tests are carried out based on Indonesian National Standards, namely the maximum number of total plates (10−2 colonies), negative tests for fungi, Staphylococcus aureus, Pseudomonas aeruginosa, and Coliform (maximum 3). Determining the best combination uses the Composite Performance Index (CPI) and Analytical Hierarchy Process (AHP). Based on organoleptic tests, the best sample is 10% myristate. The analysis of organoleptic results is consistent with the analysis of laboratory results which states that the lotion sample made from 10% sucrose myristate ester is the best sample. The best lotion samples have good emulsion stability and are not contaminated by microbes.

Lipase-catalyzed synthesis of laurate esters from puerarin and its β-D-fructofuranosyl-(2→6)-puerarin derivative

This study investigates the transesterification of isoflavones puerarin and β-D-fructofuranosyl-(2→6)-puerarin to enhance their lipophilicity for specific pharmacological applications. The process achieved high yields (80-100%) in the isoflavones conversion when commercial lipases from Candida antarctica (CALB) and Thermomyces lanuginosus (TL IM) were used. The acylation patterns between CALB and TL IM varied depending on the substrate; both enzymes yielded principally monoacylated products from puerarin and β-D-fructofuranosyl-(2→6)-puerarin. However, TL IM also produced di- and triacylated derivatives of β-D-fructofuranosyl-(2→6)-puerarin in substantial amounts. Structural characterization by NMR identified puerarin-6ʹʹ-O-laurate and β-D-fructofuranosyl-(2→6)-puerarin-6ʹʹʹ-O-laurate as the primary products in CALB and TL IM reactions. These acyl derivatives presented improved lipophilicity (Log P from −1.0 − 0.16 to 3.26 − 3.58) and antioxidant activity (67.2-97.3 to 102.5-131.4 µM TE/mmol). Therefore, these compounds have potential pharmacological applications.

Optimization of Enzymatic Synthesis of D-Glucose-Based Surfactants Using Supported Aspergillus niger Lipase as Biocatalyst

Surfactants are amphiphilic molecules with the ability to modify the surface tension between two surfaces. They can be obtained by various methods, the main one being synthetic, from petroleum-based substrates. Their universal use in a wide range of fields has created a global market and, consequently, ecological, and economic expectations for their production. Biocatalyzed processes, involving enzymes, can address this objective with processes complying with the principles of green chemistry: energy saving, product selectivity, monodispersity, and reduction in the use of solvents, with energy eco-efficiency. For example, fatty-acid carbohydrate esters are biobased surfactants that can be synthesized by lipases. In this work, we were interested in the synthesis of D-glucose lauric ester, which presents interesting properties described in the literature, with Aspergillus niger lipase, rarely described with sugar substrates. We optimized the synthesis for different parameters and reaction media. This lipase appeared to be highly selective for 6-O-lauroyl-D-glucopyranose. However, the addition of DMSO (dimethyl sulfoxide) as a co-solvent displays a duality, increasing yields but leading to a loss of selectivity. In addition, DMSO generates more complex and energy-intensive purification and processing steps. Consequently, a bio-sourced alternative as co-solvent with 2MeTHF3one (2-methyltetrahydrofuran-3-one) is proposed to replace DMSO widely described in the literature.

Optimization of nanofiber‐caproate/laurate esters synthesis, their characterization, and usage as emulsifier in o/w emulsion

AbstractThe aim of this study is to optimize the esterification of nanofibers with caproyl/lauroyl chlorides at different substitution degrees' (DS) and to investigate the usage of nanofiber derivatives in model emulsions. First, cellulosic material was obtained and milled into nanofibers using a micro‐fluidizer. Then, these nanofibers were esterified with caproyl/lauroyl chlorides in a solvent of DMAc/LiCl with DMAP as an acid scavenger. The esterification of nanofibers with caproyl/lauroyl chlorides was optimized for fatty acid chloride mole and reaction time. Esterification reactions were carried out at 80°C with various molar ratios of acyl chlorides (3–15 moles) versus anhydroglucose unit of nanofibers and for various time durations (30–360 min). The hydrophobic derivatives with DS in the range of 0.34–2.77 were successfully obtained. Using the data obtained as a result of the optimization, nanofiber‐fatty acid esters with different DS (0.50–2.75) were produced and characterized. Analyzes showed that the esterification process was successful and as the degree of esterification increased, the crystallinity index and thermal stability of the derivatives decreased. Then, the nanofiber‐caproate/laurate esters with different DS were used as emulsifier (0.5 wt%) in an oil‐in‐water model emulsion containing 25 wt% oil and the emulsions were analyzed. The nanofiber caproate/laurate esters with a DS of 0.50–1.25 were suitable for o/w emulsions, while samples with a DS of 2.00 and above were not found suitable. Emulsions prepared by using nanofiber derivatives with 1.25 DS had higher G′ and G″ and viscosity values and lower droplet sizes than those of other group.

Green composites made of polyhydroxybutyrate and long-chain fatty acid esterified microcrystalline cellulose from pineapple leaf.

Pineapple leaf fibres are an abundant agricultural waste product that contains 26.9% cellulose. The objective of this study was to prepare fully degradable green biocomposites made of polyhydroxybutyrate (PHB) and microcrystalline cellulose from pineapple leaf fibres (PALF-MCC). To improve compatibility with PHB, the PALF-MCC was surface modified using lauroyl chloride as an esterifying agent. The influence of the esterified PALF-MCC laurate content and changes in the film surface morphology on biocomposite properties was studied. The thermal properties obtained by differential scanning calorimetry revealed a decrease in crystallinity for all biocomposites, with 100 wt% PHB displaying the highest values, whereas 100 wt% esterified PALF-MCC laurate showed no crystallinity. The addition of esterified PALF-MCC laurate increased the degradation temperature. The maximum tensile strength and elongation at break were exhibited when adding 5% of PALF-MCC. The results demonstrated that adding esterified PALF-MCC laurate as a filler in the biocomposite film could retain a pleasant value of tensile strength and elastic modulus whereas a slight increase in elongation can help to enhance flexibility. For soil burial testing, PHB/ esterified PALF-MCC laurate films with 5-20% (w/w) PALF-MCC laurate ester had higher degradation than films consisting of 100% PHB or 100% esterified PALF-MCC laurate. PHB and esterified PALF-MCC laurate derived from pineapple agricultural wastes are particularly suitable for the production of relatively low-cost biocomposite films that are 100% compostable in soil.

DES-Based Biocatalysis as a Green Alternative for the l-menthyl Ester Production Based on l-menthol Acylation.

The deep eutectic solvent (DES)-based biocatalysis of l-menthol acylation was designed for the production of fatty acid l-menthyl ester (FME) using fatty acid methyl ester (FAME). The biocatalytic reaction was assisted by a lipase enzyme in the DES reaction medium. ւՒ-menthol and fatty acids (e.g., CA—caprylic acid; OA—oleic acid; LiA—linoleic acid; and LnA—linolenic acid) were combined in the binary mixture of DES. In this way, the DES provided a nonpolar environment for requested homogeneity of a biocatalytic system with reduced impact on the environment. The screening of lipase enzyme demonstrated better performance of immobilized lipase compared with powdered lipase. The performance of the biocatalytic system was evaluated for different DES compositions (type and concentration of the acid component). l-menthol:CA = 73:27 molar ratio allowed it to reach a maximum conversion of 95% methyl lauric ester (MLE) using a NV (Candida antarctica lipase B immobilized on acrylic resin) lipase biocatalyst. The recyclability of biocatalysts under optimum conditions of the system was also evaluated (more than 80% recovered biocatalytic activity was achieved for the tested biocatalysts after five reaction cycles). DES mixtures were characterized based on differential scanning calorimetry (DSC) and refractive index analysis.

Starch Formates: Synthesis and Modification.

Starch can be efficiently converted into the corresponding formates homogeneously using N-formyl imidazole obtained by the reaction of 1,1′-carbonyldiimidazole and formic acid in dimethyl sulfoxide as a solvent. Starch formates are soluble in polar aprotic solvents, not susceptible against hydrolysis, and not meltable. Thermoplastics could be generated by conversion of starch formates with long-chain fatty acids exemplified by the conversion with lauroyl chloride in N,N-dimethylacetamide, leading to mixed starch laurate formates. The mixed esters show melting temperatures mainly dependent on the amount of laurate ester moieties.

An Integrated Enzymatic Approach to Produce Pentyl Xylosides and Glucose/Xylose Laurate Esters From Wheat Bran.

Alkyl glycosides and sugars esters are non-ionic surfactants of interest for various applications (cosmetics, food, detergency,…). In the present study, xylans and cellulose from wheat bran were enzymatically converted into pentyl xylosides and glucose and xylose laurate monoesters. Transglycosylation reaction catalyzed by the commercial enzymatic cocktail Cellic Ctec2 in the presence of pentanol led to the synthesis of pentyl β-D-xylosides from DP1 to 3 with an overall yield of 520 mg/g of xylans present in wheat bran. Enzymatic hydrolysis of wheat bran with Cellic Ctec2 and subsequent acylation of the recovered D-glucose and D-xylose catalyzed by the commercial lipase N435 in the presence of lauric acid or methyl laurate produced one D-glucose laurate monoester and one D-xylose laurate monoester. An integrated approach combining transglycosylation and (trans)esterification reactions was successfully developed to produce both pentyl xylosides and D-glucose and D-xylose laurate esters from the same batch of wheat bran.

Enzymatic Synthesis of Glucose‐ and Xylose Laurate Esters Using Different Acyl Donors, Higher Substrate Concentrations, and Membrane Assisted Solvent Recovery

AbstractGlucose‐ and xylose laurate esters are enzymatically synthesized using equimolar substrate concentrations in 2‐methyl‐2‐butanol, comparing free lauric acid with methyl‐ and vinyl‐laurate as acyl donors. All reactions result in ≥70% acyl donor conversions after 72 h but the activated donors are also partially hydrolyzed to lauric acid, highlighting the difficulty in controlling water presence in this particular reaction system. The esterification of xylose generates a complex product profile, with several regioisomers of monoesters and diesters. The esterification of glucose is quite selective, forming mainly the 6‐O monoester (≥96%) with a small presence of two diester isomers (4%). Increasing substrate concentration up to 800 millimoles kg−1 results in lower conversion values (down to 58%) but shows that the reaction proceeds successfully even in the presence of high amounts of insoluble glucose. However, the reaction is less selective and the proportion of diester increases, becoming up to 46% (molar fraction) of the final product. Solvent recovery after esterification can be achieved by organic solvent nanofiltration through a polymeric membrane able to retain ≥80% of all reaction substrates and products.Practical Applications: The use of high substrate concentrations during the enzymatic synthesis of sugar ester biosurfactants leads to product titers that are more industrially appealing, without the need to find a solvent that can solubilize all initial substrate. The sustainability of the enzymatic conversion at mild temperatures can be enhanced by recycling of the reaction solvent through organic solvent nanofiltration, an energy efficient alternative to other traditional methods like distillation.

Sustainable production of biodiesel and transformation of glycerol to glycerol laurate esters over inner diameter-controlled sulfonic acid functionalized ethyl-bridged-organosilica nanotubes

Solid acid-catalyzed biodiesel production from inedible oils offers a promising mean to reduce the cost of feedstocks and avoid the competition with edible oil market. Here we demonstrate a series of inner diameter-controlled sulfonic acid functionalized ethyl-bridged-organosilica nanotubes (Ar/PrSO3H–Si(Et)Si) by a toluene swollen mixed Pluronic surfactant micelle-templating co-condensation route for transesterification of tripalmitin or plant oils with methanol to produce fatty acid methyl esters and esterification of glycerol with lauric acid to produce mono- and di-glycerol esters. By combination of superstrong Brønsted acidity, unique hollow tubular nanostructure, excellent porosity properties and hydrophobic surface, the Ar/PrSO3H–Si(Et)Si nanotubes display higher catalytic activity as compared with acidic resin and zeolite. Additionally, the inner diameters and lengths of Ar/PrSO3H–Si(Et)Si nanotubes influence the activity obviously. The Ar/PrSO3H–Si(Et)Si nanotubes also show excellent catalytic reusability, attributing to covalent bonding of Ar/PrSO3H groups within silica/carbon framework and surface hydrophobicity of the catalysts.

Facile synthesis Cobalt catalysts for regulating the deoxygenation pathways in producing diesel-like hydrocarbon fuels

The key technical issues for establishing an economical and advanced deoxygenation process of vegetable oil for producting the diesel-like hydrocarbons are to develop the low-cost non-sulfided heterogeneous catalytic systems with good performance. Herein, we report two facile strategies for preparing Co-based catalysts in an effort to explore the highly efficient heterogeneous catalysts for the deoxygenation of laurate ester. Interestingly, the deoxygenation paths can be regulated by altering the synthesized methods of the Co-based catalysts. For example, the Co-MOF-700 catalyst prepared via pyrolysis of one cobalt metal-organic framework (Co-MOF: [Co(tia)(H2O)2]n, tia2− = 5-(1H-1,2,3-triazol-1-yl) isophthalate) at 700 °C under N2 atmosphere for 4 h can orient the catalytic hydrogenation of laurate ester towards decarboxylation/decarbonylation with full conversion and 67.6% selectivity of undecane. While, Co/ZSM-5 synthesized through impregnation-reduction method can promote transformation of methyl laurate to dodecane via hydrodeoxygenation path, in which the conversion and selectivity can be up to 100% and79.12%, respectively.

Lipase-catalyzed laurate esterification of cellulose nanocrystals and their use as reinforcement in PLA composites

Cellulose nanocrystals (CNCs) were surface-modified using immobilized lipase (Novozyme 435) to catalyze the formation of laurate ester groups on the CNC surface and thus facilitate homogeneous dispersion within a poly(lactic acid) (PLA) matrix. Results of dynamic contact angle measurement revealed that the modified CNCs (CNC-LAA) presented greater hydrophobicity than their CNC controls. FT-IR, 13C-NMR, XRD, and TGA were used to characterize the structure and stability of the CNCs before and after modification. PLA reinforced with the modified CNCs were prepared, and the effect on mechanical properties was studied. SEM micrographs suggested uniform dispersion of modified CNCs throughout the PLA matrix at a maximum 1 wt% loading, which was found to be the optimal loading level. The CNC-LAA were able to achieve a 0.4 maximum degree of substitution. DSC indicated enhanced crystallization of PLA chains due to the inclusion of CNC-LAA, indicating that the nanofillers behaved as nucleating agents and also revealed improved compatibility. Tensile strength tests showed slightly improved mechanical properties for breaking strength and elongation at breakage.

Comparative evaluation on rheology performance and thermal stability of ester based drilling fluids

Drilling fluid plays an important role in ensuring smooth drilling operations. Application of ester based drilling fluid (EBDF) is desirable as it shows comparable performance to the conventional oil based drilling fluid (OBDF) as well as environmental friendly. The ester used as a base in the EBDF is usually derived from vegetable oils such as palm oil. In this study, methyl laurate (ML), methyl palmitate (MP), and isopropyl laurate (IPL) esters were used as a base in the EBDF formulation. Subsequently, their physical and rheological properties were determined. In addition, thermal stability of the EBDF was tested to estimate the maximum operating temperature for the EBDF application. Isopropyl laurate (IPL) based EDBF was found to have better rheological properties at standard test condition as compared to the other two esters used. The IPL based EBDF also showed improved viscosity at 90°C. Thermal stability test conducted on the IPL drilling fluid indicated that it is stable up to 150°C.

Regioselective Acylation of Levoglucosan Catalyzed by Candida Antarctica (CaLB) Lipase Immobilized on Epoxy Resin

Every year, a large amount of residual agroindustrial waste has been generated and only around 10% is in fact reused. The development of new strategies for biomass valorization is important to add value to these commodities, since biomass is an excellent alternative feedstock to obtain chemicals of interest from renewable resources. The major compound of pyrolytic treatment of lignocellulosic biomass is levoglucosan (1,6-anhydroglucopyranose), an anhydro-sugar that can be transformed into glucose and is greatly valued in the most diverse industrial sectors as a surfactant, emulsifier, or even a lubricant. In this work, levoglucosan was acylated by lipase-catalyzed transesterification in acetonitrile with great conversions and selectivities with different acyl donors such as ethyl esters of lauric, palmitic, stearic, and oleic acids prepared in situ in an integrated strategy mediated by commercial lipases Novozym435 (N435), PSIM, and the home-made biocatalyst CaLB_epoxy. As a result, all biocatalyst generated mostly monoesters, with N435 being more selective to produce lauric esters (99% at 50°C) and PSIM to produce oleic esters (97% at 55 °C) while CaLB_epoxy was more selective to produce oleic esters of levoglucosan (83% at 55°C). This is the first report in the literature on the production of high selectivity levoglucosan esters.

Synthesis, characterization and application of lipase-conjugated citric acid-coated magnetic nanoparticles for ester synthesis using waste frying oil.

In the present work, magnetic nanoparticles (MNPs) were prepared by chemical precipitation of trivalent and divalent iron ions which were functionalized using citric acid. The bacterial isolate Staphylococcus epidermidis KX781317 was isolated from oil-contaminated site. The isolate produced lipase, which was purified and immobilized on magnetic nanoparticles (MNPs) for ester synthesis from waste frying oil (WFO). The characterization of MNPs employed conventional TEM, XRD and FTIR techniques. TEM analysis of MNPs showed the particle size in the range of 20-50nm. FTIR spectra revealed the binding of citric acid to Fe3O4 and lipase on citric acid-coated MNPs. The citric acid-coated MNPs and lipase-conjugated citric acid-coated MNPs had similar XRD patterns which indicate MNPs could preserve their magnetic properties. The maximum immobilization efficiency 98.21% of lipase-containing citric acid-coated MNPs was observed at ratio 10:1 of Cit-MNPs:lipase. The pH and temperature optima for lipase conjugated with Cit-MNPs were 7 and 35°C, respectively. Isobutanol was found to be an effective solvent for ester synthesis and 1:2 ratio of oil:alcohol observed significant for ester formation. The ester formation was determined using TLC and the % yield of ester conversion was calculated. The rate of ester formation is directly proportional to the enzyme load. Formed esters were identified as isobutyl laurate ester and isobutyl myristate ester through GC-MS analysis.

D-Xylose and l-arabinose laurate esters: Enzymatic synthesis, characterization and physico-chemical properties

Efficient enzymatic synthesis of d-xylose and l-arabinose lauryl mono- and diesters has been achieved by transesterification reactions catalysed by immobilized Candida antarctica lipase B as biocatalyst, in organic medium in the presence of d-xylose or l-arabinose and vinyllaurate at 50 °C. In case of l-arabinose, one monoester and one diester were obtained in a 57% overall yield. A more complex mixture was produced for d-xylose as two monoesters and two diesters were synthesized in a 74.9% global yield. The structures of all these pentose laurate esters was solved. Results demonstrated that the esterification first occurred regioselectively onto the primary hydroxyl groups. Pentose laurate esters exhibited interesting features such as low critical aggregation concentrations values all inferior to 25 μM. Our study demonstrates that the enzymatic production of l-arabinose and d-xylose-based esters represents an interesting approach for the production of green surfactants from lignocellulosic biomass-derived pentoses.

Cellulose laurate ester aerogel as a novel absorbing material for removing pollutants from organic wastewater

Cellulose laurate ester (CE) aerogels were successfully prepared by regeneration of a CE tetrahydrofuran solution from ethanol followed by drying. The adsorption behavior of CE aerogels for pyridine and chlorobenzene in simulated organic wastewater was investigated through a batch static adsorption process. The effects of the contact time, initial concentration and degree of substitution (DS) on adsorption were studied in detail. The results demonstrated that the adsorption capacity of CE aerogels was highly correlated to the DS, and the maximum equilibrium adsorption capacity was determined to be 9.63 mmol/g for pyridine and 18.38 mmol/g for chlorobenzene. Due to the porous network structure of CE aerogels, the adsorption capacity for chlorobenzene of the CE aerogel was twice that of CE. Furthermore, the adsorption rate was fast, with more than 90% of the maximum equilibrium adsorption capacity achieved in 30 min. The isothermal adsorption of chlorobenzene by CE aerogels was compiled using the Langmuir isotherm model, and the kinetic adsorption was in good agreement with the Lagergren pseudo-second-order adsorption kinetics equation, which implied that cellulose laurate aerogels are promising adsorbents for the removal of pyridine and chlorobenzene from wastewater.

Preparation and characterization of cellulose laurate ester by catalyzed transesterification

The preparation of cellulose laurate was investigated through transesterification in 1-allyl-3-methylimidazolium chloride (AmimCl)/dimethyl sulfoxide (DMSO) cosolvent system by using vinyl laurate as an acylation reagent and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an effective catalyst. The effects of reaction temperature, reaction time and the molar ratio of vinyl laurate to anhydride glucose unit (AGU) were investigated. The degree of substitution (DS) ranged from 1.47 to 2.74 under the selected conditions and the reaction order of three hydroxyl groups was C-6>C-3>C-2. The chemical structure cellulose laurate were explored by Fourier transform infrared (FT-IR) spectroscopy, 1H-nuclear magnetic resonance (NMR), 13C NMR, heteronuclear single quantum correlation (HSQC) and X-ray diffraction (XRD) to confirm the occurrence of transesterification. The improved thermal stability of cellulose laurate was proved by the thermogravimetric analysis (TGA). The tensile analysis and the contact angle measurement confirmed the ductile behavior and the hydrophobicity of the films made from cellulose laurate.

Antibacterial Effect of Fructose Laurate Synthesized by Candida antarctica B Lipase-Mediated Transesterification.

Sugar esters are valuable compounds composed of various sugars and fatty acids that can be used as antibacterial agents and emulsifiers in toothpaste and canned foods. For example, fructose fatty acid esters suppress growth of Streptococcus mutans, a typical pathogenic bacterium causing dental caries. In this study, fructose laurate ester was chosen as a target material and was synthesized by a transesterification reaction using Candida antarctica lipase B. We performed a solvent screening experiment and found that a t-butanol/dimethyl sulfoxide mixture was the best solvent to dissolve fructose and methyl laurate. Fructose laurate was synthesized by transesterification of fructose (100 mM) with methyl laurate (30 mM) in t-butanol containing 20% dimethyl sulfoxide. The conversion yield was about 90%, which was calculated based on the quantity of methyl laurate using high-performance liquid chromatography. Fructose monolaurate (Mr 361) was detected in the reaction mixture by high-resolution mass spectrometry. The inhibitory effect of fructose laurate on growth of oral or food spoilage microorganisms, including S. mutans, Bacillus coagulans, and Geobacillus stearothermophilus, was evaluated.