Alkyl Glyceryl Ethers Research Articles

Spatial Organization of Immobilized Multienzyme Systems Improves the Deracemization of Alkyl Glyceryl Ethers

Spatial Organization of Immobilized Multienzyme Systems Improves the Deracemization of Alkyl Glyceryl Ethers

Smartwater Synergy with Chemical EOR: Studying the Potential Synergy with Surfactants

Summary The potential synergy between smartwater and various enhanced oil recovery (EOR) processes has recently attracted significant attention. In previous work, we demonstrated such favorable synergy for polymer floods not only from a viscosity standpoint but also in terms of wettability. Recent studies suggest that smartwater synergy might even extend to surfactant floods. In this work, we investigate the potential synergy between smartwater and surfactant flooding. Opposed to previous work, the potential synergy is investigated from ground zero. We concurrently developed two surfactant formulations for conventional high-salinity injection water and low-salinity smartwater. To design the optimal surfactant-polymer (SP) formulations, we followed a systematic all-inclusive laboratory workflow. Oil displacement studies were performed in preserved core samples using the two developed formulations with conventional injection water and smartwater. The results demonstrated the promising potential of binary surfactant mixtures of olefin sulfonate (OS) and alkyl glyceryl ether sulfonate (AGES) for both waters. The designed binary formulations were able to form Winsor Type III emulsions besides achieving ultralow interfacial tensions (IFTs). Most importantly, in terms of oil displacement, the developed SP formulations in both injection water and low-salinity smartwater were capable of recovering more than 60% of the remaining oil post waterflooding. A key novelty of this work is that it investigates the potential synergy between smartwater and surfactant-based processes from the initial step of surfactant formulation design. Through well-designed from-scratch evaluation, we demonstrate that surfactant-based processes exhibit limited synergies with smartwater. Comparable processes in terms of performance can be designed for both high-salinity and low-salinity waters. It is also quite possible that the synergistic benefits of smartwater on oil recovery cannot be effective in SP flooding processes, especially with specific surfactant formulations under optimal salinity conditions.

1-O-Octadecyl-2-O-benzyl-sn-glyceryl-3-phospho-GS-441524 (V2043). Evaluation of Oral V2043 in a Mouse Model of SARS-CoV-2 Infection and Synthesis and Antiviral Evaluation of Additional Phospholipid Esters with Enhanced Anti-SARS-CoV-2 Activity.

Early antiviral treatments, including intravenous remdesivir (RDV), reduce hospitalization and severe disease caused by COVID-19. An orally bioavailable RDV analog may facilitate earlier treatment of non-hospitalized COVID-19 patients. Here we describe the synthesis and evaluation of alkyl glyceryl ether phosphodiesters of GS-441524 (RVn), lysophospholipid analogs which allow for oral bioavailability and stability in plasma. Oral treatment of SARS-CoV-2-infected BALB/c mice with 1-O-octadecyl-2-O-benzyl-sn-glyceryl-3-phospho-RVn (60 mg/kg orally, once daily for 5 days starting 12h after infection) reduced lung viral load by 1.5log10 units versus vehicle at day 2 and to below the limit of detection at day 5. Structure/activity evaluation of additional analogs that have hydrophobic ethers at the sn-2 of glycerol revealed improved in vitro antiviral activity by introduction of a 3-fluoro-4-methoxy-substituted benzyl or a 3- or 4-cyano-substituted benzyl. Collectively, our data support the development of RVn phospholipid prodrugs as oral antiviral agents for prevention and treatment of SARS-CoV-2 infections.

Synthesis and properties of alkyl glyceryl ether sulfonate

Abstract In this work, alkyl glyceryl ether sulfonates with two alkyl chain lengths were synthesised by etherification and sulfonation. The structures of these sulfonates were characterised by FTIR, 1H NMR and MS. Their characterisations were investigated for their surface properties and thermodynamic properties by surface tension, conductivity and fluorescence methods. The critical micelle concentration (CMC) of surfactants increases with increasing temperature and decreases with increasing alkyl chain length. The micellation process of alkyl glyceryl ether sulfonates is spontaneous and driven by entropy.

Thermodynamic equilibrium analysis on the dehydration of glycerol with monohydric alcohols to alkyl glyceryl ethers

AbstractUnder the conditions of the feed of 400 moles of alcohol + 100 moles of glycerol, 313–573 K and 0.1 MPa, based on Gibbs free energy global minimization, an improved genetic algorithm was used for the thermodynamic equilibrium analysis on the synthesis processes of alkyl glyceryl ethers, respectively, from methanol + glycerol, ethanol + glycerol, isobutanol + glycerol, and tert‐butanol + glycerol. The columnar stacking charts and three‐dimensional contour graphs were used to compare the effects of temperature, pressure, and the feed ratio to the equilibrium conversion, product selectivity, and equilibrium composition. The basic laws of the synthesis processes of alkyl glycerol ethers in homogeneous and heterogeneous states were investigated in a wide temperature range. Through comparison, it was found that the isopropanol + glycerol system is easier to convert into alkyl glycerol ethers, followed by the ethanol + glycerol system. The methanol + glycerol system and tert‐butanol + glycerol system are greatly affected by pressure and temperature, and their conversions and selectivities are relatively low.

Alkyl glyceryl ethers as water-based lubricant additives in mixtures with xanthan gum

Water-based lubricants are greener and more environmentally friendly than comparable oil-based lubricants. However, water-based lubricants typically have a poorer performance and, thus, need to be formulated with various additives. Here, alkyl glyceryl ethers, a class of nonionic surfactants, were investigated as lubricant additives. To this purpose, aqueous solutions of newly synthesized ethers (with different alkyl chain lengths, C8, C10, C12, and C14) were formulated with xanthan gum. The lubrication performance of these formulations was then tested experimentally. Clearly, alkyl glyceryl ethers showed a significantly improved performance (higher friction reduction) with increasing the alkyl chain length. However, the ethers had to be formulated with xanthan gum, with which they formed a complex, which promoted ether dispersion and probably adsorption on the metal surface in the aqueous phase, thereby drastically reducing friction. Thus, the alkyl glyceryl ethers synthesized in this work are attractive green and highly efficient lubricant additives, which can improve the sustainability of industrial lubrication processes.

An all-inclusive laboratory workflow for the development of surfactant/polymer formulations for EOR in harsh carbonates

Carbonate reservoirs are challenging for chemical EOR, particularly in selecting fine-tuned chemical formulations which combine high performance, stable behavior, and trouble-free operations. The design of suitable formulations requires substantial laboratory work and a solid methodology. In this paper, a systematic all-inclusive laboratory workflow to design a surfactant-polymer (SP) formulation for a carbonate reservoir is presented. The experimental steps were clearly delineated including the preparation of representative oils. A key novelty of the adopted workflow is the integration of topside assessment. Beside a clear layout of the methodology, the work demonstrates that a surfactant-polymer formulation can successfully be designed for high temperature carbonate reservoirs and provide encouraging guidelines with respect to SP impact on topside facilities.In summary, the results demonstrate the potential of a binary surfactant mixture of a highly hydrophobic Olefin Sulfonate (OS) and a slightly hydrophobic Alkyl Glyceryl Ether Sulfonate (AGES). The results also illustrate couple of extended stability polymers suitable for high temperature carbonates: an associative polymer, and an AM/AMPS (acrylamide/2-acrylamido-2-methyl propane sulfonic acid) copolymer. Moreover, single-phase displacements clearly supported the SP formulation transportability across and within the porous media. More importantly, the developed SP formulation was capable of recovering around 62% of the remaining oil in core post waterflooding (ROIC). Finally, in terms of topside effects, the presence of surfactant and polymer in the brine clearly improved the separation kinetics; nevertheless, a manageable deterioration in separated water quality was observed.

Salt-tolerance of alkyl-glyceryl ether carboxylates hydrotropes and surfactants. Dramatic effect of the methylation of the glyceryl spacer

HypothesisThe insertion of polyether spacers between the anionic head and the alkyl chain of ionic surfactants significantly improves their salt-tolerance. The aim of this work is to study whether the petro-based polyethoxy spacer can be replaced by a glyceryl ether group for high salinity applications. ExperimentsA series of amphiphilic sodium salts of alkyl glyceryl ether carboxylates are synthesized with different alkyl chain lengths from 4 to 12 and various spacers between the glyceryl and the carboxylate groups. Their aggregation behavior is studied by tensiometry and their amphiphilicities are assessed by the PIT-slope method. The dramatic effect of the methylation of the glyceryl spacer on the salt-tolerance is highlighted, and rationalized by DFT calculations and molecular dynamics. FindingsIn contrast to the corresponding sodium soap, n-C6H13-CO2Na, and to the non-methylated counterpart, the sodium salt of 1-pentyl-3-methyl glyceryl ether methylene carboxylate ([5.0.1]-CH2CO2Na) exhibits an excellent salt-tolerance since it remains water-soluble with NaCl or CaCl2 concentrations greater than 20 wt% at 25 °C. Amphiphiles with short alkyl chains (<C8) act as hydrotropes whereas longer compounds behave as surfactants whose CMC are lower than their corresponding isomers with ethoxy spacers n-Ci(EO)2CH2CO2Na.

Quantitative determination and validation of ethylhexylglycerin using Gas chromatography method

Ethylhexylglycerin, an alkyl glyceryl ether, used in various cosmetics and deodorants is also known to have anti-microbial activity and hence used as an adjuvant along with other preservatives to produce synergistic effect. In the present study, a gas chromatographic method has been employed and validated to determine the presence of impurities along with ethylhexylglycerin. A column having the dimension of DB-1 30m x 0.32mm; 0.25µm with acetone as solvent was found to be optimal for the ideal separation of ethylhexylglycerin from its impurities. Injection volume was set to 1 µl and temperature was maintained at 240°C. A clear peak was observed with the retention time of 8.002 minutes. As per ICH guidelines, the developed method was validated with respect to specificity, sensitivity, Limit of detection, Limit of quantification, linearity, precision, and also stability studies. As per the method, it shows a good correlation co-efficient (R2) value of 0.999 within the concentration range of 0.1- 0.75µg. Therefore, a gas chromatographic method was proposed which can be precise, specific and can be employed for the determination of ethylhexylglycerin in various pharmaceutical formulations.&#x0D; Keywords: Ethylhexylglycerin; Adjuvant; ICH guidelines; Validation; Stability studies

Chimyl Alcohol Suppresses PGE2 Synthesis by Human Epidermal Keratinocytes through the Activation of PPAR-γ.

Alkyl glyceryl ethers (AKGs) are widely used as emulsion stabilizers, and their anti-inflammatory effects are well known. Daily exposure to environmental stresses, such as chemicals, low humidity and ultraviolet light (UV), can initiate and promote the development of various skin problems. Among those stresses, it has been established that UV induces skin pigmentation and accelerates premature skin aging due to the inflammation that results. Here, we investigated whether chimyl alcohol (CA), which is an AKG, suppresses the inflammatory process. The suppression of cell damage and the reduction of intracellular levels of reactive oxygen species (ROS) in normal human epidermal keratinocytes (NHEKs) after UVB exposure was evaluated using the Neutral red (NR) and the 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) assays, respectively. Moreover, the expression levels of mRNAs and proteins related to inflammation were evaluated by Real-time RT-PCR and ELISA assays, respectively. CA suppressed prostaglandin E2 (PGE2) production in UVB-exposed NHEKs according to the down-regulated expression level of cyclooxygenase-2 (COX-2) mRNA. Furthermore, CA up-regulated the mRNA expression levels of peroxisome proliferator-activated receptor (PPAR)-γ, nuclear factor E2-related factor 2 (Nrf2) and γ-glutamyl cysteine synthase (γ-GCS) in NHEKs. Finally, we examined the effects of CA on siPPAR-γ transfected NHEKs. siPPAR-γ transfection of NHEKs abolished the mRNA expression levels of Nrf2 and UVB-stimulated PGE2 secretion that were regulated by CA. Hence, CA suppresses the UVB-induced COX-2 mRNA expression and PGE2 production through PPAR-γ as an agonist. We conclude that CA provides useful protection and/or alleviation against UV damage.

Sesquiterpenes from the Saudi Red Sea: Litophyton arboreum with their cytotoxic and antimicrobial activities.

A new pseudoguaiane-type sesquiterpene named litopharbol (1) was isolated from the methanolic extract of the Red Sea soft coral Litophyton arboreum, along with known sesquiterpenoids alismol (2), alismorientol B (3), teuhetenone A (4), and calamusin I (5); steroid, 24-methyl-cholesta-5,24(28)-diene-3β-ol (6), alkyl glyceryl ether, chimyl alcohol (7); sphingolipid, erythro-N-dodecanoyl-docosasphinga-(4E,8E)-dienine (8); and nitrogenous bases, thymine (9) and thymidine (10). The structures were determined on the basis of nuclear magnetic resonance (NMR) spectroscopic (1D and 2D NMR data including heteronuclear single quantum coherence spectroscopy, heteronuclear multiple-bond correlation spectroscopy, and nuclear Overhauser effect spectroscopy) and mass spectrometric analyses. Compounds 1-5 were explored for antimicrobial activity and cancer cell line sensitivity tests. Compound 1 exhibited antibacterial activity against Bacillus cereus with a minimum inhibition concentration of 1.8 μg/mL, whereas compound 3 showed significant potent cytotoxic effect against MCF-7 (breast cancer cells) with IC50 4.32 μM.

Synthesis of C4 chain glyceryl ethers via nickel-catalyzed butadiene hydroalkoxylation reaction

The catalytic hydroalkoxylation of butadiene with glycerol has been performed for the first time thanks to the use of nickel catalysts and an appropriate solvent. Optimization of the reaction conditions allowed obtaining 100% glycerol conversion into a mixture of glyceryl mono- and dibutenyl ethers. The experimental protocols used involved batch experiments or continuous feeding of butadiene at atmospheric pressure. The reaction has then been scaled up to produce multigrams of each pure monoethers and diethers according to simple decantation/distillation procedures. The ethers were further hydrogenated to their corresponding alkyl glyceryl ethers.

Kribellosides, novel RNA 5'-triphosphatase inhibitors from the rare actinomycete Kribbella sp. MI481-42F6.

Yeast capping enzymes differ greatly from those of mammalian, both structurally and mechanistically. Yeast-type capping enzyme repressors are therefore candidate antifungal drugs. The 5'-guanine-N7 cap structure of mRNAs are an essential feature of all eukaryotic organisms examined to date and is the first co-transcriptional modification of cellular pre-messenger RNA. Inhibitors of the RNA 5'-triphosphatase in yeast are likely to show fungicidal effects against pathogenic yeast such as Candida. We discovered a new RNA 5'-triphosphatase inhibitor, designated as the kribellosides, by screening metabolites from actinomycetes. Kribellosides belong to the alkyl glyceryl ethers. These novel compounds inhibit the activity of Cet1p (RNA 5'-triphosphatase) from Saccharomyces cerevisiae in vitro with IC50s of 5-8 μM and show antifungal activity with MICs ranging from 3.12 to 100 μg ml-1 against S. cerevisiae.

Prediction of Optimal Salinities for Surfactant Formulations Using a Quantitative Structure–Property Relationships Approach

Each oil reservoir could be characterized by a set of parameters such as temperature, pressure, oil composition, and brine salinity, etc. In the context of the chemical enhanced oil recovery (EOR), the selection of high performance surfactants is a challenging and time-consuming task since this strongly depends on the reservoir’s conditions. The situation becomes even more complicated if the surfactant formulation is a blend of two or more surfactants. In the present work, we report quantitative structure–property relationships (QSPR) correlating surfactants’ structures and their composition in a mixture with optimal salinity (Sopt), corresponding to minimal interfacial tension in the reference brine/surfactants/n-dodecane system, at T = 313 K and P = 0.1 MPa. Particular attention was paid to selected families of surfactants: α-olefin sulfonate (AOS), internal olefin sulfonate (IOS), alkyl ether sulfate (AES), and alkyl glyceryl ether sulfonate (AGES). The models were built and validated on the database containing Sopt values for 75 surfactants’ formulations. Molecular structures of amphiphilic molecules were encoded by functional group count descriptors (FGCD), ISIDA substructural molecular fragment (SMF) descriptors, and CODESSA molecular descriptors (CMD). For mixtures, descriptors were calculated as linear combinations of descriptors of individual compounds weighted by their mass fractions in mixtures. Different machine-learning methods—support vector machine (SVM), partial least-squares (PLS) regression, and random subspace (RS)—have been used for the modeling. Both global (on the entire database) and local (on individual families) models have been built. Models display reasonable accuracy (about 0.2 log Sopt units) which is comparable with the experimental error of measured Sopt. Our results show that the suggested approach can be successfully used to build predictive models for relatively small data sets of mixtures of chemical compounds.

Neritinaceramides A–E, New Ceramides from the Marine Bryozoan Bugula neritina Inhabiting South China Sea and Their Cytotoxicity

Five new ceramides, neritinaceramides A (1), B (2), C (3), D (4) and E (5), together with six known ceramides (6–11), two known alkyl glycerylethers (12 and 13) and a known nucleoside (14), were isolated from marine bryozoan Bugula neritina, which inhabits the South China Sea. The structures of the new compounds were elucidated as (2S,3R,3′S,4E,8E,10E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,3′-triol (1), (2S,3R,2′R,4E,8E,10E)-2-(hexadecanoylamino)-4,8,10-octadecatriene-l,3,2′-triol (2), (2S,3R,2′R,4E,8E,10E)-2-(octadecanoylamino)-4,8,10-octadecatriene-l,3,2′-triol (3), (2S,3R,3′S,4E,8E)-2-(hexadecanoylamino)-4,8-octadecadiene-l,3,3′-triol (4) and (2S,3R,3′S,4E)-2-(hexadecanoylamino)-4-octadecene-l,3,3′-triol (5) on the basis of extensive spectral analysis and chemical evidences. The characteristic C-3′S hydroxyl group in the fatty acid moiety in compounds 1, 4 and 5, was a novel structural feature of ceramides. The rare 4E,8E,10E-triene structure in the sphingoid base of compounds 1–3, was found from marine bryozoans for the first time. The new ceramides 1–5 were evaluated for their cytotoxicity against HepG2, NCI-H460 and SGC7901 tumor cell lines, and all of them exhibited selective cytotoxicity against HepG2 and SGC7901 cells with a range of IC50 values from 47.3 μM to 58.1 μM. These chemical and cytotoxic studies on the new neritinaceramides A–E (1–5) added to the chemical diversity of B. neritina and expanded our knowledge of the chemical modifications and biological activity of ceramides.

Safety Assessment of Alkyl Glyceryl Ethers as Used in Cosmetics

Alkyl glyceryl ethers function mostly as skin-conditioning agents in cosmetic products applied to the skin and hair. The Cosmetic Ingredient Review expert panel reviewed the available animal toxicity and clinical data, including the low dermal absorption, and concluded that the alkyl glyceryl ethers are safe in the present practices of use and concentration described in this safety assessment.

Plasmalogens, fatty acids and alkyl glyceryl ethers of marine and freshwater clams and mussels

Abstract Shelled molluscs constitute an excellent source of protein, sugars and lipids, and the demand for various mollusks species is increasing. We analysed lipid composition of different bivalves, quite important in the diet of East Mediterranean inhabitants. Plasmamlogens, glyceryl ethers, and diacyl phospholipid forms as well as their fatty aldehydes, fatty alcohols, and fatty acid derivatives were examined. PE of clams and mussels, containing aldehydes C16 (variations from 4% to 31%), C18 (29–46%), C9–18:1(6–32%), C11–20:1 (3–19%), and several minor aldehydes, were detected. The major saturated 1-O-alkyl glycerol ethers C16 and C18. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in both PE and PS plasmalogens were dominated acids. The sum of these acids in PE varied from 33% to 43%, and in PS, from 45% to 66%. EPA levels in PE (30–37%) and PS (39–57%) of marine species were higher than those in freshwater species (PE, 13–16%; PS, 23–29%), and levels of DHA were higher in freshwater than in marine mollusks. A series of saturated fatty aldehydes C12–C24, with major C18:0 in all studied species (over 40%) and C16:0 (10–25%), as well as of unsaturated C16:1 (1–7%) and 18:1 (18–36%) species were isolated from neutral plasmalogens. Predominant fatty acids in neutral plasmalogens were found to be 16:0 (12–17%), 20:5n−3 (9–27%), and 22:6n−6 (9–18%). Distribution of plasmalogens, alkyl glyceryl ethers, and their fatty aldehydes and fatty alcohols in mollusks and other invertebrates is discussed.

Homologues and isomers of noladin ether, a putative novel endocannabinoid: interaction with rat cannabinoid CB 1 receptors

Two regioisomers and 13 analogues of the putative endocannabinoid noladin ether (2-arachidonyl glyceryl ether, 2-AGE, 1) were synthesized and tested for their interaction with CB 1 receptors in rat brain membranes. The results showed that a C-20 tetra-unsaturated moiety is necessary for high affinity, and that a series of alkyl glyceryl ethers of potential occurrence in brain tissues have less affinity than 2-AGE for CB 1 receptors.

Self‐assembly of compounds based on a glycerin skeleton as C‐3 building block. Part II

AbstractPart I reviewed the properties of alkyl glyceryl ethers and their derivatives in forming self‐assemblies such as liquid crystals. Part II covers strategies for the synthesis of several types of artificial ether lipids with a glycerin backbone, such as dicephalic surfactants, gemini surfactants, calamitic bola‐amphiphiles, dendrimers, and membrane components of archaebacteria, which have been reported to constitute unique self‐assemblies useful as materials for future nanochemistry.

Self‐assembly of compounds based on a glycerin skeleton as a C‐3 building block. Part I

AbstractBiological structures from proteins through viruses to cellular organelles with dimensions of 1 to 100 nm require molecular self‐assembly and self‐organization to form nanostructures. In contrast to covalent bonding, noncovalent interactions such as hydrogen bonding and hydrophobic association involve lower bond energies (2–20 kcal/mol) to attain the mobility and fluidity properties of biological structures. Noncovalent interactions are also well‐known with amphiphilic molecules bearing both hydrophilic head groups and hydrophobic groups and are responsible for the formation of several types of self‐assemblies such as micelles, liquid crystals, and lipid bilayers. As typical amphiphiles with a glycerin skeleton as a C‐3 building block, alkyl glyceryl ethers and their derivatives have been of interest since they show unique self‐assembly structures such as liquid crystals with hitherto unknown character.