Novel enzymatic assay for determination of alkyl polyglycosides with short chain fatty alcohols

An enzymatic assay has been developed for the quantitative detection of alkyl polyglycosides after enzymatic hydrolysis with different carbohydrolases. A three-step enzymatic method was used for the quantification of alkyl polyglycosides. In the first step the enzymatic hydrolysis of alkyl polyglycosides was performed with different carbohydrolases, or an acid hydrolysis was used. The second step was quantification of free glucose with an enzyme electrode, which was covered with an immobilized glucose oxidase membrane; glucose was used as standard. The last step was the enzymatic quantification of fatty alcohols, which are the second substrate after enzymatic hydrolysis of alkyl polyglycosides. Surprisingly, the enzyme alcohol dehydrogenase ADH (E.C. 1.1.1.1) from bakers' yeast could efficiently oxidize a wide variety of aliphatic alcohols and had the highest catalytic specificity with short and medium fatty alcohol substrates, including octanol and decanol.     

Characterisation of ethoxylated fatty chains of anionic surfactants and determination of residual ethoxylated fatty alcohols

Bachus et al. [1] recently described a new derivatisation method using 2-furoyl chloride for the characterisation of mixtures of polyethoxylated alcohols and their corresponding sulfates. This paper deals with the control of the derivatisation steps; hydrolysis and extraction conditions were optimised. The method is extended to the characterisation of alkyl sulfosuccinates, alkyl sulfoacetates and alkyl phosphates and to the analysis of residual polyethoxylated alcohols in surfactants. Extraction of non-ionic compounds using solid-phase extraction cartridges was performed before derivatisation. Residual amounts of alcohol were determined in five commercial anionic surfactants. Moreover, direct derivatisation without preliminary SPE in the same anionic surfactants proved to be efficient for dry samples.     

Efficient and simple method for the quantification of alkyl polyglycosides by hydrolysis and photometric determination of reducing sugars

Alkyl polyglycosides (APG) are important biodegradable surfactants for many applications. The lack of a chromophoric group and the mixture of stereoisomers and oligomers make the quantification by merely chromatic separation difficult. A simple and efficient quantification assay was developed based on the acid hydrolysis of alkyl polyglycoside and subsequent quantification of the hydrolytically cleaved glucose using the neocuproine assay. Complete hydrolysis of alkyl polyglycoside is achieved with 16 wt% sulfuric acid at 100 °C after 30  min and the separation of fatty alcohol and clouding of the reaction mixture is prevented by adding 1,2-propylene-glycol. Hydrolytically cleaved sugars reduce the Cu^(II)-neocuproine complex, leading to a color shift which permits the spectrophotometric quantification at 452 nm. A linear correlation between the absorbance of reduced Cu^(II)-neocuproine complex and glucose or alkyl polyglycoside concentration is observed up to an analyte concentration of 25 mg/L. Statistical analysis according to one-tailled T-test (S’ 95%), has shown that the lower detection limit for alkyl polyglycosides is 2.97 mg/L and the limit of quantification 8.24 mg/L, respectively. Apart from the simple execution, the assay is reliable and can be utilized both as scientific technique to quantify APG as well as for process and quality control in the industry.     

Determination of alkyl sulfates in the influent and effluent of a laboratory activated sludge plant by HPLC

Summary A method for the determination of alkyl sulfates by HPLC is described. The method is based on the decomposition of the alkyl sulfates by sulfuric acid, extraction of the resulting alkyl alcohols, derivatization of the alcohols by phenyl isocyanate, and reversed-phase HPLC with UV-detection. The described method is well suited to investigate the biodegradability of alkyl sulfates in laboratory activated sludge plants. An advantage of the HPLC procedure in comparison to the determination of methylene-blue-active substances (MBAS) is that informations about the kinetics of the biodegradation, the structure of substances and possible metabolites can be obtained.     

Analysis of tensides in complex samples with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry

Multidimensional gas-chromatographical analysis of various tensides of natural or synthetic origin in cosmetic products is demonstrated. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry allows the qualitative and quantitative determination of alkyl polyglucosides (AG), fatty alcohol ethoxylates (FAEO), fatty alcohol sulfates (FAS), fatty alcohol ether sulfates (FAES) and cocamidopropyl betaines (CAPB) in shower gel and cleaning agents. The samples were aliquoted in two parts. The first part was silylated, diluted and analysed; then, in order to detect anionic tensides (FAES, FAS) too, the second aliquot was hydrolysed before being silylated for analysis. Because of their amphoteric character, the betaines can only be analysed by gas chromatography after thermal decomposition in the injector, which leads to the corresponding amidoamines among other products.     

A Study on Alkyl Polyglycosides of the Starch

The alkyl polyglycosides (APG) is new type the surfactants that is made by regenerationresource of the starch and the grease, since the nineties of 20th century it is energetically exploited ininternational extent. APG not only good in surface activity, but also plenty on bubble, thin greasyand stabilization, there are good decontamination, compatibility, innocuity, not incitation and uniquefunction that organism decomposition of swiftness and downrightness, and so on.APG is to get production that loses one molecule water with half condensation aldehyde hydroxyand sebum alcohol hydroxy under acid catalysis. The production not is one simplicity compound, butis one of sugar polymerization degree, so it is mixture of the alkyl single glucoside, the alkyl twoglucoside and the alkyl three glucoside.Author synthesizes the surfactants of the alkyl polyglycosides, with the oleaster and potato starchand sebum alcohol, that was chosen to use duality system activator of plant acid and p-toluene-sulfoacid for the first time. The adoption way is that the lower alkyl polyglycosides is firstly formed byreaction of lower alcohol with starch then exchanged with high alcohol to obtain APG. The study isto make certain most technics condition, determining capillary tension and the pastern sheafdeepness of critical, calculating HLB value, determining construction by 1R.To synthesize principium:Peroration :[1]Duality system activator of plant acid and p-toluene-sulfo acid is compare idea activator that was the lower alkyl polyglycosides is firstly formed by reaction of lower alcohol with glucose then exchanged with high alcohol to obtain high alkyl polyglycosides. The advantage is that it overcomes agglomeration, there is reaction entirety, high of sugar transform ratio, reaction time short.[2]Most good reaction temperature is 90～ 170℃, the dosage of activator is 0.5%～0.9%, the mated ratio: The APG of glucose basic butane ratio starch is 5:1, the APG of potato starch basic glycol ratio starch is 6:1, the APG of the oleaster starch basic glycol ratio starch is 12:1, the APG of the mealiest starch basic glycol ratio starch is 6:1, the product of complex is good property.[3]The alkyl polyglycosides is the products of surfactant. IR determines the functional group of the products. On the basis of group of the hydrophile and to close on oil, that the feature peak of α-1, 4- glucoside.[4]The capillary tension of the APG is 26.8～31.0mN/m, the HLB value is 16～18, the products is better emulsifying agent of water- solubility. (O/W).     

High temperature gas chromatography of trimethylsilyl derivatives of alcohol ethoxylates and ethoxysulfates

Conversion of ethoxylated alcohols to trimethylsilyl derivatives and subsequent high temperature gas chromatography allowed for the determination of alkyl chain distribution, mole average degree of ethoxylation and weight percent distribution of several commercial mixtures. Repetitive derivatizations and analyses of a mixture with a vendor specified mole average degree of ethoxylation of 3.0 (Neodol 23-3), yielded an experimental result of 2.93 ± 0.05 (n = 6). Mixtures with different alkyl chain distributions and higher degrees of ethoxylation provided similar accuracy. Extension of the method to the analysis of ethoxylated alcohol sulfate raw materials and ethoxylated alcohol sulfates in dishwashing liquids is discussed.     

Colloid chemistry principles of separation of pure alkyl sulfates

Sodium dodecyl sulfate and other alkyl sulfates were treated by the method of polythermal conductometry to remove primary alcohols. The electrical conductivity polytherms were analyzed. The composition of the liquid and solid phases in equilibrium in the mixed solutions was determined. The method of the synthesis of chemical purity colloids of alkyl sulfates and other ionogenic micelle forming surfactants was suggested based on the optimal choice of crystallization temperature of the solutions.     

Alkyl Polyglycosides—Properties and Applications of a new Class of Surfactants

A new generation of nonionic surfactants that are widely applicable and simultaneously ecologically compatible has been developed in the alkyl polyglycosides. Their production from the renewable resources glucose and fatty alcohol and their ultimate biodegradation into carbon dioxide, water, and assimilated bacterial biomass is an example for a closed cycle. As a result of their physico-chemical properties and ecotoxicological evaluation, they have become very important as high-performance components of detergents and cosmetic preparations.     

Thorpe-Ingold effect in the reaction of vicinal amino primary alcohol hydrogen sulfates and carbon disulfide

The Thorpe-Ingold effect is a key factor that affects the ring-closure rates and efficiency, as well as the structure of products in some ring-closure reactions. The reaction of vicinal amino primary alcohol hydrogen sulfates and carbon disulfide in the presence of potassium hydroxide produces the desired 4,4-disubstituted thiazolidine-2-thiones, and their isomers 5,5-disubstituted derivatives companying with their oxygen analogues 4,4-disubstituted oxazolidine-2-thiones. The formation of 5,5-disubstituted thiazolidine-2-thiones was rationalized via 2,2-disubstituted aziridine-1-carbodithioate intermediates, which were generated due to the Thorpe-Ingold effect. 4,4-Disubstituted oxazolidine-2-thiones were generated from carbon disulfide and free amino alcohols yielded via basic hydrolysis of active amino alcohol hydrogen sulfates in the reaction system.     

有效碳链长度与脂肪醇的沸点

脂肪醇沸点(b.p.)变化规律可用下述关系式表示:ln(800.386-T~b)=6.64919-2.94828×10^-^2N~E~C~C+0.150955ΔPEI。式中N~E~C~C为醇中烷基的有效碳链长度, ΔPEI是具有相同碳原子数目的支链烷基与直链烷基的极化效应指数的差值, 它表示羟基对醇的沸点的影响。     

The Dispersion Properties of Precipitated Calcium Carbonate Suspensions Adsorbed with Alkyl Polyglycoside in Aqueous Medium

The zeta potentials and dispersion properties of precipitated calcium carbonate suspensions adsorbed with alkyl polyglycosides in aqueous medium were investigated. Within the investigated pH ranges, the adsorption curves of alkyl polyglycosides on calcium carbonates show sigmoidal shapes, and the zeta potential decreases as the amount of adsorption increases. At positively charged surfaces of low pH, the adsorption amounts were greater than those at negatively charged surfaces, indicating that alkyl polyglycosides were negatively charged in aqueous solutions. At low concentrations of alkyl polyglycosides, the dispersion stabilities of suspensions were very poor and showed no linearity with zeta potentials over the entire range of pHs, which may be attributed to the onset of hydrophobic interaction between particles due to the adsorption of surfactant molecules. This destabilization continued until monolayer coverage by the surfactant layer was complete. Based on the classical DLVO theory, there may be a strong hydrophobic interaction between particles. Beyond monolayer adsorption, the dispersion stability increases, probably by the formation of hemimicelle or admicelle. Therefore, it is believed that ionization of alkyl polyglycosides and admicelles of surfactants on particle surface plays a key role in the stability of dispersions and the abrupt increase in adsorption. Copyright 2000 Academic Press.     

Microwave-accelerated Fischer glycosylation

Fischer glycosylation has been used for decades for the synthesis of simple alkyl and aryl glycosides from free sugars. The reaction proceeds under reflux in the presence of catalytic acid with the alcohol as solvent. The main deficiency of this reaction is the long reaction time required. In this study microwave heating has been utilised for the Fischer glycosylation reaction of N-acetyl-d-glucosamine, N-acetyl-d-galactosamine, d-glucose, d-galactose and d-mannose with a variety of alcohols (methanol, ethanol, benzyl alcohol and allyl alcohol). Remarkable acceleration of the glycosylation reactions (minutes compared to hours) over conventional reflux heating was observed with good yields and production of the α-glycoside as the dominant product.     

Fluorous scavenger for parallel preparation of tertiary sulfonamides leading to secondary amines

Alkylation of secondary sulfonamides by alkyl halides or alcohols (Mitsunobu reaction) is an efficient method for secondary amines preparation. However, its application to parallel chemistry is often difficult due to partial reaction. In this Letter, we propose a fluorous technique to bypass this problem. Thus, o-nitrobenzenesulfonamides were prepared and alkylated in parallel (Fukuyama method) with various alkyl halides or alcohols. Depending on the nature of the alkyl halide or alcohol, this step remained incomplete. A reactive fluorous alkyl iodide was then used to trap the unreacted sulfonamide allowing for a rapid and efficient fluorous solid-phase extraction (FSPE). Some examples of the isolated tertiary sulfonamides were converted in parallel to the corresponding secondary amines with good purity.     

Release studies on niosomes containing fatty alcohols as bilayer stabilizers instead of cholesterol

Monomers of some amphiphiles organize into bilayers to form liposomes and niosomes. Such bilayers are unstable or leaky and hence cholesterol is a common ingredient included to stabilize them. Cholesterol stabilizes bilayers, prevents leakiness, and retards permeation of solutes enclosed in the aqueous core of these vesicles. Other than cholesterol a material with good bilayer-stabilizing properties is yet to be identified. We have substituted cholesterol with fatty alcohols in niosomes containing polyglyceryl-3-di-isostearate (PGDS) and polysorbate-80 (PS-80) to explore their membrane-stabilizing property via permeation studies. Niosomes of polyglyceryl-3-di-isostearate, fatty alcohol/cholesterol, and polysorbate were prepared by ether injection method. Aqueous solution of ketorolac tromethamine (KT) was entrapped in them. The effects of alkyl chain length of fatty alcohols (C(12), C(14), C(16), C(18), and C(16+18)), of acyl chain length of polyoxyethylene sorbitan monoester surfactants, and of the molar ratio of lipid mixture on the release rate of ketorolac from niosomes were assessed by employing modified dissolution-dialysis method. Niosomes with cholesterol or fatty alcohols have exhibited a common release pattern. Niosomes containing fatty alcohol showed a considerably slower release rate of KT than those containing cholesterol. Based on the release rate, fatty alcohols can be ranked as stearyl相似文献   

Rapid procedure for the isolation and analysis of fatty acid and fatty alcohol fractions from wax esters of marine zooplankton

A rapid and simple method for the isolation of fatty acid methyl esters and fatty alcohols from the lipid fraction of marine zooplankton is described. Wax esters are the dominant lipid class in most calanoid copepods and trans-esterification results in a high fatty alcohol content in the analytical extract. Current procedures for the separation and purification of lipid classes by preparative thin-layer chromatography are time-consuming and are subject to low recovery of the analytes. In this method, fatty acid methyl esters and fatty alcohols were separated by liquid chromatography using silica or honded amino-silica as the stationary phase. The procedure is equally applicable to the analysis of zooplankton with low wax ester (and hence fatty alcohol) content, for example, a number of species of euphausiid and, generally, for samples of low mass.     

A mild C-O bond formation catalyzed by a rhenium-oxo complex

A mild method for the regioselective synthesis of propargyl ethers by the coupling of propargyl alcohols with a range of other alcohols is described. The method employs an air- and moisture-tolerant rhenium-oxo complex ((dppm)ReOCl3) as a catalyst for the formation of sp3-carbon-oxygen bonds without the need for prior activation of the propargyl alcohol or deprotonation of the alcohol nucleophile. A broad range of functional groups is tolerated, including aryl halides, olefins, esters, and acid-labile functional groups such as acetals. Furthermore, displacement of the alcohol occurs preferentially even in the presence of other electrophiles such as primary alkyl halides and conjugated esters.     

A Study of the Solvation Structure of l‐Leucine in Alcohol–Water Binary Solvents through Molecular Dynamics Simulations and FTIR and NMR Spectroscopy

The solvation structures of l ‐leucine (Leu) in aliphatic‐alcohol–water and fluorinated‐alcohol–water solvents are elucidated for various alcohol contents by using molecular dynamics (MD) simulations and IR, and ¹H and ¹³C NMR spectroscopy. The aliphatic alcohols included methanol, ethanol, and 2‐propanol, whereas the fluorinated alcohols were 2,2,2‐trifluoroethanol and 1,1,1,3,3,3‐hexafluoro‐2‐propanol. The MD results show that the hydrophobic alkyl moiety of Leu is surrounded by the alkyl or fluoroalkyl groups of the alcohol molecules. In particular, TFE and HFIP significantly solvate the alkyl group of Leu. IR spectra reveal that the Leu C?H stretching vibration blueshifts in fluorinated alcohol solutions with increasing alcohol content, whereas the vibration redshifts in aliphatic alcohol solutions. When the C?H stretching vibration blueshifts in the fluorinated alcohol solutions, the hydrogen and carbon atoms of the Leu alkyl group are magnetically shielded. Consequently, TFE and HFIP molecules may solvate the Leu alkyl group through the blue‐shifting hydrogen bonds.     

A STUDY OF GEL STRUCTURE IN THE NONIONIC SURFACTANT / CETOSTEARYL ALCOHOL / WATER TERNARY SYSTEMS BY DIFFERENTIAL SCANNING CALORIMETER

Cetostearyl alcohol has been incorporated into cosmetic or pharmaceutial emulsions to give them an appropriate consistency and a long term stability. It is well known that cetostearyl alcohol forms a gel phase with a nonionic surfactant in an aqueous system, and the properties of the gel phase depend on several factors such as the ratio of fatty alcohols. The aim of the present paper is to investigate the effect of the structural difference of the lipophilic part of surfactants on the stability of the gel phase in the nonionic surfactant / cetostearyl alcohol / water ternary systems using differential scanning calorimeter.

It is concluded that the gel phase formed by the surfactant having the bended alkyl chain is more unstable than that formed by the case of     

Percolation in alkyl polyglycoside microemulsions

Mixtures of oil, water, alkyl polyglycosides and long-chain alcohols form almost-temperature-invariant microemulsions. The phase behaviour depends on the content of cosurfactant, usually long-chain alcohols. We show that the system C_8/10G_1.5/octane/water/octanol exhibits cosurfactant-induced percolation phenomena. The percolation transition from an electrically conducting oil-in-water microemulsion to an electrically non-conducting water-in-oil microemulsion with increasing cosurfactant content is observed by measurements of electrical conductivity and time-resolved electric birefringence. The field-off relaxation time yields information on the internal length scale. The scaling behaviour of field-off relaxation times and Kerr constants with respect to the percolation point leads to insight into the influence of cosurfactant on phase behaviour. Received: 27 July 1999/Accepted: 8 February 2000