Analytical Characterization and Comparison of Tristyrylphenol Ethoxylates Used in Agrochemical Formulations

Tristyrylphenol ethoxylates are a group of technical nonionic surfactants that contain no single defined molecule but have a polymeric distribution with an average of 3 styrene and 16 ethylene oxide units. To analyze differences in the ethylene oxide distribution of the surfactant from various suppliers, and thus to specify more precisely the required quality for its use in agrochemical formulations, an analytical method was developed using liquid chromatography coupled to time‐of‐flight mass spectrometry with exact mass measurement in combination with multivariate data analysis. The method investigated here enables a fast and comprehensive characterization and comparison of the tristyrylphenol ethoxylates from different sources. The batches showed significant differences among suppliers with regard to composition and content of by‐products. Differences include the content of the different styrenated phenol ethoxylates (e.g., mono‐, di‐, tri‐, and tetrastyrylphenol ethoxylates) and of mono‐ and distyrylphenol copolymerized propoxylates–ethoxylates. The supplier of a given sample could be traced based on these differences by using a combination of principal component analysis and hierarchical clustering analysis. This was possible using either the raw material or a model agrochemical formulation containing the surfactant.     

Determination of diester formation in diethylene glycol and tetraethylene glycol monoesters

Polyethylene glycol monoesters on standing rearrange to form diesters. The formation of diester in monoester samples stored at 3 C, 25 C, and 37 C, respectively, for approximately 3 months was determined by reverse phase high performance liquid chromatography (HPLC) in less than one-half hour. Formation of diester increased with increasing storage temperature, regardless of the chemical nature of the     

Poly(1‐octene) synthesis using high performance supported titanium catalysts

Poly(1‐octene) was synthesized by polymerization of 1‐octene using high performance MgCl₂‐supported TiCl₄ in combination with triethyl aluminum (TEAl) as cocatalyst in n‐hexane for 2 h. Two catalysts, C₁ (diester catalyst) having di‐isobutyl phthalate as internal donor and C₂ (monoester catalyst) having ethyl benzoate as internal donor were utilized for the atmospheric polymerizations to evaluate the influence of structurally different internal donors on the productivity, rate of polymerization and molecular weight profiles. The kinetic profile assessed in terms of variation of reaction parameters like temperature, cocatalyst to catalyst molar ratio and monomer concentration was found to be dependent on them. From these kinetic analyses, optimize conditions for polymerizations of 1‐octene using diester as well as monoester catalyst were elucidated. The difference in the performance of diester and monoester catalyst system can be explained in terms of stability of active titanium species and chain transfer process. NMR spectroscopy of synthesized poly(1‐octene) indicate predominantly isotactic nature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

An Analytically Defined Fire‐Suppressing Foam Formulation for Evaluation of Fluorosurfactant Replacement

A 4‐component, analytically defined, reference fluorosurfactant formulation (Ref‐aqueous film forming foam [AFFF]) composed of 0.3% fluorocarbon‐surfactant concentrate (Capstone 1157), 0.2% hydrocarbon‐surfactant concentrate (Glucopon 215 UP), and 0.5% diethylene glycol mono butyl ether by volume in distilled water was found to have rapid fire extinction comparable to a commercial AFFF in tests conducted on a bench scale and a large scale (28 ft², part of US Military Specification, MIL‐F‐24385F). The Ref‐AFFF was analytically characterized to provide the identity and quantity of the chemical structures of the surfactant molecules that were lacking for commercial AFFF formulations. To arrive at an acceptable Ref‐AFFF formulation, 3 candidate formulations containing different hydrocarbon surfactants in varying amounts were evaluated and ranked relative to a commercial AFFF using a bench‐scale fire‐extinction apparatus; varying the hydrocarbon surfactant was found to affect the fire‐extinction time. The ranking was confirmed by the large‐scale tests suggesting that the bench‐scale apparatus is a reasonable research tool for identifying surfactants likely to succeed in the large‐scale test. In the future, replacing the fluorocarbon surfactant with an alternative surfactant in the Ref‐AFFF enables a direct comparison of fire extinction and environmental impact to identify an acceptable fluorine‐free formulation.     

Herstellung von Alkylenglykomonoestern durch Alkoxylierung von Carbonsäuren

Preparation of Alkyleneglycol Monoesters by Alkoxylation of Carboxylic Acids A new process of alkoxylation using amines as catalysts is reported for the preparation of alkyleneglycol monoesters of aliphatic carboxylic acids. Prim., sec. and tert. amines act as highly selective catalysts at about 80°C. The monoester contents amount to 85–100%. The formation of diester and polyglycol is almost completely suppressed.     

On One Leg: Trehalose Monoesters Activate Macrophages in a Mincle‐Dependent Manner

The C₂₂ and C₂₆ trehalose monoesters, each containing a single acyl chain, were synthesised in good overall yields and found to activate macrophages in a Mincle‐dependent manner. The activities of the monoesters paralleled those of their diester counterparts, and both mono‐ and diesters could activate the immune response in the absence of priming. This is the first time that trehalose monoesters have been found to activate macrophages, and these studies thus provide an important framework for the rational design of other Mincle agonists.     

Chemical Nature and Diversity of Phosphorus in New Zealand Pasture Soils Using <Superscript>31</Superscript>P Nuclear Magnetic Resonance Spectroscopy and Sequential Fractionation

Information on the phosphorus (P) forms of pasture soils is central to agricultural and environmental sustainability. We used a combination of ³¹P nuclear magnetic resonance (NMR) spectroscopy of NaOH–EDTA extracts and sequential fractionation to investigate P forms, with an emphasis on organic P in relation to environmental and biophysical variables, in 24 diverse pasture soils taken from around New Zealand (organic C 19–102 g kg⁻¹, total P 116–2746 mg kg⁻¹, pH 5.2–7.0). Soils were separated by cluster analysis of soil physicochemical properties and sequentially extracted P pools into those either derived from volcanic-ash materials or not. This separation was also evident for organic P species in NaOH–EDTA extracts, which removed about 75% of total soil organic P. The major organic P compound class was monoesters (24–60% of extracted P), made up of 14 to 91% myo-inositol hexakisphosphate. The next largest organic P class was diesters (0–4% of P extracted), which were enriched in volcanic-ash soils (monoester to diester ratio = 14) compared to non volcanic-ash soils (ratio = 30). Correlation analysis indicated that mean annual temperature had a significant negative and positive effect on monoester and diester concentrations, respectively. This was attributed to better physical protection of monoesters (especially inositol phosphates) from mineralization, and increased diesters from microbial activity and biological turnover. The anomalous behaviour of volcanic-ash soils was attributed to slow mineralization and the sampling of soils at different times of year without full knowledge of the large and highly dynamic microbial biomass P pool which is predominantly diesters.     

Lipase-catalyzed synthesis of lesquerolic acid wax and diol esters and their properties

Lesquerolic acid was and α,Ω-diol esters were synthesized via immobilizedRhizomucor miehei lipase-(Lipozyme) catalyzed esterification of lesquerolic acid and alcoholysis of lesquerella oil. For each wax ester synthesis, when alcohol substrate was present at a slight (ca. 20%) stoichiometric excess and water content was kept low, over 94% of the hydroxy acyl groups were esterified. The extent of reaction and the ratio of monoester to diester produced for α,Ω-diol reactions was controlled by the solubility of diol in the medium. This latter quantity increased as alcoholysis proceeded due to the formation of partial glycerides and monoesters, which increased the polarity of the medium. Alcoholysis reactions were significantly slower when the medium diol content was above saturation. As the diol chainlength increased, diol solubilization decreased, the ratio of monoester to diester decreased, and the extent of hydrolysis increased. Alcoholysis reactions involving either fatty alcohols or diols suffered from acyl migration, which lowered the purity of lesquerolic acid esters. Several lesquerolic acid esters, synthesized on a preparative scale and purified via column chromatography, were evaluated for their properties: density, viscosity, and melting point. Potential applications for lesquerolic acid esters are discussed.     

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

Glucose- 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.     

五氧化二磷改性水性环氧树脂的合成及性能

为获得具有良好表面活性的水性环氧树脂,采用五氧化二磷为磷酸化试剂对环氧树脂进行改性,并对此磷酸化工艺过程进行优化。从反应投料比、时间、温度等主要因素考察了反应条件对产物环氧值和单双酯含量的影响,确定了较佳的反应条件：反应投料摩尔比n（E20）∶n（P2O5）=1.2∶1,反应时间为3 h,反应温度为85 ℃。此工艺条件下制备产物的环氧值为0.057 mol/100 g,单酯含量为0.44 %,双酯含量为0.56 %。使用红外光谱仪、核磁共振谱仪对改性环氧树脂的结构进行了表征,并对其热稳定性、乳液的黏温、黏浓特性、粒径及表面活性进行了测试。结果表明,改性后样品的分子结构中有部分环氧键断裂,同时有磷酸单双酯官能团的出现,说明合成了新的产物;改性环氧树脂的热稳定性较好;乳液的平均粒径较小;乳液质量分数低于10 %时,其黏度几乎不受质量分数的影响,具有较好的表面活性;乳液质量分数为0.5 %时,乳液的表面张力最小。     

Improved synthesis of sucrose fatty acid monoesters

The base-catalyzed synthesis of four sucrose fatty acid esters (caprylate, laurate, myristate, and palmitate) was performed in dimethylsulfoxide by transesterification of sucrose with the corresponding vinyl esters using disodium hydrogen phosphate as catalyst. In using a molar ratio sucrose/vinyl ester 4∶1 and mild reaction conditions (40°C and atmospheric pressure), yields were higher than 85%. The isolated sucroesters had a higher percentage of monoesters (≥90%) and a lower content of diesters in comparison with commercial derivatives. In all cases, 2-O-acylsucrose was the major product (≥60%) in the monoester fraction.     

Synthesis,Stabilization and Activation of Pt Nanoparticles for PEMFC Applications

Amongst the main challenges of catalyst materials for Proton Exchange Membrane Fuel Cells (PEMFCs) are activity and durability. Here we report on the synthesis of monodisperse nanoparticles and stabilization with traces of the surfactant, here Na‐AOT (bis‐(2‐ethylhexyl) sulfosuccinate sodium salt), used in the synthesis procedure. The surfactants prevent agglomeration and reduce Ostwald ripening. We compare the performance of Pt catalyst nanoparticles synthesized in dense microemulsions, Na‐AOT/heptane/water and Triton X‐100/toluene/water, with a commercial state‐of‐the‐art catalyst for the Oxygen Reduction Reaction (ORR). The produced catalyst nanoparticles were extracted onto a carbon support, Vulcan XC‐72R, washed and activated by heat‐treatment, which led to heavy agglomeration, or by electrochemical treatment, which led to an enhanced activity for ORR. Additionally, in comparison to the other two catalysts an increased durability of the platinum nanoparticles synthesized in the microemulsion of Na‐AOT/heptane/water was observed.     

Assessment of variable effects on solvent‐free monoacylglycerol enzymatic production in AOT surfactant

This work reports the application of a lipase in the glycerolysis of olive oil for the production of monoacylglycerols (MAG). For this purpose, the enzymatic glycerolysis of olive oil with an immobilized lipase (Novozym 435) was accomplished using sodium (bis‐2‐ethyl‐hexyl) sulfosuccinate (Aerosol‐OT or AOT) as surfactant in a solvent‐free system. A sequential strategy was used applying two experimental designs to optimize the MAG production. In general, it was observed that the temperature had a negligible effect on MAG conversion while the enzyme and AOT concentrations present a positive significant effect (p <0.05) and the stirring rate a negative one. An empirical model was then built so as to assess the effects of process variables on the reaction conversion. Afterwards, the operating conditions that optimized MAG production were established as follows: temperature of 70 °C, stirring rate of 600 rpm, 16 wt‐% of AOT and 7.5 wt‐% of enzyme, leading to a reaction conversion as high as 55%.     

Activity of horseradish peroxidase in aqueous and reverse micelles and back‐extraction from reverse‐micellar phases

Studies on the activity of the enzyme horseradish peroxidase (HRP) have been carried out in micellar as well as reverse‐micellar media. The activity of the enzyme was studied in the presence of different classes of surfactants – ionic as well as non‐ionic. In aqueous media, the activity of the enzyme varied depending on whether the concentration of the surfactant used was above or below the critical micellar concentration (CMC). The enzyme was also studied in reverse‐micellar systems. HRP was introduced into the reverse micellar phase by the injection method and its activity within the reverse micelles was determined. The effect of water to surfactant ratio (W_o) on activity within reverse micelles was studied, and an almost two‐fold increase in activity was seen when the enzyme was encapsulated within reverse micelles of aqueous phase fractional hold‐up (?) of 0.0072 (v/v) consisting of sodium bis‐(2‐ethylhexyl) sulfosuccinate (AOT) in isooctane at a W_o of 20. The activity of HRP was measured over a wide range of AOT concentrations having different W_o values. Back‐extraction of HRP from these reverse micelles was carried out at varying ionic strengths of phosphate buffer. Back extraction was found to be highest at pH 7.0 in 40 mol m^?3 phosphate buffer and 100 mol m^?3 sodium chloride. © 2001 Society of Chemical Industry     

Kinetic study of the enantioselective hydrolysis of a meso‐diester using pig liver esterase

A kinetic study of the hydrolysis of the diester dimethyl cis‐cyclohex‐4‐ene‐1,2‐dicarboxylate, to the (1S,2R)‐monoester, catalysed by the enzyme Pig Liver Esterase (PLE) was performed. The effects of the most relevant parameters that influence the enzymatic conversion were studied, such as pH, temperature and concentration of substrate and reaction products. It was concluded that the pH at which the enzyme exhibits a maximum activity is pH 7. At 25 °C PLE presents a better long‐term stability and enantioselectivity than at higher temperatures, although the reaction rate is slower. The kinetic results obtained are well described by the Michaelis–Menten equation, although a slight deviation to this model was observed for low substrate concentrations. Methanol, a co‐product of the enzymatic hydrolysis, was found to act as a non‐competitive inhibitor of the reaction. The Michaelis–Menten parameters were determined and a comprehensive kinetic model, which already accounts for methanol inhibition, is presented. © 2000 Society of Chemical Industry     

Phase behavior of a sodium dodecanol allyl sulfosuccinic diester/n‐pentanol/methyl acrylate/butyl acrylate/water microemulsion system and preparation of acrylate latexes by microemulsion polymerization

Pseudoternary phase diagrams of quaternary microemulsion systems composed of the reactive surfactant sodium dodecanol allyl sulfosuccinic diester, n‐pentanol, methyl acrylate/butyl acrylate, and water were made. The influence of the mass ratio of sodium dodecanol allyl sulfosuccinic diester to the cosurfactant (n‐pentanol) in the system and the influence of electrolyte sodium chloride on the microemulsion area were examined. The microstructure of the microemulsion was determined with a conductance technique. The results suggested that there were three structures in the microemulsion system: water in oil, oil in water, and a bicontinuous phase. Microemulsion polymerizations were carried with some point in the microemulsion region being chosen as the formulation. The structure and configuration of the polymer latexes were determined and analyzed with Fourier transform infrared, differential scanning calorimetry, and scanning electron microscopy. The results suggested that the reactive surfactant could participate in the polymerization with the monomers to some extent; the glass‐transition temperature of the latex was ?31.4°C. The polymer latex was transformed gradually from an open porous structure to a closed porous structure when its pregnant microemulsion was varied from a bicontinuous structure to an oil‐in‐water structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

磷酸酯功能单体的缓释法合成研究

采用溶剂分散P2O5投料方式,缓释法合成了丙烯酸羟丙基磷酸酯的功能单体,研究了分散剂及其用量、反应物料比、反应时间及有无水解反应对磷酸酯中单、双酯含量的影响。结果表明,当分散剂选用正己烷且m（正己烷）：m（P2O5）=4：1,原料配比n（HPA）In（P2O5）=2．4：1,酯化反应温度为70℃,反应时间4h,酯化反应后,达到水解温度再保温10min时,磷酸酯中单、双酯物质的量比值最高。与传统的P2O5粉末直接投料法相比,该方法合成的丙烯酸羟丙基磷酸酯中单酯、双酯的物质的量比值由3．85提高到10．36。     

Synthesis of porous emulsion‐templated monoliths from a pulp mill by‐product

Black liquor is a by‐product of the paper mill Kraft process that deserves more valorization than its present use as low‐grade fuel. In this work, we present an original approach allowing the preparation of macroporous interconnected monolithic materials using as‐received black liquor as main raw material. The process involves the formulation of an oil‐in‐water medium internal phase emulsion as soft templating porosity medium. The oil (internal phase) used is castor oil, whereas the continuous phase is constituted of black liquor containing a hydrophilic surfactant and epichlorohydrin as lignin crosslinking agent. Due to the high viscosity of the system, a specially designed emulsifying device was employed. The proper choices of the surfactant and emulsification conditions allow obtaining cellular biopolymers with almost monodisperse, interconnected void structure and satisfactory mechanical properties. These innovative results are promising for the future development of fully bio‐based emulsion‐derived materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Immobilisation of different Candida rugosa lipases by adsorption onto polypropylene powder: application to chiral synthesis of ibuprofen and trans‐2‐phenyl‐1‐cyclohexanol esters

Candida rugosa lipases (CRLs) were immobilised by adsorption onto a commercial polypropylene powder EP100?. Two commercial CRLs from Sigma and Amano were used together with two CRLs obtained by fed‐batch fermentation using oleic acid as a carbon source (UAB‐CRL). Significant differences were observed in the isotherm adsorption patterns for the commercial and fermented lipases, probably caused by differences in their polysaccharide content. The commercial lipases showed a classical Langmuir adsorption pattern, whereas fed‐batch produced lipases with high polysaccharide content tended to conform to a BET multilayer adsorption equation. Immobilised CRLs also showed different behaviour in the resolution of two interesting pharmaceutical products: ibuprofen and trans‐2‐phenyl‐1‐cyclohexanol (TPCH) in the enantioselective esterification reaction in organic media. In the case of ibuprofen, CRLs showed important differences in terms of esterification rate, probably due to diffusional limitation effects caused by the high polysaccharide content present in UAB‐CRLs. In the case of TPCH, however, polysaccharide content did not appear to influence the esterification rate. A high enantioselective esterification was observed for all CRLs tested in the resolution of both products. © 2002 Society of Chemical Industry     

Self‐Assembly Behaviors of Anionic–Cationic Binary Surfactant Systems in Poly(ethylene glycol) 200

The self‐assembly behaviors of mixtures of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) and didodecyl dimethylammonium bromide (DDAB) in polyethylene glycol 200 (PEG 200) and in water were investigated by surface tension, conductivity, steady‐state fluorescence and dynamic light scattering (DLS) methods. The results show that the oppositely charged binary surfactant system can form micelles in PEG 200; the critical micellization concentration (CMC) decreases for the binary system versus those of either surfactant alone. Although there is no charge screening in the PEG 200 system, the CMC values significantly increase and the system does not precipitate or show turbidity at any proportion of AOT to DDAB, while a multiphase composition gap exists in water due to the strong electrostatic attraction. It is speculated that the weak polarity of PEG 200, the decreased solvophobic interaction between the alkyl chain and PEG 200, and the loose structure of the resulting micelles might explain the experimental phenomena. Observed from the values of the interaction parameter, it is found that there are a strong attractive interaction and a synergistic effect between AOT and DDAB in aqueous solution, in comparison, the synergy between them in PEG 200 is very weak.