Selective Extraction of Embelin from Embelia ribes by Hydrotropes

Abstract

The research work proposes an alternate strategy of the extraction of embelin (2,5‐dihydroxy‐3‐undecyl‐p‐benzoquinone) from Embelia ribes. The aromatic hydrotropes such as sodium n butyl benzene sulfonate (NaNBBS), and sodium cumene sulfonate (NaCS) were found to be effective for the selective extraction of embelin with a recovery of 95% embelin from the aqueous solution of hydrotropes with high purity. The process was further optimized with respect to concentration of hydrotropes and temperature of extraction.     

Hydrotropic Extraction of Reserpine from Rauwolfia vomitoria Roots

Aqueous solutions of sodium cumene sulfonate give quantitative and faster extraction of reserpine from Rauwolfia vomitoria as compared to the extraction using methanol. The extraction rate is influenced by intraparticle diffusion and increases with increasing temperature and hydrotrope concentration. The dynamic extraction data were fitted in a mass transfer model to evaluate diffusion coefficient of reserpine in the solid plant matrix. Amongst all hydrotropes, sodium cumene sulfonate, gave the best extraction and extraction rates of reserpine. The reserpine crystals recovered from aqueous hydrotrope solutions were much smaller in size and showed different morphology than those from methanol.     

Extraction of Piperine from Piper Nigrum (Black Pepper) by Aqueous Solutions of Surfactant and Surfactant + Hydrotrope Mixtures

Abstract

The effect of combining butyl benzene sulfonate as hydrotrope with a surfactant in aqueous solutions is investigated for isolation of piperine, an alkaloid, from black pepper. The standard free energy change associated with piperine solubilization in the aqueous solutions of surfactant and hydrotrope individually and in their mixtures is determined from the solubility of piperine in these solutions. A combination of sodium dodecyl sulfate (SDS) and the hydrotrope gives increased percentage extraction of piperine as compared to the hydrotrope alone. The piperine purity recovered from aqueous solutions was higher as compared to the purity of piperine recovered using organic solvents. The piperine crystallized from aqueous solutions of surfactants and hydrotrope also showed cleaner surfaces and uniform structures with sharp edges, unlike the particles crystallized from organic solvents.     

Partitioning of o/p-Nitrophenols in the Presence of Hydrotropes in Aqueous Solutions

Abstract

Partitioning of o/p-nitrophenols between organic solvents and water in the presence of hydrotropes such as sodium toluene sulfonate, sodium xylene sulfonate, and sodium cumene sulfonate, has been experimentally investigated and modelled in terms of co-aggregation of the hydrotrope and nitrophenols in aqueous solutions. The phenol-hydrotrope and hydrotrope-hydrotrope interactions are characterized by an aggregation model. The experimental data for a series of hydrotropes are further used to predict the partitioning behavior of p-nitrophenol in the presence of sodium butyl benzene sulfonate (Na-NBBS). The aggregation number of NaNBBS, (～30) obtained from the partitioning data, matches well with that obtained by small angle neutron scattering.     

Effective Separation of Petro Products through Hydrotropy

This paper presents a comprehensive study on the effect of hydrotropes such as sodium salicylate, sodium benzoate, and nicotinamide on the separation of a near boiling mixture, o‐/p‐xylene. The influence of a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303 to 333 K) on the separation of o‐/p‐xylene were studied. All hydrotropes used in this work showed an enhancement in the percentage extraction of p‐xylene to different degrees. The percentage extraction of p‐xylene from the o‐/p‐xylene mixture increases with an increase in hydrotrope concentration and also with system temperature. A minimum hydrotrope concentration (MHC) was found essential to initiate significant extraction of p‐xylene from the o‐/p‐xylene mixture. The maximum enhancement factor, which is the ratio of the value in the presence and absence of a hydrotrope, was determined for both cases. The Setschenow constant, k_s, a measure of the effectiveness of a hydrotrope, was determined for each case.     

Effect of hydrotropes on the aqueous solution behavior of surfactants

Aqueous solutions of surfactants—cationic: tetradecyltrimethylammonium bromide (C₁₄TABr); anionic: sodium dodecyl sulfate (SDS); and nonionic: polyoxyethylene t-octylphenol (trade name Triton X-102, also called OPE-8)— in the presence of three hydrotropes, viz., sodium xylene sulfonate, sodium p-toluene sulfonate, and sodium chlorobenzene sulfonate, were examined by measuring surface tension, viscosity, and cloud points for the nonionic surfactant. The results show a marked decrease in the critical micelle concentration with increase in hydrotrope concentration for C₁₄TABr, a marginal decrease for SDS, and very little change for OPE-8 up to 0.1 M hydrotrope. The viscosity of cationic surfactant solutions showed a remarkable increase in the presence of trace amounts of hydrotropes (up to 15 mM). In contrast, the SDS solution showed only a slight increase in viscosity at high hydrotrope concentration (150 mM), and the viscosity of the OPE-8 solution remained constant. The cloud point of OPE-8 increased in the presence of hydrotropes, unlike its behavior with the simple salt NaCl. The strong dependence of the solution behavior of cationic surfactants on the presence of hydrotropes is discussed in terms of electrostatic interaction.     

Claisen–Schmidt reaction in a hydrotropic medium

The Claisen–Schmidt condensation of benzaldehydes with acetophenones was carried out in an aqueous medium using sodium butylmonoglycolsulfate (NaBMGS) and sodium salts of aromatic sulfonic acids as hydrotropes. Substantial enhancement in the rate of the reaction was obtained, along with the easy recovery of the product. Recycling of the hydrotrope solutions has been tested without any loss in the rate of the reaction.     

EXTRACTIVE DISTILLATION WITH AQUEOUS SOLUTIONS OF HYDROTROPES

The effect of hydrotropes on vapor-liquid equilibrium of a mixture provides a potential technique of extractive distillation for systems which are difficult or impossible to separate by normal rectification. Various hydrotropes, such as sodium toluate, sodium toluence sulfonate, sodium cymcnc sulfonate, sodium mesitylene sulfonate and sodium salicylate, in aqueous solutions have been tested for the separation of close-boiling point mixtures, such as p-cresol/2,6-xylenol, isopropanol/ fm-butanol, and wc-butanol/rert-butanol. The changes in the relative volatility increase with the concentration of hydrotrope and with the hydrotrope to solute ratio.     

Pseudohydroxide Extraction from Aqueous Sodium Hydroxide Solutions with 3,5‐di‐tert‐Butylphenol in Isopar® L Modified with 1‐Octanol

Abstract

Pseudohydroxide extraction (PHE) was investigated for recovering sodium hydroxide (NaOH) from alkaline process solutions. PHE relies on the deprotonation of a lipophilic weak acid by hydroxide ion with concomitant transfer of sodium ion into an organic phase. Contact of the sodium‐loaded organic phase with water results in the reconstitution of the extractant in the organic phase and NaOH in the aqueous phase, thus leading to a process in which NaOH equivalents are transferred from an alkaline feed solution to an aqueous stripping solution. In this work, we investigated PHE using a process‐friendly diluent—Isopar^® L. The lipophilic cation exchanger 3,5‐di‐tert‐butylphenol (35‐DTBP) was used as the extractant. The Isopar^® L diluent was modified with 1‐octanol to improve its solvation properties and the solubility of 35‐DTBP so that practical Na⁺ concentrations could be achieved in the process solvent. The PHE mechanism at process‐relevant conditions was explored by Raman and Fourier transform infrared spectroscopic measurements. Complementary electrospray ionization mass spectrometry studies were also performed. Equilibrium computer modeling suggested that the Na⁺ extraction behavior can be largely explained by the formation of 1∶1 and 1∶2 Na/35‐DTBP species in the organic phase. Extraction isotherms obtained using simulated caustic leaching solutions indicate the potential utility of this approach for recycling NaOH from complex alkaline mixtures.     

Effect of hydrotropes on solubility and mass transfer coefficient of lauric acid

A comprehensive investigation on the solubility and mass transfer coefficient enhancement of lauric acid through hydrotropy has been undertaken. The solubility and mass transfer studies were carried out using hydrotropes such as sodium cumene sulfonate, sodium p-xylene sulfonate and sodium p-toluene sulfonate under a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303 to 333 K). The effectiveness of hydrotropes was measured in terms of Setschnew constant K _s and reported for all hydrotropes used in this study. The solubility data are also fitted in a polynomial equation as the function of hydrotrope concentration.     

Rheological Investigation of Wormlike Micelles Based on Gemini Surfactant in EG–Water Solution

The self‐assembly behavior of gemini surfactants in ethylene glycol (EG)‐water (5/95, v/v) mixed solvent was investigated by rheological measurements at 10 °C. The influence of molecular structure of the gemini surfactant and added hydrotrope on the solution properties was studied. Sodium salicylate (NaSal) showed stronger ability to induce 2‐hydroxyl‐propanediyl‐α,ω‐bis‐(dimethyldodecylammonium bromide), referred to as 12‐3(OH)‐12, to form wormlike micelles than sodium benzoate. Less NaSal is required to promote a sphere to rod transition and to reach the peak viscosity. Moreover, the concentrations of hydrotrope and gemini surfactant are both lower than conventional single‐chain surfactant systems to reach a comparable viscosity. The strong hydrophobicity of gemini surfactants and hydrotropes is responsible for the high efficiency in forming wormlike micelles in EG/water systems. The geometric structure of gemini surfactants also plays a vital role in self‐assembly into wormlike micelles. Dimethylene‐1,2‐bis‐(dodecyl dimethylammonium bromide), referred to as 12‐2‐12, shows absolute superiority over 12‐3(OH)‐12 in constructing wormlike micelles. The present study will be helpful for developing de‐icing fluids and anti‐freezing solutions, which need rheology control in EG‐aqueous medium at low temperature.     

Intensification of heterogeneous reactions through hydrotropy: Alkaline hydrolysis of esters and oximation of cyclododecanone

Hydrotropic substances are capable of increasing the solubility of sparingly soluble organic compounds in aqueous solutions and can thus enhance the rates of two-phase reactions substantially. The increase in the solubility of sparingly soluble organic substances due to hydrotropes has been found to be an exponential function of the hydrotrope concentration over a wide range. A study of the rates of solid—liquid and liquid—liquid alkaline hydrolysis of esters and solid—liquid oximation of cyclododecanone, in the presence of different hydrotropes, was carried out. The potassium salts of different hydrotropes, such as, butyl monoglycol sulfate, p-cumyl phenol, cumene sulphonic acid were found to be more effective than the corresponding sodium salts. In some cases intensification factors as high as 1000 were observed.     

ENHANCEMENT OF SOLUBILITY AND MASS-TRANSFER COEFFICIENT OF 1,2-DIHYDROXY-9,10-ANTHRAQUINONE (ALIZARIN) THROUGH HYDROTROPY

The effect of hydrotropes potassium p-toluene sulfonate (KPTS), citric acid, and nicotinamide on the solubility and mass-transfer coefficient of 1,2-dihydroxy-9,10-anthraquinone (alizarin) was studied. Solubility studies were carried out under a wide range of hydrotrope concentrations (0 to 3.0 mol·L^?1) and different system temperatures (303 to 333 K). It was observed that the solubility and mass-transfer coefficient of alizarin increases with an increase in hydrotrope concentration and system temperature. The maximum enhancement factor, the ratio of the value of solubility in the presence and absence of a hydrotrope, was determined for all experiments under study. The effectivity of hydrotropes was measured by the determination of the Setschenow constant, K_s. The order of effectiveness of various hydrotropes based on K_s values is potassium p-toluene sulfonate > citric acid > nicotinamide.     

Additive-induced association in unconventional systems: A case of the hydrotrope

It is well known that hydrotropes have a very high minimum hydrotrope concentration (MHC), posing a question on their applications. We have found that MHC (obtained by conductivity and surface tension measurements) can be reduced by the addition of foreign materials. The association tendency can be improved by the addition of salts, n-alkanols, and ureas. Urea decreases or increases the MHC depending on whether the urea content is lower or higher (e.g., the increased solubility of sparingly soluble riboflavin corroborates the increase in the hydrotropic properties of the system). In the present work, the association tendencies of sodium salicylate (a well-known hydrotrope), sodium dodecyl sulfate, and sodium bromide were compared. The results have direct implications in the mechanism of protein denaturation and may provide insight into the role of urea in supramolecular assemblies.     

Soil Clean Up by in-situ Surfactant Flushing. III. Laboratory Results

Abstract

Data on the solubilization of p-dichlorobenzene (DCB), naphthalene, and biphenyl in aqueous solutions of sodium dodecylsulfate (SDS) (0-100 mM concentration) indicate increases in effective solubilities of these hydrophobic compounds by factors of roughly 20 to 100. DCB is effectively removed from spiked clay-sand mixtures by leaching with SDS solutions in laboratory columns. Surfactant solutions loaded with DCB are satisfactorily treated by gentle extraction with hexane, and the recovered surfactant solution satisfactorily solubilizes biphenyl. A simple model for predicting the solubilization behavior of surfactants is developed and tested experimentally.     

Hydrotropic properties of some short-chain alkylbenzene- and alkylnaphthalene sulfonates

Alkylbenzene sulfonates based on toluene, xylene and cumene, and alkylnaphthalene sulfonates act as hydrotropes in surfactant systems. One measure of hydrotropicity is the amount of hydrotrope required to clear a cloudy detergent formulation; some hydrotropes are more effective than others, depending on the surfactant formulation. Another measure is the modification of the viscosity of surfactant formulations; the change in the viscosity depends on the amount and type of hydrotrope used and on the specific formulation involved. Additionally, alkylnaphthalene sulfonate hydrotropes change the solubility of nonionic surfactants in water, and both types of hydrotrope raise the cloud point of nonionic surfactant solutions; however, the naphthalene-based hydrotropes are more efficient. Ross-Miles foam test data are used to compare the foam characteristics of different alkylnaphthalene sulfonates. A critical micelle concentration (CMC) was determined for the alkylnaphthalene sulfonates, but although alkylbenzene sulfonates do show some surface activity, a CMC could not be found for these materials. Presented as a poster session at the AOCS Annual Meeting & Expo, May 1997, Seattle, Washington, and at Soaps, Detergents, and Oleochemicals: An AOCS International Conference, October 1997, Fort Lauderdale, Florida.     

Selective Solubilization of Nitrophenols and Adsorption on Ion Exchange Resins in Nonaqueous Conditions

Abstract

Separation of nitrophenols (NP) has been studied by selective solubilization in organic solvents of different polarities. o‐NP dissolves very well in heptane and toluene while intermolecular hydrogen bonding among p‐NP molecules decreases its solubilization in these solvents. Thus partial separation of o‐/p‐nitrophenols is achieved by selective solubilization of o‐NP in heptane. The trace amounts of p‐NP from the o‐NP solutions are removed by its selective sorption on basic ion exchange resins. The sorption of nitrophenols, individually and in mixtures, is experimentally determined from their solutions in heptane, toluene, and methanol by using weakly basic Indion‐850 and Duolite A‐308 resins and strongly basic Indion‐810 resin. The equilibrium adsorption studies show very selective adsorption of p‐NP from heptane with a high loading capacity on Indion‐850.     

The Solvent Extraction of Boron with Synthesized Aliphatic 1,3‐Diols: Stripping and Extraction Behavior of Boron by 2,2,5‐Trimethyl‐1,3‐hexanediol

Abstract

A variety of aliphatic 1,3‐diols (4a–c, 5a–c, 6a–c) was synthesized from β‐hydroxy carbonyl compounds (1–3) for potential use in the solvent extraction of boron. Primary‐secondary and primary‐tertiary alcohol structures of 1,3‐diols substituted with isopropyl, isobutyl, and isopentyl groups have been demonstrated to be very efficient for the solvent extraction of boric acid from aqueous solutions. The extraction ability of 2,2,5‐trimethyl‐1,3‐hexanediol (5b) was investigated as a function of 5b concentration, solution pH, solvent properties, and stripping conditions. Extraction efficiency increased with increasing concentration of 5b, and the best extraction of boron (96.8%) was found to be at an equilibrium pH of 2 with 0.5 M of 5b. Chloroform, toluene, chlorobenzene, 2‐octanol, and n‐amyl alcohol were found to be suitable solvents for the solvent extraction of boron. The boron complex can be recovered from the organic phase by treatment with an aqueous solution of sodium hydroxide. The highest ratio (96.7%) of boron was recovered by 0.1 M of sodium hydroxide solution.     

3-烷氧基-2-羟丙基三甲基氯化铵对甲基黄的增溶作用

用分光光度法研究了不同温度下 3 烷氧基 2 羟丙基三甲基氯化铵 (RnTAC)、十二烷基磺酸钠 (R12 SO3 Na)及其复配体系 (RnTAC/R12 SO3 Na)对甲基黄的增溶作用。实验表明 ,温度升高可使RnTAC的增溶能力提高。复配体系的增溶量高于单纯体系。     

Solubilization of triglycerides by hydrotropic interaction: Liquid crystalline phases

An investigation of the possibility of preparing aqueous solutions of triglycerides has been made by determining phase regions in systems of three and four components. The results have shown that isotropic aqueous solutions with solubilized triglyceride of up to about 15 wt % can be achieved. A primary solubilization of the triglyceride into a liquid crystalline phase of monoglyceride is followed by the addition of a hydrotrope which transforms the liquid crystalline phase into an isotropic liquid in which the triglyceride is soluble at certain component ratios.