Takatoshi Sato

VOLATILITY AND SOLUBILIZATION OF SYNTHETIC FRAGRANCES BY PLURONIC P-85

ABSTRACT The volatility of synthetic fragrances (benzyl formate, benzyl acetate, benzyl propionate) from pluronic P-85 aqueous solution has been investigated by the dynamic headspace method The experimental results showed that the volatility of a more hydrophobic fragrance was strongly controlled by pluronic P-85. This volatile behavior was explained by the solubilization constants of fragrances between the micelle and bulk phase by semiequilibrium dialysis method.

Determination of Stability Constants for Alkanol/α-Cyclodextrin Inclusion Complexes using the Surface Tension Method

The stability constants for the inclusion of alkanols withα-cyclodextrin (α-CD) in aqueous solutionhave been determined using the surface tension method. Dataanalyses assuming 1 : 1 stoichiometry were appliedto estimate the stability constants of thesecomplexes. The stability constants obtained using this methodwere in reasonable agreement with the corresponding values inthe literature. Chemically modified α-CDs could not beused in this method because those CDs themselves have surfaceactivity. In addition, the relation between the stability constantsand the carbon number of alkanols is discussed.

Micellar structure and micellar inner polarity of octaethylene glycol n-alkyl ethers

The effects of the alkyl chain length of non-ionic surfactants on micellar structure and micellar inner polarity have been investigated. The aggregation number increases while the degree of hydration decreases with increased alkyl chain length. Also, a decrease in micellar inner polarity is found to occur as the alkyl chain length increases. An interpretation of these results is given.

Effects of Inorganic Salts on Solubilization of Estriol in an Aqueous Solution of Poly(ethylene oxide)/Poly(propylene oxide)/Poly(ethylene oxide) Triblock Copolymer

The effects of inorganic salts on the solubilization of estriol was studied in an aqueous solution of a poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer (Pluronic L-64). The solubility of estriol increased with increasing Pluronic L-64 and salt concentrations. Furthermore, two clear transition points corresponding to the polymolecular micelle formation and a pronounced change in micellar structure of Pluronic L-64 were found on the solubility curves. The effectiveness of inorganic salts for increasing solubility of estriol followed approximately the lyotropic or Hofmeister series, except Li+.

Surface-tension studies of inclusion complexes of hexanediols with cyclodextrins in aqueous solutions

Abstract A surface-tension method developed previously was used to investigate the formation of an inclusion compound between hexanediols (HDs) and cyclodextrins (CDs) in an aqueous solution. A global nonlinear least-squares fit of surface tension data was applied to estimate binding constants for complexes between HD and CD, 1,2-HD forms a 1:1 complex (HD/CD) with CD while 1,6-HD and 2,5-HD form predominantly a 2:1 complex (2HDs/CD) with CD. Binding effects are discussed in relation to the different positioning of the hydroxyl groups of HDs.

Solubilization behavior ofn-octane andn-octanol in polyoxyethylated nonionic micelles

The solubilization ofn-octane andn-octanol in nonionic micelles was investigated by means of various techniques including solubilization, fluorescence and dynamic light-scattering measurements. With respect to the effect of oxyethylene chainlength of the surfactants, different solubilization behavior was observed betweenn-octane andn-octanoli.e., the solubilization ofn-octane decreases with an increase in oxyethylene chainlength, while that ofn-octanol increases. This solubilization behavior is explained from the standpoint of the volume of hydrophobic and hydrophilic regions in a micelle.

ポリ(オキシエチレン)硬化ヒマシ油のミセル形成及びミセル構造

The effects of the oxyethylene chain length of poly(oxyethylene) hydrogenated castor oil (HCOn) on the micellar formation and on the micellar structure were investigated. Some physicochemical properties of HCOn (critical micelle concentration cmc, surface tension at cmc, free energy of micellization, and surface excess) concerning surface-activity were measured. These physicochemical properties were little affected by the oxyethylene chain length of HCOn. In addition, several physical techniques have been used to study the micellar structure of HCOn. It was found that HCOn micelles were spherical or nearly spherical, and that an increase in the oxyethylene chain length led to an increase in the looseness of HCOn micelle.

Effects of micellar structure on solubilization ofn-octane andn-octanol

The solubilization ofn-octane andn-octanol in nonionic micelles of octaethylene glycoln-alkyl ethers was investigated by means of various techniques including solubilization, fluorescence, and dynamic light-scattering measurement. With respect to the effect of alkyl chain length of the surfactants, different solubilization behavior was observed betweenn-octane andn-octanol. That is to say, it was shown that the solubilization ofn-octane increases with an increase in the alkyl chain length, while that ofn-octanol decreases. An interpretation of these solubilization mechanisms is explained from the standpoint of the volume of hydrophobic and hydrophilic regions in a micelle.

Preparation and hydrolysis of poly(2-benzoyloxyethyl vinyl ether) with a narrow molecular weight distribution

2-Benzoyloxyethy vinyl ether (BOEVE) was cationically polymerized with the hydrogen iodide/zinc iodide (HI/ZnI 2 ) initiating system in toluene at -15°C to form a narrow molecular weight distribution (MWD). The poly(BOEVE) obtained had a narrow MWD (M W /M n <1.2, M w : weight-average molecular weight, M n : number-average molecular weight). The M n of the poly(BOEVE) increased directly in proportion to the BOEVE conversion and to the reciprocal of the initial HI concentration, that is, the reaction was found to be a living polymerization. The hydrolysis rate of the polymer in the alkaline dioxane-water system decreased with increase in the M n of the polymer.

Copolymerization of 2-Bromomaleic Anhydride with Styrene and Its Dehydrobromination

2-Bromomaleic anhydride (BrMAn) and styrene (St) were found to make a charge-transfer complex at a 1 : 1 ratio. The copolymerization followed the generalized mechanism for alternating copolymerization, and an alternating copolymer was obtained over a relatively wide feed composition range. The monomer reactivity ratios, rBrMAn and rSt, were found to be 0 and 0.05, respectively, at 60°C. The copoly(BrMAn/St) was dehydrobrominated by heating under reduced pressure and a polymer with a structure similar to the maleic anhydride moiety in the polymer chain was obtained. The dehydrobromination was completed by heating at 190°C for 1 h.