摘要:

Ethoxylation of the solvent range low molecular weight alcohols in a falling film reactor is described. It is shown how plug flow favors the selectivity of the target species in this reaction even though the polyaddition degree is low, for the exemplary study case : production of monoethylene glycol butyl ether by ethoxylation of butanol in the presence of sulfuric acid.

ISSN:0193-2691    

DOI:10.1080/01932699808913186

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Lysine residues offer a convenient way of incorporating various chemical groups on to the surface of proteins. The effect of introducing chemical groups of various nature on the protein surface on its adsorption properties at the alumina/water interface have been studied. Hydrophilic sugar groups have been introduced by glycosylation, hydrophobic meihyl group has been introduced by reductive alkylation and negatively charged phosphate group has been introduced by pyridoxylation of β-lactoglobulin. The adsorption density of these modified proteins on alumina were compared with that of the unmodified protein. It has been found that all of the above modifications significantly reduced the affinity of β-lactoglobulin for the solid surface at all the three pH's studied here.

ISSN:0193-2691    

DOI:10.1080/01932699808913187

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699808913188

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Water-in-crude oil emulsions are stabilised by the natural surfactants present in the crude oil. The Theological properties of the interface have often been mentioned to control the stability and demulsification of such emulsions. In this work, dynamic interfacial tension at the crude oil / water interface and dilational modulus of such systems have been studied by using a microprocessor controlled drop-volume interfacial tension measurement apparatus and micro videography.

ISSN:0193-2691    

DOI:10.1080/01932699808913189

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The stability of the silver iodide and iron(lll) oxide dispersions has been investigated in the presence of monoamino-monocarboxylic acid, neutral amino acid. The critical coagulation concentrations of the dispersions, Ccincreased with increasing amino acid concentration and then decreased. The optimum amino acid concentration for the stabilization decreased with increasing number of carbon atoms of amino acid. The results indicate that the stabilization of the dispersions by amino acids is due to the adsorption of amino acids onto the particles. The stabilizing effect is discussed in terms of the total potential energy of interaction between the particles which was calculated by considering the existence of the adsorbed layers on the particles using the experimentally determined Hamaker constants and outer Helmholtz plane potentials.

ISSN:0193-2691    

DOI:10.1080/01932699808913190

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A general reaction model for styrene hydrogenation in the CTAB/l-hexanol(l-pentanol or l-butanol)/water reversed micellar solutions was proposed to interpret the catalytic behavior of monodisperse nickel boride particles prepared in situ. Based on this model, the effect of reversed micellar components on hydrogenation activity of the catalyst has been discussed in detail. It is worth noticing that, in the three reversed micellar systems, adding ethanol into the reversed micellar solutions will result in the change of catalyst's activity in the different ways, i.e. decrease for the reversed micellar solution with the low CTAB concentration (6 wt%) and increase for those with the high CTAB content (23 wt % or 38 wt%). The result is attributed to the combined

ISSN:0193-2691    

DOI:10.1080/01932699808913191

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Despite the fact that the monodisperse cobalt boride particles prepared in CTAB / 1-hexanol / water reversed micellar systems are the quite small particles with a narrow size distribution, they exhibited little hydrogenation activity in reversed micellar solution. The chief cause are due to combined effect of both adsorption of the CTAB molecules on the catalyst and the slow transport process of hydrogen from the organic phase of the reversed micellar solution to the surface of catalyst. The experiments have revealed an interesting fact that addition of ethanol to the reversed micellar solutions simultaneously lead to the increase in catalytic activity and coagulation of catalyst particles.

ISSN:0193-2691    

DOI:10.1080/01932699808913192

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

New possibilities on the substitution of pentanol as cosurfactant on the preparation of microemulsions with anionic surfactants, are suggested. Alternative systems with more skin compatible ingredients as are oleic acid and glycols, allows to obtain microemulsions of potential application in fields as are the cosmetic and dermopharmaceutical ones, in which the requirements of harmlessness of the ingredients reduces the possibility of application of the conventional microemulsions with pentanol. The capacities of solubilizing hydrocarbon, were stated depending on the chain lenght of the glycol as well as on the ratio of combination water/glycol. The possibilities of the different systems were evidenced by means of the corresponding phase diagrams, resulting that the shorter the hydrocarbon chain lenght of the glycol is (ethylenegtycol), the wider is the realm of microemulsion obtained, and being established an optimal ratio water/glycol around 1/1. Moreover, the system with oleic acid and ethylenegrycol allows to prepare easily both W/O and O/W microemulsions, overcoming the possibilities of the classical system with pentanol.

ISSN:0193-2691    

DOI:10.1080/01932699808913193

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Transfer of a series of isotopic labelled nonionic surfactant between toluene and water has been investigated in this paper. Mass of the transfer was measured in lime by liquid scintillation counting technique. The experiment dale show a fractal interface was existence, and at the same condition, the fractal dimension of the interface correlate to the HLB of the nonionic surfactant.

ISSN:0193-2691    

DOI:10.1080/01932699808913194

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699808913195

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor