Unreacted Alcohol Research Articles

Influence of ethoxylate distribution on interfacial properties of linear and branched ethoxylate surfactants

The influence of ethoxylate distribution on interfacial properties of linear and branched hydrophobe C 12 and C 13 alcohols is examined at the air-water, decane-water, and Teflon-water interfaces. In the polydisperse ethoxylates, the presence of unreacted alcohol and broad ethoxylate distribution causes interfacial properties to change significantly at the decane-water interface and moderately at the Teflon-water and air-water interfaces. The linear hydrophobe ethoxylate is more sensitive to the presence of unreacted alcohol and broad ethoxylate distribution than the branched hydrophobe ethoxylate.

Phase behavior of monodisperse and polydisperse ethoxylated alcohols

Model polydisperse ethoxylated alcohols were prepared by the reaction of pure dodecanol with ethylene oxide. The patterns of phase behavior of the model polydisperse surfactants were directly compared with those of monodisperse ethoxylated alcohols in water and oil/water mixtures. The polydisperse surfactants are effectively less hydrophilic than monodisperse surfactants in pseudobinary mixtures with water since cloud points occur at lower temperatures. In pseudoternary mixtures with oil and water ( 50 50 ), the microemulsion phases occur at higher temperatures and thus polydisperse surfactants are effectively more hydrophilic than monodisperse surfactants. The differences are traced to the significant amounts of unreacted alcohol and ethoxylated alcohols with low levels of ethylene oxide within the polydisperse distribution. Quantitative analysis of the oil-rich and microemulsion phases within the three-phase region indicates that the partitioning of the polydisperse ethoxylated alcohols (which contain up to 20 components) is complex and cannot be simply described by assuming the mixture behaves as one or two pseudocomponents.

ChemInform Abstract: High‐Pressure Glycosylations of Unreactive Alcohols and the Formation of N‐Glycosylcollidinium Salts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

High-pressure glycosylations of unreactive alcohols and the formation of N-glycosyl collidinium salts

The yields of disaccharide glycosylation products in tetramethylammonium bromide or silver triflate-collidine activated reactions between hindered alcohols and glycosyl halides were not greatly affected when a pressure of 15 kbar was applied. The formation of orthoester products was greatly increased under pressure. When orthoester formation was not possible both disaccharides and the related N-glycosyl collidinium salts were found.

Catalytic reactions of ethanol on H3+xPMo12−xVxO40 catalysts

The catalytic decomposition of ethanol on heteropolyacids (HPA) of the series H3+xPMo12−xVxO40 (x=0,1,2,3) was investigated at 240°C, using a pulse method. It has been shown that besides ethyl ether, ethylene, acetaldehyde and unreacted alcohol, a certain amount of alcohol was irreversibly sorbed by HPA. The amount of the latter decreased with x, which is considered to be due to the tighter bonding of Keggin units (KU) with an increasing number of intramolecular hydrogen bonds. The yield of ethyl ether forming at the surface was almost constant but that of ethylene and acetaldehyde decreased in the series x=0,1,2, which was connected with the increasingly difficult penetration of HPA molecules into the bulk. Some differences in the behavior of the sample with x=3 were the result of partial decomposition of this thermally stable catalyst.

Quantitative analysis of ethoxylated alcohols by supercritical fluid chromatography

AbstractThis work was undertaken to develop a relatively simple, rapid, reproducible and accurate method for measuring the ethylene oxide distribution, overall ethylene oxide ratio, and percent free alcohol in ethoxylated alcohols. Using single isomer ethoxylate standards comprised of from one to eight ethylene oxide units per alcohol, a response factor correlation for the flame ionization detector on a supercritical fluid Chromatograph was established. Response factors for ethoxylates with higher than eight ethylene oxide units were estimated by extrapolation of this correlation. Supercritical fluid Chromatographic separation of ethoxylates was accomplished using a density‐programmed carbon dioxide mobile phase and a poly (dimethylsiloxane) coated open tubular column. The validity and accuracy of this method was demonstrated by comparing its results for unreacted alcohol levels, ethylene oxide‐to‐alcohol average ratios, and weights of samples injected relative to internal standards with values measured independently by standard methods. In addition, supercritical fluid Chromatographic determinations of ethylene oxide molar distributions are in agreement with theoretical Weibull‐Nycander distributions.

The preparation of esters of formic acid using boron oxide

Boron oxide has been found to act as an efficient reagent in the preparation of a number of formate esters by the direct esterification of formic acid with the alcohol. The reaction is most appropriate for primary and secondary alcohols, including unsaturated alcohols. The formate ester so produced is free of contamination by unreacted alcohol.

Effects of the ethylene oxide distribution on nonionic surfactant properties

AbstractDetergent‐range primary alcohols are readily converted into nonionic surfactants by reaction with ethylene oxide. Optimum performance properties for these surfactants generally are attained by varying the number of moles of ethylene oxide reacted with each mole of alcohol or by altering the structure of the primary alcohol. However, variations in the ethoxylate‐adduct distribution also affect surfactant properties in such a way that products with relatively narrow distributions possess features which are highly desirable in many household and industrial applications. For a given cloud point narrow‐range ethoxylates have lower molecular weights and therefore lower pour points than broad‐range surfactants. Because narrow‐range ethoxylates contain less unreacted alcohol and other water‐insoluble species, they are capable of forming aqueous solutions with much lower cloud points than their broad‐range counterparts. Aqueous solutions of narrow‐range products have lower viscosities, exhibit lower gel temperatures and remain fluid over a wider concentration range than solutions of broad‐range surfactans. While the foams obtained with narrow‐range surfactants in the Ross‐Miles test are higher initially, they are less stable than those produced by conventional nonionic surfactants. Draves wetting data show that narrow‐range products wet cotton substrates more efficiently than normal‐distribution materials. Narrow‐range ethoxylates exhibit higher aqueous surface tension and higher polyester adhesion tension values than their broad‐range counterparts. In addition, narrow‐range surfactants reduce the interfacial tension against paraffin oil more efficiently and more effectively than broad‐range products. These results, along with laboratory detergency data, suggest that the use of narrow‐range ethoxylates may lead to cleaning systems with improved performance and/or physical properties.

Reflectance measurements on gels and emulsions containing cetrimide and cetostearyl alcohol--a preliminary investigation.

Various light scattering properties-the reflectivity, contrast ratio and scattering index of a series of gels and emulsions containing cetrimide, cetostearyl alcohol, water and liquid paraffin have been examined using reflectance measurements made at 560 nm using a four-filter, tristimulus colorimeter. The scattering properties of both systems were dependent on the total interfacial surface area of either the dispersed unreacted cetostearyl alcohol and/or the dispersed droplets of liquid paraffin, and hence increased with increasing concentration of both ingredients. For the emulsion containing liquid paraffin, the scattering properties increased linearly with the concentration of liquid paraffin but with the ternary gel system the scattering properties were not directly related to cetostearyl alcohol concentration. This was confirmed by microscopy as due to the changes in the size of the dispersed unreacted cetostearyl alcohol. The results illustrate the potential of this simple, reproducible non-destructive technique in the study of the structure of such systems.

PH-dependent changes of intrinsic fluorescence of chemically modified liver alcohol dehydrogenases.

Horse liver alcohol dehydrogenase specifically carboxymethylated on cysteine-46 (a ligand to the zinc in the active site) or acetimidylated on 25 of the 30 lysine residues per subunit (including residue 228) was studied. The tryptophan fluorescence of these enzymes decreased by 35% as pH was increased, with an apparent pKa of 9.8 +/- 0.2, identical with that of native enzyme. Native enzyme in the presence of 30mM-imidazole, which displaces a water molecule ligated to the zinc, also had a pKa of 9.8. The ionoizable group is thus neither the water molecule nor one of the modified groups. Binding of NAD+ shifted the pKa for the fluorescence transition to 7.6 with native enzyme and to 9.0 with acetimidylated enzyme, but did not shift the pKa of carboxymethylated enzyme. Binding of NAD+ and trifluoroethanol, an unreactive alcohol, gave maximal fluorescence quenching at pH7 with all three enzymes. The acetimidylated enzyme--NAD+--trifluoroethanol complex had an apparent pKa of 5.0, but the pK of the native enzyme complex was experimentally inaccessible. The results are interpreted in terms of coupled equilibria between two different conformational states. On binding of NAD+, the modified enzymes apparently change conformation less readily than does native enzyme, but binding of alcohol can drive the change to completion.

Crystallography of liver alcohol dehydrogenase complexed with substrates

Horse liver alcohol dehydrogenase was crystallized at pH 7 and 5 °C from an equilibrium mixture containing predominantly NAD + and p-bromobenzyl alcohol and lower concentrations of NADH and p-bromobenzaldehyde. It is assumed from the results of kinetic studies in solution that most of the enzyme was complexed with NAD + and p-bromobenzyl alcohol. A ternary complex with NAD + and trifluoroethanol (an unreactive alcohol) and complexes with NAD + or NADH and 2-methyl-2,4-pentanediol (the crystallization agent, which partially occupies the substrate-binding pocket) were also crystallized. All of these complexes formed triclinic crystals that were isomorphous with the enzyme-NADH-dimethylsulfoxide complex, which has been solved to a resolution of 4.5 Å. X-ray diffractometer data (at 4.5 Å) were used to compute electron density difference maps, which showed that both subunits of the dimeric enzyme bound p-bromobenzyl alcohol or trifluoroethanol in a substrate binding pocket that was close to the position occupied by dimethylsulfoxide. These complexes appeared to have the same protein and coenzyme structure as the complex with NADH and dimethylsulfoxide. Since the dimethylsulfoxide appeared to be ligated to the catalytic zinc atom, it was not possible to see a direct connection between the alcohols and the zinc ion in these difference maps. However, maps computed from the differences in amplitudes between the NAD +-alcohol complexes and NAD(H)-methylpentanediol complexes and the phases from the NADH-dimethylsulfoxide complex showed continuous electron density from the bromo or trifluoromethyl positions of the substrates to the zinc ion. Using the structure of the orthorhombic form of apoenzyme, which has been solved to a resolution of 2.4 Å, as a guide for interpreting the various maps, we constructed a provisional model of the active site. This model led us to conclude that the oxygen of either alcohol is directly ligated to the zinc ion (2 Å), while carbon 1 of the alcohol is 3.5 Å from carbon 4 of the nicotinamide ring. Studies at higher resolution are required to confirm these conclusions and to reveal further details.

Aminopyridines as acylation catalysts for tertiary alcohols

The acylation of unreactive alcohols with acid anhydrides is greatly facilitated by the addition of a catalytic (0.02–0.1 equivalent) amount of a 4-dialkylaminopyridine. The reaction is faster in nonpolar than in polar solvents and acetyl chloride is not as effective as acetic anhydride. Several pyridine, pyridazine, and quinoline derivatives have been examined as potential acylation catalysts. Of the systems examined, only a few of the 4-substituted pyridines were found to be acylation catalysts, the most effective being 4-pyrrolidinopyridine 4 and 1,1,3,3-tetramethyl-4-(4-pyridyl)guanidine 8 . The reaction of t-butanol with an isocyanate is also accelerated by the presence of 4 but not as much as in the case of acylations. The cause of the pronounced effect of these pyridine species in catalyzing acylation reactions seems to be a combination of the increased donor ability of the 4-substituent and the stabilizing effect that this substituent has on an acyl pyridinium intermediate.

The Compositions of the Reaction Products of Phosphorus Pentoxide with Alcohols

Three well separated peaks assigned to isolated orthophosphate and end, and middle phosphates groups in linear polyphosphoric acid were found in 31p NMR spectra of the reaction mixtures. Relative proportions of these structural building units as well as orthophosphate and unreacted alcohol as a function of the ROH/P4O10 mole ratio were determined. The results obtained were discussed.

Spin label synthesis using NN′-thionyldiimidazole coupling reagent

Spin-labelled esters of both cortisol and testosterone have been synthesized using the coupling reagent NN′-thionyldiimidazole (1); use of more conventional coupling or dehydrating reagents failed to give these spin labels, suggesting that (1) may be useful in the esterification of other hindered, relatively unreactive alcohols.

Hydrophobic interactions of some alcohols with acyl trypsins

The variation of the apparent reactivity of added nucleophiles competing with water in the deacylation of some acyltrypsins has been studied with different ester substrates: Lysine ethyl and methyl ester, arginine methyl ester and α-N- carbobenzoxy- l-lysine p- nitrophenyl ester. The efficacy of the primary aliphatic alcohols increases with the length of the apolar chain. For instance, the reactivity of heptanol toward lysyl trypsin is about 45 times greater than that of ethanol. These data cannot be explained merely in terms of the chemical reactivity of the alcohols. It is necessary to assume that water as well as the aliphatic primary alcohols used as nucleophiles interact with a corresponding site of the enzyme. The apparent reactivity of nucleophilic compounds is interpreted in terms of hydrophobic interactions between an apolar site of the acyl enzyme and the hydrocarbon chain of the alcohols. Results obtained with organic solvents such as dimethyl-formamide and isopropanol, an unreactive alcohol, are in good agreement with such an interpretation.

Resolution of endo-dicyclopentadiene and interaction of DL- asec-butyl alcahol with enantiomeric aendo-dicyclopentadiene in platinum and palladium chloride complexes

Resolution of endo-dicyclopentadine has been accomplished through fractional crystallization of choloro (3a,4,7,7a,tetrahydro-exo-6-methoxy-endo-4,7-methanoindene-endo-5σ,2π) (S-α-methylbenzylamine) platinum (II). and -palladium (II) complexes react with an excess of dl-sec-butyl alcohol to give the corresponding dicyclopentadiene sec-butoxy choloride complexes. The unreacted alcohol was recovered and was found to be optically active. This indicates the existance of asymmetric induction in the butoxylation reaction. In the most favorable run, the degree of stereoselectivity, calculated from experimental data, was about 18%.

Component distribution of alcohol ethylene oxide adducts

AbstractThe relative reaction constants for the base‐catalyzed ethoxylation of primary straight chain alcohols have been determined for the unreacted alcohol and the first three ethylene oxide adducts. The distribution of the ethoxylates was found using molecular distillation, nuclear magnetic resonance analysis and gas liquid partition chromatography.A mathematical model describing the distributions was set up and programmed on a 7090 digital computer. Solution of the program gave the relative reaction constants for the alcohol and the first three adducts.The relative reactivities of the adducts in the base‐catalyzed ethoxylation of primary straight chain alcohols are shown to increase with adduct number, but tend to a constant value as the adduct number increases. Results also show that alcohols from C6 to C18 are equally reactive to ethylene oxide on a molar basis.

Nitro compounds in diene additions, esterifications, and reductions of functional groups

1. The application of Diels-Alder reactions for the preparation of new substituted nitro-olefins and the identification of very reactive but unstable polynitro compounds by means of this reaction; 2. the demonstration that polyphosphoric acid is an excellent catalyst to produce esters of either sterically hindered alcohols or unreactive alcohols of acid character, and 3. the salts of borohydrides and aluminohydrides have provided an elegant breakthrough in selective reduction techniques for the production of polynitroalcohols and -glycols.

Catalytic hydrocondensation of carbon monoxide with olefins Part 9. Reaction of methanol and ethanol with ethylene

1. Similarly to carbon monoxide, methanol and ethanol promote the reaction of condensation of ethylene and hydrogen, and at the same time enter into the hydrocondensation with ethylene. 2. The total yield of condensate (not counting water and unreacted alcohol) amounts to 17–35 ml per liter of catalyst per hour. 3. The experimental results confirm the view that the process involves the preliminary decomposition of the alcohols, with production of carbon monoxide and hydrogen, which then, through the intermediate stage of formation of methylene radicals, enter unusual into the reaction of hydrocondensation with ethylene.