Péter Sallay

Determination of molar mass distribution of alkyl polyethylene glycol ethers

A process based on gas chromatographic separation and on the computerized evaluation of the results has been developed for the determination of the distribution and distribution coefficients of alkyl polyglycol ethers, formed in the competitive, consecutive reaction of fatty alcohol and ethylene oxide. A comparison of experimental and theoretical distributions showed that the distribution is the Weibull-Nycander-Gold type for potassium hydroxide catalyst, and the Flory type in the antimony pentachloride catalyst. The characteristic of the distribution does not change with reaction parameters in either type of distribution, though actual distribution is slightly modified by temperature. In determinations of Weibull-Nycander-Golds c and Natta-Manticas ci-s distribution coefficients, the Weibull-Törnquist effect, i.e., the changing of the distribution coefficients with ethoxylation, has been experimentally proven in the example of ethoxylation catalyzed with potassium hydroxide.

A novel way for ethoxylation with basic catalysts

Ethoxylation of dodecyl alcohol catalyzed by alkali hydroxides are accelerated by adding complexing agents for the alkali ions. The rate of ethoxylation could be increased by crown ether and dodecyl alcohols of a higher degree of ethoxylation. The effect is more pronounced with the crown ether; thus, reactions not taking place under other circumstances could also be carried out. The complexing additives have no significant effect on the molar mass distribution, The reaction could also be accelerated by using more bulky organic cations (e.g., triethylbenzylammonium ion) instead of the alkali cation.

Nitrogen containing compounds

Bridge-head nitrogen-containing compounds, (1,4-diaza-bicyclo-[2.2.2]-octane, 1-azabicyclo-[2.2.2]-octane, 1,5-diaza-bicyclo-[5.4.0]-undec-5-ene and l-azabicyclo-[2.2.2]-octane-3-one), successfully catalyze the ethoxylation of dodecyl alcohol. The catalytic activity of any of the first two compounds was four to five times higher than that of an open-chain, symmetrical trialkylamine of similar basicity. The molar mass distribution of the ethoxylated dodecyl alcohol derivatives was of the Weibull-Nycander-Gold type. No Weibull-Törnquist effect could be detected, however, unlike the case realized in ethoxylated systems gained in the presence of trialkylamines. No change in the distribution constant (calculated according to Natta and Mantica) could be observed in the course of these ethoxylation reactions.

Removal of dyes from industrial wastewater by cucurbiturils

Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[6]) and cucurbit[8]uril (CU[8]) have been isolated by means of solvent extraction. Inclusion complexes of different acid, reactive and disperse dyes have been produced by them. CU[8] was decidedly more efficient in complex formation with all the studied dyes than CU[6]. Competitive complex formation between randomly methylated ß-cyclodextrin and the respective cucurbiturils with disperse dyes has been studied and superiority of CU[8] could be demonstrated. The complex forming efficiency of the cucurbiturils with acid and reactive dyes was markedly increased in the presence of Ca, Mg, K and Na ions, respectively, in water solution.

A Novel Way for Hydroxyethylation by Using Clay Catalysts

Abstract Hydroxyethylation of aralkyl alcohols (benzyl alcohol, 2-phenylethanol, 3-phenylpropanol) in the presence of a clay catalyst (K10) was successful. This method has some advantages in contrast with the conventional ones: effective, works at mild reaction conditions, easy the separation of catalyst from the reaction mixture.

Catalytic effect of amines on the ethoxylation of dodecyl alcohol

The catalytic activity of several tertiary amines on the ethoxylation of dodecyl alcohol has been investigated. It has been established that the rate of the reaction is proportional to the concentration of the catalyst over the range of 10–25% and that the reaction rate has an extremum at 80 C.The catalytic effect of trialkyl amines increases if two of the alkyl groups are methyl. The product distribution is that of the Weibull-Nycander-Gold type and is independent of the concentration of the catalyst and reaction temperature. Distribution constants calculated according to Natta-Mantica vary with the average degree of ethoxylation, i.e., the Weibull-Törnquist effect is observed. This can be explained if an interaction is assumed between the polyethylene glycol chain formed and the quaternary ammonium ion formed in the first step of ethoxylation.

Applicability of Weimer-Cooper’s distribution model for ethoxylated products

The Natta-Mantica distribution constants characterizing the molecular mass distribution of ethoxylated product mixtures, discussed in an earlier paper, cannot be considered real constants because their values depend on the average degree of ethoxylation (Weibull-Törnquist effect). As the average degree of ethoxylation is included in the starting equation of the Weimer-Cooper’s model, it was applied in an attempt to characterize the molecular mass distribution of an ethoxylated fatty alcohol. However, only a qualitative approximation of the distribution was possible with the Weimer-Cooper’s constants. Consequently, the constants had to be calculated separately from measured mass distribution data. It was demonstrated that the two models predict the same constants when they are in modified form.