Vapor pressure of selected aliphatic alcohols by ebulliometry. Part 1

Vapor pressures for liquid 2,2-dimethyl-1-propanol (CAS Registry Number 75-84-3), 1-hexanol (CAS Registry Number 111-27-3), 1-heptanol (CAS Registry Number 111-70-6), 1-octanol (CAS Registry Number 111-87-5) and 1-tetradecanol (CAS Registry Number 112-72-1) were measured by the precision comparative ebulliometry over an approximate pressure range from 8 to 100 kPa. The relative uncertainty in pressure is estimated to be less than or equal to 0.05% of the measured value and the absolute uncertainty in temperature is estimated at less than or equal to 0.01 K on ITS-90. The results are represented by the Antoine equation and compared with available literature data. A new transformation of vapor pressure data, which facilitates the detection of systematic errors, is presented.     

Kinetics and mechanism of oxidation of aliphatic alcohols by tetrabutylammonium tribromide

Oxidation of nine primary aliphatic alcohols by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of the corresponding aldehydes. The reaction is first order with respect to TBATB. Michaelis-Menten type kinetics is observed with respect to alcohols. The reaction failed to induce the polymerization of acrylonitrile. Tetrabutylammonium chloride has no effect on the reaction rate. The proposed reactive oxidizing species is the tribromide ion. The oxidation of [1,1-²H₂]ethanol exhibits a substantial kinetic isotope effect. The effect of solvent composition indicates that the rate increases with increase in the polarity of the solvent. The reaction is susceptible to both polar and steric effects of substituents. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.     

Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic alkanediamines H₂N–(CH₂)_n–NH₂ with n = (3 to 12) have been determined using the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the alkanediamines with the number n and with the Kovat’s indices has been found, proving the internal consistency of the measured data.     

New strategy for production of primary alcohols from aliphatic olefins by tandem cross-metathesis/hydrogenation

Primary alcohols are widely used in industry as solvents and precursors of detergents.The classic methods for hydration of terminal alkenes always produce the Markovnikov products.Herein,we reported a reliable approach to produce primary alcohols from terminal alkenes combining with biomass-derived allyl alcohol by tandem cross-metathesis/hydrogenation.A series of primary alcohol with different chain lengths was successfully produced in high yields(ca.90%).Computational studies revealed that self-metathesis and hydrogenation of substrates are accessible but much slower than crossmetathesis.This new methodology represents a unique alternative to primary alcohols from terminal alkenes.     

柱前荧光衍生脂肪醇的高效液相色谱分离及质谱鉴定

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙酸（BCAA）作为柱前衍生化试剂,以乙腈为溶剂,1-乙基-3-（3-二甲氨基丙基）环己碳二亚胺（EDAC）作为缩合剂,4-二甲氨基吡啶（DMAP）为催化剂,55℃下衍生反应25 min后获得稳定的荧光产物。在Eclipse XDB-C8色谱柱上,通过梯度洗脱对12种游离脂肪醇进行了分离和在线质谱定性。激发和发射波长分别为λex=333 nm,λem=390nm。采用大气压化学电离源（APCI）正离子模式,对洗发水（含十二烷基硫酸钠）中游离脂肪醇进行定性及测定。脂肪醇的线性回归相关系数大于0.9997,检出限在9.40-25.32 fmol。     

Inclusion of aliphatic alcohols in pockets of (S)-threonyl-(S)-phenylglycine using grinding method

Inclusion compounds of a dipeptide, (S)-threonyl-(S)-phenylglycine (Thr-Phg), with several aliphatic alcohols were easily prepared by grinding them in a mortar. Thr-Phg molecules arranged in antiparallel to construct a sheet, and guest alcohols were accommodated in a chiral pocket between the sheets. 3-Butyn-2-ol and 2-butanol were included with moderate enantioselectivity, 57% ee (R) and 49% ee (R), respectively. The role of the hydroxy group of Thr-Phg is not only to construct the unique pocket but also to capture guest alcohols by hydrogen bonding.     

Vapor pressure data for non-aqueous electrolyte solutions. Part 5. Tetraalkylammonium salts in acetonitrile

Precise vapor pressure data for solutions of Et₄NBr (concentration range of 0.04–1]<0.4), Pr₄NBr (0.044NBr (0.024NCl (0.044NI (0.054NBr (0.06相似文献   

A sol‐gel based solid phase microextraction fiber for the analysis of aliphatic alcohols in apple juices

A new fiber based on titania‐chitin sol‐gel coated on a silver wire for the headspace solid phase microextraction of aliphatic alcohols from apple juice samples was developed. The influences of fiber coating composition and microextraction conditions (extraction temperature, extraction time, and ionic strength of the sample matrix) on the fiber performance were investigated. Also, the influence of temperature and time on desorption of analytes from fiber were studied. Under the optimized conditions, a porous fiber with a high extraction capacity and good thermal stability (up to 250°C) was obtained. The proposed headspace solid‐phase microextraction‐GC method was successfully used for the analysis of aliphatic alcohols in apple juice and concentrate samples. The recovery values were from 92.8 to 98.6%. The RSD (n=5) for all analytes were below 7.8%.     

Vapor pressure measurements on nonaqueous solutions. Part IV. HNC calculations using Friedman's cosphere overlap model

Vapor pressure data for solutions of various alkali metal and tetraalkylammonium salts in methanol at 25° and NaI solutions in ethanol, 2-propanol, and acetonitrile at 25° in the concentration range 0.04–1]<0.75 are used to show the applicability of the HNC integral equation method to nonaqueous electrolyte solutions. Friedman's model of overlapping cospheres is used to express the non-electrostatic part of the ion-interaction potential. Data analysis is based on the Rasaiah-Friedman algorithm for the calculation of g₊₊ and g_+– functions. After conversion from Lewis-Randall to the McMillan-Mayer system the measured osmotic coefficients of all electrolyte solutions can be reproduced with the help of the calculated correlation functions.     

Vapor pressure of dimethyl sulfoxide and water binary system

The total vapor pressures of dimethyl sulfoxide (DMSO) and water mixtures have been measured at 15, 20, 25 and 30°C. The activity coefficients and molar excess Gibbs energies of the system have been calculated. Possible association interaction in the system are discussed.     

Vapor pressure measurements on non-aqueous electrolyte solutions. Part 2. Tetraalkylammonium salts in methanol. Activity coefficients of various 1-1 electrolytes at high concentrations

Precise vapor pressure data for solutions of Et₄NBr, Bu₄NBr, Bu₄Nl, Bu₄NClO₄, and Am₄NBr in methanol at 25°C in the concentration range 0.04–1]<1.6 are communicated and discussed. Polynomials in molalities are given which may be used for calculating precise vapor pressure depressions of these solutions. Osmotic coefficients are calculated by taking into account the second virial coefficient of methanol vapor. Discussion of the data at low concentrations is based on the chemical model of electrolyte solutions taking into account non-coulombic interactions; ion-pair association constants are compared to those of conductance measurements. Pitzer equations are used to reproduce osmotic and activity coefficients at high concentrations; the set of Pitzer parameters b=3.2, ₁ = 2.0, and ₂ = 20.0 is proposed for methanol solutions.     

Sorption of aliphatic alcohols from aqueous solutions by starch cryotextures

Capillary GLC was applied to study the sorption ofn-butanol,n-hexanol,n-octanol, and linalood from aqueous solutions by com starch cryotextures. The concentrations of alcohols in aqueous solutions were varied from 0.5 to 15 mmol L⁻¹. The sorption of alcohols by crytotextures formed of sols containing these alcohols and the coefficients of their. distribution depend on the initial concentration and structure of the alcohols.n-Butanol is not sorbed by the corn starch cryotextures over the range of 0.5–80 mmol L⁻¹. The sorption of other alcohols increases with increasing length of the alkyl substituent and the concentration of the alcohol. The highest sorption capacity of the cryotexture (88%) was observed forn-octanol. The sorption of linalool decreases due to the double bonds and branching in its molecules. Translated fromIzestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 734–737, April, 1999.     

OH reactions with aliphatic alcohols: evaluation of kinetics by direct optical absorption measurement. A pulse radiolysis study

The kinetics of the reactions of hydroxyl radicals with aliphatic alcohols in aqueous solution were studied using pulse radiolysis. Based on the optical absorption observed in the UV region, the rate constants for the reaction of hydroxyl radicals with methanol, ethanol, 2-propanol and tert-butyl alcohol were determined to be 9.0×10⁸, 2.2×10⁹, 2.0×10⁹ and 6.2×10⁸ dm³ mol⁻¹ s⁻¹, respectively. The values obtained here by direct observation of the alcohol radicals basically confirm the values which were earlier determined indirectly by competition.     

Multi-walled carbon nanotubes as the gas chromatographic stationary phase: role of their functionalization in the analysis of aliphatic alcohols and esters

Presented hereafter is the novel application of differently functionalized multi-walled carbon nanotubes (f-MWCNTs) as stationary phases for the GC separation of C(1)-C(5) alcohols and esters. Low-cost packed columns, easily prepared in laboratory, were used with satisfactory results. Depending on the functional groups introduced on the pristine MWCNTs, remarkably different behaviours have been observed, thus indicating that derivatization is a key factor to achieve optimal resolution. The best performance was shown by the 2,2'-(ethylenedioxy)diethylamine derivatized MWCNTs, allowing the separation of alcohol isomers, for this reason chosen for the investigation of fermentation by-products in distilled spirits. The degree of derivatization has been assessed for each packing material by thermogravimetric analysis (TGA). A computational study has been performed to correlate the physico-chemical properties of alcohol probes with the retention behaviour.     

Investigation on properties of aqueous foams stabilized by aliphatic alcohols and polypropylene glycol

Foams stabilized by nonionic surfactants are usually moderately stable due to high drainage rate and intense bubble coalescence and coarsening. This study aimed to investigate comparatively the foam properties of aliphatic alcohols (methyl isobutyl carbinol (MIBC) and 2-octanol) and polypropylene glycol (PPG400). Experiments were conducted using the FoamScan method at various surfactant concentrations and gas flow rates where the foam volume, liquid content of foam and foam half-life were determined. The results showed that both foamability and foam stability of surfactant solution increased with increasing gas flow rate and surfactant concentration for all tested surfactants. PPG400 was an unusually strong surfactant having the largest surface activity compared with MIBC and 2-octanol, which exhibited the maximum foaming performance and foam stability at all tested gas flow rates and concentrations. The present study suggested that foam properties depended primarily on the type of surfactant and its concentration and secondarily on the gas flow rate. In addition, properties of interface are closely related to that of foam, which is a significant point if one wants to produce foams for specific applications.     

Pd-catalyzed nucleophilic allylic alkylation of aliphatic aldehydes by the use of allyl alcohols

Under catalysis of Pd(OAc)₂-(P-n-Bu)₃, Et₂Zn promotes a variety of allyl alcohols to undergo nucleophilic allylation of aliphatic aldehydes and ketones at room temperature and provides homoallyl alcohols in 60-90 and ca. 60% isolated yield, respectively. The reaction is irreversible and kinetically controlled, and unique regio- and stereoselectivities observed for the allylation with unsymmetrically substituted allyl alcohols are discussed.     

Vapor pressures of non-aqueous electrolyte solutions. Part 1. Alkali metal salts in methanol

Precise vapor pressure data for solutions of NaCl, NaBr, NaI, NaClO₄, KBr, KI, RbI, and CsI in methanol at 25°C in the concentration range 0.02m (mol-kg^–1)0.7 are communicated and discussed. Measurements were carried out by procedures and equipment known to produce data of high precision. Polynomials of fourth degree in molalities are given for the vapor pressure of methanol solutions which can be used for calculating precise reference values as needed in indirect methods. Osmotic coefficients were calculated by taking into account the second virial coefficient of methanol vapor. Discussion of the data is based on the chemical model of electrolyte solutions taking into account short range interactions. Ion-pair association constants are compared to those of conductance measurements.