Analysis of alcohols

FIGURE 14 2 Aretrosyn thetic analysis of alcohol preparation by way of the addition of a Grignard reagent to an aldehyde or ketone... 

V. Analysis of Alcohol Sulfates and Alcohol Ether Sulfates 278... 

V. ANALYSIS OF ALCOHOL SULFATES AND ALCOHOL ETHER SULFATES... 

The analysis of alcohol sulfates has been known for many years. Alcohol ether sulfates are analyzed in a similar way but the presence of ethoxy groups makes the complete procedure longer and more complex. 

An analysis of alcohol and alcohol ether sulfates should determine the anionic active matter, the unsulfated matter, the inorganic sulfate content, the chloride content, and water. Other more precise analysis must determine the alkyl chain distribution of the alcohol and in the case of alcohol ether sulfates the number of ethoxy groups and its distribution, as well as other more specialized determinations, such as the content of 1,4-dioxane and other impurities. 

The complete analysis of alcohol sulfates is described in the Standard Methods of the International Organization of Standards (ISO) [200] and of the American Society for Testing and Materials (ASTM) [201]. These methods describe the analysis of inorganic sulfate content, chloride content, unsulfated matter, and water as well as other analytical values. Other ISO standards describe the analysis of sodium secondary alkyl sulfates [202], determination of pH [203], determination of water content [204,205], chlorides [206], total active matter in sul fated ethoxylated alcohols and alkylphenols [207], mean relative molecular mass in sulfated ethoxylated alcohols and alkylphenols [208], sulfate content... 

Capillary tube isotachophoresis using a potential gradient detector is another technique that has been applied to the analysis of alcohol sulfates, such as sodium and lithium alcohol sulfates [303]. The leading electrolyte solution is a mixture of methyl cyanate and aqueous histidine buffer containing calcium chloride. The terminating electrolyte solution is an aqueous solution of sodium octanoate. 

The ion spray liquid chromatography/mass spectrometry (LC-MS) interface coupled via a postsuppressor split with an ion chromatography (IC) has been used in the analysis of alcohol sulfates. The IC-MS readily produces the molecular weight while the tandem mass spectrometric detection IC-MS-MS provides structural information [305]. 

Murphy, R.E., Schure, M.R., Foley, J.P. (1998b). One and two-dimensional chromatographic analysis of alcohol ethoxylates. Anal. Chem. 70(20), 4353 1360. 

The analysis of alcohol reactivities in reactions with the peroxyl radicals will be discussed later. The values of the rate constants of chain propagation in oxidized alcohols are collected in Table 7.4. 

We observe the sufficiently higher activity of H02VH0R02 radicals in their reactions with alcohols than that of R OO. The next section will be devoted to detailed analysis of alcohol reactivity in reactions with peroxyl radicals. 

Consider the quantitative gas chromatography analysis of alcohol-blended gasoline for ethyl alcohol by the internal standard method, using isopropyl alcohol as the internal standard. The peaks for these two substances are well resolved from each other and from other components. Assume there... 

The combination of normal (silica) and reversed (C18) phase HPLC in a comprehensive 2D LC system was used for the first time for the analysis of alcohol ethoxylates [64] the NP separation was run using aqueous solvents, so the mobile phases used in the two dimensions were miscible, resulting in the easy injection of the entire first-dimension effluent onto the second-dimension column. 

Johnson, Elliot and Penning introduced this reagent, easily made from /-ephedrine, for 31P-NMR analysis of alcohols and amines40. The method for amines is simpler as the reaction with alcohols requires butyllithium. 

Note Analysis of alcohol is included here because it can be run simultaneously with acetone, using the same distillate... 

This approach can be illustrated by unsaturated polyesters based on an almost equimolar combination of maleate and phthalate of propylene glycol, crosslinked by styrene (45 wt%) (Mortaigne el al., 1992). Six samples differing by the prepolymer molar mass were analyzed. The chain-ends concentration, b, was determined by volumetric analysis of alcohols and acids in the initial reactive mixture. Then, the system was cured, elastic measurements were made in the rubbery state at Tg + 30° C, and the shear modulus G was plotted against chain-ends concentration (Fig. 14.7). The following relationship was obtained ... 

Thermoanalytical and single crystal X-ray diffraction analysis of alcohol-... 

In addition to TMS ethers, dimethylsilyl ethers [36] were studied for the analysis of alcohols and phenols. They were prepared by reaction with reagents analogous to those used for TMS ethers [dimethylmonochlorosilane and tetramethyldisilazane in pyridine (1 3 9)] and they provide shorter retention times in comparison with TMS ethers on Apiezon L. Grant [37] converted phenols into bromomethyldimethylsilyl ethers. In addition to a higher sensitivity, selective detection, permitting, e.g., phenolic substances to be determined in tars without any preliminary separation, was even achieved by using an ECD. 

Phthalic anhydride 225 has been used in the environmental analysis of alcohol ethoxylates, which are widely found surfactants. Samples are derivatized with phthalic anhydride converting the ethoxylates into phthalate half-esters. Under analysis by electrospray LCMS, the derivatized alcohols gave stronger signals with less background in the negative ion spectra <2005JCH39>. 

While a hydrophobic ion-pair is retained on hydrophobic stationary phases better than an ionized analyte, the retention of the duplex on normal phases is easily predicted to be lower than that of the ionized analyte because polar interactions are reduced. Actually the trend of k versus IPR concentration under normal phase IPC is the opposite of reversed phase IPC [34]. An aminopropyl, a cyanoethyl, and a silica stationary phase were compared for the analysis of alcohol denaturants. The cyanoethyl phase was selected and anionic IPRs were used to reduce retention of cationic analyte, suppressing their interactions with negatively charged silanols... 

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