Alcohol standards

Alcohol Standards. The alcohols chiefly used are the acetylene derivates 1-butanol, 2-ethylbutanol, 1-hexanol, 2-ethylhexanol, and isononyl alcohol produced from octene by the oxo synthesis. 

FID. Retention times for isobutyl alcohol (standard) 667 s and for isovaleraldehyde 869 s. 

Sodium perchlorate is hygroscopic and is readily soluble in water and alcohol. Standard product contains 1 mole of crystal water. 

Iron (MA-F-AS322-05-FER). Reference method it is quantified by AAS in the diluted and dealcoholized wine at 248.3 nm. Iron (970.19). Method I a diluted solution of wine is analyzed by AAS at 248.3 nm and the concentration is quantified in comparison with alcoholized standards. 

Note that the viscosities and non-volatile contents of the systems should be equal. The viscosities of several pigmented systems studied are essentially equal, but the 2-NP systems dry faster than the 100% alcohol standard. If the systems wetted the substrate equally, the 2-NP systems would flow less because of their faster dry. However, the 2-NP systems flowed further than the standard system. Thus the 2-NP polyamide system wets the substrate better than the standard polyamide system and exhibits better flow even though the dry is faster. 

The blood alcohol content of an individual is determined enzymatically by reacting ethanol with NAD" in the presence of the enzyme alcohol dehydrogenase to produce NADH (Table 22.1). The rate of formation of NADH is measured at 340 nm (Figure 22.4). The following absorbances are recorded for a 0.100% (wt/vol) alcohol standard and the unknown, treated in the same way. Use a spreadsheet to calculate the rates of absorbance changes and from these, the unknown concentration. 

If the titration is done with indicators, it is preferable to titrate to phenolphthalein first, then add bromophenol blue and titrate to the low-pH end-point with alcoholic standard acid. The first titration measures both acids, and the second the fatty acid alone. This procedure makes the phenolphthalein end-point easier to see. 

In these procedures, the hydroxyl-containing polymer is reacted with an excess of a standard non-aqueous solution of acetic anhydride or phthalic anhydride, sometimes in the presence of a catalyst such as p-toluene sulfonic acid. After ester formation is complete, an excess of water is added to convert excess anhydride to the free carboxylic acid. The acid is titrated with aqueous or alcoholic standard potassium hydroxide to the phenol phthalein end-point to determine unconsumed acid. A blank run is carried out in which the sample is omitted. The hydroxyl... 

M hydrochloric acid/alcohol, standardized, dissolve 4.2 ml concentrated hydrochloric acid in 1 cm absolute ethanol. 

In the standard method, the metal enclosure (called the air chamber) used to hold the hydrocarbon vapors is immersed in water before the test, then drained but not dried. This mode of operation, often designated as the wet bomb" is stipulated for all materials that are exclusively petroleum. But if the fuels contain alcohols or other organic products soluble in water, the apparatus must be dried in order that the vapors are not absorbed by the water on the walls. This technique is called the dry bomb" it results in RVP values higher by about 100 mbar for some oxygenated motor fuels. When examining the numerical results, it is thus important to know the technique employed. In any case, the dry bomb method is preferred. 

The excess of unchanged acetic anhydride is then hydrolysed by the addition of water, and the total free acetic acid estimated by titration with standard NaOH solution. Simultaneously a control experiment is performed identical with the above except that the alcohol is omitted. The difference in the volumes of NaOH solution required in the two experiments is equivalent to the difference in the amount of acetic add formed, i.e., to the acetic acid used in the actual acetylation. If the molecular weight of the alcohol is known, the number of hydroxyl groups can then be calculated. 

It is essential to standardise the alcoholic potassium hydroxide solution immediately before use by titration with standard 0-5N or 0-25N hydrochloric or sulphuric acid using phenolphthalein as indicator. 

These are crystalline compounds with sharp melting points, and possess the further advantage that their equivalent weights may be determined by dissolving in dilute alcohol and titrating with standard alkali. Nitro-phenols, however, give unsatisfactory derivatives. 

The procedure is to pass purified hydrogen through a hot solution of the pure acid chloride in toluene or xylene in the presence of the catalyst the exit gases are bubbled through water to absorb the hydrogen chloride, and the solution is titrated with standard alkali from time to time so that the reduction may be stopped when the theoretical quantity of hydrogen chloride has been evolved. Further reduction would lead to the corresponding alcohol and hydrocarbon ... 

The standard redox potentials of inorganic oxidants used in organic synthesis are generally around or above + 1.0 V. Organic substrates do not have such high potentials. The values for the CH4/CH3OH and CjHj/CjHjOH couples are at +0,59 V and 0.52 V, respectively. The oxidation of alcohols and aldehydes corresponds to values around 0.0 V (W.M. 

It IS often necessary to prepare ketones by processes involving carbon-carbon bond formation In such cases the standard method combines addition of a Gngnard reagent to an aldehyde with oxidation of the resulting secondary alcohol... 

Acyl transfer from an acid an hydride to an alcohol is a standard method for the prep aration of esters The reaction IS subject to catalysis by either acids (H2SO4) or bases (pyri dine)... 

The concentration of chromic acid can be determined from its reduction by alcohols under conditions when the kinetics are pseudo-first-order in analyte. One approach is to monitor the absorbance of the solution at a wavelength of 355 nm. A standard solution of 5.1 X lO " M chromic acid yields absorbances of 0.855 and 0.709 at, 100 s and 300 s, respectively, after the reaction s initiation. When a sample with an unknown amount of chromic acid is analyzed under... 

Filters for use in sterile gas filtration must conform to standards similar to those mandated for sterile hquid filtration. Nondestmctive integrity tests may be apphed. The tests are performed by wetting the filter with an appropriate solvent, commonly 60/40 isopropyl alcohol/water for hydrophobic membranes, and applying air or nitrogen gas at a preset pressure. 

Port-type ted dessert wines require skin contact time to extract the anthocyanins, but the fermentation must be short to retain the sugar level neat the 6—10% level desired. The winemaker cannot always achieve desired composition in individual lots. In order to teach the desired standard, it is necessary to make new lots to enable blending to that standard. The right volume of a tedder, less sweet wine will need to be made to bring to standard a lot with low color and mote sugar, for example, while keeping the alcohol also within the desired limits. 

Chlorine and bromine add vigorously, giving, with proper control, high yields of 1,2-dihaloethyl ethers (224). In the presence of an alcohol, halogens add as hypohaUtes, which give 2-haloacetals (225,226). With methanol and iodine this is used as a method of quantitative analysis, titrating unconsumed iodine with standard thiosulfate solution (227). 

The benefits of alcohol fuels include increased energy diversification in the transportation sector, accompanied by some energy security and balance of payments benefits, and potential air quaUty improvements as a result of the reduced emissions of photochemically reactive products (see Air POLLUTION). The Clean Air Act of 1990 and emission standards set out by the State of California may serve to encourage the substantial use of alcohol fuels, unless gasoline and diesel technologies can be developed that offer comparable advantages. 

In 1973 the Semiconductor Equipment and Materials Institute (SEMI) held its first standards meeting. SEMI standards are voluntary consensus specifications developed by the producers, users, and general interest groups in the semiconductor (qv) industry. Examples of electronic chemicals are glacial acetic acid [64-19-7] acetone [67-64-17, ammonium fluoride [12125-01 -8] and ammonium hydroxide [1336-21 -6] (see Ammonium compounds), dichloromethane [75-09-2] (see Cm.OROCARBONSANDcm.OROHYDROCARBONs), hydrofluoric acid [7664-39-3] (see Eluorine compounds, inorganic), 30% hydrogen peroxide (qv) [7722-84-1] methanol (qv) [67-56-1] nitric acid (qv) [7697-37-2] 2-propanoI [67-63-0] (see Propyl alcohols), sulfuric acid [7664-93-9] tetrachloroethane [127-18-4] toluene (qv) [108-88-3] and xylenes (qv) (see also Electronic materials). 

Another group of natural flavoring ingredients comprises those obtained by extraction from certain plant products such as vanilla beans, Hcotice root, St. John s bread, orange and lemon peel, coffee, tea, kola nuts, catechu, cherry, elm bark, cocoa nibs, and gentian root. These products are used in the form of alcohohc infusions or tinctures, as concentrations in alcohol, or alcohol—water extractions termed fluid or soHd extracts. Official methods for their preparation and specifications for all products used in pharmaceuticals are described (54,55). There are many flavor extracts for food use for which no official standards exist the properties of these are solely based on suitabiUty for commercial appHcations (56). 

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