Isopropyl alcohol, as solvent

As discussed before, a,P-unsaturated ketones are usually reduced to saturated ketones in isopropyl alcohol as solvent, the reaction proceeding via the enol after H-abstraction by the carbonyl group. When some selected a,p-enones are irradiated in their n-n absorption band (i.e. excitation... 

Manchalk reaction. Some years ago Marschalk et al. found that leucoquinizarin (1), prepared in situ by reduction of quinizarin with alkaline dithionite, reacts with aldehydes to form 2-alkylquinizarins (2). It is not possible to obtain 2,3-disubstituted quinizarins in this way. Lewis found that pyridinium acetate with isopropyl alcohol as solvent is superior to a base or an acid catalyst for this reaction yields as high as 90% of 2 can be obtained. In addition, aromatic aldehydes can be used successfully. The leuco forms of 2 can be alkylated in this way to give 2,3-dialkylquinizarins in 40-70% yields. 

In eqn [13], pK corresponds to the titrant. The most common titrant solution for the titration of acids in non-aqueous solvents is tetrabutylammonium hydroxide, and stable commercial solutions use methyl or isopropyl alcohol as solvents. The addition of isopropyl alcohol to 7-butyl alcohol can be neglected because their relative permittivity values are not very different. Methanol addition causes larger variations in pKg, values. Thus, the use of titrants without or with low contents of methanol is strongly recommended. For application of eqn [13], pKt values of tetrabutylammonium hydroxide are 2.58 in isopropyl alcohol and 4.91 in 7-butyl alcohol. 

Comparisons between hexane and isopropyl alcohol as solvents for rice bran oil extraction have been undertaken by several investigators (Proctor and Bowen, 1996 Hu et at, 1996). In general, isopropyl alcohol compares favorably with hexane with regard to oil yield and quality. Hu et al. (1996) reported that a 3 1 solvent bran ratio and a 60°C extraction temperature were optimal regardless of the solvent used. Preheating the solvent prior to extraction significantly enhanced oil, tocol and oryzanol yields. An increase in temperature from dO C to hO C resulted in 4% and 6% increases in crude oil yield for hexane and isopropyl alcohol, respectively similar trends were found for... 

Little quantitative information is available on the acidities of the amides although they are known to be strong acids compared to the amines. The data of Hine and Hine (184) on the strengths of some weak acids in isopropyl alcohol as solvent shows a fairly good correlation of the pK s of several amides as acids with the strengths of their conjugate acids in aqueous media. This will be considered in greater detail in a later section. 

N-ethyl-3-chloropiperidine was prepared according to the method of Fuson and Zirkle described in Volume 70, J. Am. them. Soc., p 2760. 12.0 g (0.0B1 mol) of N-ethyl-3-chloropiperidine was mixed with 1B.6 g (0.0B1 mol) of benzilic acid and 80 cc of anhydrous isopropyl alcohol as a solvent. The mixture was refluxed for 72 hours. The solution was then filtered and concentrated at 30 mm of mercury. The concentrate was dissolved in water, acidified with hydrochloric acid and extracted with ether to remove the unreacted benzilic acid. 

Alcoholic KOH. We have reported on the use of isopropyl alcohol as an H-donor solvent in coal conversion, and specifically on the effects of the addition of strong bases such as KOH to the system (la). We found that i-PrOH brought about a conversion of Illinois No. 6 coal very similar to the conversion level obtained by Tetralin under the same conditions. These results are listed in Table IV in text, along with the results of more recent experiments using methanol as the solvent and adding KOH to the system (lb). 

Prepare 0.01 M solutions of leucine, methionine, valine, and lysine using a solvent that is 70% isopropyl alcohol and 30% water. Liquid food samples, such as fruit juice samples, can be used directly. Solid food samples must be soluble in the isopropyl alcohol-water solvent. Prepare solutions of solid samples as concentrated as possible. 

For the purpose of this case study we will select Isopropyl alcohol as the crystallization solvent and assume that the NRTL-SAC solubility curve for Form A has been confirmed as reasonably accurate in the laboratory. If experimental solubility data is measured in IPA then it can be fitted to a more accurate (but non predictive) thermodynamic model such as NRTL or UNIQUAC at this point, taking care with analysis of the solid phase in equilibrium. As the activity coefficient model only relates to species in the liquid phase we can use the same model with each different set of AHm and Tm data to calculate the solubility of the other polymorphs of Cimetidine, as shown in Figure 21. True polymorphs only differ from each other in the solid phase and are otherwise chemically identical. 

P(RNCH2CH2)3N (R = Me, i-Pr), alcohol as solvent, 4-24h, 81-100% yield. Acetates are formed from an alcohol, vinyl acetate, or isopropenyl acetate, and this catalyst in excellent yield. The isopropyl derivative results in less racemi-zation of amino acid esters than does the methyl derivative. ... 

Window cleaners constitute a specialty within the solvent cleaner category. Because any residue left on glass after drying leads to streaking or an otherwise undesirable appearance, these products are highly dilute aqueous solutions containing extremely low surfactant levels — most often nonionic surfactants — and a combination of glycol ethers and isopropyl alcohol as the solvent system. 

DNAPL extraction without vertical displacement of the contaminant can also be achieved by adjusting the density of the microemulsion which is formed in the subsurface to the density of water by the addition of organic components with densities of considerably less than 1 g/cm3. Co-solvents, co-surfactants and some non-ionic surfactants can be considered for this purpose. Whereas the addition of isopropyl alcohol as co-solvent to the surfactant was successful [48, 62, 73], an attempt with pentanol as co-surfactant was not successful, because partitioning of the co-surfactant into perchloroethylene was... 

The synthesis of many important organic compounds begins with isopropyl alcohol as a raw material. Among these compounds are acetone, glycerol, and isopropyl acetate, itself widely used as a solvent for organic substances. Among the other uses to which isopropyl alcohol is put are ... 

A second type of very useful behavior occurs in aprotic (or sometimes inert ) solvents, which usually exhibit very weak acid properties. Examples are dimethylformamide, dimethylsulfoxide, dioxane, ether, various nitriles, methyl isobutyl ketone, hydrocarbons, carbon tetrachloride. These solvents often permit differentiation (or stepwise titration) of a series of acidic or basic species which, in water, either titrate together or not at all. For example, perchloric, hydrochloric, salicylic, and acetic acids and phenol can be titrated stepwise in methyl isobutyl ketone solvent to obtain discernible endpoints for each compound, using tetrabutyl ammonium hydroxide in isopropyl alcohol as titrant. 

Titanium tetrachloride (TiCL,) Water as diluting, Hydrochloric acid as catalyst. Isopropyl alcohol as co-solvent Without calcination, 83, 15 10 190 Brookite Nanoparticles [157]... 

Resolubilization of the column-deposited immiscible liquid phases is time-consuming but can typically be accomplished through the use of a universal solvent (e.g., acetone or isopropyl alcohol). As discussed above, redissolving solid precipitates is at best difficult, and typically not possible, especially if ttie precipitate has formed in the pores of the support material or inlet frit. 

PROBLEM 16.47 Starting from isopropyl alcohol as your primary source of carbon, incidental organic reagents such as bases and solvents, as well as inorganic reagents of your choice (including labeled materials as needed), devise syntheses of the following labeled compounds. It is not necessary to write mechanisms. 

Reaction time and temperature depend on the nature of the alcohol. Primary and secondary alcohols are acylated in ether or benzene in the presence of pyridine after 2 hr standing. Tertiary alcohols react much more slowly, and therefore require higher reaction temperatures. They also incline to the formation of by-products (olefins, tertiary chlorides these are formed especially in the absence of acceptors—pyridine, for example). It is advantageous to use isopropyl ether as solvent for the preparation of tertiary 3,5-dinitrobenzoates of alcohols, and to add pyridine to the reaction mixture. 

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