Purification, general alcohols

Manufacture and Uses. Acetoacetic esters are generally made from diketene and the corresponding alcohol as a solvent ia the presence of a catalyst. In the case of Hquid alcohols, manufacturiag is carried out by continuous reaction ia a tubular reactor with carefully adjusted feeds of diketene, alcohol, and catalyst, or alcohol—catalyst blend followed by continuous purification (Fig. 3). For soHd alcohols, an iaert solvent is used. Catalysts used iaclude strong acids, tertiary amines, salts such as sodium acetate [127-09-3], organophosphoms compounds, and organometaHic compounds (5). 

Modem commercial wet-acid purification processes (see Fig. 4) are based on solvents such as C to Cg alcohols, ethers, ketones, amines, and phosphate esters (10—12). Organic-phase extraction of phosphoric acid is accompHshed in one or more extraction columns or, less frequently, in a series of countercurrent mixer—settlers. Generally, 60—75% of the feed acid P2 s content is extracted into the organic phase as H PO. The residual phosphoric acid phase (raffinate), containing 25—40% of the original P2O5 value, is typically used for fertilizer manufacture such as triple superphosphate. For this reason, wet-acid purification units are almost always located within or next to fertilizer complexes. 

The following are some of the typical industrial applications for liquid-phase carbon adsorption. Generally liquid-phase carbon adsorbents are used to decolorize or purify liquids, solutions, and liquefiable materials such as waxes. Specific industrial applications include the decolorization of sugar syrups the removal of sulfurous, phenolic, and hydrocarbon contaminants from wastewater the purification of various aqueous solutions of acids, alkalies, amines, glycols, salts, gelatin, vinegar, fruit juices, pectin, glycerol, and alcoholic spirits dechlorination the removal of... 

Alethylated spirit, or spirits of wine 60—70 over-proof, may generally replace the more costly absolute alcohol as a solvent after undergoing a process of purification. The methylated spirit must be of the old kind, co-nsisting of a mixture of 9 parts spirit of wine and i part purified wood-spirit, without the... 

N -Ethyl-jK-toluidine has been obtained by passing m-toluidine and ethyl alcohol over a catalyst at high temperatures,1 and by the use of ethyl />-toluenesulfonate 2 as an alkylating agent. The present method of purification is a modification of a general procedure for secondary amines developed by Diepolder.3... 

Simple substances, and in particular those which are also readily volatile, such as hydrocarbons, alcohols, esters, the lower acids and amines, are distilled under atmospheric pressure. All substances which decompose easily, and those which have especially high boiling points, are distilled under reduced pressure. In general solid substances should only be distilled when purification by crystallisation has been unsuccessful on account of too great solubility or for other reasons. Naturally in each case the possibility of distillation (without decomposition) must be established in advance. 

The procedure described below is quite general and uses finely, freshly machine--powdered KOH, which is added to a solution of the primary or secondary (acetylenic) alcohol and a 10-15% molar excess of tosyl chloride in Et20, kept around 0 C The excess of tosyl chloride is destroyed during the reaction of the excess of KOH. Side- and subsequent reactions ("saponification of the ester by KOH and 1,2-elimination of p-toluenesulfonic acid from thtfester) can be suppressed by keeping the temperature of the reaction mixture below 5 C. This procedure can be carried out within 2 h and generally gives excellent (often almost quantitative) yields of the tosylates. Purification of acetylenic tosylates by distillation, which is risky because of the limited thermal stability of the esters, is not necessary because the... 

Tandem reaction generally attracts much interest because it allows us to effect multiple transformations, all in one pot. Two types are known at present. The most popular approach is a combination of several reactions with PKR. Properly functionalized 1,6- or 1,7-enynes are readily obtained from the propargyl alcohol-dicobalt hexacarbonyl complexes and a properly nucleophilic allylic moiety in the presence of a Lewis acid. The resultant enynes are subjected to the promoter-assisted PKR without purification to afford the desired PKR products (Scheme 9).82,82a-82e... 

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