Alcohol purification

Scheme 5.2 PEG-sup-ported boranes for j8-amino alcohol purification.

This work also suggests other research and development directions needed to bring the price of ethanol down to an automotive fuel level. We need a lower capital cost hydrolysis process which can produce a concentrated sugar solution. We also need a fermentation process adaptable to concentrated sugar solutions to lower alcohol purification costs. Finally we need to recover and include by-product values - lignin, furfural, acids, methanol, etc. -in our income. 

Id (Scheme 3) . This was prepared via the corresponding phosphite, which can be synthesized by reaction of the alcohol with chlorodiethyl phosphite and triethylamine. The phosphite then undergoes nucleophihc substitution reaction with anhydrous H2O2 forming the hydroperoxide Id (enantiomeric ratio S/R 65/35) and isomeric hydroperoxide le in a 2 1 mixture in 74% overall yield starting from the alcohol. Purification was possible by normal-phase HPLC. So in this case transformation of the phosphite to the hydroperoxide proceeds with partially retained configuration. 

Fig. 18.26. Ethers—Axens. Includes alcohol purification (1), hydrocarbon purification (2), main reactor (3), reactive distillation system (4), wastewater system to remove water from the raffinate (5), and product fractionation column (6). (Source Hydrocarbon Processing, 2004 Refining Process Handbook. CD-ROM. September 2004 copyright 2004 by Gulf Publishing Co., all rights reserved.)...

Fig. 11 Monte Carlo simulation of separation efficiency for alcohol purification. (View this art in color at www.dekker.com.)...

Although membranes could be used for the entire alcohol purification process, a great many stages would be needed, and it is cheaper to use distillation for most of the separation. If a membrane selectively permeable to alcohol could be developed, it might be feasible to separate alcohol from dilute solutions entirely by membranes. 

The first commercial DWC in Korea was developed through the retrofit of an SSC and was installed successfully in a plant of LG Chem. Ltd. (Lee et al, 2011b). Their case study reports this industrial implementation of the DWC with particular attention paid to the practical aspects of the retrofit project. Figure 9.16 shows an alcohol-purification unit in a 2-ethylhexanol (2-EH) production plant. This unit consists of three main distillation... 

Figure 9.16 Alcohol-purification unit in a 2-EH production plant.

The traditional method for alcohol purification is distillation. When the alcohol concentrations in the mixture and in the steam reach 95.57 and 97.6%, respectively, the mixture cannot be further purified, so a second distillation must be carried out. At present, the domestic secondary distillation methods include calcium oxide dehydration, azeotropic distillation, extraction distillation, absorption, molecular sieves, and vacuum dehydration. In addition, chemical film separation is a very promising alcohol purification technology, but it is still in the experimental stage. 

Outstanding performance of hydrophilic zeolite membranes for dehydration of ethanol has been reported (Caro, Noack, Kolsch, Schafer, 2000 Caro, Noack, Kolsch, 2005). The reported permeate fluxes are about 7 kg/m /h with separation factors of about 10,000 for feed concentrations of 90% (w/w) ethanol solution. The application of 16 pervaporation modules in a multipurpose plant for dehydration of alcohols was reported by Morigami, Kondo, Abe, Kita, and Okamoto (2001). Alcohol purification from 90% to 99.8% (w/w) was achieved in this stody. 

Preparative Method from the corresponding mesylate upon treatment with sodium iodide in acetone. The mesylate can be prepared from the commercially available alcohol. Purification distillation in the dark (25°C/0.5 mroHg, trap at -78 °C).2... 

Absolute methyl alcohol. The synthetic methanol now available is suitable for most purposes without purification indeed, some manufacturers claim a purity of 99 85 per cent, with not more than 0 1 per cent, by weight of water and not more than 0 02 per cent, by weight of acetone. Frequently, however, the acetone content may be as high as 0 1 per cent, and the water content 0-5-1 per cent. 

The crude bromide contains a little unchanged alcohol and is said to contain some n-butyl ether (b.p. 141°). The former is removed by washing with concen. trated hydrochloric acid and this purification process is satisfactory for most purposes. Both the alcohol and the ether are removed by washing with 11-12 ml. of concentrated sulphuric acid the butyl bromide is not affected by this reagent. 

It is important to use dry ethyl acetate, but it should contain 2-3 per cent, of alcohol. The so-called absolute or anhydrous ethyl acetate of commerce is satisfactory. Experimental details for the purification of 95-97 p>er cent, ethyl acetate are given in Section 11,47,29. 

Zemplen helped his students in many ways. I remember an occasion in the difficult postwar period. The production of the famous Hungarian salami, interrupted by the war, was just in the process of being restarted for export. The manufacturer wanted a supportive analysis from the well-known professor. Zemplen asked for a suitable sample of some hundreds of kilograms, on which the whole institute lived for weeks. When it was gone he rightly could offer an opinion that the product was quite satisfactory. After the war, grain alcohol was for a long time the only available and widely used laboratory solvent, and, not unexpectedly, it also found other uses. Later, when it was denatured to prevent human consumption, we devised clever ways for its purification. The lab also manufactured saccharine, which was... 

Purification of the Methylamine HCI is in order now, so transfer all of the crude product to a 500mL flask and add either 250mL of absolute Ethanol (see end of FAQ for preparing this) or, ideally, n-Butyl Alcohol (see Footnote 4). Heat at reflux with a Calcium Chloride guard tube for 30 minutes. Allow the undissolved solids to settle (Ammonium Chloride) then decant the clear solution and cool quickly to precipitate out Methylamine HCI. Filter rapidly on the vacuum Buchner funnel and transfer crystals to a dessicator (see Footnote 3). Repeat the reflux-settle-cool-filter process four... 

Purchasing research Pure alcohols Pure ethyl silicate Pure Natural Pure silicon PUREX Purex process PUR foams Purgatives Purging Purification Purified Pork Insulin... 

MetaUic ions are precipitated as their hydroxides from aqueous caustic solutions. The reactions of importance in chlor—alkali operations are removal of magnesium as Mg(OH)2 during primary purification and of other impurities for pollution control. Organic acids react with NaOH to form soluble salts. Saponification of esters to form the organic acid salt and an alcohol and internal coupling reactions involve NaOH, as exemplified by reaction with triglycerides to form soap and glycerol,... 

Selectivity. Solvent selectivity is intimately linked to the purity of the recovered extract, and obtaining a purer extract can reduce the number and cost of subsequent separation and purification operations. In aqueous extractions pH gives only limited control over selectivity greater control can be exercised using organic solvents. Use of mixed solvents, for example short-chain alcohols admixed with water to give a wide range of compositions, can be beneficial in this respect (6). 

The purification of the galHum salt solutions is carried out by solvent extraction and/or by ion exchange. The most effective extractants are dialkyl-phosphates in sulfate medium and ethers, ketones (qv), alcohols, and trialkyl-phosphates in chloride medium. Electrorefining, ie, anodic dissolution and simultaneous cathodic deposition, is also used to purify metallic galHum. 

Ammonium lactate [34302-65-3] ia coaceatrated aqueous solutioas has beea coaverted to ammonia and the ester by alcoholysis at temperatures ranging from 100—200°C usiag a variety of alcohols and water entrainers, such as toluene. Ester yields ranging from 50—80% were obtained. This method has also been suggested as a recovery and purification method from impure solutions of lactate (29). However, a considerable amount of the lactate is not converted to the recoverable ester and is lost as lactamide (6). 

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