Primary alcohol production

Reduction of the bicyclic ketotosylate 332 which gave the exo-methylene primary alcohol product 335 via the intermediates 333 and 334 was observed by Kraus (93). 

Entry Primary Alcohol/Product Alkanols MX Molar Ratio Substrate Pb(OAc)4 MX Conversion (%) Yield (%) ... 

Step 2 Add a proton. In a second step, the chemist adds a dilute acid solution to protonate the alkoxide function of the tetrahedral carbonyl addition compound to give the primary alcohol product. 

A remarkable, and so far unexplained, reversal in the ratio of secondary to primary alcohol product was observed in the one-pot reductive cleavage of 5,6-epoxide (6) in 1,2-dimethoxyethane under reflux, from 15 1 by use of lithium iodide... 

Whilst acetylenic alcohols can be employed directly in Cadiot-Chodkiewicz reactions [9], protection of the alcohol (usefully as the Thp ether) is necessary for Castro coupling [14]. A variation based upon these two processes involves coupling of terminal alkynes with 3-bromopropynol (10) in the presence of pyridine [15]. For primary alcohol products, oxidation to the aldehyde with nickel peroxide followed by base-catalyzed decarbonylation generates the new terminal acetylene e.g. Fig. 1.10. 

P -f lOROH -f 5Br, — 2H3PO, -f lORBr -f 2H,0 The reaction is of general application with primary alcohols (n propyl to n hexadecyl) the yields are over 90 per cent, of the theoretical, but with secondary alcohols the yields are 50-80 per cent. in the latter case a small quantity of high boiling point by-product is also formed which can, however, be readily removed by fractional distillation. The reaction is conveniently carried out in a special all glass apparatus. 

The above simple process cannot be applied to the preparation of the homo-logues a higher temperature is requir (di-n-amyl ether, for example, boils at 169°) and, under these conditions, alkene formation predominates, leading ultimately to carbonisation and the production of sulphur dioxide. If, however, the water is largely removed by means of a special device (see Fig. Ill, 57,1) as soon as it is formed, good 300 of ethers may be obtained from primary alcohols, for example ... 

Hydnde shifts often occur during the dehydration of primary alcohols Thus although 1 butene would be expected to be the only alkene formed on dehydration of 1 butanol It IS m fact only a minor product The major product is a mixture of cis and trans 2 butene... 

If the temperature is not kept below 25°C dunng the reaction of primary alcohols with p toluenesulfonyl chloride in pyndine it is sometimes observed that the isolated product is not the desired alkyl p toluenesulfonate but is instead the corresponding alkyl chlonde Suggest a mech anistic explanation for this observation... 

Primary alcohols by this analysis are seen to be the products of Grignard addi tion to formaldehyde... 

When applied to the synthesis of ethers the reaction is effective only with primary alcohols Elimination to form alkenes predominates with secondary and tertiary alcohols Diethyl ether is prepared on an industrial scale by heating ethanol with sulfuric acid at 140°C At higher temperatures elimination predominates and ethylene is the major product A mechanism for the formation of diethyl ether is outlined m Figure 15 3 The individual steps of this mechanism are analogous to those seen earlier Nucleophilic attack on a protonated alcohol was encountered m the reaction of primary alcohols with hydrogen halides (Section 4 12) and the nucleophilic properties of alcohols were dis cussed m the context of solvolysis reactions (Section 8 7) Both the first and the last steps are proton transfer reactions between oxygens... 

Rea.ctlons, Butynediol undergoes the usual reactions of primary alcohols. Because of its rigid, linear stmcture, many reactions forming cycHc products from butanediol or i j -butenediol give only polymers with butynediol. 

Secondary alcohols (C q—for surfactant iatermediates are produced by hydrolysis of secondary alkyl borate or boroxiae esters formed when paraffin hydrocarbons are air-oxidized ia the presence of boric acid [10043-35-3] (19,20). Union Carbide Corporation operated a plant ia the United States from 1964 until 1977. A plant built by Nippon Shokubai (Japan Catalytic Chemical) ia 1972 ia Kawasaki, Japan was expanded to 30,000 t/yr capacity ia 1980 (20). The process has been operated iadustriaHy ia the USSR siace 1959 (21). Also, predominantiy primary alcohols are produced ia large volumes ia the USSR by reduction of fatty acids, or their methyl esters, from permanganate-catalyzed air oxidation of paraffin hydrocarbons (22). The paraffin oxidation is carried out ia the temperature range 150—180°C at a paraffin conversion generally below 20% to a mixture of trialkyl borate, (RO)2B, and trialkyl boroxiae, (ROBO). Unconverted paraffin is separated from the product mixture by flash distillation. After hydrolysis of residual borate esters, the boric acid is recovered for recycle and the alcohols are purified by washing and distillation (19,20). 

Esters of nitro alcohols with primary alcohol groups can be prepared from the nitro alcohol and an organic acid, but nitro alcohols with secondary alcohol groups can be esterified only through the use of an acid chloride or anhydride. The nitrate esters of the nitro alcohols are obtained easily by treatment with nitric acid (qv). The resulting products have explosive properties but are not used commercially. 

Price and Demand. In terms of production volume, isopropyl alcohol is about the fourth largest chemical produced from propylene (66). Total 1993 U.S. nameplate capacity for isopropyl alcohol production was 8.48 x 10 metric tons. The total world capacity is about 2.0 x 10 metric tons (Table 4) (126—128). The 1995 U.S. prices were 0.55/L ( 2.10/gal) for refined 91 vol % and 0.62/L ( 2.36/gal) for anhydrous alcohol (129), an increase from the 0.18/L ( 0.70/gal) average price of 1977. The price of isopropyl alcohol is driven by the price of propylene, the primary feedstock, and by the price of ethyl alcohol, a competing solvent. 

Composition. Shellac is primarily a mixture of aUphatic polyhydroxy acids in the form of lactones and esters. It has an acid number of ca 70, a saponification number of ca 230, a hydroxyl number of ca 260, and an iodine number of ca 15. Its average molecular weight is ca 1000. Shellac is a complex mixture, but some of its constituents have been identified. Aleuritic acid, an optically inactive 9,10,16-trihydroxypalmitic acid, has been isolated by saponification. Related carboxyflc acids such as 16-hydroxy- and 9,10-dihydroxypalmitic acids, also have been identified after saponification. These acids may not be primary products of hydrolysis, but may have been produced by the treatment. Studies show that shellac contains carboxyflc acids with long methylene chains, unsaturated esters, probably an aliphatic aldehyde, a saturated aliphatic ester, a primary alcohol, and isolated or unconjugated double bonds. 

Although the Ziegler reaction provides a more direct method for produciag primary alcohols, aluminum alkyl chemistry requires special handling and is fairly cosdy. The by-product aluminum salts usuaUy require some treatment for disposal (115). 

Synthesis. Titanium alkoxy halides are intermediates in the preparation of alkoxides from a titanium tetrahaUde (except the fluoride) and an alcohol or phenol. If TiCl is heated with excess primary alcohol, only two chlorine atoms can be replaced and the product is dialkoxydichlorotitanium alcoholate, (RO)2TiCl2 ROH. The yields are poor, and some alcohols, such as aHyl, ben2yl, and /-butyl alcohols, are converted to chlorides (46). Using excess TiCl at 0°C, the trichloride ROTiCl is obtained nearly quantitatively, even from sec- and / f/-alcohols (47,48). 

Most flavors that are designed for beverage alcohol products use ethanol as the primary solvent for the flavor. Glycerol [56-81-5] propylene glycol [57-55-6] and water are other common solvents in Hquid flavors. Some beverage alcohol concepts require the addition of an emulsified flavor, either as a vehicle to solubilize the oils in the beverage or as a deflberate attempt to cloud the product. This can best be accompHshed at lower proofs with the alcohol breaking the emulsion. 

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