Ethylene-1,2-diols synthesis

Poly(ethylene adipate), synthesis by diacid-diol reaction, 95-97 Poly(ethylene isophthalate) (PEI) homopolyesters, 89-90 Poly (ethylene isophthalate-co-tere-phthalate) (PEIT), synthesis of, 106-107... 

Corey and Wat17 found that the method of forming cycloolefins from allylic dihalides and nickel carbonyl provides an unusually efficient route for the formation of large rings. Because it leads to cyclic 1,5-dienes, it makes available a variety of cyclic structures not obtainable in a practical way via the acyloin synthesis. Diacetylenic diols (10) were converted by selective reduction into the corresponding cis.cis- and owu,/ra -ethylenic diols followed by reaction with PBr3 to form the diallylic dibromides (12), which were then cyclized with nickel carbonyl. 

Another exemple of application in the field of agrochemicals can be found in the synthesis of ethylenic diol 25 (19)... 

We have already seen how different types of catalysts can be used to arrest the hydrogenation of a triple bond at the double-bond stage. A solvent or additive can also accomplish this by competitive chemisorption on the catalyst. An example (reaction 6.42) is the hydrogenation of dehydrolinalyl acetate (46) to linalyl acetate (47), a perfumery chemical, without further hydrogenation to the unwanted dihydrolinalyl acetate (48). Compound (48) should be present in less than 2% to preserve the perfumery quality of (47). This can be accomplished by using Pd/C as catalyst with pyridine as the additive or solvent (Gilbert and Mercier, 1993). A similar application can be found in the synthesis of ethylenic diol (Baillard et al., 1988) used in agrochemicals. 

As early as 1904, 1,2-Propanediol Dinitrate was proposed (Ref 3) as an additive to lower the freezing temp of NG, but its practical application on a large scale was hindered by lack of the raw material, propane-1,2-diol. It is only recently that the synthesis of glycol from ethylene led to the development of a method for producing methyl glycol from propylene via cnioro-hydrin. Even so, propylene-1,2-glycol is somewhat more expensive than glycols derived from ethylene (Ref 9)... 

The addition of Grignard reagents to aldehydes, ketones, and esters is the basis for the synthesis of a wide variety of alcohols, and several examples are given in Scheme 7.3. Primary alcohols can be made from formaldehyde (Entry 1) or, with addition of two carbons, from ethylene oxide (Entry 2). Secondary alcohols are obtained from aldehydes (Entries 3 to 6) or formate esters (Entry 7). Tertiary alcohols can be made from esters (Entries 8 and 9) or ketones (Entry 10). Lactones give diols (Entry 11). Aldehydes can be prepared from trialkyl orthoformate esters (Entries 12 and 13). Ketones can be made from nitriles (Entries 14 and 15), pyridine-2-thiol esters (Entry 16), N-methoxy-A-methyl carboxamides (Entries 17 and 18), or anhydrides (Entry 19). Carboxylic acids are available by reaction with C02 (Entries 20 to 22). Amines can be prepared from imines (Entry 23). Two-step procedures that involve formation and dehydration of alcohols provide routes to certain alkenes (Entries 24 and 25). 

Oxidation is the first step for producing molecules with a very wide range of functional groups because oxygenated compounds are precursors to many other products. For example, alcohols may be converted to ethers, esters, alkenes, and, via nucleophilic substitution, to halogenated or amine products. Ketones and aldehydes may be used in condensation reactions to form new C-C double bonds, epoxides may be ring opened to form diols and polymers, and, finally, carboxylic acids are routinely converted to esters, amides, acid chlorides and acid anhydrides. Oxidation reactions are some of the largest scale industrial processes in synthetic chemistry, and the production of alcohols, ketones, aldehydes, epoxides and carboxylic acids is performed on a mammoth scale. For example, world production of ethylene oxide is estimated at 58 million tonnes, 2 million tonnes of adipic acid are made, mainly as a precursor in the synthesis of nylons, and 8 million tonnes of terephthalic acid are produced each year, mainly for the production of polyethylene terephthalate) [1]. 

The catalytic asymmetric epoxidation of a,/i-unsaturated carbonyl compounds is one of the synthetically useful reactions in organic synthesis.The resulting chiral epoxides are easily converted to various useful chiral compounds. We developed a new yttrium-(5)-6,6 -[oxybis(ethylene)dioxy]biphenyl-2,2 -diol (1) (Figure 6.10)... 

SYNTHESIS OF (5)-6,6 -[OXYBIS(ETHYLENE)DIOXY]BIPHENYL-2,2 -DIOL(l)... 

Synthesis of the cyclic acetal 25 in 63% yield by reaction of the unsaturated bromo-nitrilo sugar 24 (E configuration) with ethylene glycol in the presence of sodium hydroxide has been reported.40 An extension of this work was given for sugars having a vicinal diol... 

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF T1TANOCENE-CONTAINING POLYETHERS BASED ON REACTION WITH ETHYLENE OXIDE-CONTAINING DIOLS, INCLUDING POLY (ETHYLENE GLYCOL)... 

Pyrolytic decomposition of cyclic carbonate eaten of 1,2-diols hjus been utilized on occasion for epoxide synthesis. Ethylene Oxide jiml glycidol, for example, have been prepared26 mc from ethylene carbonate and glyceryl carbonate respectively (Eq. 314). 

Maleic and phthalic anhydrides and fumaric acid are mainly used for polyester resin synthesis. However, dihydric alcohols such as ethylene and propylene glycols, diethylene, dipropylene, triethylene and neopentyl glycols, and hydrided or oxypropylened diphenylolpropane are also used.5 7 Different combinations of dibasic acids with diols allow us to vary the composition and properties of the resulting polyester resins over a wide range. 

Physical properties are related to ester-segment structure and concentration in thermoplastic polyether-ester elastomers prepared hy melt transesterification of poly(tetra-methylene ether) glycol with various diols and aromatic diesters. Diols used were 1,4-benzenedimethanol, 1,4-cyclo-hexanedimethanol, and the linear, aliphatic a,m-diols from ethylene glycol to 1,10-decane-diol. Esters used were terephthalate, isophthalate, 4,4 -biphenyldicarboxylate, 2,6-naphthalenedicarboxylate, and m-terphenyl-4,4"-dicarboxyl-ate. Ester-segment structure was found to affect many copolymer properties including ease of synthesis, molecular weight obtained, crystallization rate, elastic recovery, and tensile and tear strengths. 

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