1.5- Diols ethylene derivatives

Asymmetric [2 + 2] cycloaddition.6 The chiral titanium reagent 4, prepared from TiCl2(0-i-Pr)2 and the chiral diol 1, derived from L-tartaric acid and known to effect asymmetric Diels-Alder reactions (14, 232-233), can also promote asymmetric [2 + 2]cycloadditionof l,l-bis(methylthio)ethylene to a,P-unsaturated N-acylox-azolidinones. 

Hydrogen per oxide/formic acid Diols from ethylene derivatives... 

Cleavage of ethylene derivs. to alcohols and amines Diols and diamines from cyclic ethylene derivs. 

The formation of the diol (167) from the reaction of di-t-butyl ketone with sodium in diethyl ether has been re-investigated, and a new mechanism (Scheme 93) proposed the involvement of ethylene, derived from diethyl... 

Ozone/sodium tetrahydridohorate Diols by oxidative ring opening of cyclic ethylene derivatives via a-hydroxy-a -alkoxyperoxides Retention of carboxyl groups... 

Lithium perchlorate/calcium carbonate Ring expansion of isocyclic diol monotosylates with preceding preferential formation of glycols from ethylene derivatives and preferential O-tosylation... 

Alcohols from ethylene derivatives 1,4-Diols by abnormal isomerization... 

Diols that bear two hydroxyl groups m a 1 2 or 1 3 relationship to each other yield cyclic acetals on reaction with either aldehydes or ketones The five membered cyclic acetals derived from ethylene glycol (12 ethanediol) are the most commonly encoun tered examples Often the position of equilibrium is made more favorable by removing the water formed m the reaction by azeotropic distillation with benzene or toluene... 

Diol Components. Ethylene glycol (ethane 1,2-diol) is made from ethylene by direct air oxidation to ethylene oxide and ring opening with water to give 1,2-diol (40) (see Glycols). Butane-1,4-diol is stiU made by the Reppe process acetylene reacts with formaldehyde in the presence of catalyst to give 2-butyne-l,4-diol which is hydrogenated to butanediol (see Acetylene-DERIVED chemicals). The ethynylation step depends on a special cuprous... 

Polyester and polyether diols are used with MDI in the manufacture of thermoplastic polyurethane elastomers (TPU). The polyester diols are obtained from adipic acid and diols, such as ethylene glycol, 1,4-butanediol, or 1,6-hexanediol. The preferred molecular weights are 1,000 to 2,000, and low acid numbers are essential to ensure optimal hydrolytic stabihty. Also, caprolactone-derived diols and polycarbonate diols are used. Polyether diols are... 

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)... 

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

Figure 25.3 b) shows a generic polyester-based polyurethane. The most common polyester repeat units are derived from the polycondensation of adipic acid and a diol, such as ethylene glycol, which results in the structure shown in Fig, 25.4. The average molecular weight of the polyester sequences between urethane links commonly ranges between 400 and 6,000 g/mol. 

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