Butan-l-4-diol

Thermoplastic copolyester elastomers are generally block copolymers produced from short-chain aUphatic diols, aromatic diacids, and polyalkjlene ether-diols. They are often called polyesterether or polyester elastomers. The most significant commercial product is the copolymer from butane-l,4-diol, dimethyl terephthalate, and polytetramethylene ether glycol [25190-06-1J, which produces a segmented block copolyesterether with the following stmcture. 

The reaction is performed under dry conditions. 40.5 g l,2-diphenyl-l-[4-[2-(N,N-dimethylamino)ethoxy]phenyl]butane-l,4-diol and 150 ml of acetic acid anhydride are placed in a flask. The temperature is raised to 90°C, where it is kept until the primary OH-group is completely acetylated. [4-Acetoxy-1,2-... 

Dioxepanes (7-membered ring acetals derived from butane-l,4-diol) hydrolyse faster than 1,3-dioxanes or 1,3-dioxolanes owing to relief of transan-nular strain in the 7-membered ring.1617... 

Ritter et al. [147-155] have been studying side chain poiyrotaxanes. They synthesized side chain poiyrotaxanes by amide coupling of polymer-carrying carboxylic acid moieties with various semirotaxanes of methylated /l-CD(s) and an axle bearing an amine group at one end [147-154]. These works have been reviewed in an excellent review by Raymo and Stoddard [78]. Ritter et al. [155] reported recently a new type of side chain polyrotaxane. They polymerized inclusion complexes of di(meth)acrylates of butan-l,4-diol and hexan-l,6-diol with a-CD and with methylated /1-CD using a redox initiator system in aqueous media, and characterized the polyrotaxane structure by IR and glass-transition temperature measurements. 

This listing of chain extenders or cross-linkers is obviously incomplete since many other types of chain extenders may be used where special end use requirements may have to be met, for example, for flame retardance. In this case, halogenated diols, for example, 2,3-dibromo-2-butane-l,4-diol (GAF Corp.), or phosphate or phosphonate group-containing diols, for example, Fyrol 6 (Stauffer Chemical Co.), may be used. 

FIGURE 20.8 Methyl donors and alkylating compounds choline 1, methionine 2, S-adenosyl-methionine 3, dimethyl sulfate 4 and butane-l,4-diol bis-methane sulfonate 5 (busulfan). 

The enzymatic synthesis of peptides (Scheme 6.24) from which proteins can be constructed is not so limited, and chemical synthesis has an even wider application, but these are not yet suitable techniques for manufacture. Moreover, there are no general methods for building the peptides into full protein structures. Nevertheless, enzymes do have a role in the manufacture of peptides themselves. In a mixture of butan-l,4-diol and water, trypsin will catalyse the exchange of the carboxy-terminal alanine of porcine insulin with threonine t-butyl ester (Scheme 6.25). The reaction is essentially a transpeptidation in which the acyl group of lysine is transferred from one amino group on alanine to another on the threonine. This converts porcine insulin into the ester of the human hormone, and a simple deprotection yields one of the commercial products. 

Horseradish peroxidase Trypsin (protease) Subtilisin (protease) Phenol polymerization Transpeptidation Ester hydrolysis Ethylacetate Butan-l,4-diol Dioxane, chloroform, etc. 

In 1981, their structures on the two principal lignans in both human pregnant female urines and female rat urines were determined as 2,3-bis 3 -hydroxybenzyl)-butyrolactone (HPMF, HBBL, 45) and 1,3-bisQ -hydroxybenzyl)-butane-l,4-diol (HBBD, 47) (Figure 11), respeetively. Additionally, dimethoxy analog of 2,3-Z>/s(3 -hydroxybenzyl)-butane-l,4-diol (HBBD, 47) has been temporarily identified from human urine [55]. 

Setehell KD, Lawson AM, Conway E, Taylor NF, Kirk DN, Cooley G, Farrant RD, Wynn S, Axelson M. The definitive identification of the lignans ira s-2,3-i/5 (3-hydroxybenzyl)-gamma-butyrolactone and 2,3-Z)/s(3-hydroxybenzyl)butane-l,4-diol in human and animal urine. Biochem. J. 197,447-458, 1981. 

Crystallization of nylon-6 has been carried out from solution. - Shish-kebab structures were obtained from solutions of butane-l,4-diol in the latter case, while crystallization from hexane-1,2,6-triol produced lamellar single crystals. The chain-repeat distances in the a-phase crystal have been measured from —150 to 150 The wide-angle X-ra.y scattering, and isotope xchange extinction coefficients, as well as JT-ray diffraction measurements have all been applied to the examination of crystal structure and molecular packing of nylon-6. Cyclic oligomers of caprolactam with 2—7 units in the chain have been found to migrate to the surface of nylon-6 filament when it is exposed to either water or alcohol vapour. "... 

Typical diisocyanates include 2,4- and 2,6-toluene diisocyanate (TDI), and methylenediphenyl-4,4 -diisocyanate (MDI). Depending on whether a rigid or elastomeric flexible polyurethane is required, the diols can be either simple diols, e.g. butan-l,4-diol, or polymeric poly ether diols (e.g. poly-THF) or hydroxy-terminated polyesters. Cross-linkage is provided by the addition of small amounts of glycerol. Carbon dioxide is liberated by the presence of trace amounts of water and this is often used as the blowing agent for foams. 

Substituted benzeneboronic acids have been evaluated for the gas chromatographic determination of bifunctional compounds (e.g. pinacol, propane-1,3-diamine, butane-l,4-diol). Phenylboronic and diphenylborinic acid have... 

Symmetrical 1,3-diacylglycerols have been made by acylation and reduction of dihydroxyacetone. One French report describes several ways of making triacylglycerols having three different acyl groups and another is concerned with the mono- and di-oleatesof 2-methyl-and2,2-dimethyl-butane-l,4-diol. ... 

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