Tetramethylene glycol

Note. Both tetramethylene glycol (1 4-butanediol) and hexamethylene glycol (1 6 hexaiiediol) may be prepared more conveniently by copper-chromium oxide reduction (Section VI,6) or, for small quantities, by reduction with lithium aluminium hydride (see Section VI,10). 

Thus with R = CHj, CjHj and C H, , the compounds are called methyl carhitoli carbitol and butyl carbitol respectively. None of these compounds can be conveniently prepared in the laboratory by elementary students they are, however, readily available commercially. The preparation of one glycol, pinacol or tetramethylene glycol from acetone, has already been described (Section 111,77). 

Butanediol. 1,4-Butanediol [110-63-4] tetramethylene glycol, 1,4-butylene glycol, was first prepared in 1890 by acid hydrolysis of N,]S3-dinitro-l,4-butanediamine (117). Other early preparations were by reduction of succinaldehyde (118) or succinic esters (119) and by saponification of the diacetate prepared from 1,4-dihalobutanes (120). Catalytic hydrogenation of butynediol, now the principal commercial route, was first described in 1910 (121). Other processes used for commercial manufacture are described in the section on Manufacture. Physical properties of butanediol are Hsted in Table 2. 

Tetrahydrofuran is polymerized to poly(tetramethylene glycol) with fuming sulfuric acid and potassium biduoride (29). 

The biodegradation of poly(alkylene glycols) is hindered by their lack of water solubiUty, and only the low oligomers of poly(propylene glycol) are biodegradable with any certainty (179—181), as are those of poly(tetramethylene glycol) (182). A similar xo-oxidation mechanism to that reported for poly(ethylene glycol) has been proposed. 

Polyether Polyols. Polyether polyols are addition products derived from cyclic ethers (Table 4). The alkylene oxide polymerisation is usually initiated by alkah hydroxides, especially potassium hydroxide. In the base-catalysed polymerisation of propylene oxide, some rearrangement occurs to give aHyl alcohol. Further reaction of aHyl alcohol with propylene oxide produces a monofunctional alcohol. Therefore, polyether polyols derived from propylene oxide are not truly diftmctional. By using sine hexacyano cobaltate as catalyst, a more diftmctional polyol is obtained (20). Olin has introduced the diftmctional polyether polyols under the trade name POLY-L. Trichlorobutylene oxide-derived polyether polyols are useful as reactive fire retardants. Poly(tetramethylene glycol) (PTMG) is produced in the acid-catalysed homopolymerisation of tetrahydrofuran. Copolymers derived from tetrahydrofuran and ethylene oxide are also produced. 

Butanediol (tetramethylene glycol) [110-63-4] M 90.1, f 20.4 , b 107-108 /4mm, 127 /20mm, d 1.02, n 1.4467. Distd and stored over Linde type 4A molecular sieves, or crystd twice from anhydrous diethyl ether/acetone, and redistd. Also purified by recrystn from the melt and doubly distd in vacuo in the presence of Na2S04. 

Tetramethylene chlorohydrin was first prepared in a pure state by the action of thionyl chloride on tetramethylene glycol in the presence of pyridine. The method given here has been published recently... 

The reluctance of acrylic monomers to polymerise in the presence of air has been made a virtue with the anaerobic acrylic adhesives. These are usually dimethacrylates such as tetramethylene glycol dimethacrylate. The monomers are supplied with a curing system comprising a peroxide and an amine as part of a one-part pack. When the adhesive is placed between mild steel surfaces air is excluded, which prevents air inhibition, and the iron present acts as a polymerisation promoter. The effectiveness as a promoter varies from one metal to another and it may be necessary to use a primer such as cobalt naphthenate. The anaerobic adhesives have been widely used for sealing nuts and bolts and for a variety of engineering purposes. Small tube containers are also available for domestic use. 

Hexamethylene glycol, HO(CH2)gOH. Use 60 g. of sodium, 81 g. of diethyl adipate (Sections 111,99 and Ill.lOO) and 600 ml. of super- y ethyl alcohol. All other experimental details, including amounts of water, hydrochloric acid and potassium carbonate, are identical with those for Tetramethylene Glycol. The yield of hexamethylene glycol, b.p. 146-149717 mm., is 30 g. The glycol may also be isolated by continuous extraction with ether or benzene. 

Firstly, catheter sample 1 was dissolved in deuterated trifluoroacetic acid, and the solution analyzed by [H NMR spectroscopy. The [H NMR spectrum of the sample is shown in Figure 52. The peaks at 1.16 ppm, 2.56 ppm, and 3.40 ppm are consistent with a polyamide-12 (PA-12) structure. The signal at 3.58 ppm can be attributed to tetramethylene glycol (TMG) protons adjacent to the ether linkages. The signal at 1.60 ppm is composed of overlapping resonances from both components. The smaller peaks are most likely due to polymer end groups or protons at the junction of two blocks the material is an amide-ether block... 

Tetramethylene glycol. See Butanediol Tetramethylene sulfoxide (TMSO) as PVDC solvent, 25 705 Tetramethylethylenediamine (TMEDA), 25 163... 

Butanediol, also known as tetramethylene glycol, is produced by the hydrogenation of butynediol (made from acetylene and formaldehyde). 

The hard-soft block copolymer approach employed to produce segmental PUs (Section 7.6) has also been used with polyesters, with the hard block formed from 1,4-butadienediol and terephthalic acid while the soft block is provided by oligomeric (approximate molecular weight of 2000 Da) poly(tetramethylene glycol) and is sold under the trade name Hytrel. 

Figure 10.4 Stress-strain curves for control and modular polymers. The curve in the bottom (—) is for the polyurethane (PU) made fiom poly(tetramethylene glycol) and...

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