1, 6-hexamethylene glycol

In a steel reaction vessel (Note x), capable of withstanding high pressures with an adequate safety factor (Note 2) and having a capacity of 400 cc. or more, are placed 252 g. (1.25 moles) of ethyl adipate (b.p. i44 i45°/29 mm.) (Org. Syn. 17, 32) and 20 g. of copper chromite catalyst, prepared either with or without the addition of barium (p. 31). The reaction vessel is closed, made gas tight, and secured in a suitable agitating device. After connection is made with the hydrogen supply, hydrogen is introduced until a pressure of 2000 to 3000 lb. per sq. in. is reached (Note 2). 

Agitation is started, and the reaction system is heated as rapidly as possible to 2550. The temperature is maintained at 255° (Note 3), and hydrogenation is continued until hydrogen absorption is complete (Note 4). The agitation is now stopped, the vessel cooled, and the pressure released. With the aid of four 25-cc. portions of 95 per cent alcohol the contents is transferred to a 600-cc. beaker. The catalyst is removed by filtering or centrifuging, and is washed with four more 25-cc. portions of alcohol (Note 5). To the reaction product (Note 6), 50 cc. of 40 per cent sodium hydroxide solution is added, and the alcoholic 

Suitable reaction vessels and apparatus for agitation of the reaction mixture are commercially available 1,2 or may be constructed.3 

The temperature is controlled preferably by an automatic controller operating through a relay which cuts off periodically the supply of electric current. 

The time (six to twelve hours) required to complete the reaction is a function of the pressure of the hydrogen, activity of the catalyst, and purity of the ethyl adipate. Unless a high pressure of hydrogen is used originally or the reaction vessel is of large capacity (2 1) it will be necessary to introduce more hydrogen into the reaction vessel so that the pressure is never less than 1500 lb. per sq. in if the reaction is to run smoothly to completion. 

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Hexamethylene glycol, HO(CH2)gOH. Use 60 g. of sodium, 81 g. of diethyl adipate (Sections 111,99 and III,100) and 600 ml. of super-d ethyl alcohol. All other experimental detaUs, including amounts of water, hydrochloric acid and potassium carbonate, are identical with those for Telramelhylene Glycol. The yield of hexamethylene glycol, b.p. 146-149°/ 7 mm., is 30 g. The glycol may also be isolated by continuous extraction with ether or benzene. 

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). 

Alcohols are the most frequently formed products of ester hydrogenolysis. The hydrogenation of esters to alcohols is a reversible reaction with alcohol formation favored at high pressure, ester at low pressure (/). Copper chromite is usually the catalyst of choice. Details for the preparation of this catalyst (/7) and a detailed procedure for hydrogenation of ethyl adipate to hexamethylene glycol (/[Pg.80]

Hexamethylene glycol [629-11-8] M 118.2, m 41.6°. Fractionally crystd from its melt. Hexamethylenetetramine [100-97-0] M 140.2. Crystd from EtOH and stored in a vacuum. 

PP -Dihydroxydiethyl ether. (8) Hexamethylene glycol. (9) Ethylene glycol di-((J hydroxyethyl) ether. 

Hexamethylene, glycol, h59 Hexamethylene oxide, o47 Hexamethylethane, tlOO... 

In this extra thermodynamic expression, the chemical potential (per mole) is given the symbol, /, and the solute is pictured as being divided into m lipophilic and / hydrophilic segments. Such a solute is hexamethylene glycol, where m = 6 and / = 2. Now one can predict the requirements needed for Equation 1 to hold. 

The telomeric aliphatic polyesters were produced by polycondensation based on adipic acid and hexamethylene glycol in various stoichiometric amounts to generate polyesters of different end group functionality. The polyesters of different molar mass and corresponding reference samples were synthesized at the Center for Macromolecular Chemistry, Berlin, Germany. These types of polyesters are widely used as lacquers and precursors for the production of several important polyurethanes. 

Hexamethylene chlorohydrin has been prepared by the reaction of hydrochloric acid with hexamethylene glycol, without a catalyst or in the presence of cuprous chloride. ... 

Urethane dimethacrylate 43% Hexamethylene glycol dimethacrylate 10% Pentadecafluorooctyl methacrylate 2% UV initiator 2% photocrosslinking agent 30 54" 3.58(1.06) ... 

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