Hexamethylene bromide

Trimethylene bromide... Hexamethylene bromide. Nonamethylene bromide... 

Heterocyclic block copolymers, 282-284 Heterocyclic diamines, rigid, 281 Heterocyclic polymers, structure-property relationships in, 273-274 Heterocyclic ring formation, PQ and PPQ synthesis by, 309-310 Hexadecyltrimethylammonium bromide (HTMAB), 549-550 Hexamethylene diisocyanate (HDI), 199, 210. See also HDI trimer Hexamethylenediamine-adipic acid salt, 169, 170... 

Hexamethylene tetramine (77 g., 0.55 mole) is dissolved in 200 ml. of chloroform, and 88 g. (0.5 mole) of 3-thenyl bromide (p. 96) is added as rapidly as possible with shaking (Note 1). A reflux condenser is attached, and the mixture is refluxed over a steam bath for 30 minutes. After being cooled, the mixture of chloroform and crystalline product (Note 2) is poured into 250 ml. of water and stirred until all the salt dissolves. The chloroform layer is separated and washed twice with 125-ml. portions of water, and the combined water extracts are steam-distilled. When the distillate comes over clear (about 1 1. of distillate is usually collected), it is acidified with a little hydrochloric acid (Note 3) and extracted with three 100-ml. portions of ether. After drying over Drierite, the ether is evaporated, and the residue is distilled. 3-Thenaldehyde is collected at 72-78°/12 mm. or 195-199°/744 mm., = 1.5860 (Note 4). The yield is 30-40 g. (54-71%). 

For sodium/hexamethylene-l,6-bis-carbamidocaprolactam system, Sibal et al. [64] found the value of the constant k in Equation 1.4 to be 17.5. Note that the values of the constant k in Equation 1.4 that defines the relative complex viscosity rise during anionic ring opening polymerization of caprolactam are comparable for both caprolactam-magnesium-bromide/isophthaloyl-bis-caprolactam and sodium/hexamethylene-l,6-bis-carbamidocapro-lactam as the catalyst/initiator systems even though the kinetic constants for anionic polymerization for these systems are extremely different (see Table 1.2). 

The kinetics of anionic ring opening polymerization of caprolactam initiated by iso-phthaloyl-bis-caprolactam and catalyzed by caprolactam-magnesium-bromide satisfactorily fit Malkin s autocatalytic model below 50 percent conversion. The calculated value of the overall apparent activation energy for this system is 30.2kJ/mol versus about 70kJ/mol for Na/hexamethylene-l,6,-bis-carbamidocaprolactam as the initiator/catalyst system. 

Hexamethylene diamine Sodium hydroxide Dimethyl sulfate Hydrogen bromide... 

Curing of the acetylenic polyacetals to rubbery polyurethanes could be achieved with any of a number of commercially available diisocyanates, including 2,4-toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dianisidine diisocyanate (DADI), and 4,4 -diisocyanatodiphenyl-methane (MDI). The first two diisocyanates were studied most extensively. The reactions were carried out in solution in benzene, toluene, and ethylene bromide, and in bulk. The bulk reaction, which is the only... 

The effect of ring aize on the reaction of oyoUo ethers with tri- phenylmethyl bromide waa shown by tetrahydrofuran giving incom-pleto reactkHi. The deavage of tetrahydrofuran, 1,4-dioxane and hexamethylene oxide with methyl iodide at IdO, reported by Muller Atid cO Workers.txsi oould doubtloss be extended to many uxetanes. 

In the improved synthesis of Ifetroban described previously, environmental concerns due to special handling of copper bromide waste and hazards associated with hexamethylene tetramine (HMT) on manufacturing scale led to further perfection of the synthesis. Mechanistic considerations suggested that an oxidized form of aminoamide B (Scheme 4) would eliminate the necessity for a late-stage copper-mediated oxidation. This was indeed accomplished. The cyclization-elimination sequence was initiated by a Lewis add and completed by base-mediated elimination to afford the Ifetroban penultimate. In addition to eliminating the need for... 

Hexamethylene glycol has been prepared by treating hexa-methylene iodide with silver acetate and hydrolyzing the acetate, by hydrolyzing the bromide, by reducing ethyl adipate with sodium and alcohol, and by the method here described. The catalytic hydrogenation over copper-chromium oxide of the... 

---