Hexamethylene diamine preparation

Uses. The principal use of adiponitrile is for hydrogenation to hexamethylene diamine leading to nylon-6,6. However, as a result of BASE s new adiponitrile-to-caprolactam process, a significant fraction of ADN produced may find its way into nylon-6 production. Adipoquanamine, which is prepared by the reaction of adiponitrile with dicyandiamide [461-58-5] (cyanoguanidine), may have uses in melamine—urea amino resins (qv) (see "Benzonitrile, Uses"). Its typical Hquid nitrile properties suggest its use as an extractant for aromatic hydrocarbons. 

The N,N -dibenzyl-N,N -bis-[2-(3, 4 -dihydroxyphenyl)-2-oxoethyl] -hexamethylene-diamine-dichlorohydrate-monohydrate used as the starting material was prepared as follows 2 mols of chloroaceto pyrocatechin were dissolved in 2,000 cc of acetone and heated to boiling with 2 mols of N,N -dibenzylhexamethylene-diamine for 12 hours, almost the theoretical quantity of N,N -dibenzylhexamethylene-diamine-dichlorohydrate being precipitated and removed by suction after cooling. Excess HCI was added to the filtrate, approximately 66% of the theoretically possible quantity of crude dichlorohydrate of the N,N -dibenzyl-N,N -bis-[2-(3, 4 -dihydroxyphenyl)-2-oxoethyl] -hexamethylene-diamine being precipitated. The product was cleaned by recrystallization from water with the addition of animal charcoal. After drying the substance contained water of crystallization at ambient temperature, MP 206° to 209.5°C. 

Furfural is a natural monomer obtained by the steam acid digestion of corncobs, bagasse, rice husks, oat hulls, or similar materials. It acts as the precursor for the preparation of two important monomers (Scheme 1), adipic acid and hexamethylene diamine, used in the... 

The main use of acrolein is to produce acrylic acid and its esters. Acrolein is also an intermediate in the synthesis of pharmaceuticals and herhicides. It may also he used to produce glycerol hy reaction with isopropanol (discussed later in this chapter). 2-Hexanedial, which could he a precursor for adipic acid and hexamethylene-diamine, may he prepared from acrolein Tail to tail dimenization of acrolein using ruthenium catalyst produces trans-2-hexanedial. The trimer, trans-6-hydroxy-5-formyl-2,7-octadienal is coproduced. Acrolein, may also he a precursor for 1,3-propanediol. Hydrolysis of acrolein produces 3-hydroxypropionalde-hyde which could he hydrogenated to 1,3-propanediol. ... 

Direct use of dimethyl adipate from the oxycarbonylation process to produce nylon 6,6 could be an attractive alternative to current adipic acid/nylon 6,6 technology. Dimethyl adipate condensation with hexamethylene diamine would give methanol rather than water. Reactors, which currently use caprolactam to prepare nylon 6, could also easily be retrofitted to produce nylon 6,6. Dimethyl hex- nedioate or dimethyl adipate are also useful raw materials for preparation of other high volume chemicals including hexamethylene diamine, caprolactam, and 1, -hexanediol. 

Uses. The principal use of adiponitrile is for hydrogenation to hexamethylene diamine leading to nylon-6,6. Adipoquanamine, prepared by the reaction of adiponitrile with dicyandiamide (cyanoguanidine), has typical liquid nitrile properties that suggest its use as an extractant for aromatic hydrocarbons. 

Nylon-6,6, poly(hexamethylene adipamide), prepared by reacting substantially equimolar quantities of adipic acid and hexamethylene diamine, has for many years been the world s major wholly synthetic fibre. The rapid rate of growth of polyester production indicates that nylon will soon be supplanted as the major fibre by poly(ethylene terephthalate). 

Nylon-6,6, discovered by Carothers in 1929, is by far the most important polyamide prepared by condensation polymerization. Nylon 6, prepared by the ring-opening (non-condensation) polymerization of e-caprolactam, will not be discussed in this chapter. Other commercially important polyamides prepared by condensation techniques include nylon-6,10, from hexamethylene diamine and sebacic acid, poly(/n-... 

Suppose we wish to prepare a nylon with an M of 16,000 using adipic acid (H02C(CH2)4C02H) and hexamethylene diamine (H2N(CH2)gNH2), which represents an A-A, B-B type of polycondensation. The common, or trade name of the product, poly(hexamethylene adipamide), H0[0C(CH2)4 CONH(CH2)gNH] H, is nylon 6,6, or nylon 66. The first 6 refers to the number of carbon atoms between amide nitrogens for the amine component, and the second 6 refers to the number of carbon atoms separating nitrogens for the acid component. What monomer feed ratio would be required to achieve this M ... 

Hexamethylene diamine is also prepared from furfuraldehyde by the following series of reactions ... 

In the nylon 66 sujterpolyamide molecule there are equal numliers of adipic acid and hexamethylene diamine molecules. To ensure that the components are balanced the first stage in polymerization consists of preparing hexamethylene diammonium adipate, which is conMuonly called nylon 66 salt. 

The hexamethylene di-isocyanate is prepared by dissolving hexamethylene-diamine in dichlorobenzene, converting into hexamethylene diammonium carbonate by passing COj into the solution and then treating with phosgene ... 

Journal of Microencapsulation 18, No.6, Nov./Dec. 2001, p.801-9 MORPHOLOGY AND STRUCTURE OF MICROCAPSULES PREPARED BY INTERFACIAL POLYCONDENSATION OF METHYLENE BIS(PHENYL ISOCYANATE) WITH HEXAMETHYLENE DIAMINE Jabbari E... 

Polyurethane-urea microcapsules were prepared by the interfacial polycondensation of methylene bis(phenyl isocyanate), hexamethylene diamine and anionic sodium hgnin sulphonate, as the emulsifying agent, and 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide, as a herbicide. The morphology amd microstractuie of these microcapsules were investigated by TEM and scanning electron microscopy and the effect of caldrun chloride on the stabihty of the microcapsule stractuie examined. 22 refs. 

Nylon 6,6 may also be prepared by direct amidation of adipic acid and hexamethylene diamine. In this process, the molten monomers are added to a vessel in approximately stoichiometric proportions, but usually with a slight excess of acid. The exothermic salt formation produces sufficient heat to raise the batch temperature to approximately 200 °C, so polymerization proceeds rapidly. As the polymerization proceeds, the stoichiometry is adjusted to exactly equal molar portions of diacid and diamine, and the autoclave temperature and pressure are raised to 275 C and 250 Ib/in., respectively. After a specified heating time, pressure is reduced, and the temperature is maintained to complete polymerization. 

Hexahydro-l(//)-azepine may be prepared by the Cu/Al202-catalyzed cyclization of 6-amino-l-hexanol <89AC107>, and hexamethylene diamine is converted to the cyclic imine by pea seedling diamine oxidase <90TL6907>. 

The most important of these compounds were the monomers of nylon 66, hexamethylene diamine (HMDA) and adipic acid. During World War II, I.G. Farben (and Du Pont) prepared both compounds from coal tar products, but Reppe and his coworkers devised several new routes from propargyl alcohol and butynediol. Similarly, caprolactam, the monomer of the rival nylon 6, was also synthesized from butynediol. ... 

W. Nielinger, W. Alewelt, R. Binsack, L. Bottenbruch, and H.-J. Fullmann. Process for the preparation of copolyamide from adipic add, terephthaUc acid and hexamethylene diamine. US Patent 4762910, assigned to Bayer Aktiengesellschaft (Leveikusen, DE), August 9, 1988. 

PP-Based CPNC In PP, Tg 0°C, and at r< T, as for PS or PA-6, for different clay loadings the dynamic moduli of CPNC versus T nearly parallel each other hence, the relative moduli E j. = E (CPNC)/ (matrix) is almost constant. Wu et al. [2005b] prepared PP-based CPNC by solution blending of PP -I- PP-MA with MMT preintercalated with cetyl pyridinium and hexamethylene diamine (HMDA)-modifled PP-MA. The nanocomposites contained 0 to 5wt% of well-dispersed organoclay. DMA... 

In the preparation of nylon-6,6 salt, DuPont discloses a process for making highly concentrated solutions of nylon salt at maximum solubility [192], In the first step of this process, a concentrated salt solution for nylon-6,6 is made with 73.5-77.5 wt% of adipic acid and 22.5-26.5 wt% of hexamethylene diamine at 55-60°C. The solution contains 60-69.5 wt% solute as compared to an ordinarily stoichiometric solution containing 56% diacid and 44% diamine with a maximum solute concentration of about 59 wt%i. The second step is to remove water from the solution by evaporation to a solution concentration of 93-96 wt%. When the concentrated solution is ready to be polymerized, addition hexamethylene diamine is added to complete the reaction. A process with similar reaction modifications is developed to prepare an essentially anhydrous mixture of adipic acid and hexamethylene diamine [193], The reaction mixture is heated to 120-135°C to allow evaporation of water while reacting. The resulting product has a ratio of adipic acid to hexamethylene diamine of 81 19. The molten acid-rich mixture is withdrawn in a continuous process. 

As an alternate intermediate, adiponitrile is employed to react with hexamethylene diamine and steam in a multistage distillation column to prepare nylon-6,6 [194]. The process is carried out in the presence of an oxygen-containing phosphorous catalyst at an elevated temperature and pressure. Nylon-6,6 of high molecular weight can be produced by the postpolymerization of lower molecular weight polymer in the molten state in the presence of a phosphonic acid catalyst [195] or in the solid state [196]. In a different approach, a prepolymer is formed in a reactor system. 

La Saponara and co-workers have demonstrated that the non-covalent surface treatment of the CNTs using hexamethylene diamine and one of two surfactants, (Triton X-100) or cetyl pyridinium chloride (CPC), enabled the production of reinforced fibreglass-reinforced panels, which were prepared with treated CNT/epoxy by hand lay-up. The surface treatment with diamine/CPC resulted in the most superior composites with improved mechanical performance, higher resistance to fatigue and impact damage (over 30... 

The nylons are named by the number of carbon atoms in the repeat units. The materials formed by polymerizations of lactams therefore carry only one number in their names like, for instance, nylon 6 that is formed from caprolactam. By the same method of nomenclature, a nylon prepared by condensing a diamine with a dicarboxylic acid like, for example, hexamethylene diamine with adipic acid, is called nylon 6,6. It is customary for the first number to represent the number of carbons in the diamine and the second number to represent the number of carbons in the diacid. 

Nylon 6,10 is prepared by the same procedure as nylon 6,6 from a salt of hexamethylenediamine and sebacic acid, while nylon 6,9 is prepared from a salt of hexamethylene diamine and azelaic acid. 

Common monomers for copoly(amide)s are adipic acid, TPA, hexamethylene diamine (HMD), and s-cap-rolactam [5]. 2-Methylpentamethylenediamine and 2-ethyltetramethylenediamine are used for transparent PPA in combination with IPA [10,14]. These diamines can be prepared by hydrogenation of the corresponding dinitriles. For example, 2-methylpenta-methylenediamine can be prepared by hydrogenating... 

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