Diamines hydrogenation

Potassium permanganate N,N-Diethylene diamine Hydrogen chloride Dimethyl sulfate Hydrogen... 

Geigy A one-stage process for making ethylenediamine tetra-acetic acid (EDTA) from ethylene-diamine, hydrogen cyanide, and formaldehyde. 

Nylon has a crystalline structure. The lattice has the property of being made essentially of dipolar layers which form a 60° angle with the chain axis the period, measured along the chain, is 1.74 nm. This arrangement results from the repetition of the add-diamine hydrogen bond... 

With the success of reducing nitriles in the presence of a 1,3-diamine to make hexahydropyrimidines, we turned our attention to the use of 3-hydroxy-1-aminopropane (22) as a surrogate for the 1,3-diamine. Hydrogenation of aceton-trile with Raney Ni in the presence of 22 in a 1 1 mole ratio at 95 °C and 500 psig produced tetrahydro-2-methyl-l,3-oxazine (23) in 90% selectivity and 70% conversion of 22 by intramolecular cyclization of the hydroxy to the intermediate enamine. This synthesis is quite different from other syntheses (7) which involve Pd or Pt homogeneous complexes for the intramolecular hydroamination of ami-nopropyl vinyl ether to give 23. 

Radioactive iodine Triethylene diamine Hydrogen cyanide Cr/Cu/Ag salts Cu/Zn/Mo salts... 

Dissolve about o i g. of />-phenylene diamine in about 10 ml. of water. Place 5 ml. of milk in each of two test-tubes A and B. Boil the milk in B thoroughly for 2 minutes and then cool. In each test-tube place 5 drops of the phenylenc diamine solution and then add i drop of 20 vol. hydrogen peroxide solution, and mix. A green coloration is produced in A, and then very rapidly changes to a slate-blue. No coloration is produced in B. This test therefore readily differentiates fresh from boiled milk. 

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 Showa Denka Company practices this reaction with a PX—MX mixture (24), whereas Mitsubishi Gas Chemical Company uses high purity MX first to form the dicyanide (25). In both processes, hydrogenation to the diamine follows. y -Xylenediamine is reacted with phosgene to give / -xylene diisocyanate, which is used in urethane resins (26—28). 

Reduction. Hydrogenation of dimethyl adipate over Raney-promoted copper chromite at 200°C and 10 MPa produces 1,6-hexanediol [629-11-8], an important chemical intermediate (32). Promoted cobalt catalysts (33) and nickel catalysts (34) are examples of other patented processes for this reaction. An eadier process, which is no longer in use, for the manufacture of the 1,6-hexanediamine from adipic acid involved hydrogenation of the acid (as its ester) to the diol, followed by ammonolysis to the diamine (35). 

Diamine. 2,2-Dimethyl-l,3-propanediamine [7328-91-8] (5) has been prepared by amination of neopentyl glycol by treating the glycol with ammonia and hydrogen at 150—250°C at 10—31 MPa (1500—4500 psig) over a Ni catalyst. The diamine is useflil for preparation of crystalline polyureas by reaction with diisocyanates (36). 

In the multistep production of IPDI, isophorone is first converted to 3-cyano-3,5,5-trknethylcyclohexanone (231—235), then hydrogenated and ammoniated to 3-aminomethyl-3,5,5-trknethyl-l-aminocyclohexane (1) (236,237), also known as isophorone diamine (IPDA). In the final step IPDA is phosgenated to yield IPDI (2) (238). Commercial production of IPDI began in the United States in 1992 with the startup of Olin s 7000 t/yr plant at Lake Charles, Louisiana (239), and the startup of Hbls integrated isophorone derivatives plant in Theodore, Alabama (240). Hbls has a worldwide capacity for IPDA of 40,000 t/yr. 

Because almost any diacid can be leaddy converted to the acid chloride, this reaction is quite versatile and several variations have been developed. In the interfacial polymerization method the reaction occurs at the boundary of two phases one contains a solution of the acid chloride in a water-immiscible solvent and the other is a solution of the diamine in water with an inorganic base and a surfactant (48). In the solution method, only one phase is present, which contains a solution of the diamine and diacid chloride. An organic base is added as an acceptor for the hydrogen chloride produced in the reaction (49). Following any of these methods of preparation, the polymer is exposed to water and the acid chloride end is converted to a carboxyhc acid end. However, it is very difficult to remove all traces of chloride from the polymer, even with repeated washings with a strong base. 

This same method, followed by hydrogenation, is also used to produce the C-12 and C-13 diamines from the corresponding diacids in the... 

Its manufacture begins with the formation of dodecanedioic acid produced from the trimeri2ation of butadiene in a process identical to that used in the manufacture of nylon-6,12. The other starting material, 1,12-dodecanediamine, is prepared in a two-step process that first converts the dodecanedioic acid to a diamide, and then continues to dehydrate the diamide to the dinitrile. In the second step, the dinitrile is then hydrogenated to the diamine with hydrogen in the presence of a suitable catalyst. 

The synthesis of y -phenylenediarnine [108-45-2] is also straightforward it proceeds via the formation of y -dinitroben2ene [99-65-0] by the nitration of ben2ene, followed by hydrogenation to the diamine. 

Conditions cited for Rh on alumina hydrogenation of MDA are much less severe, 117 °C and 760 kPA (110 psi) (26). With 550 kPa (80 psi) ammonia partial pressure present ia the hydrogenation of twice-distilled MDA employing 2-propanol solvent at 121°C and 1.3 MPa (190 psi) total pressure, the supported Rh catalyst could be extensively reused (27). Medium pressure (3.9 MPa = 566 psi) and temperature (80°C) hydrogenation usiag iridium yields low trans trans isomer MDCHA (28). Improved selectivity to aUcychc diamine from MDA has been claimed (29) for alumina-supported iridium and rhodium by iatroduciag the tertiary amines l,4-diazabicyclo[2.2.2]octane [280-57-9] and quiaucHdine [100-76-5]. 

Cycloahphatic diamines such as (13) [115172-12-8] which retain some aromatic character have been made from end-ring hydrogenation (44) of l,3-bis(p-aminocumyl)ben2ene [2687-27-6] the double alkylation adduct of aniline to y -diisopropenylben2ene [3748-13-8] (45) using Ru catalysts (46). 

CycIohexanediamine s commercial origin is its presence as a minor 0.1 <1% coproduct of hexamethylenediamine [124-09-4] produced by hydrogenation of adiponittile [111-69-3]. Fractional distillation by up to four columns in a series is routine commercial practice to purify nylon grade acychc diamine the cmde cycloahphatic diamine requires further refining before use as a specification intermediate. 

Dicyclopentadiene (24) [77-73-6] is an inexpensive raw material for hydrocyanation to (25), a mixture of l,5-dicarbonittile [70874-28-1] and 2,5-dicarbonittile [70874-29-2], then subsequent hydrogenation to produce tricyclodecanediamine, TCD diamine (26). This developmental product, a mixture of endo and exo, cis and trans isomers, is offered by Hoechst. 

Use of 1,3 cycloaHphatic diamines in polyamides may be similarly limited by internal amide dehydration of the conformationaHy labile cis isomers to form a tetrahydropyrimidine (38) rather than high molecular weight polyamide. 1,3-Cyclohexanediamine is, however, a component of Spandex polyureas Du Pont uses the hydrogenation product of y -phenylenediamine [108-45-2] (24) captively to produce Lycra (see Fibers, elastomeric). 

Gyanoethylation. The reaction of primary fatty amines with acrylonitrile followed by hydrogenation produces diamines and ttiamines (4,7,31,32,37,38). 

V-Phenylsuccinimide [83-25-0] (succanil) is obtained in essentially quantitative yield by heating equivalent amounts of succinic acid and aniline at 140—150°C (25). The reaction of a primary aromatic amine with phosgene leads to formation of an arylcarbamoyl chloride, that when heated loses hydrogen chloride to form an isocyanate. Commercially important isocyanates are obtained from aromatic primary diamines. 

The 4,4 -MDA is sold commercially with a diamine assay of 98 —99%. The major impurity is the 2,4 -MDA isomer, which can be present in amounts up to 3%. PMDA products are normally defined by hydrogen equivalent weight and viscosity. Typical products exhibit a 50 hydrogen equivalent weight and a viscosity of 80 140 mPa-s(=cP) at 70°C. PMDA products normally contain, in addition to the isomers and oligomers of MDA, small amounts of aniline, water, chlorides, and various alkylated amines. AH MDA products should be stored in sealed containers in a cool dry area. 

Toluene Diisocyanate. Toluene diisocyanate is the basic raw material for production of flexible polyurethane foams. It is produced by the reaction sequence shown below, in which toluene is dinitrated, the dinitrotoluene is hydrogenated to yield 2,4-diaminotoluene, and this diamine in turn is treated with phosgene to yield toluene 2,4-diisocyanate. 

---