4,4 -diaminodiphenylmethane, reaction

By contrast with tertiary amines used in catalytic quantities, primary and secondary amines or acid anhydrides may be used to bring about the cure of epoxy resins by reaction in stoichiometric proportions. A typical amine curing agent used at this level is diaminodiphenylmethane (DDM), which reacts with an individual epoxy-group in the way shown in Reaction 4.17. 

The most important starting materials for process A are 4,4, 4"-triamino-triphenylmethane, pararosaniline (119), and parafuchsin (118). Aniline and formaldehyde are treated at 170°C to form, apart from some formaldehyde-aniline intermediates, 1,3,5-triphenylhexahydrotriazine as the main component. Subsequent treatment with an acidic catalyst, for instance with hydrochloric acid, in excess aniline as a solvent initially affords 4,4 -diaminodiphenylmethane, which is finally oxidized to yield parafuchsin (118). Iron(III)chloride and nitrobenzene, which in the past were used as oxidants, are no longer used. The reaction is now performed by air oxidation in the presence of vanadium pentoxide as a catalyst. 

The technically important new fuchsine synthesis from a primary aromatic amine and formaldehyde falls, in the case of aniline, into the above reaction scheme since the formation of the intermediate product, p-diaminodiphenylmethane, is readily intelligible. 

Diaminodiphenylmethane reacted with HN03 and as a result of this reaction 4,4-diamino-2,2-dinitro-diphenylmethane was obtained. 

It should be stressed that the viscosity changes during formation of polyurethanes even from bifiinctional compounds can be correlated with gelation most likely they are connected with the formation of a physical network then crosslinks arise from sufficiently strong specific interactions like hydrogen bonds [50]. An example of such a process is the reaction of macro (diisocyanate) with 3,3 -dichloro-4,4 -diaminodiphenylmethane [43]. 

The production of aniline is a major international business, carried on in the US, Europe and Asia, mainly for the conversion, by reaction with formaldehyde under acid-catalyzed conditions, into diaminodiphenylmethanes 9a, 9b and 9c, and then into isocyanates, mainly 4,4/-methylenebis(phenylisocyanate) (MDI, also known as 4,4 -methylene-di-paraphenylene isocyanate, 4,4 -diphenylmethane diisocyanate, methylene diphenylene diisocyanate and diisocyanato diphenyl methane) (9d), from which polyurethanes are produced. This accounts for well over 60% of total demand (Figure 1). Aniline is also used in bulk for the production of antioxidants and vulcanization accelerators for rubber. Some 15.5 million lbs. of cyclohexylamine are made each year mainly by catalytic hydrogenation of aniline. Half the demand is for use as a boiler water additive. Other major uses include in the manufacture of herbicides, plasticizers, emulsifying agents, dyes, dry-cleaning soaps, acid gas absorbents and, in Asia, cyclamate sweeteners. Apart from India, the use of aniline for dyestuff manufacture represents about 10% of demand. 

The first stage in the production of MDI (9d) is condensation between aniline and formaldehyde, in the presence of HC1, under subatmospheric pressure, at 70-105 °C. This affords 4,4, 2,4 and 2,2 isomers of diaminodiphenylmethane (9a, 9b and 9c). Reaction with phosgene in an inert solvent, such as chlorobenzene, first at low temperature, and then heating to 120 °C, gives, for the 4,4 isomer (9a), MDI, trimers, tetramers and higher oligomers, the latter known as poly-MDI or PMDI. Continuous liquid-phase phosgenation is favored. 

The PMR range of resin materials utilize a two-step reaction, in which a norbornene-terminated prepolymer is formed in situ by the condensation reaction of low molecule weight diamines with norbornene-capped imides or acid esters [37]. The PMR-15 designation refers to polymerization of monomeric reactants, with a mixture of diaminodiphenylmethane and a dimethyl ester and a norbornene-containing monomethyl ester, to form a condensation prepolymer having molecular weight approximately equal to 1500. PMR resins are used as matrix materials in high performance composites in the aerospace industry. 

Oxidative cyclization. The reaction of 2,2 -diaminodiphenylmethanes (1) with iodosobenzene diacetate in benzene at room temperature for several days affords dibenzo-[c,f]-[l,2]diazepines (2) in 30-60% yield.2 The reaction is not applicable to 2,2 -diaminobenzophenones. 

The reaction of trimellitic anhydride (7) with ethanolamine (9) giving the hydroxy acid (10) and with 4,4 -diaminodiphenylmethane (8) giving the diacid (11) has been published in the first poly(ester-imide) patent [l].The second one is nowadays the predominant reaction for making poly(ester-imide)s. Trimellitic anhydride is the basic dianhydride for introducing the imide structure into the polyesters. Nearly every example in patents is based on trimellitic anhydride alone or mixtures with other anhydrides, e.g., tetrahydrophthalic anhydride [59]. The imides made from aromatic anhydrides are thermally more stable than the ones resulting from aliphatic structures (Fig. 4). Both types have been protected by patents, and products made from them are on the market. 

The synthesis of poly(ester-imide) resins used in wire enamels is performed world-wide in a high tonnage. The resins are produced in reaction vessels, with volumes between 1 m3 and 25 m3, from ethylene glycol, THEIC, dimethyltereph-thalate, trimellitic anhydride and 4,4 -diaminodiphenylmethane. The process... 

The polymer industry requires large quantities of 4,4 -diaminodiphenyl-methanes. These compounds are used in various applications as polymer additives. Currently they are manufactured by the acid-catalysed condensation of anilines with formaldehyde but like so many reactions of this type, the processes require the neutralisation of waste acid leading to large amounts of salt waste. Cleaner processes are required and solid acids offer a way forward. One potentially useful example of this is the aqueous reaction of aromatic anilines adsorbed on kaolinite with formaldehyde which cleanly give the desired products (Figure 3.5).36 In a typical experiment, the clay is stirred with water before aniline is added to the stirred solution. To this is slowly added formaldehyde solution. The precipitated 4,4 -diaminodiphenylmethane can be extracted in hot ethanol in a yield of 96%. Similarly, several substituted analogues have been prepared in yields of 70-99%. 

TIN, TIN FLAKE, or TIN POWDER (7440-31-5) Finely divided material is combustible and forms explosive mixture with air. Contact with moisture in air forms tin dioxide. Violent reaction with strong acids, strong oxidizers, ammonium perchlorate, ammonium nitrate, bis-o-azido benzoyl peroxide, bromates, bromine, bromine pentafluoride, bromine trifluoride, bromine azide, cadmium, carbon tetrachloride, chlorine, chlorine monofluoride, chlorine nitrate, chlorine pentafluoride, chlorites, copper(II) nitrate, fluorine, hydriodic acid, dimethylarsinic acid, nitrosyl fluoride, oxygen difluoride, perchlorates, perchloroeth-ylene, potassium dioxide, phosphorus pentoxide, sulfur, sulfur dichloride. Reacts with alkalis, forming flammable hydrogen gas. Incompatible with arsenic compounds, azochlo-ramide, benzene diazonium-4-sulfonate, benzyl chloride, chloric acid, cobalt chloride, copper oxide, 3,3 -dichloro-4,4 -diaminodiphenylmethane, hexafluorobenzene, hydrazinium nitrate, glicidol, iodine heptafluoride, iodine monochloride, iodine pentafluoride, lead monoxide, mercuric oxide, nitryl fluoride, peroxyformic acid, phosphorus, phosphorus trichloride, tellurium, turpentine, sodium acetylide, sodium peroxide, titanium dioxide. Contact with acetaldehyde may cause polymerization. May form explosive compounds with hexachloroethane, pentachloroethane, picric acid, potassium iodate, potassium peroxide, 2,4,6-trinitrobenzene-l,3,5-triol. 

Since there are few salts that are not appreciably water-soluble, there are few important precipitation reactions of the aqueous ions. A unique case is the precipitation by methanolic solutions of 4,4 -diaminodiphenylmethane... 

PAI types that are soluble in cresol can be produced by the reaction of trimellitic acid anhydride with cresol to give the cresyl ester. This ester is reacted with MDI and then with 4,4 -diaminodiphenylmethane. PAI is rendered soluble in cresol by the modification with -caprolactam. A disadvantage is that this type is no longer purely aromatic and the thermal properties are adversely affected. 

Aniline is coupled by reaction with formaldehyde to produce 4,4 -diaminodiphenylmethane ... 

NTI with a molecular weight of llOO g/mole, prepared from the reaction of appropriate molar amounts of BTDA, 3,3 -diaminodiphenylmethane, and nadic anhydride in N,N-dimethylformamide, was evaluated as a high temperature adhesive (eq. 7). This material has been referred to as LARC-13. The nadic group on NTI undergoes a thermally... 

The most important commercial intermediates from aniline are the mixture of 4,4 - and 2,4 -diaminodiphenylmethane, obtained by reaction with formaldehyde, and the higher polyamines as well as 2-mercaptobenzothiazole and cyclohexyl-amine, used as rubber additives. N,N-Dialkylanilines are commonly used for the production of dyestuffs, while phenylhydrazine is used as an intermediate in the manufacture of plant protection agents, pharmaceuticals and dyestuffs. Other important aniline products are sulfanilic acid and acetanilide. 

Trimellitic anhydride is used as a raw material for plasticizers, as a component in polyesterimides and as a hardener for epoxy resins. High-temperature resistant and high-strength polyimides are produced by the reaction of trimellitic acid chloride with an aromatic diamine, such as 4,4 -diaminodiphenylmethane (e.g. Torlan, Amoco),... 

A widely studied nanohybrid system is based on epoxy-siUca [148,149], which is generally prepared upon blending the epoxy monomer and siUca nanoparticles, followed by the addition of a hardener to perform the curing reaction (e.g., diaminodiphenylmethane [150], diaminodiphenylsulfone [151], diethylphosphite [150], PA-amine [152, 153], or hexahydro-4-methylphthalic anhydride [154]). The compatibility between the epoxide compounds and the colloidal silica was optimized upon mixing the diglycidylether of bisphenol-A together with colloidal suspensions of silica nanoparticles dispersed in methylisobutylketraie [150]. 

Reaction mechanism and network build-up for curing of N,N-diglycidyl-aniline (DGAT and N,N,N N -tetraglycidyl-4,4 -diaminodiphenylmethane "(TGDDM) The main features of the reaction of N,N-diglycidylamine deriva-tives with amines are [10] ... 

Reyx, D. and Costes, B., Homopolymerisation of tetraglycidyl-4,4 diaminodiphenylmethane (TGDDM). Identification of cyclic reaction products. Polymer Commun., in press. 

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