Benzene- 1,3-diisocyanate

BENZENE, 1,2-DICHLORO- see DEP600 BENZENE, o-DIETHOXY- see CCP900 BENZENE, l,2-DIETHOXY-(9CI) see CCP900 BENZENE, p-DIHYDROXY- see HIHOOO BENZENE-l,3-DIISOCYANATE see BBPOOO BENZENE-1,3-DIISOCYANATE see BBPOOO BENZENE, 1,3-DIISOCYANATO- see BBPOOO BENZENE-, 1,3-DIISOCYANATOMETHYL- see TGM740... 

Abstract Three series of new polyimides were prepared by condensation of imidazole-blocked 2,5-bis(n-alkoxymethyl)-1,4-benzene diisocyanates with pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic dianhydride (BPDA), and naphthalene tetracarboxylic dianhydride (NTDA), respectively. After the polymers obtained were spectroscopically characterized, their solubilities, thermal properties and crystalline structures were measured and discussed. It was found that structures and properties of the polyimides having regularly substituted n-alkoxymethyKn-CHjOC Hj j, m=4,6,8) side branches are governed not only by side chain length, but also by main chain rigidity. 

This mechanism of initiation is confirmed by the fact that, when the PAN-PEO block copolymer is treated with diisocyanate in benzene in the presence of pyridine acting as catalyst, copolymers lose their solubility in DMF as a result of the formation of intermolecular chemical bonds75). 

Polyurethane networks were prepared from polyoxypropylene (POP) triols(Union Carbide Niax Polyols) after removal of water by azeotropic distillation with benzene. For Niax LHT 240, the number-average molecular weight determined by VPO was 710 and the number-average functionality fn, calculated from Mjj and the content of OH groupSj determined by using excess phenyl isocyanate and titration of unreacted phenyl isocyanate with dibutylamine, was 2.78 the content of residual water was 0.02 wt.-%. For the Niax LG-56, 1 =2630, fn=2.78, and the content of H2O was 0.02wt.-%. The triols were reacted with recrystallized 4,4"-diphenylmethane diisocyanate in the presence of 0.002 wt.-% dibutyltin dilaurate under exclusion of moisture at 80 C for 7 days. The molar ratio r0H = [OH]/ [NCO] varied between 1.0 and 1.8. For dry samples, the stress-strain dependences were measured at 60 C in nitrogen atmosphere. The relaxation was sufficiently fast and no extrapolation to infinite time was necessary. 

Oil-Based SINs. The SINs produced were based on a castor oil polyester-urethane and styrene crosslinked with 1 mole percent of technical grade (55%) divinyl benzene (DVB) (7). This structure may be written poly[(castor oil, sebacic acid, TDI)-SIN-(Styfene, DVB)], poly[(CO,SA,TDI)-SIN-(S,DVB)]. Benzoyl peroxide (BP) (0.48%) was used as the free radical initiator for the styrene and 1,4-tolylene-diisocyanate (TDI) was used as the crosslinker for the polyester prepolymer. A 500 ml resin kettle equipped with a N inlet, condenser, thermometer, and high torque stirrer was used as the polymerization reactor. 

Toluene is used more commonly than the other BTXs as a commercial solvent. There are scores of solvent applications, though environmental constraints and health concerns diminish the enthusiasm for these uses. Toluene also is used to make toluene diisocyanate, the precursor to polyurethane foams. Other derivatives include phenol, benzyl alcohol, and benzoic acid. Research continues on ways to use toluene in applications that now require benzene. The hope is that the dealkylation-to-benzene or disproportionation steps can be eliminated. Processes for manufacturing styrene and terephthalic acid—the precursor to polyester fiber—are good, commercial prospects. 

AI3-00040, see Cyclohexanol AI3-00041, see Cyclohexanone AI3-00045, see Diacetone alcohol AI3-00046, see Isophorone AI3-00050, see 1,4-Dichlorobenzene AI3-00052, see Trichloroethylene AI3-00053, see 1,2-Dichlorobenzene AI3-00054, see Acrylonitrile AI3-00072, see Hydroquinone AI3-00075, see p-Chloro-rrr-cresol AI3-00078, see 2,4-Dichlorophenol AI3-00085, see 1-Naphthylamine AI3-00100, see Nitroethane AI3-00105, see Anthracene AI3-00109, see 2-Nitropropane AI3-00111, see Nitromethane AI3-00118, see ferf-Butylbenzene AI3-00119, see Butylbenzene AI3-00121, see sec-Butylbenzene AI3-00124, see 4-Aminobiphenyl AI3-00128, see Acenaphthene AI3-00134, see Pentachlorophenol AI3-00137, see 2-Methylphenol AI3-00140, see Benzidine AI3-00142, see 2,4,6-Trichlorophenol AI3-00150, see 4-Methylphenol AI3-00154, see 4,6-Dinitro-o-cresol AI3-00262, see Dimethyl phthalate AI3-00278, see Naphthalene AI3-00283, see Di-rj-butyl phthalate AI3-00327, see Acetonitrile AI3-00329, see Diethyl phthalate AI3-00399, see Tributyl phosphate AI3-00404, see Ethyl acetate AI3-00405, see 1-Butanol AI3-00406, see Butyl acetate AI3-00407, see Ethyl formate AI3-00408, see Methyl formate AI3-00409, see Methanol AI3-00520, see Tri-ocresyl phosphate AI3-00576, see Isoamyl acetate AI3-00633, see Hexachloroethane AI3-00635, see 4-Nitrobiphenyl AI3-00698, see IV-Nitrosodiphenylamine AI3-00710, see p-Phenylenediamine AI3-00749, see Phenyl ether AI3-00790, see Phenanthrene AI3-00808, see Benzene AI3-00867, see Chrysene AI3-00987, see Thiram AI3-01021, see 4-Chlorophenyl phenyl ether AI3-01055, see 1.4-Dioxane AI3-01171, see Furfuryl alcohol AI3-01229, see 4-Methyl-2-pentanone AI3-01230, see 2-Heptanone AI3-01231, see Morpholine AI3-01236, see 2-Ethoxyethanol AI3-01238, see Acetone AI3-01239, see Nitrobenzene AI3-01240, see I idine AI3-01256, see Decahydronaphthalene AI3-01288, see ferf-Butyl alcohol AI3-01445, see Bis(2-chloroethoxy)methane AI3-01501, see 2,4-Toluene diisocyanate AI3-01506, see p,p -DDT AI3-01535, see 2,4-Dinitrophenol AI3-01537, see 2-Chloronaphthalene... 

Table 8.9 shows the non-fuel uses of toluene. Some of the toluene goes into gasoline depending on its supply and price compared to other octane enhancers. Of the other uses of toluene about half is converted into benzene by hydrodealkylation, though this amount varies with the price difference between benzene and toluene. 2,4-Toluene diisocyanate (TDI) is a monomer for polyurethanes. Included in miscellaneous uses is 2,4,6-trinitrotoluene (TNT) as an explosive. 

The two key isocyanates that are used in the greatest volumes for polyurethane polymers are toluene diisocyanate (TDl) and methylene diphenyl diisocyanate (MDl). Both isocyanates are produced first by nitration of aromatics (toluene and benzene, respectively), followed by hydrogenation of the nitro aromatics to provide aromatic amines. In the case of MDl, the aniline intermediate is then condensed with formaldehyde to produce methylene dianiline (MDA), which is a mixture of monomeric MDA and an oligomeric form that is typical of aniline/formaldehyde condensation products [2]. The subsequent reaction of phosgene with the aromatic amines provides the isocyanate products. Isocyanates can also be prepared by the reaction of aromatic amines with dimethylcarbonate [3, 4]. This technology has been tested at the industrial pilot scale, but is not believed to be practiced commercially at this time. 

Fig. 2. Reactivity of aromatic diisocyanates 0.02 M with 2-ethyihexanol 0.4 M and diethylene glycol adipate polyester in benzene at 28°C. (A) l-Chloro-2,4-phenylene diisocyanate. (B) m-Phenylene diisocyanate. (C) p-Phenylene diisocyanate. (D) 4,4 -Methylene bis(phenyl isocyanate). (E) 2,4-Tolylene diisocyanate. (F) Tolylene diisocyanate (60%, 2,4-isomer, 40% 2,6-isomer). (G) 2,6-Tolylene diisocyanate. (H) 3,3 -Dimethyl-4,4 -biphenylene diisocyanate (0.002 M) in 0.04 M 2-ethylhexanol. (I) 4,4 -Methylene bis(2-methylphenyl isocyanate). (J) 3,3 -Dimethoxy-4,4 -biphenylene diisocyanate. (K) 2,2,5,5 -Tetramethyl-4,4 -biphenylene diisocyanate. (L) 80% 2,4- and 20% 2,6-isomer of tolylene diisocyanate with diethylene glycol adipate polyester (hydroxyl No. 57, acid No. 1.6, and average molecular weight 1900). Reprinted from M. E. Bailey, V. Kirss, and R. G. Spaunburgh, Ind. Eng. Chem. 48, 794 (1956). (Copyright 1956 by the American Chemical Society. Reprinted by permission of the copyright owner.)...

Chlorine atoms in (trichloromethyl)benzenes which have fluoro, chloro, dichloromethyl, chloroformyl, cyano, isocyanato, jV-phthalimino or methyl substituents in the ring are substituted by fluorine using antimony(III) fluoride (Swarts reaction).3 4 2-(Trifluoromethyl)phen-yl isocyanate, 4-chloro-2-(trifluoromethyl)phenyl isocyanate, 2,4- and 2,5-bis(trifluoro-methyl)phenyl isocyanate, and 2,4-bis(trifluoromethyl)-l,5-phenylenc diisocyanate can be obtained in this way.5... 

Solubility 2,4- and 2,6-Toluene diisocyanates decompose in water and are very soluble in acetone and benzene (Lide, 1997)... 

Amberlite XAD-2 and XAD-4 resins, for example, contain significant quantities of alkyl derivatives of benzene, styrene, naphthalene, and biphenyl as received from the supplier. PUF products, on the other hand, generally contain numerous contaminants peculiar to one of the several patented commercial manufacturing processes. These include, but are not limited to, the following classes of chemical contaminants isocyanate derivatives (e.g., toluene diisocyanates), alkyl amines, aliphatic acids, and brominated aromatics (e.g., fire retardants). 

The dealkylation of toluene is a prime source of benzene, accounting for about one-half of toluene consumption. The production of diisocyanates from toluene is increasing. As a component of fuels, the use of toluene is lessening. Toluene takes part in several industrially important syntheses. The hydrogenation of toluene yields methyl cyclohexane (C6HnCH3), a solvent for fats, oils, rubbers, and waves. Trinitrotoluene [TNT, CH3C6H2(N02)3] is a major component of several explosives. When reacted with sulfuric acid, toluene yields o- and p-toluene sulfonic acids... 

Aniline (C6H5NH2) is made by nitration of benzene to nitrobenzene, followed by hydrogenation over a Cu/Si02 catalyst. The major use of aniline is in making diisocyanates, which are used in producing polyurethane materials (e.g., for home insulation). 

Nitrobenzene Nitrobenzene is made by the direct nitration of benzene with nitric/sulfuric acid mixtures primarily for aniline production. And aniline is a raw material for the manufacture of methylene diphenyl diisocyanate (MDI) that is used to make rigid foams. 

Many nitro derivatives of benzene and naphthalene were of importance in the past, since toluene - the starting compound in the manufacture of TNT - could only be prepared by distillation of coal. Owing to the advances in petrochemistry, toluene is now available in practically unlimited amounts the bulk of the toluene now produced is employed as the starting material for the preparation of toluene diisocyanate (TDI) used in the production of plastics. 

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... 

SYNS BENZENE-L3-DIISOCYANATE BENZENE, 1,3-DIISOCYANATO- 1,3-DIISOCYANATOBENZENE... 

SYNS BENZENE, l,3-BIS(ISOCYANATOMETHYL). (9CI) l,3-BIS(ISOCYANATOMETHYL)BENZENE 1,3-BIS-(ISOKYANATOMETHYL)BENZEN m-PHENYL-ENEDIMETHYLENE ISOCYANATE TAKENATE TAKENATE 500 m-XDI m-XYLIDENE DIISOCY-ANATE m-XYLYLENDIISOKYANAT m-XYT.YT.F.NE DIISOCYANATE XYLYLENDIISOKYANAT (CZECH)... 

The reactions of several diisocyanates with a large excess of 2-ethyl-hexanol have been reported by Bailey et al. [122]. Reactions were run in benzene with the extent of reaction being followed by loss of infrared absorption at 4.4 pm, characteristic for the isocyanate group. A sharp decrease in the rate of reaction of 2,4-tolylene diisocyanate and the 80 20 isomer ratio of tolylene diisocyanate at approximately 50% reaction was found. In contrast, 2,6-tolylene diisocyanate, 4,4 -diphenyImethane diisocyanate, p-phenylene diisocyanate and m-phenylene diisocyanate showed only a slight decrease in rate as the reaction proceeded. 

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