1.4- Cyclohexane diisocyanate

CbH)I [AMINES - CYCLOALIPHATIC AMINES] (Vol2) trans-1,4-Cyclohexane diisocyanate [7517-76-2]... 

Ak2o has been iastmmental ia developiag a new process for the stereospecific synthesis of 1,4-cyclohexane diisocyanate [7517-76-2] (21). This process, based on the conversion of poly(ethylene terephthalate) [25038-59-9] circumvents the elaborate fractional crystallisation procedures required for the existing -phenylenediamine [108-45-2] approaches. The synthesis starts with poly(ethylene terephthalate) (PET) (32) or phthaUc acid, which is converted to the dimethyl ester and hydrogenated to yield the cyclohexane-based diester (33). Subsequent reaction of the ester with ammonia provides the desired bisamide (34). The synthesis of the amide is the key... 

C8H9N02 4-amino-3-methylbenzoic acid 2486-70-6 19.47 1.1446 2 13879 C8H10N2O2 trans-1,4-cyclohexane diisocyanate 7517-76-2 20.67 1.2275 2... 

Since preparation of this manuscript, subsequent studies were completed (11) on new segmented polyurethanes of type I made exclusively from polyethylene oxide diols, ethylene diamine, and 1,4-cyclohexane diisocyanate (CHDI) (no other diisocyanate was used). They were synthesized in toluene (not DMSO/pentanone)withdibutyltin dilaurate as catalyst (no catalyst was used to synthesize the polymers listed in Tables II and III) and eventually cast from hexafluroisopropanol or formic acid solutions (not DMF in which they were insoluble). 

Hexamethylene diisocyanate 2.2.4- Trimethylhexamethylene diisocyanate Hydrogenated xylylene diisocyanate 1.4- Cyclohexane diisocyanate 4,4 -Dicyclohexylmethane diisocyanate Xylylene diisocyanate Tetramethylxylylene diisocyanate Tolulene diisocyanate Diphenylmethane diisocyanate Poly(ethylene glycol) Poly(propylene glycol) Poly(tetramethylene ether glycol) Poly(hexamethylene ether glycol) Poly(ethylene adipate) Poly(butylene adipate) Poly(neopentyl adipate) Poly(3-methylpentyl adipate) Poly(caprolactone) diol... 

Trans-1,4-cyclohexane diisocyanate (CHDI)-based PU elastomers are known to be able to undergo isocyanurate crosslinking, and the procedure will now be described. 

These polyurethanes are based on the two diisocyanates, / -phenylene diisocyanate (PPDI) and trans-1,4-cyclohexane diisocyanate (CHDI). A materials-engineering specification for a hydraulic-seal application was selected to provide an objective, and this is given in Table 9.10. 

Problem 5.25 A cross-linked polyurethane is to be made from a diisocyanate, 1,4-frfl/ji-cyclohexane diisocyanate (CHDI), and a polymeric tetrol, R(OH)4, without addition of any water. Let the stoichiometric ratio of initial concentrations of NCO to OH groups be denoted by r. 

E.W. Merrill, E.W. Salzman, S. Wan, N. Mahmud, L. Kushner, J.N. Lindon, and J. Curme. Platelets-compatible hydrophilic segmented polyurethanes from polyethylene glycols and cyclohexane diisocyanate. Trans, Am. Soc. 

The elusive parent diisocyanate, 0=C=N—N=C=0, is only stable at —75°C, and therefore it is not suitable as a monomer for polyurethanes (23). The least costly aliphatic diisocyanate is hexamethylene diisocyanate (HDI), which is obtained by phosgenating the nylon intermediate hexamethylenediamine (HDA). Because of its low boiling point, HDI is mostly used in the form of its derivatives, such as biurets, allophanates, dimers, or trimers (24). Isophorone diisocyanate (IPDI) and its derivatives are also used in the formulation of rigid coatings, while hydrogenated MDI (HMDI) and cyclohexane diisocyanate (CHDI) are used in the formulation of flexible coatings and polyurethane elastomers. 

Subsequent chlorination of the amide takes place ia a two-phase reaction mixture (a dispersion of diamide ia hydrochloric acid) through which a chlorine stream is passed. The temperature of this step must be maintained below 10°C to retard the formation of the product resulting from the Hofmann degradation of amides. Reaction of the A/,A/-dichloroamide with diethylamine [109-89-7] ia the presence of base yields /n j -l,4-cyclohexane-bis-l,3-diethylurea (35), which is transformed to the urea hydrochloride and pyroly2ed to yield the diisocyanate (36). 

HMD was originally produced by Du Pont as a coproduct in the manufacture of Qiana fiber. Du Pont subsequently sold the product to Bayer. In the 1990s MDA is hydrogenated by Air Products for Bayer (see Amines, aromatic-methylenedianiline). Commercial HMDI is a mixture of three stereoisomers. Semicommercial aUphatic diisocyanates include /n j -cyclohexane-l,4-diisocyanate (CHDI) and y -tetramethylxylylene diisocyanate (TMXDI). A coproduct in the production of TMXDI is y -isopropenyl-a,a-dimethylben2yl isocyanate (TMI), which can be copolymerized with other olefins to give aUphatic polyisocyanates. 

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... 

SYNS CYCLOHEXANE, 5-ISOCYANATO-l-(ISOCYANATOMETHYL)-l,3,3-TRIMETHYL-(9CI) IPDI 3-ISOCYANATOMETHYL-3,5,5-TRIMETHYLCYCLO-HEXYLISOCYANATE ISOPHORONE DIAMINE DIISOCYANATE ISOPHORONEDIISOCYANATE, solution, 70%, by weight (DOT) TRIISOCYANATO-ISOCYANURATE, solution, 70%, bv weight (DOT)... 

Lin in his doctoral thesis. The only difference was in the type of diisocyanate - our formulation was based on aromatic diisocyanate (MDI), and Lin s formulation was based on aliphatic diisocyanate, 1,4-isocyanatomethyl cyclohexane (p-BDI). 58% conversion level at... 

Secondly, the reaction was inhibited by both strong and weak acids. Strong acids, such as HBF4, completely stopped the reaction. Weaker acids, snch as acetic acid, had a much less pronounced and concentration-dependent effect. It has been snggested that the concept of the ionic mechanism mnst be viewed with some degree of caution, since the reaction proceeded faster in non-polar solvents, snch as cyclohexane, compared with a dipolar aprotic solvent, snch as dimethylformamide, whereas one wonld expect that the polarity of the solvent wonld significantly stabilize the ionic catalyst intermediates. However, Urban et al. have demonstrated that an ionic mechanism is likely operative in the reaction of hexamethylene diisocyanate with an acrylic polyol, nsing DBTDL as catalyst. 

Triohdiisocyanate 1 1 NCO OH, 70% solution in dioxane 70 °C, 1,6-hexamethylene diisocyanate (HDD, 5-isocyanato-1-(isocyanato-methyl)-1,3,3-trimethyl-cyclohexane (IPDI), 1,1 -methylenebis[4-isocyanato-cyclohexane (H12MDI), 1,1 -methylenebis [isocyanato-benzene (MDI) and 1,3-diisocyanatomethyl-benzene (TDI). Me % = percent metal based on polymer solids... 

The amine-based Henry reaction catalyst was encapsulated via the interfacial polymerization of oil-in-oil emulsions. PEI was encapsulated by dispersing a methanolic PEI solution into a continuous cyclohexane phase. Upon emulsification, 2,4-tolylene diisocyanate (TDI) was added to initiate crosslinking at the emulsion interface, forming polyurea shells that contain free chains of PEI. The microcapsules crenate when dry and swell when placed in solvents such as methanol and dimethylformamide, suggesting a hollow capsule rather than a solid sphere formation. The catalyst loading was determined to be 1.6 mmol g . ... 

Figure 3.39 Alicyclic isocyanates, (a) Isophorone diisocyanate (or 3-isocyanato-methyl-3,5,5—trimethylcyclohexyl isocyanate), Huels IPDI (b) l,4-bis(isocyanatometh-yl)cyclohexane, Mobay s p-Desmodur (c) l,3-bis(isocyanatomethyl)cyclohexane, Takeda s Hr,XDI (S3.50) (d) Methylene bis(4—cyclohexylisocyanate), Mobay s Desmodur W ( 3.00). also known as H12MDI, RMDI (reduced MD1), and PACM [bis-/ -aminocyclohcxyl methane].

Reactivity Studies and Cast Elastomers Based on fra/is-Cyclohexane-l,4-Diisocyanate and 1,4-Phenylene Diisocyanates... 

BRN 2217800 CP 99173 Cyclohexane, 1,1 -methylenebis(4-isocyanate- Dicyclohexylmethane 4,4 -diisocyanate EINECS 225-863-2 Hydrogenated MDI Hylene W Isocyanic acid, methylenedi-... 

BRN 2726467 CCRIS 6252 Cyclohexane, 5-isocyanato-1-(isocyanatomethyl)-l,3,3-trimethyl- EINECS 223-861-6 HSDB 6337 IPDi Isophorone diamine diisocyanate Isophorone diisocyanate UN2290 Vestanat IPDI, Raw matenal for mfg. of light stable polyurethanes. Degussa-Huls Corp. 

Many polyurethenes for biomedical applications are available from commercial manufacturers (see Table A.2) Biomer (Ethicon) is composed primarily of methylenediphenylenediisocyanate, ED, and PTMO (2 1 1), see [42] Biomer and Pellethane were used in the artificial-heart program at the University of Utah. Medtronics produces polyurethanes Biostable C-19 and Biostable C-36 using cyclohexane-1,4-diisocyanate, 1,6-hexanediol, and soft segments with 18 or 36 carbons. 

Carbonyl diisocyanate (46) was shown to undergo a Diels-Alder type of cycloaddition with azomethines to give 2,3,6,7-tetrahydro-4/7,8/7-[l,3,5]triazino[2,l-Z>][l,3,5]oxadiazin-4,8-diones (16) (Scheme 5). A large variety of the triazino[2,l-ft][l,3,5]oxadiazines were realized by the suitable selection of dienophiles. Thus, l,3,5-triazino[2,l-Z>][l,3,5]oxadiazines (17), (18 R = NMe), and (19) and were synthesized by the reaction of carbonyl diisocyanate with alkyl or aryl isocyanates, dimethyl cyanamide, or aliphatic carbodiimides, respectively <86CB1133>. Due to the high reactivity of the cumulated double bonds, carbonyl diisocyanate (46) was also found to undergo [4 + 2] cycloadditions with cyclohexanone to yield cyclohexan-l-spiro-9 -[l,3,5]-oxadiazino-[3,4-e][l,3,5j-dioxazin-5 -spiro-l"-cyclohexane-2, 7 -dione (47) (Scheme 6) <76LA1634>. 

---