Toluene with phosgene

Toluene 2,4-diisocyanate is formed from the reaction of 2,4-diamino-toluene with phosgene. Write the structure for toluene 2,4-diisocyanate. What is it used for ... 

Naphthol is mainly used in the manufacture of the insecticide carbaryl (59), l-naphthyl A/-methyicarbamate/ iJ-2j5 - (Sevin) (22), which is produced by the reaction of 1-naphthol with methyl isocyanate. Methyl isocyanate is usually prepared by treating methylamine with phosgene. Methyl isocyanate is a very toxic Hquid, boiling at 38°C, and should not be stored for long periods of time (Bhopal accident, India). India has developed a process for the preparation of aryl esters of A/-alkyl carbamic acids. Thus l-naphthyl methylcarbamate is prepared by refluxing 1-naphthol with ethyl methylcarbamate and POCl in toluene (60). In 1992, carbaryl production totaled > 11.4 x 10 t(35). Rhc ne-Poulenc, at its Institute, W. Va., facihty is the only carbaryl producer in United States. 

Phosgenation. The most important reaction of y -toluenediamine is with phosgene [75-44-5] to give toluene diisocyanate TDI (see... 

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. 

Carbazole-9-carbonyl chloride [73500-82-0J M 300.0, m 100-103 , 103.5-104.5 . Recrystd from C6H6. If it is not very pure (presence of OH or NH bands in the IR) dissolve in pyridine, shake with phosgene in toluene, evaporate and recrystallise the residue. Carry out this experiment in a good fume cupboard as COCI2 is very TOXIC, and store the product in the dark. It is moisture sensitive. The amide has m 246.5-247 , and the dimethylaminoethylamide hydrochloride has m 197-198 . [Weston et al. J Am Chem Soc IS 4006 1953.]... 

Diethylmethyl propylmalonate is reacted with LiAIH4, then H2SO4 to give 2-methyl-2-propyl-1,3-propanediol. That is reacted with phosgene in toluene to give the chlorocar-bonate which is in turn reacted with butylamine to give N-butyl-2-methyl-2-propyl-3-hy-droxy-propyl carbamate. 

The TDI mixture is synthesized from dinitrotoluenes hy a frrst-step hydrogenation to the corresponding diamines. The diamines are then treated with phosgene to form TDI. The yield from toluene is approximately 85% ... 

Chloropropyl)-2-piperidone and 1 -(2-chloroethyl)-2-pyrrolidone were reacted with phosgene in toluene, and the 2-chloro derivatives (466, n = 0, 1, R2 = H, R3 = (CH2), C1, m = 2, 3, R5 = Cl) were then reacted with Meldrum s acid (421) in the presence of triethylamine to give isopropylidene [l-(3-chloroalkyl)piperidin-2-ylidene]malonate and [l-(2-chloroethyl)pyrrolidin-2-ylidene]malonate (468, n = 0, 1 R2 = H ... 

Two other derivatives of toluene are the important explosive trinitrotoluene (TNT) and the polyurethane monomer toluene diisocyanate (TDI). TNT requires complete nitration of toluene. TDI is derived from a mixture of dinitrotoluenes (usually 80% o,p and 20% o,o) by reduction to the diamine and reaction with phosgene to the diisocyanate. TDI is made into flexible foam polyurethanes for cushioning in furniture (35%), transportation (25%), carpet underlay (20%), and bedding (10%). A small amount is used in polyurethane coatings, rigid foams, and elastomers. 

The extensive use of organic isocyanates in various industrial processes for production of high polymers has brought about tonnage production. Toluene diisocyanale is made by nitraiing toluene to the dinitro compound, which is then reduced to the diamine, and treated with phosgene to obtain ihe diisocyanale ... 

Toluene diisocyanale is widely used in the manufacture of urethane plastics, particularly the urethane foamed plastics. Another isocyanate, diphenylmethane 4,4 -diisocyanaie, is produced by reaction of aniline and formaldehyde, followed by reaction with phosgene hcho coo.. 

Foams. Polyurethane foams are prepared by the polymerization of polyols with isocyanates. One of the most commonly used reactive isocyanates toluenediisocyanate, TDI. It is made from toluene by nitration and then reduction followed by treatment with phosgene. The isocyanate residue reacts readily with alcohols to give carbamates (urethanes) or amines to give ureas. 

Major uses of aniline include the manufacture of / ,//-methylene diphenyl diisocyanate (MDI), which is polymerized with a diol (HO-R-OH) to give a polyurethane. Two moles of aniline react with formaldehyde to give />,//-methylenedianiline (MDA), which reacts with phosgene to give / ,//-methylene diphenyl diisocyanate. Toluene diisocyanate (TDI) also reacts with a diol to give a polyurethane, but polyurethanes derived from />,//-methylene diphenyl diisocyanate are more rigid than those from toluene diisocyanate. 

Toluene diisocyanate is derived from a mixture of dinitrotoluenes (usually 65 to 85% o./9-dinitrotoluene and 35 to 15% o,o-dinitrotoluene) followed by reduction to the diamine and reaction with phosgene to the diisocyanate. 

The reagent is obtained (90% yield) by reaction of 2-hydroxypyridine with phosgene and N(C2H5)3 in CH2C12/toluene.1... 

Mixed bis-lactim ethers of type (20) are best prepared by the following route, outlined for the bis-lactimether (20a) of Cyclo(L-Val-Ala). L-Val, the chiral auxiliary, is converted with phosgene into its N-carboxyanhydride (L-Val-NCA, Leuchs anhydride) (17)l5). This gives with D,L-Ala-OCH3 the dipeptide (18) which on heating in toluene cyclizes to the diketopiperazine (19). This is converted into the bis-lactim ether (20a) [(3RS, 6S)-2,5-dimethoxy-6-isopropyl-3-methyl-3,6-dihydropyra-zine] with methyl Meerwein s salt. 

Cyclohexanemethylamine (68.66 g) and 200 ml 5M NaOH were stirred at — 10°C, then treated with phosgene (30.0 g) dissolved in 600 ml toluene, and stirred 20 minutes. A solid that formed was isolated, washed with 1500 ml water, dried, and the product isolated in 95% yield as a white powder, mp = 150—152°C. 

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