Toluene derivatives

Other than benzene, 30% of which is made from toluene by the hydrodealkylation process, there are no other top 50 chemicals derived from 

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. 

Finally, benzaldehyde, an ingredient in flavors and perfumes, is made by dichlorination of toluene (free radically via the easily formed benzyl radical) followed by hydrolysis. 

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Toluene [108-88-3] 7 8 colorless, mobile liquid with a distinctive aromatic odor somewhat milder than that of ben2ene. The name toluene derives... 

The nitration of active methylene compounds generally proceeds via the reaction of carbanionic intermediates with an electrophilic nitrating agent such as alkyl nitrate (alkyl nitrate nitration). Details of this process are well documented in the reviews.38 The alkyl nitrate nitration method has been used extensively for the preparation of arylnitromethanes. The toluene derivatives, which have electron-withdrawing groups are nitrated with alkyl nitrates in the presence of KNH2 in liquid ammonia (Eqs. 2.19 and 2.20).39... 

The EtsSiH/tetracyanoethylene combination reduces acetals and ketals to the corresponding ethers but the yields are mixed.500 The full reduction of benz-aldehyde acetals to the toluene derivatives is realized by the initial reduction with Et3SiH/SnBr2-AcBr followed by Bu3SnH/AIBN (azobis(isobutyronitrile)) or LiAlH4.479 The overall yields are excellent. 

Fig. 12. Indirect electrooxidation of toluene and toluene derivatives using Mn(III) as mediator [140] Industrial plant...

The target homogenous chemical reaction is the oxidation of the toluene derivative to the benzaldehyde ... 

Fig. 13. Continuous indirect oxidation of toluene and toluene derivatives using a cascade process. Pilotstate [140]...

Furthermore, the mediator has been used for the bond cleavage of benzyl ethers, the oxidation of benzyl alcohol to benzaldehyde, the oxidation of toluene derivatives to benzoic acid esters, and the oxidation of aliphatic ethers [47]. 

The semiempirical AMI MO method has been used to calculate heats of formation of a series of m- and p-substituted benzene and toluene derivatives ArY and ArCHaY, and their phenyl or benzyl cations, anions, and radicals heterolytic and homolytic bond dissociation energies (BDEs) and electron transfer energies for the ions have also been calculated and the relationship A//het = A//et-I-AWhomo has been confirmed (it being noted that A//homo is insensitive to ring substituents). The linear relationship found between and the appropriate HOMO or LUMO... 

Benzylic halides and sulfonates show a wide range of reactivity towards nucleophiles. Activation and deactivation by o-/p-donors (e.g. OR) and acceptors (e.g. N02), respectively, are consistent with PAR. In each case the benzylic carbon atom is identified as acceptor or donor. The trends are also reflected in the relative acidities of the corresponding toluene derivatives. 

The previously available methods for the preparation of such compounds were somewhat limited in their application. First, the oxidative coupling of 2 molecules of a heterocyclic-substituted toluene derivative in lie presence of sulfur results in the formation of symmetrical stil-benes,4,5 as shown by the synthesis of 4,4 -bis(benzimidazol-2-yl)stilbene (2). The disadvantages of this method are the high reaction temperatures necessary and the difficulties often involved in product workup. 

Most V6-barriers determined involve methyl groups, and V6 is invariably found to be small in corroborations with the findings above. Typical values are V6 = —24.400 0.024 J/mol for CH3N0272 V6 = -57.61 J/mol for CH3BF273), and V6 = -58.37 0.08 J/mol for CH3C6H567). For other p-toluene derivatives V6 is typically about -60 J/mol44. ... 

Toluene [108-88-3]> C7Hg, is a colorless, mobile liquid with a distinctive aromatic odor somewhat milder than that of benzene. The name toluene derives from a natural resin, balsam of Tolu, named for a small town in Colombia, South America. Toluene was discovered among the degradation products obtained by heating this resin. 

Kovache and Thibon also found that similar inflammable metal products were formed by lower nitrated toluene derivatives, e.g. p- nitrotoluene and 2,4-dinitroto-luene, and also by trinitrobenzene. Nitrobenzene and trinitroxylene did not react... 

Some features of the British method which was developed during the 1914 1918 period are worth mentioning. One of them was the use of toluene derived from petroleum (Borneo petroleum), as well as toluene from coal. 

Detoluation. Another characteristic feature of this method was the extraction of higher nitrated toluene derivatives, dissolved in the spent acids. The latter were conveyed to denitration and distillation (concentration) only after the nitro compounds present in them had been extracted with nitrotoluene, an operation which was called detoluation . Primarily it consisted in stirring the spent acids, heated to 75-80°C with a quantity of crude MNT, amounting to one quarter of the acid volume. A slight amount of nitrotoluene became nitrated due to the presence of the unreacted HN03 in the spent acid. 

The rotation in toluene derivatives will be highly dependent on the size and electronic properties of the substituents. An interesting example is provided by 3,5-dichlorobenzyl alcohol, thiol and selenol (LXXI, X = O, S, and Se, respectively),... 

Toluene has been oxidized by the silver ion catalysed reaction with peroxy-disulfate. The reaction produces a mixture of bibenzyl, benzaldehyde and benzoic acids.299 Russian workers have described the conversion of 4-methoxy-toluene to the benzaldehyde by oxidation with peroxydisulfate in the presence of silver or copper ions and oxalic acid.300 The presence of copper salts in iron or copper catalysed peroxydisulfate oxidation is believed to suppress side-reactions.301 Phillips have patented a palladium(II)/tin(IV)/persulfate system for the oxidation of toluene derivatives.302 The reactions are carried out in carboxylic acid solvents (Figure 3.78). 

The selectivity of free-radical side-chain bromination of toluene derivatives using A-bromosuccinimide and leading to mono- and dibromo-substituted toluenes has been studied in different solvents [577]. Surprisingly, yields and seleetivities are much better in solvents such as methyl formate and dichloromethane than in the more commonly used tetrachloromethane. 

Toluene derivatives bearing electronegative substituents are fluorinated on the methyl group when reacted with lead(IV) oxide, nickcl(IV) oxide, cobalt(IIl) fluoride, cobalt(lll) acetate. silver(II) fluoride, or silver(ll) oxide in liquid hydrogen fluoride. The product obtained is dependent on the substrate and the metal oxidant employed, with benzyl fluorides I or (difluoromethyl)benzenes 2 as the major products. 

Oxidative fluorination of toluene derivatives to the corresponding fluoromethylben-zenes is possible using appropriate lead or nickel complexes in liquid hydrogen fluoride, but fluorination becomes more difficult as the reaction progresses because fluorine substituents increase the oxidation potential of the substrate [146] (Figure 3.20). Consequently, it seems unlikely that the ECF process (Chapter 2, Section III) could proceed to perfluorination by an analogous mechanism. 

The oxidation of the methyl group in toluene derivatives to the aldehyde is an important stage in triarylmethane dye manufacture, p- toluene sul-fonyl chloride is first hydrolyzed in concentrated sulfuric acid and then subjected to the oxidizing action of a manganese compound to produce benzaldehyde-4-sulfonic acid [11]. 

After Beilstein and Kuhlberg completed their work on the nitrotoluenes, they set about investigating toluene to discover whether or not this substance existed in isomeric forms, thinking thereby to explain the isomerism of the toluene derivatives. Their experiments are interesting in the extreme, but are too lengthy to discuss in this book. Suffice it to say that the results of their research proved conclusively that toluene existed in but one form. 

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