Trimethyl-benzene

Finally, note that 1,2,4-trimethyl benzene will be considered in paragraph 1.5.6. The previous table thus already solves some of the forthcoming problems. 

FIGURE 3.1.1.8.2 Logarithm of vapor pressure versus reciprocal temperature for 1,2,4-trimethyl benzene. 

The Cio fraction in reformates has been considered a likely petroleum source for obtaining durene (9). However, there are 28 kinds of isomeric arenes in the fraction, and the durene content is only 5-9%. Therefore, the isolation of durene from such a complicated mixture is inefficient, and some complicated techniques are required for it. In contrast, 1,2,4-trimethyl-benzene (pseudocumene) can be easily isolated simply by the distillation of the Cg fraction of the reformates, and a high-purity pseudocumene has been produced on an industrial scale. 

Occasionally you might come across a compound called pseudo-cumene, which is a benzene ring connected to three methyl groups. This compound is an isomer of cumene known as 1,2,4-trimethyl benzene. Pseudo-cumene is a starting material for the manufacture of trimilletic anhydride, an important ingredient in alkyd resin paints and high temperature aerospace poiyimide resins. 

Synonyms The three isomers of trimethyl benzene are mesitylene (1,3,5-trimethylben-zene, sym-trimethylbenzene, 1,3,5-TMB), pseudocumene (1,2,4-trimethyl benzene,... 

Dimethylbenzylazide 1 -Azide-pseudo cumene or 1 -Azido-1,2,4-trimethyl benzene,... 

Aromatic hydrocarbons which have methyl side chains mainly behave like toluene and form aldehydes, while combustion is stimulated and selective oxidation of the nucleus is repressed. The oxidation of methyl-naphthalene, for example, exhibits a low selectivity with respect to phtha-lic anhydride formation, combustion and maleic acid formation being the dominating reactions. Durene is a special case because it resembles o-xy-lene. The oxidation of durene over a V—W—O catalyst at 420° C is reported to produce pyromellitic dianhydride, phthalic and maleic anhydride, although combustion dominates (Geiman et al. [122]). 1,2,4-Trimethyl-benzene yields dimethylbenzene and trimellitic acid if oxidized on a Sn— V—O catalyst. Kinetic data have been measured by Balsubramanian and Viswanath [37]. 

Property 1,3,5-Trimethyl- benzene 1,2,4- Trimethyl- benzene 1.2.3- Trimethyl- benzene 1,2,4,5-Te tram ethylbenzene 1,2,3,5-Tfetramethyl-benzene 1,2,3,4-Tetramethyl-benzene Pentamethyl- benzene Hexamethyl- benzene... 

Bromo-3,6-dinitr0-1,2,4-trimethyl benzene, AP06 Bromoethane, AA80 Bromo-2-ethoxybenzene, AM86 (2-Bromoethoxy)benzene, AM88... 

Aminopseudocumenes or Amino-1,2,4-trimethyl-benzenes,(CH3)3C6Ha-NHa. Several isomers are known of which the 5-aminopseudocumene is the most important. Its mono- and dinitro- compds are known but they are not expl. Azido- and diazido- derivs were not found in Beil or CA through 1956... 

Component 1 in Singapore buildings was correlated with compounds associated with humans and their activities. Human effluents have been reported to contain isoprene (Ellin et al, 1974) while tetrachloroethylene is a VOC found in dry-cleaned clothes worn by building occupants (Wallace, Pellizzari and Wendel, 1991) or from the use of consumer products (Sack et al., 1992). Tetradecane, benzaldehyde, o-xylene, naphthalene are emissions from dry process photocopiers (Leovic et al., 1996). Component 2 with high loadings ofn-decane, n- undecane, toluene, styrene, n-nonane, 1,2,4-trimethyl benzene probably reflects the emissions of carpets and vinyl floorings (Yu and Crump, 1998). Component 3 was primarily correlated with heptane and methylcyclopentane, which could be due to the emissions of water-based paints. Finally, component 4 was associated with 2-methylpentane, hexane, cyclohexane, methylcyclohexane and limonene, which is reflective of the emissions of air fresheners and cleaning products (Sack et al., 1992). 

The most widely used primary solvent is toluene. Other primary solvents are p-, m-, and mixed xylene. Pseudocumene (1,2,4-trimethyl benzene) is becoming a popular solvent for new, commercially produced scintillation cocktails. It offers the highest energy conversion efficiency of the solvents known, and has fewer restrictions on shipping and storage of a combustible liquid because of its high flash point, low volatility and lower toxicity. 

The separation effect for the mixture of 1,2,4-trimethylbenzene and 1,3,5-trimethyl-benzene is similar, and as the amount of Si(OCH3)4 used increases, the pore size of NaY zeolite is narrowed gradually, and the adsorption selectivity of the zeolite for 1,2,4-trimethylbenzene increases rapidly. When the Si(OCH3)4 amount used is 0.15 mL/g, the adsorption capacity of the zeolite for 1,2,4-trimethylbenzene remains almost unchanged, but the adsorption for 1,3,5-trimethylbenzene is very small, and the 1,2,4-trimethyl benzene adsorption selectivity is exceeds 90%, achieving an ideal separation effect as shown in Figure 6.24.[64] Comparison of the two systems reveals that to achieve an ideal separation effect, more modifier is required that is, the zeolite pore size should be narrower for separation of trimethylbenzene mixture because the size of the 1,3,5-trimethylbenzene molecule is smaller that that of 1-methylnaphthalene. 

The only aromatic components that appeared at reaction temperatures below 300 °C were toluene and p-xylene. In the case of the small-crystalline H-ZSM-5(M), however, some m- and o-xylene were present in the product mixture even at 245 °C (WHSV = 6 h- ). This can be explained by xylene isomerization at the outer zeolite surface. At conditions where the para-selectivity was high (more than 90% para), the amount of p-ethyl-toluene (PET) in the product were one order of magnitude greater than that of any other Cg-component, but when it was low, the ratio 1,2,4-trimethyl-benzene (124TMB) PET was found to be about 10 1. These experimental facts indicate that 124TMB is mainly formed by secondary xylene alkylation with methanol. Toluene, p-xylene, PET and perhaps ethyl-benzene are more likely to be the primary aromatic products formed in the MTG-reaction. To confirm this suggestion the molar product ratios EB/PX,... 

Following are the slightly smoothed heat-of-mixing data of R. P. Rastogi, J. Nath, and J. Misra [J. Chem. Thermodyn., 3, 307 (1971)] for the system trichloromethane (component 1) and 1,2,4-trimethyl benzene at 35°C. 

AI3-03976 Asymmetrical trimethylbenzene Benzene, 1,2,4-trimethyl- Benzene, 1,2,5-trimethyl- EINECS 202-436-9 HSDB 5293 NSC 65600 Pseudocumene Pseudocumol psi-Cumene as-Trimelhylbenzene Uns-trimethylbenzene. Used as a solvent in chemical manufacturing and in scintillation counters. Oil mp = -43.8° bp = 169.3° d O = 0.8578 Xm = 267, 277 nm (MeOH) insoluble in H2O, freely soluble in EtOH, EtzO, MezCO, CsHe, CCI4, petroleum ether. 

Trimethyl-1,3,5-benzene. See 1,3,5-Trimethyl benzene as-Trimethylbenzene. See 1,2,4-Trimethyl benzene sym-Trimethylbenzene. See 1,3,5-Trimethyl benzene... 

Triethyl phosphine Triethyl phosphite Triethyl phosphonoacetate Triethyl phosphonoformate Triisopropyl phosphite 3,4,5-Trimethoxybenzoyl chloride 1,2,4-Trimethyl benzene 2,4,6-Trimethylbenzoyldiphenylphosphine oxide Trimethyl phosphite Tripropylene glycol Urethane n-Valeric acid Vinyl bromide p-Xylene D(+)-Xylose intermediate, pharmacologicals... 

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