Hemimellitene 1,2,3-Trimethylbenzene

The reaction chemistry observed to date amply confirms this expectation. Because of the rich chemistry that can stem from ipso ions, it seemed important to us to select a tractable system and proceed to build a data base by examination of that system. With reference points established one can more profitably study structural variations and changes in reaction chemistry that attend such variation. The acetyl nitrate adducts derived from hemimellitene (1,2,3-trimethylbenzene) are particularly useful for this purpose. Both the cis and trans isomers may be rather easily isolated from nitration mixtures by low temperature crystallization procedures. The crystalline dienes thus obtained axe stable in the cold and may be stored for long periods. The intent of the discussion that follows is to exenplify some of the chemistry of ipso ions by reference to some of our studies of the adducts of hemimellitene. 

CAS 526-73-8 EINECS/ELINCS 208-394-8 Synonyms Hemellitol Hemimellitene Trimethylbenzene... 

All the PMBs are Hsted on the U.S. EPA s Toxic Substances Control Act NonConfidential Chemical Substances Inventory (Table 8). In the early to mid-1980s, pseudocumene, mesitylene, hemimellitene, and trimethylbenzene were coveted by TSCA Section 8(a) Preliminary Assessment Information Rule (PAIR) reporting requirements (22) and by TSCA Section 8(d) for health and safety data (23). Mesitylene is the subject of a test rule subacute oral toxicity and subchtonic oral toxicity in tats were underway in 1994 (24). The Safe Drinking Water Act (SDWA) allows monitoring for pseudocumene and mesitylene at the discretion of the State (25). Of the PMBs, only pseudocumene is subject to SARA Tide III section 313 annual release reporting (26). 

Hemimellitene. In addition to some specialized solvent appHcations, hemimellitene can be converted to musk Tibetine [145-39-17, 1-/gf/-butyl-3,4,5trimethyl-2,6-dinitrobenzene (14) via 5-/ l -butyl-l,2,3-trimethylbenzene [98-23-7] (13). 

Common Name 1,2,3-Trimethylbenzene Synonym hemimellitene Chemical Name 1,2,3-trimethylbenzene CAS Registry No 526-73-8 Molecular Formula C9H12, C6H3(CH3)3 Molecular Weight 120.191 Melting Point (°C) ... 

Hemellitol, see 1,2,3-Trimethylbenzene Hemimellitene, see 1,2,3-Trimethylbenzene Hemimellitol, see 1,2,3-Trimethylbenzene Hemiterpene, see 2-Methyl-l,3-butadiene Hemostyp, see 1-Butanol HEOD, see Dieldrin HEPT, see Tetraethyl pyrophosphate Heptachlorane, see Heptachlor... 

Polymethylbenzenes (PMBs) are aromatic compounds that contain a benzene ring and three to six methyl group substituents (for the lower homologues see Benzene Toluene Xylenes and ethylbenzene). Included are the trimethylbenzenes, C9H12 (mesitylene (1), pseudocumene (2), and hemimellitene (3)), the tetramethylbenzenes, C1QH14 (durene (4), isodurene (5), and prehnitene (6)), pentamethylbenzene, C..J1 (7), and hexamethylbenzene, C12H18 (8). The... 

Azido>1,2,3.trimethylbenzene or Azido-hemimellitene. See under Heroimellitene and Derivatives... 

HEMA. See 2-Hydroxyethyl methacrylate Hemellitol Hemimellitene. See1,2,3-Trimethylbenzene... 

Petroleum- and coal-derived heavy gasoline fractions with a boiling range of around 160 to 220 °C contain polymethylated benzenes, such as trimethylbenzenes (pseudocumene, mesitylene and hemimellitene), together with the tetramethylated benzenes durene, isodurene and prehnitene. Indane and indene compounds, penta- and hexamethylbenzene and cumene, are also present in these heavy gasoline fraction. (Cumene is predominantly converted to phenol as described in Chapter 5.2). 

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