Pentamethylbenzene Chemical Properties

Melting point:

49-51 °C (lit.)

Boiling point:

231 °C (lit.)

Density 

0.917 g/mL at 25 °C (lit.)

refractive index 

1.5270

Flash point:

196 °F

storage temp. 

Sealed in dry,Room Temperature

form 

powder to crystal

color 

White to Almost white

Water Solubility 

15.52mg/L(temperature not stated)

BRN 

1905349

CAS DataBase Reference

700-12-9(CAS DataBase Reference)

NIST Chemistry Reference

Benzene, pentamethyl-(700-12-9)

EPA Substance Registry System

Benzene, pentamethyl- (700-12-9)

Safety Information

Hazard Codes 

F,Xi

Risk Statements 

11-36/37/38

Safety Statements 

16-26-36

RIDADR 

UN 1325 4.1/PG 2

WGK Germany 

3

TSCA 

Yes

HazardClass 

4.1

PackingGroup 

III

HS Code 

29029090

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Pentamethylbenzene Usage And Synthesis

Chemical Properties

Pentamethylbenzene is a white to light yellow crystalline powder with a sweet odor. The compound is classified as an aromatic hydrocarbon. It is a relatively easily oxidized benzene derivative, with E1/2 of 1.95 V vs NHE.

Uses

Pentamethylbenzene was used to prepare a mixture of nitropentamethylbenzene and 2,3,4,5-tetramethylbenzyl nitrate. It was also used to prepare propene.

Definition

ChEBI: Pentamethylbenzene is a methylbenzene that is benzene in which five of the hydrogens are replaced by methyl groups.

Synthesis Reference(s)

Synthesis, p. 979, 1985 DOI: 10.1055/s-1985-31413

Synthesis

Pentamethylbenzene is obtained as a minor product in the Friedel–Crafts methylation of xylene to durene (1,2,4,5-tetramethylbenzene). Like durene, pentamethylbenzene is rather electron-rich and undergoes electrophilic substitution readily. Indeed, it is used as a scavenger for carbocations.
Pentamethylbenzene has been observed as an intermediate in the formation of hexamethylbenzene from phenol and alkylation of durene or pentamethylbenzene has been reported as a suitable starting material for the synthesis of hexamethylbenzene.

Purification Methods

Successively crystallise it from absolute EtOH, aqueous EtOH, MeOH, toluene *C6H6, and dry it under vacuum. [Rader & Smith J Am Chem Soc 84 1443 1962.] It has also been sublimed. The 1,3,5-trinitrobenzene complex (1:1) has m 121o (EtOH). [Beilstein 5 H 443, 5 III 1010, 5 IV 1109.]

Precautions

Incompatible with oxidizing agents. Store in cool place. Keep container tightly closed in a dry and well-ventilated place.

Pentamethylbenzene(700-12-9)Related Product Information

• o-Xylene
• p-Toluenesulfonic acid
• Tolylene-2,4-diisocyanate
• Xylene
• 4-(Aminomethyl)benzoic acid
• 1-BROMO-2,3,4,5,6-PENTAMETHYLBENZENE
• HEXAMETHYLBENZENE
• 2,3,5,6-TETRAMETHYL-P-XYLENE-ALPHA,ALPHA'-DIOL
• PENTAMETHYLBENZONITRILE
• MELLITIC ACID
• à(2),à(4)-dichloro-1,2,3,4,5-pentamethylbenzene,2,4-Bis(chloromethyl)-1,3,5-trimethylbenzene~alpha(2),alpha(4)-Dichloro-1,2,3,4,5-pentamethylbenzene
• 2 3 5 6-TETRAMETHYLBENZOIC ACID 98
• 3-Aminopyridine
• 2',3',4',5',6'-PENTAMETHYLACETOPHENONE
• 2,3,5,6-TETRAMETHYLACETOPHENONE
• 2,3,5,6-TETRAMETHYLBENZYL CHLORIDE
• 1-(HYDROXYMETHYL)-2,3,4,5,6-PENTAMETHYLBENZENE
• DECACYCLENE