General Description
Colorless to light tan crystalline powder or solid. Odor threshold 1.2 mg/L. Taste threshold 0.05 mg/L.
Reactivity Profile
3,4-DIMETHYLPHENOL(95-65-8) is incompatible with bases, acid chlorides, acid anhydrides, and oxidizing agents. 3,4-DIMETHYLPHENOL(95-65-8) corrodes steel, brass, copper, and copper alloys.
Air & Water Reactions
Hygroscopic. Insoluble in water.
Fire Hazard
Flash point data for this chemical are not available. 3,4-DIMETHYLPHENOL is probably combustible.
Chemical Properties
YELLOW TO BROWNISH CRYSTALLINE MASS
Occurrence
Reported found in coffee, tomato, parmesan and romano cheese, smoked fatty fish, white wine, katsuobushi
(dried bonito) and wood vinegar.
Uses
Applications of 3,4-dimethylphenol:
- It can react with ethyl cinnamates in trifluoroacetic acid to form the corresponding dihydrocoumarin derivatives.
- Bromination of 3,4-dimethylphenol using bromine can lead to 6-bromo-3,4-dimethylphenol.
- It can react with 1-fluoro-4-chloromethyl-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoro-borate) (Selectfluor? F-TEDA-BF4) to form 4-fluoro-3,4-dimethylcyclohexa-2,5-dienone.
Definition
ChEBI: 3,4-xylenol is a member of the class of phenols that is phenol substituted by methyl groups at positions 3 and 4. It derives from a hydride of an o-xylene.
Aroma threshold values
Detection: 1.2 ppm
Purification Methods
Heat 3,4-xylenol with an equal weight of conc H2SO4 at 103-105o for 2-3hours, then dilute it with four volumes of water, reflux it for 1hour, and either steam distil or extract it repeatedly with diethyl ether after cooling to room temperature. The steam distillate is also extracted and evaporated to dryness. (The purification process depends on the much slower sulfonation of 3,4-dimethylphenol than most of its likely contaminants.). It can also be crystallised from water, hexane or pet ether, and sublimed in a vacuum. [Kester Ind Eng Chem (Anal Ed) 24 770 1932, Bernasconi & Paschalis J Am Chem Soc 108 29691986, Beilstein 6 IV 3099.]
Toxics Screening Level
The current initial threshold screening level (ITSL) for 3,4-dimethylphenol is 3.5 μg/m3 based on an annual averaging time.
