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Guide on the application of REACH Regulation

3.2 Group of Substances :

Substances

Well defined Substances Substances with Unknown or Variable
composition / Complex reaction products /

Biological Substances (UVCB)

Mono constituent Substances Multi constituent Substances Substance defined by
more than the chemical
- One Main - Defined reaction
Constituent ≥ 80% mass composition
(remaining 20% can - Chemical
be impurities or bye- - Each component ≥
products) 10% but ≤ 80% composition as
mono or multi
- CAS No / EC No of - CAS No / EC No of constituent
main constituent main constituent - Additional
information required
- Named according - Name as reaction
to main constituent mass of constituents Carbon / Graphite
(not starting
- Typical products) CAS [82600-58-6]
concentration
(upper / lower limit) - Typical Cyrstallomorphology
concentration and mineral composition
Benzene (upper / lower)

CAS No Chlorination of toluene
giving a Reaction mass
71-42-3 of

Content 86-94% - 2-Chlorotoluene [95-
49-8]

30-35%

- 3-Chlorotoluene
[108-41-8]

15-25%

- 4-Chlorotoluene
[106-43-4]

40-45%

Multi constituent substances should not be confused with preparations (mixtures) wherein the latter,
the other components are added intentionally and not present as a course of reaction (as bye-

products or impurities)

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