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The hydroformylation process, involves the preparation of oxygenated organic compounds by the reaction of carbon monoxide and hydrogen (synthesis gas) with olefinic carbon compounds. Olefins which do not react, and paraffins produced by side reactions are the primary components of Mixed LOF.


The oxo reaction is performed under hydroformylation conditions in the presence of a carbonylation catalyst or catalyst precursor such as dicobaltoctacarbonyl, and results in the formation of a compound (e.g. an aldehyde) which has one more carbon atom in its molecular structure than the feedstock. Subsequent hydrogenation of the hydroformylation product leads to formation of the desired product alcohols. By virtue of the nature of the feedstock commonly available to industry, and indeed of the catalyst and reaction parameters employed, the hydroformylation reaction inevitably yields a range of products due to the numerous secondary reactions which take place.


Mixed LOF (Alkenes, C6-10, hydroformylation products, low-boiling; no CAS RN; EC number 931-285-8) is a byproduct from C7-C11 alcohol production. In the hydroformylation process olefins (alkenes) are catalytically reacted with carbon monoxide and hydrogen, resulting in a range of products including primary alcohols. Alcohols are separated from the reaction mixture by distillation, with the remaining LOF containing unreacted olefins (alkenes) and paraffins (alkanes), frequently of the branched [iso-] form. Compositional analysis indicates Mixed LOF is approximately a 50/50% mixture of olefins and paraffins with a boiling point range of 102 – 182 ºC.


 While toxicity data are not available for LOF, based on composition and physical chemical characteristics it is appropriate to use data from naphtha petroleum streams with low levels of aromatic groups and carbon number ranges similar to C6-10. Naphtha streams are derived from the same original feedstock (crude petroleum) with a key process difference – feedstocks to the hydroformylation process (e.g., propylene, butene, and pentenes and combinations thereof) have very low to neglible aromatic material (e.g., benzene or toluene). Thus, use of naphtha streams can generally be considered a conservative read-across approach.


Light Catalytic Cracked Naphtha (LCCN; CAS No. 64741-55-5, consisting of hydrocarbons derived from a catalytic cracking process in the range of 4 to 11 carbons with a boiling range of approximately 65 to 230 degrees centigrade;) or Light Straight Run Naphtha (LSRN; CAS No. 64741-46-4, 64741-46-4, consisting predominantly of aliphatic [paraffinic and isoparaffinic] hydrocarbons in the range of 4 to 10 carbons and boiling between -20 to 180 degree centigrade) as read-across.


There is a relatively large database on genetic toxicity studies of gasoline covering both in vivo and in vitro tests. Blended gasoline was not mutagenic, either with or without metabolic activation, in in vitro test systems, including Salmonella typhimurium, Saccharamyces cerevisiae, a mammalian cell line (L5178Y), and human lymphoblastoid cells, or in in vivo test systems, including rat micronucleus and rat chromosome aberration assays.

Endpoint Conclusion:

Justification for classification or non-classification

Unlike LCCN, benzene concentrations in LOF are at levels that would not warrant classification as a genetic toxin according to the general classification and labeling requirements for dangerous substances and preparations (Directive 67-548-EEC) or the classification, labeling and packaging (CLP) regulation (EC) No 1272/2008.

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