Tetramethyl acetyloctahydronaphthalenes

Chemical Summary

OTNE is the abbreviation for the fragrance material with Chemical Abstract Service (CAS) numbers 68155-66-8, 54464-57-2 and 68155-67-9 and EC List Nr: 915-730-3. It is a multi-constituent isomer mixture containing:

1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one (CAS# 54464-57-2)

1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one (CAS# 68155-66-8)

1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one (CAS# 68155-67-9)

All isomers conform to the chemical formula C16H26O and have a molecular weight of 234.4

Physical-chemical properties

OTNE is a clear yellow liquid at 20 °C. Its melting point is below -20 °C at atmospheric pressure (101320 Pa), and its boiling point is determined to be at around 290 °C (modified OECD 103 method). All physical-chemical data have been obtained from the OTNE REACH registration dossier.

History

OTNE was patented in 1975 as an invention of International Flavors and Fragrances.

Odour

OTNE has a woody, floral, ambergris odour. Its odour is long-lasting on skin and fabric.,

Environmental data

OTNE is classified as H410 Very toxic to aquatic life with long-lasting effects (EU-CLP) or R51/53 Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment (EU DSD). The biodegradation of OTNE in fresh water (T1/2) is <40 days and <120 days in sediment (OECD 314 test), though the biodegradation within the 28day window was around 11% (OECD 301-C). Given the outcome of the OECD 314 test OTNE does not meet the criteria for “Persistent” (P) or “very Persistent” (vP). The measured Bio Concentration Factor (BCF) is 391L/Kg, which is well below the EU limit of 2000 and US limit of 1000 for Bioaccumulation (B) classification. The LogKow for OTNE has been measured to be 5.65.

OTNE is therefore not classified as a PBT or vPvB substance for the EU or any other global criteria.

OTNE has been detected in surface water at levels of 29-180 ng/L., These values are well below the Predicted No Effect Concentration (PNEC) and as a result the overall environmental risk ratio (also referred to as RCR or PEC/PNECS) is determined to be below 1.

Human health

OTNE is not toxic and not a CMR substance.,.

OTNE is classified as a skin irritant (R38 EU DSD, H315 EU CLP) and is positive in the Local Lymph Node Assay (LLNA – OECD 429) and therefore classified as a skin sensitiser (R43 EU DSD, H317 EU CLP), though OTNE lacks any structural alerts for sensitisation in in-silico prediction models (DEREK) and is not identified as an allergen in in-vivo Human Repeated Patch Tests.

Several health related studies have been conducted on OTNE, and based on these studies, OTNE has been determined to be safe under the current conditions of use.,

Given the sensitization classification of OTNE, and its use in fragrances, the International Fragrance Association (IFRA) has published safe use levels for OTNE in consumer products, which have been in effect since August 2009.

Regulatory status

OTNE is registered on all major chemical inventories (US, Japan, China, Korea, Philippines, and Australia) and has been EU REACH registered in 2010. In 2014 the US National Toxicology Program (NTP) conducted a 13-week repeat dose toxicity study and found no adverse effects.

OTNE has been recommended for inclusion in an update for the EU Fragrance Allergens labelling for cosmetic products based on a small number of positive reactions in dermatological clinics of around 0.2% to 1.7% of patients tested in three studies

If the proposed SCCS Opinion is taken forward into legislation then OTNE will be labelled on cosmetic products in the EU, several years after publication of a new legislation.