Dimethyl itaconate

Appearance / physical state / colour

Description of key information

Solid, consisting of hygroscopic, transparent crystals belonging to the monocline, monosymetric system; can exist as supercooled liquid

Key value for chemical safety assessment

Physical state at 20°C and 1013 hPa:

solid

Additional information

The publication of Anschütz (1905) reports the synthesis of highly pure submission item. At the time of the publication no guideline existed, but the procedures of the OPPTS 830.6302, 830.6303 and 830.6304 test guidance documents from 1996 were basically met. During the investigation of its melting and boiling behaviour the material was visually inspected. In addition to that the substance was crystallographically investigated. The chemical identity was verified by burning with subsequent elemental analysis, whereas the molecular weight was confirmed by measuring effects on melting point decrease / boiling point increase of solutions and finally by determination of the vapour density. The observations are reported in great detail. However an old publication, the experiments are deemed valid, conclusive and thus suitable for assessment (reliable without restrictions, Klimisch score 1). Further observations are available from the determination of the vapour pressure and the partition coefficient investigated in a GLP-compliant study (Brekelmans 2010). The experiment is deemed valid, conclusive and thus suitable for assessment (reliable without restrictions, Klimisch score1). The data are considered relevant and taken together adequate for assessment.

Physical state: Solid at standard conditions (ISO 5011, i.e. 20 °C and 101.3 kPa), ambient and expected handling temperatures, but possibly appearing as supercooled liquid

Supercooled liquid characteristics: It was assessed by Brekelmans (2010) that the submission item shows a behaviour typical for supercooled liquids. He reports that the material can be supplied in both forms unless a crystallization inhibitor will be added. Anschütz (1905) observed that it remains liquid below the melting/freezing point unless it will be nucleated or stressed. He describes that a seed crystal is required to achieve the solid form after cooling the material below its melting/freezing temperature. This explains feigned contradictions between the assessed physical form and appearance statements made e.g. in study reports. In case of soil contact of the supercooled liquid nucleation on some of the diverse soil components seems likely. Therefore only the solid form is considered relevant in the terrestrial environment.

Hygroscopicity: Anschütz (1905) describes the crystals as very hygroscopic. Brekelmans (2010) notes that his test item was hygroscopic and needed to be stored in well-sealed containers to prevent water attraction.

Crystal properties: Co-workers of Anschütz (1905) found its material belonging to the monocline, monosymetric system. Crystals were characterized as brittle but not cleavable with an alternating habitus.

Colour: Brekelmans (2010) reports differences in colour between pale orange and yellowish as subjective and potentially influenced by the size of crystals, while (Anschütz 1905) states its freshly prepared crystalline material as transparent.

Odour: No remarkable odour is reported.

Conclusion: The submission item is considered a solid, consisting of hygroscopic, almost transparent crystals belonging to the monocline, monosymetric system, which can exist as supercooled liquid and has no remarkable odour.

Remark: A liquid state at ambient temperature, e.g. stated in a study report, can be attributed to the supercooled liquid properties and does thus not mean that the test item was liquefied due to solution in hygroscopically attracted water (which would mean reduced purity).

• Anschütz R (1905). 107. Ueber den einfachen Itaconsäuremethylester. ISSN 1099 -0682 CODEN CHBEA Berichte der Deutschen Chemischen Gesellschaft (Berlin, since 1947 renamed in Chemische Berichte) 38:691-3.
• Brekelmans IJC (2010). Determination of physico-chemical properties of Dimethyl itaconate (DMI). Testing Laboratory: NOTOX B.V., Hambakenwetering 7, 5231 DD 's-Hertogenbosch, the Netherlands. Report no. 492870. Owner company: DSM Resins B. V., Ceintuurbaan 5, 8022 AW Zwolle, the Netherlands. Report date: 2010-03-04.