4-метилбензофенон

Химические свойства

white to beige crystalline powder or crystals

Использование

4-Methylbenzophenone is used as clear coatings for wood, plastic and metal, overprint varnish.

Общее описание

4-Methylbenzophenone is a photo-initiator for printing inks, mainly applied to the cardboard boxes used for packing. It is reported to be a non-genotoxic carcinogen. However, it can contaminate foodstuffs when it comes in contact with the package contents.

Профиль безопасности

Poison by intraperitoneal route. A flammable liquid. When heated to decomposition it emits acrid smoke and irritating fumes.

Методы очистки

Crystallise the ketone from MeOH, Et2O (m 58-59o) or pet ether. The cis-oxime has m 154o(153-156o) (from EtOH), and the trans-oxime has m 114-116o (from pet ether). [Beilstein 7 H 440, 7 III 2127, 7 IV 1403.]

Структура и конформация

4-Methylbenzophenone was one of the first organic compounds for which polymorphism was observed. It crystallizes in two modifications, the stable monoclinic α-form (mp 59°C) and a metastable trigonal β-form (mp 55 ℃). The metastable β-form is rather stable and almost indefinitely preserved if not subjected to severe mechanical load or brought into contact with the stable form. If it converts into a stable form, the crystal becomes milky white and non-transparent due to micro-cracking. There are no conditions under which the β-form is more stable than the α-form. 4-Methylbenzophenone crystallizes in a monoclinic stable form (mp 59 ℃) with a = 5.70 Å, b = 13.89 Å, c = 14.08 Å, p = 95.18° and space group P2_1/c, and a trigonal metastable form (mp 55°C) with a = 9.12 Å, c = 11.28 Å and space groups P3₁, or P3₂[1].