The Ketene dimer with CAS registry number of 674-82-8 is also known as 2-Oxetanone, 4-methylene-. The IUPAC name is 4-Methylideneoxetan-2-one. It belongs to product categories of Pharmaceutical Intermediates; Aromatic amine products. Its EINECS registry number is 211-617-1. In addition, the formula is C₄H₄O₂ and the molecular weight is 84.07. This chemical is a colorless liquid and should be stored in sealed containers in cool, dry place and away from oxidizing agents, acids, bases and amines.

Physical properties about Ketene dimer are: (1)ACD/LogP: 0.27; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 0.27; (4)ACD/LogD (pH 7.4): 0.27; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 33.28; (8)ACD/KOC (pH 7.4): 33.28; (9)#H bond acceptors: 2; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 0; (12)Index of Refraction: 1.449; (13)Molar Refractivity: 19.91 cm³; (14)Molar Volume: 74.1 cm³; (15)Surface Tension: 28.5 dyne/cm; (16)Density: 1.13 g/cm³; (17)Flash Point: 97.9 °C; (18)Enthalpy of Vaporization: 36.8 kJ/mol; (19)Boiling Point: 127.4 °C at 760 mmHg; (20)Vapour Pressure: 11.1 mmHg at 25 °C.

Preparation of Ketene dimer: it is prepared by thermal decomposition by acetic acid, acetone, acetic anhydride and acetate. Acetic pyrolysises at 750-780 °C in the presence of triethyl phosphate to get ketene, then polymerizes at 8-10 °C to get the product.

CH₃COOH→CH₂CO→C₄H₄O₂

Uses of Ketene dimer: it is used to produce N-acetoacetyl-N'-cyclohexylsulfamide by reaction with cyclohexyl-sulfamide. The reaction occurs with reagent aq.NaOH at ambient temperature for 2 hours. The yield is about 36%. This chemical is also used as raw materials of fine chemicals, dyes, pharmaceuticals, pesticides, food and feed additives, additives and others.

When you are using this chemical, please be cautious about it. As a chemical, it is flammable and harmful by inhalation. There is limited evidence of a carcinogenic effect. During using it, wear suitable protective clothing and gloves. Avoid contact with skin and eyes. What's more, take precautionary measures against static discharges and do not breathe gas/fumes/vapour/spray. After using it, keep it in a cool place and keep away from sources of ignition.

You can still convert the following datas into molecular structure:
1. Canonical SMILES: C=C1CC(=O)O1
2. InChI: InChI=1S/C4H4O2/c1-3-2-4(5)6-3/h1-2H2
3. InChIKey: WASQWSOJHCZDFK-UHFFFAOYSA-N

The toxicity data is as follows: