IARC Cancer Review: Group 2B IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 11 (1976),p. 225.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory.

The β-Butyrolactone, with the CAS registry number 3068-88-0 and EINECS registry number 253-093-7, has the systematic name of 4-methyloxetan-2-one. And the molecular formula of this chemical is C₄H₆O₂. It is a kind of colourless liquid, and belongs to the following product categories: Oxetanes; Simple 4-Membered Ring Compounds.

The physical properties of β-Butyrolactone are as following: (1)ACD/LogP: -0.84; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): -0.84; (4)ACD/LogD (pH 7.4): -0.84; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 8.36; (8)ACD/KOC (pH 7.4): 8.36; (9)#H bond acceptors: 2; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 0; (12)Polar Surface Area: 26.3 Å²; (13)Index of Refraction: 1.429; (14)Molar Refractivity: 20.27 cm³; (15)Molar Volume: 78.5 cm³; (16)Polarizability: 8.03×10^-24cm³; (17)Surface Tension: 30.1 dyne/cm; (18)Density: 1.096 g/cm³; (19)Flash Point: 34.1 °C; (20)Enthalpy of Vaporization: 39.97 kJ/mol; (21)Boiling Point: 163.2 °C at 760 mmHg; (22)Vapour Pressure: 2.09 mmHg at 25°C.

Preparation of β-Butyrolactone: This chemical can be prepared by acetaldehyde and ketene. The reaction will need reagents boron fluoride and diethyl ether. 

Uses of β-Butyrolactone: It can react with methoxymethyl-oxirane to produce 4-methoxymethyl-[1,3]dioxolan-2-one and propene. This reaction will need catalyst TBAB, and the solvent toluene. The reaction time is 15 hours with temperature of 100°C, and the yield is about 96.1%.

You should be cautious while dealing with this chemical. It irritates eyes and skin. And there's limited evidence of a carcinogenic effect. Therefore, you had better take the following instructions: Wear suitable protective clothing, and in case of contacting with eyes, rinse immediately with plenty of water and seek medical advice.

You can still convert the following datas into molecular structure:
(1)SMILES: O=C1OC(C)C1
(2)InChI: InChI=1/C4H6O2/c1-3-2-4(5)6-3/h3H,2H2,1H3
(3)InChIKey: GSCLMSFRWBPUSK-UHFFFAOYAG

The toxicity data is as follows: