Этоксид сурьмы

Description

Antimony ethoxide (antimony triethoxide, Sb(OEt)3) is an organometallic compound of trivalent antimony with ethoxy groups, a colorless liquid. Serves as a model and industrial catalyst for transesterification and polycondensation in the production of polyesters, primarily polyethylene terephthalate. Belongs to the family of antimony alkoxides along with methoxide and propoxide - all of which are prepared by reacting antimony trichloride or antimony trioxide with the appropriate alcohol under anhydrous conditions, since the Sb-O-C alkoxide bond is easily hydrolyzed by moisture.

Basic Attributes

• CAS No: 10433-06-4
• Chemical formula: C2H6O 1/3Sb (in terms of ethoxide group; full formula Sb(OC2H5)3)
• Molecular Weight: 256.94
• Exact weight: 256.006
• EU number: 233-914-5
• DSSTox ID: DTXSID60146392
• PSA Specifications: 27.69
• XLogP3: 1.4616

Physico-chemical characteristics

• Appearance: colorless liquid
• Density: 1.524 g/cm3
• Boiling point: 71-73 °C at 0.5 torr pressure
• Flash point: 140°F (about 60°C)
• Refractive index: n20/D 1.495 (according to literature data)

Scope of application

The transesterification catalyst of diethyl terephthalate with ethanol is a model reaction used to study the mechanism of polycondensation of polyesters. The metal coordinates with the carbonyl oxygen atom of the ester, and the ethoxy group of the ligand attacks the carbonyl carbon atom of the ester to form a four-center transition state—the same mechanism by which antimonium alkoxides catalyze the industrial synthesis of polyethylene terephthalate. In the production of PET, antimony ethoxide is used along with other antimony catalysts - antimony trioxide, antimony acetate and antimony glycolate - at the stage of transesterification of bis(2-hydroxyethyl) terephthalate or dimethyl terephthalate with ethylene glycol. The liquid state of aggregation gives antimony ethoxide an advantage over solid catalysts - trioxide and acetate - when dosing in continuous production lines, where the accuracy of supply of small volumes of the reagent is important.

Toxicity and danger

• Packing level: III
• Hazard category: 3
• Transport codes: UN 1993, 3/page. 3
• WGK Germany: 2
• Hazard class code: 20/22-51/53-10
• Safety instructions: 61
• Tags: Xn, N
• Precautionary statements: P273
• Hazard Statements: H226 (flammable liquids and vapours, 59.38% GHS), H302+H332, H411

Storage

Store in a tightly closed container, away from sources of ignition - flammable liquid (H226). The room is dry, ventilated, the storage temperature should prevent overheating of the container. Due to the sensitivity of the Sb-O-C alkoxide bond to hydrolysis, the container is protected from moisture and stored under a layer of inert gas or in sealed packaging.