Description
Vinyl acetate monomer (VAM) is a colourless liquid, immiscible or slightly soluble in water.
VAM is a flammable liquid. VAM has a sweet, fruity smell (in small quantities), with sharp,
irritating odour at higher levels. VAM is an essential chemical building block used in a wide
variety of industrial and consumer products. VAM is a key ingredient in emulsion polymers,
resins, and intermediates used in paints, adhesives, coatings, textiles, wire and cable polyethylene
compounds, laminated safety glass, packaging, automotive plastic fuel tanks, and
acrylic fibres. Vinyl acetate is used to produce polyvinyl acetate emulsions and resins. Very
small residual levels of vinyl acetate have been found present in products manufactured
using VAM, such as moulded plastic items, adhesives, paints, food packaging containers,
and hairspray.
Chemical Properties
Vinyl acetate is a colorless, flammable liquid with a pungent odor. The odor threshold is 0.12 ppm 0.3 ppm (NY, NJ).it is the precursor to polyvinyl acetate, an important polymer in industry.
Physical properties
Colorless, watery liquid with a pleasant, fruity odor. Experimentally determined detection and
recognition odor threshold concentrations were 400 μg/m
3 (120 ppb
v) and 1.4 mg/m
3 (400 ppb
v),
respectively (Hellman and Small, 1974).
Uses
Vinyl acetate is primarily used to produce polyvinyl acetate
emulsions and polyvinyl alcohol. The principal use of these
emulsions has been in adhesives, paints, textiles, and paper
products.
Uses
In polymerized form for plastic masses, films and lacquers; in plastic film for food packaging. As modifier for food starch.
Definition
ChEBI: Vinyl acetate is an acetate ester.
Production Methods
Vinyl acetate is an industrial chemical that is produced in large amounts in the United States. The worldwide production capacity of vinyl acetate monomer (VAM) was estimated at 6,154,000 tonnes/annum in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000) . The average list price for 2008 was $1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7 %), Chang Chun Group (6%) and LyondellBasell (5%).
It is a key ingredient in furniture-glue.
Preparation
The major industrial route involves the reaction of ethylene and acetic acid with oxygen in the presence of a palladium catalyst.
Ethylene + acetic acid + 1/2 O
2 → Vinyl acetate +H
2O
But by products are also generated:
Ethylene + 3 O
2 → 2CO
2 + 2H
2O
Vinyl acetate is also prepared by the gas-phase addition of acetic acid to acetylene.
Reactions
Vinyl acetate undergoes many of the reactions anticipated for an alkene and an ester. Bromine adds to give the dibromide. Hydrogen halides add to give 1-haloethyl acetates, which cannot be generated by other methods because of the non - availability of the corresponding halo-alcohols. Acetic acid adds in the presence of palladium catalysts to give ethylidene diacetate, CH
3CH(OAc)
2. It undergoes transesterification with a variety of carboxylic acids.The alkene also undergoes Diels - Alder and 2 + 2 cycloadditions.
General Description
Vinyl acetate appears as a clear colorless liquid. Flash point 18 °F. Density 7.8 lb / gal. Slightly soluble in water. Vapors are heavier than air. Vapors irritate the eyes and respiratory system. May polymerize if heated or contaminated. If polymerization occurs inside a container, the container may violently rupture. Used to make adhesives, paints, and plastics.
Air & Water Reactions
Highly flammable. Slightly soluble in water.
Reactivity Profile
Vinyl acetate may undergo spontaneous exothermic polymerization on exposure to light. Reacts with air or water to produces peroxides that initiate explosively violent polymerization. Reacts with hydrogen peroxide to form explosive peracetic acid. Reacts with oxygen to form explosive peroxides. Forms explosive Vinyl acetate ozonide on contact with ozone. Undergoes violent or explosive reactions with 2-aminoethanol, chlorosulfonic acid, ethylenediamine, mineral acids (hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid, oleum), and peroxides [Lewis, 3rd ed., 1993, p. 1311]. Polymerization initiated by dibenzoyl peroxide in ethyl acetate accelerated out of control, ignited and exploded [Vervalin, 1973, p. 81]. Polymerization in toluene solution has caused several large industrial explosions [MCA Case History No. 2087].
Health Hazard
Vinyl acetate has been related to reproductive abnormalities. It is a skin and upper respiratory tract irritantand a central nervous system depressant. Exposure caused gradual deterioration of heart muscles.
Fire Hazard
When heated to decomposition, Vinyl acetate burns and emits acrid fumes. Highly dangerous when exposed to heat, flames or oxidizers; explosion hazard with strong acids and strong oxidizers. Incompatible with alumina, oxidizing materials, 2-aminoethanol, chlorosulfonic acid; ethyleneimine; 36% hydrochloric acid; 48.7% hydrofluoric acid; 70% nitric acid; oleum; 96% sulfuric acid; ethylene diamine; peroxides and silica gel. Avoid light or any polymerizing initiator. Hazardous polymerization can be initiated by organic and inorganic peroxides; azo compounds; redox systems (including organometallic components); light; and high energy radiation.
Flammability and Explosibility
Highly flammable
Safety Profile
Confirmed carcinogen
with experimental carcinogenic and
tumorigenic data. Moderately toxic by
ingestion, inhalation, and intraperitoneal
routes. A skin and eye irritant. Experimental
reproductive effects. Human mutation data
reported. Highly dangerous fire hazard when
exposed to heat, flame, or oxidzers. A
storage hazard, it may undergo spontaneous
exothermic polymerization. Reaction with
air or water to form peroxides that catalyze
an exothermic polymerization reaction has
caused several large industrial explosions.
Reaction with hydrogen peroxide forms the
explosive peracetic acid. Reacts with oxygen
above 50℃ to form an unstable explosive
peroxide. Reacts with ozone to form the
explosive vinyl acetate ozonide. Solution
polymerization of the acetate dmolved in
toluene has resulted in large industrial
explosions. Polymerization reaction with
dibenzoyl peroxide + ethyl acetate may
release ignitable and explosive vapors. The
vapor may react vigorously with desiccants
(e.g., sihca gel or alumina). Incompatible
(explosive) with 2-amino ethanol,
chlorosulfonic acid, ethylenediamine,
ethyleneimine, HCl, HF, HNO3, oleum,
peroxides, H2SO4. See also ESTERS.
Potential Exposure
Vinyl acetate is used primarily in
polymerization processes to produce polyvinyl acetate;
polyvinyl alcohol, and vinyl acetate copolymer. The polymers,
usually made as emulsions, suspensions, solutions, or
resins, are used to prepare adhesives, paints, paper coatings,
and textile finishes. Low molecular weight vinyl acetate is
used as a chewing gum base.
Carcinogenicity
There is inadequate evidence
in humans for the carcinogenicity of vinyl acetate. There is
limited evidence in experimental animals for the carcinogenicity
of vinyl acetate. Therefore, IARC has classified vinyl
acetate as possibly carcinogenic to humans (Group 2B). This
conclusion was based on the following evidence: vinyl
acetate is rapidly transformed into acetaldehyde in human
blood and animal tissues, there is sufficient evidence in
experimental animals for the carcinogenicity of acetaldehyde,
both vinyl acetate and acetaldehyde induce nasal
cancer in rats after administration by inhalation, and vinyl
acetate and acetaldehyde are genotoxic in human cells in
vitro and in animals in vivo .
Shipping
UN1301 Vinyl acetate, stabilized, Hazard Class: 3;
Labels: 3-Flammable liquid.
Purification Methods
Inhibitors such as hydroquinone and other impurities are removed by drying with CaCl2 and fractionally distilling under nitrogen, then refluxing briefly with a small amount of benzoyl peroxide and redistilling it under nitrogen. Store it in the dark at 0o. Add inhibitor (~0.004%) for storage. [Beilstein 2 IV 176.]
Polymerization
It can be polymerized, either by itself to make polyvinyl acetate or with other monomers to prepare copolymers such as ethylene-vinyl acetate (EVA), vinyl acetate-acrylic acid (VA / AA), polyvinyl chloride acetate (PVCA), and polyvinylpyrrolidone (Vp / Va Copolymer, used in hair gels). Due to the instability of the radical, attempts to control the polymerization via most 'living/controlled' radical processes have proved problematic. However, RAFT (or more specifically MADIX) polymerization offers a convenient method of controlling the synthesis of PVA by the addition of a xanthate or a dithiocarbamate chain transfer agent.
Toxicity evaluation
On January 31, 2009, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not considered to be harmful to human health . This decision under the Canadian Environmental Protection Act (CEPA) was based on new information received during the public comment period, as well as more recent information from the risk assessment conducted by the European Union.
Incompatibilities
Vinyl acetate may undergo spontaneous
exothermic polymerization on exposure to light. Vapors
may form explosive mixture with air. Incompatible with oxidizers
(chlorates, nitrates, peroxides, permanganates, perchlorates,
chlorine, bromine, fluorine, etc.); contact may
cause fires or explosions. Keep away from alkaline materials,
strong bases, strong acids, oxoacids, epoxides, strong
light and UV. The vapor may react vigorously with silica
gel or aluminum, acids, bases, silica gel; alumina, oxidizers,
azo compounds. Ozone readily polymerizes in elevated temperatures,
under the influence of light, or peroxides. Usually
contains a stabilizer to prevent polymerization.
Waste Disposal
Dissolve or mix the material
with a combustible solvent and burn in a chemical
incinerator equipped with an afterburner and scrubber. All
federal, state, and local environmental regulations must be
observed.
