Vinyl acetate is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
CH
3CO
2CH=CH
2. This colorless liquid is the precursor to
polyvinyl acetate
Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, PVA glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and ...
and
ethene-vinyl acetate copolymers, important industrial polymers.
[
]
Production
The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
s/year 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 US$1600/tonne. Celanese
Celanese Corporation, formerly known as Hoechst Celanese, is an American technology and specialty materials company headquartered in Irving, Texas. A Fortune 500 corporation, the company is the world’s leading producer of acetic acid, produc ...
is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation
China Petrochemical Corporation () or Sinopec Group is the world's largest oil refining, gas and petrochemical conglomerate, administered by SASAC for the State Council of the People's Republic of China. It is headquartered at Chaoyangmenwa ...
(7%), Chang Chun Group (6%), and LyondellBasell (5%).[
It is a key ingredient in furniture glue.
]
Preparation
Vinyl acetate is the acetate
An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
of vinyl alcohol
Vinyl alcohol, also called ethenol (IUPAC name; not ethanol), is the simplest enol. With the formula , it is a labile compound that converts to acetaldehyde. It is not a precursor to polyvinyl alcohol.
Synthesis
Vinyl alcohol can be formed by th ...
. Since vinyl alcohol is highly unstable (with respect to acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the mos ...
), the preparation of vinyl acetate is more complex than the synthesis of other acetate esters.
The major industrial route involves the reaction of ethylene
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).
Ethylene i ...
and acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...
with oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
in the presence of a palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...
catalyst.
: 2 C2H4 + 2 CH3CO2H + O2 -> 2 CH3CO2CHCH2 + 2 H2O
The main side reaction is the combustion of organic precursors.
Mechanism
Isotope labeling and kinetics experiments suggest that the mechanism involves PdCH2CH2OAc-containing intermediates. Beta-hydride elimination
β-Hydride elimination is a reaction in which an alkyl group bonded to a metal centre is converted into the corresponding metal-bonded hydride and an alkene. The alkyl must have hydrogens on the β-carbon. For instance butyl groups can undergo th ...
would generate vinyl acetate and a palladium hydride, which would be oxidized to give hydroxide.
Alternative routes
Vinyl acetate was once mainly prepared by hydroesterification In industrial chemistry, carboalkoxylation is a process for converting alkenes to esters. This reaction is a form of carbonylation. A closely related reaction is hydrocarboxylation, which employs water in place of alcohols
A commercial applicat ...
, i.e., the addition of acetic acid to acetylene
Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...
in the presence of metal catalysts. Using mercury(II) catalysts, vinyl acetate was first prepared by Fritz Klatte
Fritz Klatte (28 March 1880, Diepholz – 11 February 1934) was a German chemist and the discoverer of polyvinyl acetate, with German patent (GP 281687 1912) for its preparation from acetylene gas.See:(1) Deutsche Reichs Patent no. 281687 (4 ...
in 1912. Presently, zinc acetate
Zinc acetate is a salt with the formula Zn(CH3CO2)2, which commonly occurs as the dihydrate Zn(CH3CO2)2·2H2O. Both the hydrate and the anhydrous forms are colorless solids that are used as dietary supplements. When used as a food additive, it ha ...
is used as the catalyst:
:
Approximately 1/3 of the world's production relies on this route, which, because it is environmentally messy, is mainly practiced in countries with relaxed environmental regulations, such as China.
Another route to vinyl acetate involves thermal decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ...
of ethylidene diacetate
Ethylidene diacetate is an organic compound with the formula (CH3CO2)2CHCH3. A colorless low-melting solid, it once served as a precursor to vinyl acetate.
Preparation
A major industrial route involves the reaction of acetaldehyde and acetic anhy ...
:
:
Polymerization
It can be polymerized to give polyvinyl acetate
Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, PVA glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and ...
(PVAc). With other monomer
In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
Classification
Mo ...
s it can be used to prepare various copolymer
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are some ...
s such as ethylene-vinyl acetate (EVA), vinyl acetate-acrylic acid
Acrylic acid (IUPAC: propenoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a ...
(VA/AA), polyvinyl chloride acetate
Polyvinyl chloride acetate (PVCA) is a thermoplastic copolymer of vinyl chloride and vinyl acetate.polyvinylpyrrolidone
Polyvinylpyrrolidone (PVP), also commonly called polyvidone or povidone, is a water-soluble polymer made from the monomer ''N''-vinylpyrrolidone. PVP is available in a range of molecular weights and related viscosities, and can be selected accor ...
(Vp/Va copolymer, used in hair gel
Hair gel is a hairstyling product that is used to harden hair into a particular hairstyle.
History
Analysis of ancient Egyptian mummies has shown that they styled their hair using a fat-based gel. The researchers behind the analysis say that t ...
s). Due to the instability of the radical, attempts to control the polymerization by most "living/controlled" radical processes have proved problematic. However, RAFT
A raft is any flat structure for support or transportation over water. It is usually of basic design, characterized by the absence of a hull. Rafts are usually kept afloat by using any combination of buoyant materials such as wood, sealed barrel ...
(or more specifically, MADIX) polymerization offers a convenient method of controlling the synthesis of PVA by the addition of a xanthate
150px, Sodium salt of ethyl xanthate
Xanthate usually refers to a salt with the formula (R = alkyl; M+ = Na+, K+), thus they are the metal-thioate/''O''-esters of dithiocarbonate. The name ''xanthates'' is derived from Ancient Greek ''xanthos' ...
or a dithiocarbamate
In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thioca ...
chain transfer agent.
Other reactions
Vinyl acetate undergoes many of the reactions anticipated for an alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
and an ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
. Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simila ...
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, CH3CH(OAc)2. It undergoes transesterification with a variety of carboxylic acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
s. The alkene also undergoes Diels–Alder and 2+2 cycloadditions.
With an iridium catalyst, vinyl acetate can undergo transesterification, giving access to vinyl ethers:
: ROH + CH2=CHOAc → ROCH=CH2 + HOAc
Toxicity evaluation
Tests suggest that vinyl acetate has low toxicity. Oral for rats is 2920 mg/kg.[
On January 31, 2009, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not harmful to human health.] This decision under the Canadian Environmental Protection Act
The ''Canadian Environmental Protection Act, 1999'' (''CEPA, 1999''; french: Loi canadienne sur la protection de l'environnement (1999)) is an act of the 36th Parliament of Canada, whose goal is to contribute to sustainable development through po ...
(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.
In the context of large-scale release into the environment, it is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act
The Emergency Planning and Community Right-to-Know Act of 1986 is a United States federal law passed by the 99th United States Congress located at Title 42, Chapter 116 of the U.S. Code, concerned with emergency response preparedness.
On October ...
(), under which it "does not meet toxicity criteria but because of its acute lethality, high production volume rknown risk is considered a chemical of concern". By this law, it is subject to strict reporting requirements by facilities that produce, store, or use it in quantities greater than 1000 pounds.
See also
*Polyvinyl alcohol
Poly(vinyl alcohol) (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula H2CH(OH)sub>''n''. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) ...
*Vinyl propionate
Vinyl propionate is the organic compound with the formula CH3CH2CO2CH=CH2. This colorless liquid is the ester of propionic acid and vinyl alcohol. It is used to produce poly(vinyl propionate) as well as copolymers with acrylate esters,
vinyl ch ...
References
External links
EPA health assessment information on vinyl acetate
Summary of risk assessment by the Government of Canada
{{Authority control
Hazardous air pollutants
Monomers
IARC Group 2B carcinogens
Acetate esters
Commodity chemicals
Vinyl compounds