PRODUCTS

ACETALDEHYDE

ACETALDEHYDE = ETHANOL

CAS Number: 75-07-0
EC Number: 200-836-8
Chemical formula: C2H4O
Molar mass: 44.053 g·mol−1

C2H4O is an organic chemical compound with chemical name Acetaldehyde.

Acetaldehyde is present in various plants, ripe fruits, vegetables, smoke from tobacco, gasoline and exhaust from the engine.
Acetaldehyde is commonly used as a flavouring agent and as an intermediate in alcohol metabolism in the manufacture of acetic acid, perfumes, dyes, and medicines.
The chemical formula of Acetaldehyde is CH3CHO

Acetaldehyde is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 1 to < 10 tonnes per annum.
Acetaldehyde is used by professional workers (widespread uses), in formulation or re-packing, at industrial sites and in manufacturing.

Acetaldehyde (systematic name: ethanal) is an organic chemical compound with the formula CH3CHO, sometimes abbreviated by chemists as MeCHO (Me=methyl).
Acetaldehyde is one of the most important aldehydes, occuring widely in nature and being produced on a large scale in industry.

Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants.
Acetaldehyde is also produced by the partial oxidation of ethanol and may be a contributing factor to hangovers from alcohol consumption, produced in the liver by the enzyme alcohol dehydrogenase.

Acetaldehyde is mainly used as a precursor to acetic acid.
Acetaldehyde is also an important precursor to pyridine derivates.
Nevertheless, the global market for acetaldehyde is declining.
Acetaldehyde is toxic when applied externally for prolonged periods, an irritant and a probable carcinogen.

Acetaldehyde is also called as MeCHO.
Acetaldehyde is miscible with naptha, gasoline, xylene, ether, turpentine, alcohol and benzene.
Acetaldehyde has no colour and is a flammable liquid.
Acetaldehyde has a suffocating smell.
Acetaldehyde is non-corrosive to many metals but when Acetaldehyde has a narcotic action and can cause mucous irritation.

Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl).
Acetaldehyde is a colorless liquid or gas, boiling near room temperature.
Acetaldehyde is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry.

Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants.
Acetaldehyde is also produced by the partial oxidation of ethanol by the liver enzyme alcohol dehydrogenase and is a contributing cause of hangover after alcohol consumption.
Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke.
Consumption of disulfiram inhibits acetaldehyde dehydrogenase, the enzyme responsible for the metabolism of acetaldehyde, thereby causing Acetaldehyde to build up in the body.

Acetaldehyde is an important volatile flavoring compound found in Sherry-like wines and also in many fruits.
Acetaldehyde is mainly used as a flavoring ingredient in milk products, fruit juices and soft drinks.

When you drink alcohol, your body breaks Acetaldehyde down into a chemical called acetaldehyde.
Acetaldehyde damages your DNA and prevents your body from repairing the damage.
DNA is the cell’s “instruction manual” that controls a cell’s normal growth and function.
When DNA is damaged, a cell can begin growing out of control and create a cancer tumor.
A toxic buildup of acetaldehyde can increase your cancer risk.

The International Agency for Research on Cancer (IARC) has listed acetaldehyde as a Group 1 carcinogen.
Acetaldehyde is "one of the most frequently found air toxins with cancer risk greater than one in a million".

Acetaldehyde is a clear liquid that burns easily.
Acetaldehyde has a strong, fruity odor that in high concentrations can make breathing difficult.
Also known as ethanal, acetaldehyde forms naturally in the body and in plants.

Acetaldehyde is found in nature in many foods such as ripe fruits, cheese and heated milk.
Acetaldehyde is primarily used to produce other chemicals, including acetic acid and disinfectants, drugs and perfumes.

Acetaldehyde enters your body when you breathe air containing Acetaldehyde.
Acetaldehyde can also enter your body when you eat food or drink liquid containing acetaldehyde.
When you drink alcohol, your body makes acetaldehyde when Acetaldehyde processes the alcohol.
The effect of acetaldehyde on your health depends on how much is in your body, how long you were exposed, and how often you were exposed.
The way Acetaldehyde affects you will also depend on your health.

Another factor is the condition of the environment when you were exposed.
The way Acetaldehyde affects you will also depend on your health.
Another factor is the condition of the environment when you were exposed.
Breathing acetaldehyde for short periods can hurt your lungs.
Acetaldehyde can also hurt your heart and blood vessels.

Contact with acetaldehyde liquid or vapor can hurt the skin and eyes.
Acetaldehyde is not known if breathing, drinking or eating small amounts of acetaldehyde over long periods will hurt you.
Some animal studies show that acetaldehyde can hurt a growing fetus.
Other studies on animals show that breathing acetaldehyde can severely damage the lungs and cause cancer.
Repeated exposure to acetaldehyde in the air may cause cancer in humans.

When you drink alcohol, your liver turns acetaldehyde into an acid.
Some of the acetaldehyde enters your blood, damaging your membranes and possibly causing scar tissue.
Acetaldehyde also leads to a hangover, and can result in a faster heartbeat, a headache or an upset stomach.
The brain is most affected by acetaldehyde poisoning.

Acetaldehyde causes problems with brain activity and can impair memory.
Acetaldehyde can cause amnesia, which is the inability to remember things.
This is a common effect for people who drink too much alcohol.

Acetaldehyde is a colourless, flammable liquid with a pungent and irritating odour, volatile at ambient temperature and pressure, and is found in both indoor and outdoor air.
In Environment Canada and Health Canada’s 2000 Priority Substances List Assessment Report: Acetaldehyde, Acetaldehyde was concluded that acetaldehyde is toxic under the Canadian Environmental Protection Act, 1999 (CEPA) because Acetaldehyde may be a genotoxic carcinogen; however, there was considerable uncertainty as to the actual cancer risk.
Since the publication of the report, a number of key studies have been published, including those related to the mode of action for acetaldehyde carcinogenesis.
Therefore, in order to address the uncertainty in regards to the mode of action of acetaldehyde carcinogenesis, and to more accurately determine the risk to health from levels commonly found in Canadian homes taking into account recently published scientific data, Acetaldehyde was given high priority for a full health risk assessment and development of a Residential Indoor Air Quality Guideline (RIAQG).

The present document reviews the epidemiological, toxicological, and exposure research on acetaldehyde, as well as the conclusions from a number of comprehensive reviews from internationally recognized health and environmental organizations.
The document places an emphasis on research published since the most recent comprehensive review, and proposes new short- and long-term indoor air exposure limits.
This RIAQG for acetaldehyde is intended to provide recommended exposure limits which would minimize risks to human health and support the development of actions to limit acetaldehyde emissions.
This document also shows that, when compared to the newly proposed guidelines, levels in Canadian houses do not present a health risk.

Acetaldehyde, also known as ethanal, belongs to the class of organic compounds known as short-chain aldehydes.
These are an aldehyde with a chain length containing between 2 and 5 carbon atoms.
Acetaldehyde exists in all living species, ranging from bacteria to humans.
Within humans, acetaldehyde participates in a number of enzymatic reactions.
In particular, acetaldehyde can be biosynthesized from ethanol which is mediated by the enzyme alcohol dehydrogenase 1B.

Acetaldehyde can also be converted to acetic acid by the enzyme aldehyde dehydrogenase (mitochondrial) and aldehyde dehydrogenase X (mitochondrial).
The main method of production is the oxidation of ethylene by the Wacker process, which involves oxidation of ethylene using a homogeneous palladium/copper system: 2 CH2CH2 + O2 → 2 CH3CHO.
In humans, acetaldehyde is involved in disulfiram action pathway.
Acetaldehyde is an aldehydic, ethereal, and fruity tasting compound.
Outside of the human body, acetaldehyde is found, on average, in the highest concentration in a few different foods, such as sweet oranges, pineapples, and mandarin orange (clementine, tangerine) and in a lower concentration in.

Acetaldehyde (CH3CHO), also called ethanal, an aldehyde used as a starting material in the synthesis of 1-butanol (n-butyl alcohol), ethyl acetate, perfumes, flavourings, aniline dyes, plastics, synthetic rubber, and other chemical compounds.
Acetaldehyde has been manufactured by the hydration of acetylene and by the oxidation of ethanol (ethyl alcohol).
Today the dominant process for the manufacture of acetaldehyde is the Wacker process, developed between 1957 and 1959, which catalyzes the oxidation of ethylene to acetaldehyde.
The catalyst is a two-component system consisting of palladium chloride, PdCl2, and copper chloride, CuCl2.

Pure acetaldehyde is a colourless, flammable liquid with a pungent, fruity odour; Acetaldehyde boils at 20.8 °C (69.4 °F).

Acetaldehyde is a common name of ethanal.
Acetaldehyde is an organic chemical compound with the chemical formula CH3CHO.
Acetaldehyde is also abbreviated by chemists as MeCHO where ‘Me’ means methyl.

Acetaldehyde is one of the most important aldehydes.
Acetaldehyde is being produced on a large scale in many industries.
Acetaldehyde occurs widely in nature as in coffee, bread, and ripe fruit and is produced by plants.
Acetaldehyde is also contributing to the cause of hangover after alcohol consumption.

Pathways of exposure to acetaldehyde include air, water, land, or groundwater, as well as drink and smoke.
Consumption of disulfiram inhibits acetaldehyde dehydrogenase.
Acetaldehyde is the enzyme that is responsible for the metabolism of acetaldehyde.

Acetaldehyde is easily miscible with naptha, gasoline, xylene, ether, turpentine, alcohol and benzene.
Acetaldehyde is a colourless, flammable liquid and has a suffocating smell.
Acetaldehyde is non-corrosive to many metals but when Acetaldehyde has a narcotic action, Acetaldehyde can cause mucous irritation.
Acetaldehyde was observed by the Swedish pharmacist/chemist Carl Wilhelm Scheele in the year 1774.

Acetaldehyde is a Acetaldehyde that is produced in the human body during metabolic processes, for example when the body breaks down alcohol.
Acetaldehyde often occurs in nature as a chemical by-product in plants and in many organisms.
Acetaldehyde is also a natural ingredient in many foods, such as fruit, coffee and bread.
The taste of acetaldehyde is described as fresh with a fruity but sometimes musty odour.

Acetaldehyde is widely used in the production of other industrial chemical Acetaldehyde.
Acetaldehyde is used as a solvent in the rubber, tanning and paper industries, and as a preservative for fruit and fish.
Sometimes Acetaldehyde is also used as a flavouring agent.

Acetaldehyde is a common raw material in the organic chemical industry
Acetaldehyde has a wide range of applications and is a raw material in the manufacture of many everyday products, such as paint binders, plasticisers and superabsorbents in baby nappies.

Acetaldehyde is also used in the manufacture of various types of building materials, fire protection paints, synthetic lubricants and explosives.
In the pharmaceutical industry, Acetaldehyde is used, among other things, in the manufacture of vitamins, sleeping aids and sedatives.
Acetaldehyde is also often used as a base when producing acetic acid, which is also a basic chemical with many uses.

In the food industry, Acetaldehyde is used in the manufacture of preservatives and flavourings and occurs naturally in fruit and fruit juices.
Acetaldehyde arises naturally during fermentation and is found in low levels in foodstuffs such as milk products, soy products, pickled vegetables and non-alcoholic beverages.

Sekab produces Acetaldehyde industrially by the catalytic oxidation of ethanol.
The production process takes place with renewable bioenergy in a closed-loop system and with as little toxicological effect as possible.

Acetaldehyde is a complicated chemical to handle since Acetaldehyde reacts easily with other chemicals and with the oxygen in the air.
This implies fire hazard and explosion risk and puts demands on safe handling.
Acetaldehyde has short shelf life, which puts demands on warehouse logistics.
Sekab can ensure and satisfy all of these requirements and conditions.

Acetaldehyde (CH3CHO) is a volatile compound found in wine.
Levels in various wines are listed in Table I. On average, red wines contain 30 mg/L, white 80 mg/L, and Sherries 300 mg/L.
The high levels in sherry are considered a unique feature of this wine.
At low levels acetaldehyde can contribute pleasant fruity aromas to a wine, however, at higher levels the aroma is considered a defect and is reminiscent of rotten-apples.
The threshold in wine ranges between 100-125 mg/L.

Acetaldehyde is one of the most important sensory carbonyl compounds in wine and constitutes approximately 90% of the total aldehyde content in wine.
Acetaldehyde can be formed by yeasts and acetic acid bacteria (AAB).
AAB form acetaldehyde by oxidizing ethanol.
The amount formed by yeasts varies with species, but is considered to be a leakage product of the alcoholic fermentation.

Additionally, film yeasts (important in sherry production) will oxidize ethanol to form acetaldehyde.
Oxygen, and SO2 can all impact the amount of acetaldehyde formed by yeasts.
Wines fermented in the presence of SO2 have considerably higher amounts of acetaldehyde.
This is related to SO2 resistance of certain yeasts.

In wine, acetaldehyde concentration increases with higher temperatures, though production was higher at cooler temperatures in fermented cider with Saccharomyces cereviseae.
Acetaldehyde can also be formed as a result of oxidation of phenolic compounds.
Hydrogen peroxide, a product of phenolic oxidation, will oxidize ethanol to acetaldehyde.

At wine pH (3-4), SO2 consists mainly of bisulfite (HSO3-), and small amounts of molecular (SO2) and sulfite ion (SO32-).
The bisulfite can form complexes with carbonyl compounds, predominately acetaldehyde.
The binding of acetaldehyde to bisulfite limits Acetaldehyde sensory contribution to wine.
Addition of SO2 to ‘inhibit’ acetaldehyde production may reduce the perceived aldehyde aroma character, but is most likely only masking the aroma contribution of the acetaldehyde that is present instead of actually inhibiting Acetaldehyde production.

Acetaldehyde is primarily used as an intermediate in the manufacture of a range of chemicals, perfumes, aniline dyes, plastics and synthetic rubber and in some fuel compounds.
Acetaldehyde is also used in the manufacture of disinfectants, drugs, perfumes, explosives, lacquers and varnishes, photographic chemicals, phenolic and urea resins, rubber accelerators and antioxidants, and room air deodourisers.
Acetaldehyde is also used as a synthetic flavouring Acetaldehyde, food preservative and as a fragrance.

Acetaldehyde is a toxic molecule that is always circulating in the blood in low concentrations.
A Group 1 carcinogen, acetaldehyde can cause damage in our bodies and continued exposure can lead to cancer and other disease.
In our modern environment, acetaldehyde enters the body from a number of sources.

Acetaldehyde is also produced inside our own bodies through regular processes.
Those with ALDH2 Deficiency cannot properly break down acetaldehyde, which leads to accumulation in the body and increases the risk of long-term diseases.
Those with ALDH2 Deficiency should be aware of the major sources of acetaldehyde.

Acetaldehyde, produced from the metabolism of ethanol, may also be responsible for localized cancers, brain damage in prenatal infants, and growth suppression (in chicken embryos).
Acetaldehyde, as a direct result of ethanol metabolism in the body, has been implicated in alcoholic cardiomyopathy and cancer of the digestive tract.
Acetaldehyde DNA adducts have been observed in the lymphocytes of human alcohol abusers.
Esophageal tumors have been reportedly associated with genetic polymorphisms that result in high acetaldehyde levels after ethanol consumption, but there is inadequate evidence to associate carcinogenicity in humans with acetaldehyde exposure.
The levels of acetaldehyde in blood are directly correlated with ethanol consumption.

Acetaldehyde, also called ethanal, is the simplest aldehyde (CH3CHO).
Acetaldehyde is a colourless and volatile liquid made by the catalytic oxidation of ethanol, with a sharp and fruity odour.
Acetaldehyde is widely used industrially as a chemical intermediate.

Acetaldehyde is also a metabolite of sugars and ethanol in humans,is found naturally in the environment, and is a product of biomass combustion.
Acetaldehyde is primarily used as an intermediate in the manufacture of a range of chemicals, perfumes, aniline dyes, plastics and synthetic rubber and in some fuel compounds.
Acetaldehyde is an important reagent used in the manufacture of dyes, plastics, and many other organic chemicals.
In the presence of acids Acetaldehyde forms the cyclic polymers paraldehyde (CH3CHO)3, and metaldehyde (CH3CHO)4.

The former is used as a hypnotic, and the latter as a solid fuel for portable stoves and as a poison for snails and slugs.
Acetaldehyde is also used in the manufacture of disinfectants, drugs, perfumes, explosives, lacquers and varnishes, photographic chemicals, phenolic and urea resins, rubber accelerators and antioxidants, and room air deodourizers.
Acetaldehyde is also used as a synthetic flavouring Acetaldehyde, food preservative and as a fragrance.

Acetaldehyde is a highly flammable, volatile colourless liquid.
Acetaldehyde has a characteristic, pungent, and suffocating odour and is miscible in water.
Acetaldehyde is ubiquitous in the ambient environment.
Acetaldehyde is an intermediate product of higher plant respiration and formed as a product of incomplete wood combustion in fireplaces and woodstoves, burning of tobacco, vehicle exhaust fumes, coal refining, and waste processing.
Exposures to acetaldehyde occur during the production of acetic acid and various other industrial chemical Acetaldehyde, for instance, manufacture of drugs, dyes, explosives, disinfectants, phenolic and urea resins, rubber accelerators, and varnish.

Health Effects of Acetaldehyde:
Health effects of exposure to acetaldehyde have been examined in toxicological and controlled human exposure studies, with very little epidemiological evidence related to indoor acetaldehyde exposure.
In this assessment, the short-term exposure limit is derived from the results of a controlled human exposure study, whereas the long-term exposure limit is based on toxicological data from a study in a rodent model.
Supporting evidence is provided by the results of other toxicological and controlled human exposure studies.

Based on the evidence from human and toxicological studies, the effects of short-term and long-term acetaldehyde inhalation are observed at the site of entry.
Key health effects include tissue damage and cancer development, mainly in the upper respiratory tract.

Physical Description of Acetaldehyde:
Acetaldehyde appears as a clear colorless liquid with a pungent choking odor.
Flash point -36°F.
Boiling point 69°F.
Density 6.5 lb / gal.
Vapors are heaver than air and irritate the mucous membranes and especially the eyes.
Used to make other chemicals.

Physical Properties of Acetaldehyde:
The chemical formula for acetaldehyde is CH3CHO, and Acetaldehyde has a molecular weight of 44.06 g/mol.
Acetaldehyde is a colorless mobile liquid that is flammable and miscible with water.

Acetaldehyde has a pungent suffocating odor, but at dilute concentrations Acetaldehyde has a fruity and pleasant odor.
The odor threshold of acetaldehyde is 0.05 parts per million (ppm) (0.09 mg/m3). (1,7)
The vapor pressure for acetaldehyde is 740 mm Hg at 20 °C, and Acetaldehyde has a log octanol/water partitioncoefficient (log Kow) of 0.43.

The molecular weight/ molar mass of acetaldehyde is 44.05 gram per mole.
The density of acetaldehyde is 0.784 gram per centimetre cube.
Also, the boiling of acetaldehyde is 20.2oC.
The melting of acetaldehyde is −123.5oC.

Physical properties of Acetaldehyde:
Colorless, mobile, fuming, volatile liquid or gas with a penetrating, pungent odor; fruity odor when diluted.
Odor threshold concentrations ranged from 1.5 ppbv to 0.21 ppmv.
Katz and Talbert (1930) reported an experimental detection odor threshold concentration of 120 μg/m3 (67 ppbv).

At low concentrations, acetaldehyde imparts a pleasant, fruity, green apple or leafy green-like flavor.
Twenty-five panelists were randomly selected for testing milk products and water for determining flavor thresholds.
Flavor threshold concentrations determined by a geometric approach were 3,939 ppb for nonfat milk (0.5% milk fat), 4,020 ppb for low-fat milk (2% milk fat), 4,040 ppb for whole milk, 10,048 ppb for chocolate milk, and 167 ppb for spring water.

Chemical Properties of Acetaldehyde:
The chemical properties of acetaldehyde are similar to formaldehyde.
Acetaldehyde is a precursor in organic synthesis, especially as an electrophile.

By condensation reaction, one can gain intermediates like pentaerythritol that we can be used in organic synthesis.
Also, can be useful to produce hydroxyethyl derivatives by a reaction with a Grignard reagent.
Acetaldehyde is a building block that is in use in the synthesis of heterocycles, such as imines and pyridines.

This chemical is dangerous when exposed to heat or flame.
Acetaldehyde is sensitive to air and may undergo autopolymerization.
Acetaldehyde is also sensitive to moisture.
Upon prolonged storage, Acetaldehyde may form unstable peroxides.

Can react vigorously with acid anhydrides, alcohols, ketones, phenols, ammonia, hydrogen cyanide, hydrogen sulfide, halogens, amines phosphorous, isocyanates, strong alkalies and strong acids and is incompatible with oxidising and reducing agents.
Acetaldehyde also reacts with nitric acid, peroxides, caustic soda and soda ash.
Reactions with cobalt chloride, mercury(II)chlorate or mercury(II)perchlorate form sensitive and explosive products.
Polymerisation may occur with acetic acid.

Autoignition of vapour may occur on contact with corroded metals.
Exothermic polymerisation can occur with trace metals.
Acetaldehyde is miscible with gasoline, naptha, xylene, turpentine, ether, benzene and alcohol.
Rubber products decompose on contact with acetaldehyde, but Acetaldehyde is not corrosive to most metals.

Acetaldehyde is a highly fl ammable, volatile, colorless liquid.
Acetaldehyde has a characteristic pun- gent and suffocating odor, and is miscible in water.
Acetaldehyde is ubiquitous in the ambient environment.

Acetaldehyde is an intermediate product of higher plant respiration and formed as a product of incomplete wood combustion in fi replaces and woodstoves, burning of tobacco, vehicle exhaust fumes, coal refi ning, and waste processing.
Exposures to acetal- dehyde occur during the production of acetic acid and various other industrial chemical Acetaldehyde.
For instance, the manufacture of drugs, dyes, explosives, disinfectants, pheno- lic and urea resins, rubber accelerators, and varnish.

Acetaldehyde is a flammable, volatile, colorless liquid, or gas.
Acetaldehyde has a characteristic, penetrating, fruity odor.

Production of Acetaldehyde:
The main method of production of acetaldehyde is the oxidation of ethylene.
Acetaldehyde is done by the Wacker process.
This process involves the oxidation of ethylene by homogeneous palladium or copper system.
2CH2=CH2+O2→2CH3CHO

A small quantity of acetaldehyde can be prepared by the partial oxidation of ethanol.
Acetaldehyde is an exothermic reaction and is conducted over a silver catalyst at about 500oC to 650oC.
CH3CH2OH+1/2O2→CH3CHO+H2O

Acetaldehyde is the oldest method for the preparation of acetaldehyde.

Prior to the Wacker process and the availability of ethylene, acetaldehyde is also produced by the hydration of acetylene and is catalyzed by mercury (II) salts.
C2H2+Hg2++H2O→CH3CHO+Hg

The mechanism involves the intermediacy of vinyl alcohol that is tautomerized to acetaldehyde.
The reaction is conducted at 90oC to 95oC.
Acetaldehyde formed here is separated from water and mercury and cooled to 25oC to 30oC.
In the wet oxidation process, iron (III) sulfate is in use to reoxidize the mercury to the mercury (II) salt.
The resulting iron (II) sulfate is then oxidized in a separate reactor with nitric acid.

Traditionally, Acetaldehyde was also produced by the partial dehydrogenation of ethanol.
CH3CH2OH→CH3CHO+H2

This is an endothermic process.
Ethanol vapour is passed by a copper-based catalyst at 260oC to 290oC.

In 2003, global production was about 1 million tonnes.
Before 1962, ethanol and acetylene were the major sources of acetaldehyde.
Since then, ethylene is the dominant feedstock.

The main method of production is the oxidation of ethylene by the Wacker process, which involves oxidation of ethylene using a homogeneous palladium/copper system:
2 CH2=CH2 + O2 → 2 CH3CHO

In the 1970s, the world capacity of the Wacker-Hoechst direct oxidation process exceeded 2 million tonnes annually.

Smaller quantities can be prepared by the partial oxidation of ethanol in an exothermic reaction.
This process typically is conducted over a silver catalyst at about 500–650 °C.
CH3CH2OH + 1⁄2 O2 → CH3CHO + H2O

This method is one of the oldest routes for the industrial preparation of acetaldehyde.

Other methods of Acetaldehyde:

Hydration of acetylene:
Prior to the Wacker process and the availability of cheap ethylene, acetaldehyde was produced by the hydration of acetylene.

This reaction is catalyzed by mercury(II) salts:
C2H2 + Hg2+ + H2O → CH3CHO + Hg

The mechanism involves the intermediacy of vinyl alcohol, which tautomerizes to acetaldehyde.
The reaction is conducted at 90–95 °C, and the acetaldehyde formed is separated from water and mercury and cooled to 25–30 °C.
In the wet oxidation process, iron(III) sulfate is used to reoxidize the mercury back to the mercury(II) salt.
The resulting iron(II) sulfate is oxidized in a separate reactor with nitric acid.

Dehydrogenation of ethanol:
Traditionally, acetaldehyde was produced by the partial dehydrogenation of ethanol:
CH3CH2OH → CH3CHO + H2

In this endothermic process, ethanol vapor is passed at 260–290 °C over a copper-based catalyst.
The process was once attractive because of the value of the hydrogen coproduct, but in modern times is not economically viable.

Hydroformylation of methanol:
The hydroformylation of methanol with catalysts like cobalt, nickel, or iron salts also produces acetaldehyde, although this process is of no industrial importance.
Similarly noncompetitive, acetaldehyde arises from synthesis gas with modest selectivity.

Reactivity Profile of Acetaldehyde:
Acetaldehyde undergoes a vigorously exothermic condensation reaction in contact with strong acids, bases or traces of metals.
Can react vigorously with oxidizing reagents such as dinitrogen pentaoxide, hydrogen peroxide, oxygen, silver nitrate, etc.
Contamination often leads either to reaction with the contaminant or polymerization, both with the evolution of heat.

Can react violently with acid anhydrides, alcohols, ketones, phenols, ammonia, hydrogen cyanide, hydrogen sulfide, halogens, phosphorus, isocyanates, concentrated sulfuric acid, and aliphatic amines.
Reactions with cobalt chloride, mercury(II) chlorate or perchlorate form sensitive, explosive products.
An oxygenation reaction of Acetaldehyde in the presence of cobalt acetate at -20°C exploded violently when stirred.
The event was ascribed to peroxyacetate formation.

Reactions of Acetaldehyde:

Tautomerization of acetaldehyde to vinyl alcohol:
Like many other carbonyl compounds, acetaldehyde tautomerizes to give an enol (vinyl alcohol; IUPAC name: ethenol):
CH3CH=O ⇌ CH2=CHOH ∆H298,g = +42.7 kJ/mol

The equilibrium constant is 6×10−7 at room temperature, thus that the relative amount of the enol form in a sample of acetaldehyde is very small.
At room temperature, acetaldehyde (CH3CH=O) is more stable than vinyl alcohol (CH2=CHOH) by 42.7 kJ/mol: Overall the keto-enol tautomerization occurs slowly but is catalyzed by acids.

Photo-induced keto-enol tautomerization is viable under atmospheric or stratospheric conditions.
This photo-tautomerization is relevant to the earth's atmosphere, because vinyl alcohol is thought to be a precursor to carboxylic acids in the atmosphere.

Condensation reactions of Acetaldehyde:
Acetaldehyde is a common electrophile in organic synthesis.
In condensation reactions, acetaldehyde is prochiral.

Acetaldehyde is used primarily as a source of the "CH3C+H(OH)" synthon in aldol and related condensation reactions.
Grignard reagents and organolithium compounds react with MeCHO to give hydroxyethyl derivatives.
In one of the more spectacular condensation reactions, three equivalents of formaldehyde add to MeCHO to give pentaerythritol, C(CH2OH)4.

In a Strecker reaction, acetaldehyde condenses with cyanide and ammonia to give, after hydrolysis, the amino acid alanine.
Acetaldehyde can condense with amines to yield imines; for example, with cyclohexylamine to give N-ethylidenecyclohexylamine.
These imines can be used to direct subsequent reactions like an aldol condensation.

Acetaldehyde is also a building block in the synthesis of heterocyclic compounds.
In one example, Acetaldehyde converts, upon treatment with ammonia, to 5-ethyl-2-methylpyridine ("aldehyde-collidine").

Formulations/Preparations of Acetaldehyde:
Acetaldehyde is avail in USA with following typical specifications: purity, 99.5% min; acidity (as acetic acid), 0.1% max In the USA, to meet the requirements of the Food Chemical Codex, acetaldehyde must pass an infrared identification test and meet the following specifications: purity, 99.0% min; acidity (as acetic acid) 0.1% max; non-volatile residue, 0.006% max; and specific gravity (0 deg/20 °C),

Methods of Manufacturing of Acetaldehyde:
There is still some commercial production by the partial oxidation of ethyl alcohol and hydration of acetylene.
Acetaldehyde is also formed as a coproduct in the high temperature oxidation of butane.
A more recently developed rhodium catalyzed process produces acetaldehyde from synthesis gas as a coproduct with ethyl alcohol and acetic acid.

Dehydrogenation of ethanol.
Ethanol vapor is passed at 260-290 °C over a catalyst consisting of copper sponge or copper activated with chromium oxide in a tubular reactor.
A conversion of 25-50% per run is obtained.
By washing with alcohol and water, acetaldehyde and ethanol are separated from the exhaust gas, which is mainly hydrogen.

Pure acetaldehyde is obtained by distillation; the ethanol is separated from water and higher-boiling products by distillation and flows back to the reactor.
The final acetaldehyde yield is about 90%.
By products include butyric acid, crotonaldehyde, and ethyl acetate.

Oxidation of ethanol is the oldest laboratory method for preparing acetaldehyde.
In the commercial process, ethanol is oxidized catalytically with oxygen (or air) in the vapor phase.
Copper, silver, and their oxides or alloys are the most frequently used catalysts.

Direct oxidation of ethylene.
An aqueous solution of PdCl2 and CuCl2 is used as catalyst.
Acetaldehyde formation had already been observed in the reaction between ethylene and aqueous palladium chloride.
In the Wacker-Hoechst process, metallic palladium is reoxidized by CuCl2, which is then regenerated with oxygen.

Only a very small amount of PdCl2 is required for the conversion of ethylene.
The reaction of ethylene with palladium chloride is the rate-determining step.
One- and two-stage versions of the process are on stream.

In the one-stage method, an ethylene - oxygen mixture reacts with the catalyst solution.
During the reaction a stationary state is established in which "reaction" (formation of acetaldehyde and reduction of CuCl2) and "oxidation" (reoxidation of CuCl) proceed at the same rate.
This stationary state is determined by the degree of oxidation of the catalyst.
In the two-stage process the reaction is carried out with ethylene and then with oxygen in two separate reactors.

The catalyst solution is alternately reduced and oxidized.
At the same time the degree of oxidation of the catalyst changes alternately.
Air is used instead of pure oxygen for the catalyst oxidation.

Polymerization of Acetaldehyde:
The Acetaldehyde may polymerize under the influence of acids, alkaline materials, such as sodium hydroxide, in the presence of trace metals (iron) with fire or explosion hazard.

Polymeric forms of Acetaldehyde:
Three molecules of acetaldehyde condense to form "paraldehyde", a cyclic trimer containing C-O single bonds.
Similarly condensation of four molecules of acetaldehyde give the cyclic molecule metaldehyde.

Paraldehyde can be produced in good yields, using a sulfuric acid catalyst.
Metaldehyde is only obtained in a few percent yield and with cooling, often using HBr rather than H2SO4 as the catalyst.
At -40 °C in the presence of acid catalysts, polyacetaldehyde is produced.
There are two stereomers of paraldehyde and four of metaldehyde.

The German chemist Valentin Hermann Weidenbusch (1821–1893) synthesized paraldehyde in 1848 by treating acetaldehyde with acid (either sulfuric or nitric acid) and cooling to 0°C.
He found Acetaldehyde quite remarkable that when paraldehyde was heated with a trace of the same acid, the reaction went the other way, recreating acetaldehyde.

Acetal derivatives of Acetaldehyde:
Acetaldehyde forms a stable acetal upon reaction with ethanol under conditions that favor dehydration.
The product, CH3CH(OCH2CH3)2, is formally named 1,1-diethoxyethane but is commonly referred to as "acetal".
This can cause confusion as "acetal" is more commonly used to describe compounds with the functional groups RCH(OR')2 or RR'C(OR'')2 rather than referring to this specific compound – in fact, 1,1-diethoxyethane is also described as the diethyl acetal of acetaldehyde.

Precursor to vinylphosphonic acid:
Acetaldehyde is a precursor to vinylphosphonic acid, which is used to make adhesives and ion conductive membranes.

The synthesis sequence begins with a reaction with phosphorus trichloride:
PCl3 + CH3CHO → CH3CH(O−)PCl3+
CH3CH(O−)PCl3+ + 2 CH3CO2H → CH3CH(Cl)PO(OH)2 + 2 CH3COCl
CH3CH(Cl)PO(OH)2 → CH2=CHPO(OH)2 + HCl

Biochemistry of Acetaldehyde:
In the liver, the enzyme alcohol dehydrogenase oxidizes ethanol into acetaldehyde, which is then further oxidized into harmless acetic acid by acetaldehyde dehydrogenase.
These two oxidation reactions are coupled with the reduction of NAD+ to NADH.

In the brain, the enzyme catalase is primarily responsible for oxidizing ethanol to acetaldehyde, and alcohol dehydrogenase plays a minor role.
The last steps of alcoholic fermentation in bacteria, plants, and yeast involve the conversion of pyruvate into acetaldehyde and carbon dioxide by the enzyme pyruvate decarboxylase, followed by the conversion of acetaldehyde into ethanol.
The latter reaction is again catalyzed by an alcohol dehydrogenase, now operating in the opposite direction.

General Manufacturing Information of Acetaldehyde:

Industry Processing Sectors:
All other basic organic chemical manufacturing
Petrochemical manufacturing

China is the largest consumer of acetaldehyde.
Acetaldehyde is heavily used in the production of acetic acid.
This use will be limited in the future because new plants in China will use the methanol carbonylation process.
Other uses will grow, but the volumes are not large enough to offset the volumes used in acetic acid production.
Chinese consumption is expected to grow slightly at 1.6%/yr through 2018.

Formation during the natural alcoholic fermentation process.
Recovery is effected by suitable fractionation, subsequent preparation of the acetaldehyde ammonia, and final treatment of the addition compound with diluted sulfuric acid.

Western Europe is the second largest consumer of acetaldehyde accounting for 20% of world consumption in 2012.
The rate of growth there is expected to be 1%/yr through 2018.

Total acetaldehyde production in western Europe on January 1, 1983 was more than 0.5 million tons, & production capacity is estimated to have been nearly 1 million tons.
Most of this was based on the catalytic oxidation of ethylene; less than 10% was based on partial oxidation of ethanol, & a very small percentage was based on the hydration of acetylene.
Acetaldehyde is produced (by oxidation of ethylene) by 7 companies in Japan.
Their combined production is est to have been 278,000 tons in 1982, down from an est 323,000 tons in 1981.
Japanese imports & exports of acetaldehyde are negligible.

Clinical Laboratory Methods of Acetaldehyde:
Acetaldehyde concn in blood from 15 normal pt was approx 60 umol/L as determined by high-pressure liquid chromatography.
Acetaldehyde was probably bound to nondialyzable blood elements.

A new technique is described for measuring acetaldehyde in the breath, by freezing out the volatile components of breath in liq nitrogen, then assaying this concentrated specimen by gas chromatography.

Acetaldehyde in human blood is determined by gas chromatography.
Method utilizes sodium nitrite-sulfosalicylic acid as an inhibitor of ethanol oxidizing systems by means of which interference of ethanol is reduced.

Manufacture of Acetaldehyde:
Release to the environment of Acetaldehyde can occur from industrial use: manufacturing of the Acetaldehyde.

Human Metabolite Information of Acetaldehyde:

Tissue Locations
Adrenal Medulla
Brain
Epidermis
Erythrocyte
Fibroblasts
Intestine
Kidney
Liver
Neuron
Ovary
Pancreas
Placenta
Platelet
Skeletal Muscle
Testis
Thyroid Gland

Cellular Locations
Cytoplasm
Endoplasmic reticulum
Extracellular
Mitochondria
Peroxisome

Uses of Acetaldehyde:
Acetaldehyde is used in producing acetic acid,acetic anhydride, cellulose acetate, syntheticpyridine derivatives, pentaerythritol, terephthalicacid, and many other raw materials.
Release of acetaldehyde from poly ethyleneterephthalate (PET) bottles into carbonatedmineral waters has been observed; 180 ppm was detected in sampleskept for 6 months at 40°C (104°F).

Acetaldehyde is also known as ethanal, acetaldehyde is miscible with H2O, alcohol, or ether in all proportions.
Because of Acetaldehyde versatile chemical reactivity, acetaldehyde is widely used as a commencing material in organic syntheses, including the production of resins, dyestuffs, and explosives.
The compound also is used as a reducing agent, preservative, and as a medium for silvering mirrors.
In resin manufacture, paraldehyde (CH3CHO)3 sometimes is preferred because of Acetaldehyde higher boiling and flash points.

Acetaldehyde is used as a general solvent in organic and polymer chemical reactions.
Acetaldehyde also plays a role in fruit and food quality, ripening and deterioration.
Manufacture of paraldehyde, acetic acid, butanol, perfumes, flavors, aniline dyes, plastics, synthetic rubber; silvering mirrors, hardening gelatin fibers.
Flavoring agent in foods and beverages.
Fumigant for storage of apples and strawberries.

Acetaldehyde can also be used as an odorant, and Acetaldehyde found in nature in many foods such as ripe fruits, cheese and heated milk.
Acetaldehyde occurs naturally during fermentation, and low levels of acetaldehyde are to be found in certain foods.
Acetaldehyde is mainly used for preparation of citrus, apple, cream type essence, etc.
Acetaldehyde is mostly used in acetic acid industry.

Butanol and octanol are also the important derivatives of the acetaldehyde in the past.
Nowadays, butanol and octanol are prepared by Propylene carbonyl synthesis method.
Acetaldehyde is a very important raw material in the production of a large number of chemical products, for example paint binders in alkyd paints and plasticizers for plastics.
Acetaldehyde is also used in the manufacture of construction materials, fire retardant paints and explosives, while Acetaldehyde uses within the pharmaceutical industry include the manufacture of sedatives and tranquilisers, among other things.
Acetaldehyde can also be used as a raw material in the manufacture of acetic acid, another platform chemical with many applications.

Acetaldehyde is also used to produce pentaerythritol, peracetic acid, pyridine and Acetaldehyde derivatives.
Domestically produced acetaldehyde is mainly used as intermediate for the production of acetic acid.
Only a small amount is used for the production of pentaerythritol, butanol, trichloroacetaldehyde, trimethylolpropane, etc.
Acetaldehyde is primarily used to produce other chemicals, including acetal, Crotonaldehyde, acetic acid peroxide, hydroxyl acrylic nitrile, trichloroacetaldehyde, ethyl acetate, pentaerythritol, acetic anhydride, acetic acid, Glyoxal, phenyl acrolein, acetal, methyl ethylamine, diethylamine, α-Alanine, pyridine, α-methylpyridine, β-methylpyridine, γ-methylpyridine, etc.

The predominant use of acetaldehyde is as an intermediate in the synthesis of other chemicals.
Acetaldehyde is used in the production of perfumes, polyester resins, and basic dyes.
Acetaldehyde is also used as a fruit and fish preservative, as a flavoring agent, and as a denaturant for alcohol, in fue compositions, for hardening gelatin, and as a solvent in the rubber, tanning, and paper industries.

The predominant use of acetaldehyde is as an intermediate in the synthesis of other chemicals.

Glue sticks, glitter glues, fabric glues, craft glue, spray mounts, stencil sprays, and other adhesives used for primarily craft purposes
Cleaning and household care products that can not be placed in a more refined category

Used in synthesis of organic chemicals, resins, dyes, pesticides, disinfectants, cosmetics, gelatin, glue, lacquers, varnishes, casein products, explosives, and pharmaceuticals; also used as a hardener in photography, a flavoring agent, and a leather preservative.
Also used in leather tanning, in glue products, and in the paper industry.
A metabolite of ethanol after drinking alcohol.

Acetaldehyde is used in the production of acetic acid, acetic anhydride, cellulose acetate, vinyl acetate resins, acetate esters, pentaerythritol, synthetic pyridine derivatives, terephthalic acid, and peracetic acid.
Acetaldehyde is also used in the production of perfumes, polyester resins, basic dyes, in fruit and fish preservation, as a flavoring agent, an alcohol denaturant, as a hardening agent for gelatin, in fuel compositions, and as a solvent in the rubber, tanning, and paper industries.

Hydraulic fracturing uses a specially blended liquid which is pumped into a well under extreme pressure causing cracks in rock formations underground.
These cracks in the rock then allow oil and natural gas to flow, increasing resource production.
Although there are dozens to hundreds of chemicals which could be used as additives, there are a limited number which are routinely used in hydraulic fracturing.

Traditionally, acetaldehyde was mainly used as a precursor to acetic acid.
This application has declined because acetic acid is produced more efficiently from methanol by the Monsanto and Cativa processes.
Acetaldehyde is an important precursor to pyridine derivatives, pentaerythritol, and crotonaldehyde.
Urea and acetaldehyde combine to give a useful resin.
Acetic anhydride reacts with acetaldehyde to give ethylidene diacetate, a precursor to vinyl acetate, which is used to produce polyvinyl acetate.

The global market for acetaldehyde is declining.
Demand has been impacted by changes in the production of plasticizer alcohols, which has shifted because n-butyraldehyde is less often produced from acetaldehyde, instead being generated by hydroformylation of propylene.
Likewise, acetic acid, once produced from acetaldehyde, is made predominantly by the lower-cost methanol carbonylation process.
The impact on demand has led to increase in prices and thus slowdown in the market.

China is the largest consumer of acetaldehyde in the world, accounting for almost half of global consumption in 2012.
Major use has been the production of acetic acid.
Other uses such as pyridines and pentaerythritol are expected to grow faster than acetic acid, but the volumes are not large enough to offset the decline in acetic acid.

As a consequence, overall acetaldehyde consumption in China may grow slightly at 1.6% per year through 2018.
Western Europe is the second-largest consumer of acetaldehyde worldwide, accounting for 20% of world consumption in 2012.
As with China, the Western European acetaldehyde market is expected to increase only very slightly at 1% per year during 2012–2018.

However, Japan could emerge as a potential consumer for acetaldehyde in next five years due to newfound use in commercial production of butadiene.
The supply of butadiene has been volatile in Japan and the rest of Asia.
This should provide the much needed boost to the flat market, as of 2013.

Acetaldehyde was used as a precursor to acetic acid.
Acetaldehyde is used as a precursor to pyridine derivatives, crotonaldehyde, and pentaerythritol.
Used in the manufacturing of resin.

Acetaldehyde is used to produce polyvinyl acetate.
Acetaldehyde is used in the manufacturing of disinfectants, perfumes, and drugs
Acetaldehyde is used in the production of chemicals such as acetic acid.

As a precursor to acetic acid.
As a precursor to pyridine derivatives, crotonaldehyde, and pentaerythritol.
In the manufacturing of resin.

To produce polyvinyl acetate.
In the manufacturing of disinfectants, perfumes, and drugs.
In the production of chemicals such as acetic acid.

Acetaldehyde is an intermediate in the production of acetic acid, acetic anhydride, cellulose acetate, vinyl acetate resins, acetate esters, pentaerythritol, synthetic pyridine derivatives, terephthalic acid and peracetic acid.
Other uses of acetaldehyde include silvering of mirrors; leather tanning; denaturant for alcohol; fuel mixtures; hardener for gelatine fibres; glue and casein products; preservative for fish and fruit; synthetic flavouring agent; paper industry; and manufacture of cosmetics, aniline dyes, plastics and synthetic rubber.
The concentration of acetaldehyde in alcoholic beverages is generally below 500 mg/l. Low levels of acetaldehyde are also reported to occur in several essential oils.
Acetaldehyde is an intermediate product in the metabolism of ethanol and sugars and also occurs as a natural metabolite in small quantities in human blood.

In cosmetic products, two possibilities of occurrence of acetaldehyde can be distinguished:
1) Acetaldehyde is used as a fragrance/flavour ingredient in fragrance compounds used in cosmetic products.
The SCCNFP concluded in Acetaldehyde opinion of 25th May 2004 that acetaldehyde can be safely used as a fragrance/flavour ingredient at a maximum concentration of 0.0025% (25 ppm) in the fragrance compound.

2) In addition, acetaldehyde can also be found in cosmetic products in the form of
unavoidable traces originating mainly through:
Plant extracts and botanical ingredients
Ethanol.

Widespread uses by professional workers of Acetaldehyde:
Acetaldehyde is used in the following products: pH regulators and water treatment products and laboratory chemicals.
Acetaldehyde is used in the following areas: health services and scientific research and development.
Other release to the environment of Acetaldehyde is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners).

Uses at industrial sites of Acetaldehyde:
Acetaldehyde is used in the following products: pH regulators and water treatment products and laboratory chemicals.
Acetaldehyde is used in the following areas: health services and scientific research and development.
Acetaldehyde is used for the manufacture of: chemicals.
Release to the environment of Acetaldehyde can occur from industrial use: as an intermediate step in further manufacturing of another Acetaldehyde (use of intermediates), in processing aids at industrial sites and as processing aid.

Industry Uses of Acetaldehyde:
Fuels and fuel additives
Intermediates

Consumer Uses of Acetaldehyde:
Adhesives and sealants
Golf and Sports Turf
Paints and coatings
Paper products
Plastic and rubber products not covered elsewhere
Process Intermediates

Isolation and Evacuation of Acetaldehyde:
As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions.
LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet).
FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

Spillage Disposal of Acetaldehyde:
Remove all ignition sources.
Evacuate danger area! Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the Acetaldehyde.
Do NOT let this chemical enter the environment.
Collect leaking liquid in sealable containers.

Absorb remaining liquid in sand or inert absorbent.
Then store and dispose of according to local regulations.
Do NOT absorb in saw-dust or other combustible absorbents.
Remove vapour with fine water spray.

Cleanup Methods of Acetaldehyde:
Accidental release measures.
Personal precautions, protective equipment and emergency procedures: Use personal protective equipment.
Avoid breathing vapors, mist or gas.
Ensure adequate ventilation.

Remove all sources of ignition.
Evacuate personnel to safe areas.
Beware of vapors accumulating to form explosive concentrations.
Vapors can accumulate in low areas.

Environmental precautions: Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided
Methods and materials for containment and cleaning up: Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing and place in container for disposal according to local regulations.

(1) Remove all ignition sources (2) Ventilate area to disperse gas (3) If in gaseous form, stop flow of gas (4) If in liquid form, for small quantities absorb on paper towels.
Evaporate in safe place (fume hood).
Allow sufficient time for vapors to completely clear hood ductwork, then burn the paper in a location away from combustible materials.

Large quantities can be reclaimed or collected and atomized in a suitable combustion chamber.
Acetaldehyde should not be allowed to enter a confined space such as a sewer, because of possibility of an explosion.
Sewers designed to preclude the formation of explosive concentration of acetaldehyde vapors are permitted.

Safety Profile of Acetaldehyde:
Confirmed carcinogen with experimental carcinogenic and tumorigenic data.
Poison by intratracheal and intravenous routes.
A human systemic irritant by inhalation.

An experimental routes.
A human systemic irritant by inhalation.
An experimental teratogen.
Other experimental reproductive effects.
A skin and severe eye irritant.

A narcotic. Human mutation data reported.
A common air contaminant.
Highly flammable liquid.
Mixtures of 30-60% of the vapor in air ignite above 100℃.
Acetaldehyde can react violently with acid anhydrides, alcohols, ketones, phenols, NH3, HCN, H2S, halogens, P, isocyanates, strong alkalies, and amines.

Reactions with cobalt chloride, mercury(Ⅱ) chlorate, or mercury(Ⅱ) perchlorate form violently in the presence of traces of metals or acids.
Reaction with oxygen may lead to detonation.
When heated to decomposition Acetaldehyde emits acrid smoke and fumes.

Purification Methods of Acetaldehyde:
Acetaldehyde is usually purified by fractional distillation in a glass helices-packed column under dry N2, discarding the first portion of distillate.
Or, Acetaldehyde is shaken for 30minutes with NaHCO3, dried with CaSO4 and fractionally distilled at 760mm through a 70cm Vigreux column (p 11).
The middle fraction is collected and further purified by standing for 2hours at 0o with a small amount of hydroquinone (free radical inhibitor), followed by distillation.

Formulation or re-packing of Acetaldehyde:
ECHA has no public registered data indicating whether or in which chemical products the Acetaldehyde might be used.
Release to the environment of this Acetaldehyde can occur from industrial use: formulation of mixtures.

Handling and Storage of Acetaldehyde:

Nonfire Spill Response of Acetaldehyde:
ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area).
All equipment used when handling the product must be grounded.

Do not touch or walk through spilled material.
Stop leak if you can do Acetaldehyde without risk.
Prevent entry into waterways, sewers, basements or confined areas.
A vapor-suppressing foam may be used to reduce vapors.

Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers.
Use clean, non-sparking tools to collect absorbed material.
LARGE SPILL: Dike far ahead of liquid spill for later disposal.
Water spray may reduce vapor, but may not prevent ignition in closed spaces.

Safe Storage of Acetaldehyde:
Fireproof.
Separated from incompatible materials.
See Chemical Dangers.
Cooled.
Keep in the dark.
Store only if stabilized.

Acetaldehyde should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers.
Acetaldehyde should always be stored under an inert atmosphere of nitrogen or argon to prevent autoxidation.

Storage Conditions of Acetaldehyde:
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Recommended storage temperature: 2 - 8 °C.

Store in a cool, dry, well-ventilated location.
Inside storage should be in a standard flammable liquids storage warehouse, room, or cabinet.
Separate from oxidizing material and other reactive hazards.
Store bulk quantities in detached tanks provided with refrigeration and inert gas cover.

Acetaldehyde is recommended that steel storage tanks of suitable std be used.
Storage vessels should be fitted with temp gauges & automatic water sprays.
All tanks & equipment must be earthed.
Transfer of material by pipeline must be by pressure of nitrogen.
Drums containing acetaldehyde should never be stored in direct sunlight or other warm areas.

History of Acetaldehyde:
Acetaldehyde was first observed by the Swedish pharmacist/chemist Carl Wilhelm Scheele (1774); Acetaldehyde was then investigated by the French chemists Antoine François, comte de Fourcroy and Louis Nicolas Vauquelin (1800), and the German chemists Johann Wolfgang Döbereiner (1821, 1822, 1832) and Justus von Liebig (1835).
In 1835, Liebig named Acetaldehyde "aldehyde"; the name was later altered to "acetaldehyde".

First Aid of Acetaldehyde:
EYES: First check the victim for contact lenses and remove if present.
Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center.
Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician.
IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing.
Gently wash all affected skin areas thoroughly with soap and water.
IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop.
IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air.
IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop.
Provide proper respiratory protection to rescuers entering an unknown atmosphere.
Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING.
Volatile chemicals have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems.
If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center.
IMMEDIATELY transport the victim to a hospital.

If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body.
DO NOT INDUCE VOMITING.
IMMEDIATELY transport the victim to a hospital.

OTHER: Since this chemical is a known or suspected carcinogen you should contact a physician for advice regarding the possible long term health effects and potential recommendation for medical monitoring.
Recommendations from the physician will depend upon the specific compound, Acetaldehyde chemical, physical and toxicity properties, the exposure level, length of exposure, and the route of exposure.

Fire Fighting of Acetaldehyde:
CAUTION: All these products have a very low flash point: Use of water spray when fighting fire may be inefficient.

SMALL FIRE: Dry chemical, CO2, water spray or alcohol-resistant foam.
Do not use dry chemical extinguishers to control fires involving nitromethane (UN1261) or nitroethane (UN2842).

LARGE FIRE: Water spray, fog or alcohol-resistant foam.
Do not use straight streams.
Move containers from fire area if you can do Acetaldehyde without risk.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles.
Cool containers with flooding quantities of water until well after fire is out.
Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.
ALWAYS stay away from tanks engulfed in fire.
For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

Identifiers of Acetaldehyde:
CAS Number: 75-07-0
ChEBI: CHEBI:15343
ChEMBL: ChEMBL170365
ChemSpider: 172
ECHA InfoCard: 100.000.761
EC Number: 200-836-8
IUPHAR/BPS: 6277
KEGG: C00084
PubChem CID: 177
RTECS number: AB1925000
UNII: GO1N1ZPR3B
CompTox Dashboard (EPA): DTXSID5039224
InChI:
InChI=1S/C2H4O/c1-2-3/h2H,1H3
Key: IKHGUXGNUITLKF-UHFFFAOYSA-N
InChI=1/C2H4O/c1-2-3/h2H,1H3
Key: IKHGUXGNUITLKF-UHFFFAOYAB
SMILES:
O=CC
CC=O

Properties of Acetaldehyde:
Chemical formula: C2H4O
Molar mass: 44.053 g·mol−1
Appearance: Colourless gas or liquid
Odor: Ethereal
Density:
0.784 g·cm−3 (20 °C)
0.7904–0.7928 g·cm−3 (10 °C)
Melting point: −123.37 °C (−190.07 °F; 149.78 K)
Boiling point: 20.2 °C (68.4 °F; 293.3 K)
Solubility in water: miscible
Solubility: miscible with ethanol, ether, benzene, toluene, xylene, turpentine, acetone
slightly soluble in chloroform
log P: -0.34
Vapor pressure: 740 mmHg (20 °C)
Acidity (pKa): 13.57 (25 °C, H2O)
Magnetic susceptibility (χ): -.5153−6 cm3/g
Refractive index (nD): 1.3316
Viscosity: 0.21 mPa-s at 20 °C (0.253 mPa-s at 9.5 °C)

Molecular Weight: 44.05
XLogP3-AA: -0.3
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 1
Rotatable Bond Count: 0
Exact Mass: 44.026214747
Monoisotopic Mass: 44.026214747
Topological Polar Surface Area: 17.1 Å²
Heavy Atom Count: 3
Formal Charge: 0
Complexity: 10.3
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

Quality Level: 400
grade:
FG
Halal
Kosher
natural
reg. compliance:
EU Regulation 1334/2008 & 178/2002
FDA 21 CFR 117
vapor density: 1.52 (vs air)
vapor pressure: 14.63 psi ( 20 °C)
assay: ≥99% (GC)
form: liquid
autoignition temp.: 365 °F
expl. lim.: 60 %
refractive index: n20/D 1.332 (lit.)
pH: 5 (20 °C)
bp: 21 °C (lit.)
mp: −125 °C (lit.)
density: 0.785 g/mL at 25 °C (lit.)
application(s): flavors and fragrances
Documentation: see Safety & Documentation for available documents
food allergen: no known allergens
Organoleptic: ethereal
storage temp.: 2-8°C
SMILES string: CC=O
InChI: 1S/C2H4O/c1-2-3/h2H,1H3
InChI key: IKHGUXGNUITLKF-UHFFFAOYSA-N

Physicochemical Information of Acetaldehyde:
Boiling point: 20.4 °C (1013 hPa)
Density: 0.78 g/cm3 (20 °C)
Explosion limit: 4 - 57 %(V)
Flash point: -38.89 °C
Ignition temperature: 140 °C
Melting Point: -123.5 °C
pH value: 5 (H₂O, 20 °C)
Vapor pressure: 1202 hPa (25 °C)

Structure of Acetaldehyde:
Molecular shape:
trigonal planar (sp2) at C1
tetrahedral (sp3) at C2
Dipole moment: 2.7 D

Thermochemistry
Heat capacity (C) of Acetaldehyde:: 89 J·mol−1·K−1
Std molar entropy (So298): 160.2 J·mol−1·K−1
Std enthalpy of formation (ΔfH⦵298): −192.2 kJ·mol−1
Gibbs free energy (ΔfG˚): -127.6 kJ·mol−1

Names of Acetaldehyde:

Preferred IUPAC name of Acetaldehyde:
Acetaldehyde

Systematic IUPAC name of Acetaldehyde:
Ethanal

Other names of Acetaldehyde:
Acetic aldehyde
Ethyl aldehyde
Acetylaldehyde

Synonyms of Acetaldehyde:
acetaldehyde
ethanal
75-07-0
acetic aldehyde
ethyl aldehyde
Acetaldehyd
aldehyde
Acetylaldehyde
Acetic ethanol
Aldeide acetica
Octowy aldehyd
Aldehyde acetique
Azetaldehyd
RCRA waste number U001
Acetaldehyde (natural)
NSC 7594
NCI-C56326
ACETYL GROUP
acetaldehydes
ethaldehyde
CCRIS 1396
HSDB 230
UNII-GO1N1ZPR3B
MFCD00006991
UN1089
CHEBI:15343
AI3-31167
CH3CHO
GO1N1ZPR3B
Acetaldehyd
Ethylaldehyde
Octowy aldehyd
Aldeide acetica
Aldehyde acetique
FEMA No. 2003
EINECS 200-836-8
RCRA waste no. U001
Acetaldehyde, >=99%, meets FCC analytical specification
acetaldhyde
acetoaldehyde
Acetaldeyde
acetic hydride
ethan-1-one
Acetaldehyde 10%
MeCHO
Acetaldehyde Natural
ACETALD
Acetaldehyde-[13C]
Acetaldehyde polymerized
DSSTox_CID_2
CH2CHO
NATURAL ALDEFRESH
Oxidized polyvinyl alcohol
bmse000647
Epitope ID:145667
EC 200-836-8
WLN: VH1
DSSTox_RID_79423
oxidised poly(vinyl alcohol)
an oxidized polyvinyl alcohol
DSSTox_GSID_39224
Acetaldehyde, >=99%, FG
BIDD:ER0621
Acetaldehyde, >=99%, FCC
CHEMBL170365
GTPL6277
DTXSID5039224
Acetaldehyde, analytical standard
CHEBI:16571
NSC7594
Acetaldehyde solution, 5 M in THF
NSC-7594
STR01382
Tox21_202479
Acetaldehyde, natural, >=99%, FG
Acetaldehyde, ReagentPlus(R), 99%
STL264249
AKOS000120180
MCULE-6800925955
UN 1089
Acetaldehyde, ACS reagent, >=99.5%
CAS-75-07-0
Acetaldehyde, >=99%, FCC, stabilized
NCGC00091753-01
NCGC00260028-01
Acetaldehyde solution, 40 wt. % in H2O
Acetaldehyde, >=90.0%, SAJ first grade
Acetaldehyde [UN1089] [Flammable liquid]
Acetaldehyde solution, 50 wt. % in ethanol
FT-0621719
FT-0660962
Acetaldehyde solution, 50 wt. % (triacetin)
C00084
D78540
Q61457
Acetaldehyde solution, 40 wt. % in isopropanol
Acetaldehyde, ReagentPlus(R), >=99.0% (GC)
A838317
ACETALDEHYDE SOLUTION, 40 WT. % IN H2O
Acetaldehyde solution, natural, 50 wt. % in ethanol
BRD-K77914232-001-01-3
Q57695648
Acetaldehyde solution, natural, 50 wt. % ethanol, FG
Acetaldehyde, puriss. p.a., anhydrous, >=99.5% (GC)
F2190-0651
Acetaldehyde, United States Pharmacopeia (USP) Reference Standard
Acetaldehyde solution, natural, 50 wt. % in ethanol, analytical standard
200-836-8
462-95-3
75-07-0
Acetaldehído
Acetaldehyd
Acetaldehyde
Acétaldéhyde
Acetaldeide
acetylaldehyde
Aldehído acético
Aldehyde acetique
Aldeide acetica
Asetaldehit
Etanal
ethaldehyde
ethanal
Éthanal
ethyl aldehyde
Ethylaldehyde
MFCD0000699
Αιθανάλη
Ацетальдегид
アセトアルデヒド
2-Oxoethyl
acetaldehyde-d3
Acetaldehydemissing
acetic aldehyde
Aldeide acetica
Azetaldehyd
Ethanal, Acetic Aldehyde, Ethyl Aldehyde
formylmethyl
Methylcarbonyl
Octowy aldehyd
STR01382
VH1