75-07-0

Raw materials And Preparation Products

Hazard Information

Material Safety Data Sheet(MSDS)

Questions And Answer

• description

  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.It 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 it 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. It is also used as a synthetic flavouring substance, food preservative and as a fragrance.
  
  figure 1 Acetaldehyde 2d structural formula;

• As a flavor ingredient

  CAS.No.:	75-07-0	FL.No.:	5.001	FEMA.No.:	2003	NAS.No.:	2003
  CoE.No.:	89	EINECS.No.:	200-836-8	JECFA.No.:	80

  Regulatory Status:
  CoE: Approved. Bev.: 23 ppm; Food: 20 ppm
  FDA: 21 CFR 182.60, 582.60; 27 CFR 19.460, 21 et seq.
  FDA (other): n/a
  JECFA: ADI: Acceptable. No safety concern at current levels of intake when used as a flavoring agent (1997).
  
  Reported uses (ppm): (FEMA, 1994)

  Food Category	Usual	Max.
  Alcoholic.beverages	470	470
  Baked.goods	30	280
  Cheese	0.0005	600
  Chewing.gum	0.78	9.2
  Condiment,.relish	0.5	5
  Confection,.frosting	83	2000
  Fats,.oils	0.1	4
  Frozen.dairy	94	150
  Fruit.ices	50	100
  Gelatin,.pudding	8.1	100
  Gravies	0.61	53
  Hard.candy	9.29	21.49
  Imitation.dairy	0.2	0.7
  Jams,.jellies	23	50
  Meat.products	1.67	5.53
  Milk.products	76	76
  Nonalcoholic.beverages	38	190
  Reconstituted.vegetables	0.0085	0.02
  Snack.foods	0.25	10
  Soft.candy	3	1000
  Sweet.sauce	13	230

   Natural occurrence:
  Reported found in oak and tobacco leaves; in the fruital aromas of pear, apple, raspberry, strawberry and pineapple; in the distillation waters of Monarda punctata, orris, cumin, chenopodium; in the essential oils of Litsea cubeba, Magnolia grandiflora, Artemisia brevifolia, rosemary, balm, clary sage, Mentha arvensis, daffodil, bitter orange, camphor, angelica, fennel,mustard, Scotch blended whiskey, Japanese whiskey, rose wine, blackberry brandy and rum.;

• Uses

  1. Acetaldehyde can also be used as an odorant, and it 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. It is mainly used for preparation of citrus, apple, cream type essence, etc.
  2. 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.
  3. 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 its 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.
  4. Acetaldehyde is also used to produce pentaerythritol, peracetic acid, pyridine and its 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.
  5. 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.
  ;

• Content analysis

  65 ml of 0.5 mol/L hydroxylamine hydrochloride and 50.0 ml of triethanolamine were added to a fixed pressure-heat resistant bottle with good sealing property. A slow nitrogen flow is fed into the bottle through a glass tube slightly above the liquid surface for 2 min to exhaust the air. About 600 mg of the sample, accurately weighed, was sealed in one ampoule bottle and put in the above mixture. Several short glass rods with the diameter of about 8 mm were added to the bottle. After covering the cork, the bottle was strongly shaken to break the ampoule. Then keep the reaction for 30 min at room temperature, shaking the bottle from time to time. Remove the cork after cooling if necessary. The whole process should be careful in order to avoid the loss of the product. The above system was then titrated by certain amount of 0.5 mol/L sulfuric acid to cyan end point. At the same time a blank titration was conducted. Each 0.5 mol/L sulfur acid was equivalent to 22.03 mg acetaldehyde (C2H4O).;

• Toxicity

  GRAS(FEMA；FDA，§182．60，2000). LD501930mg/kg(rat，oral);

• Preparation

  Several production methods are used to produce ethanal.
  (1) Direct oxidation of ethylene.
  Ethylene and oxygen passed the catalysts containing palladium chloride, copper chloride, hydrochloric acid and water .Coarse acetaldehyde can be synthesyed by this one-Step direct oxidation process. Then, after a distillation process, the final product was obtained.
  (2) Ethanol oxidation.
  Under the 300-480 ℃, the air oxydehydrogenation process of ethanol vapor took place to produce acetaldehyde by using silver, copper or silver-copper alloy mesh as catalyst.
  (3) Direct hydration of ethyne.
  Under the effect of mercury catalyst or mercury free catalyst, the direct hydration reaction of acetylene and water was used to produce acetaldehyde. Due to the toxicity of mercury, this method has been gradually replaced by other methods.
  (4) Ethanol dehydrogenation
  Under the effect of copper catalyst with the addition of cobalt, chromium, zinc or other compounds, ethanol dehydrogenation took place to produce acetaldehyde.
  (5) Saturated hydrocarbon oxidation.
  Material Consumption Quota: one ton product of acetaldehyde costs 610kg ethyne(99%) by direct hydration of ethyne method; 1200kg ethanol (95%) by ethanol oxidation method; 710kg ethylene(99%) and 300m3 oxygen（99%） by ethylene oxidation method (one-step).
  (6) Acetaldehyde can be prepared by ethylene oxidation.
  Acetaldehyde can be prepared by gas phase hydrogenation of Ethanol.
  Acetaldehyde can be prepared by simultaneous destructive distillation calcium acetate and calcium formate.
  ethanal can be prepared by adduct reaction of acetylene and water.;

• Hazardous Substances Data Bank (HSDB)

  Acetaldehyde has been classified by the International Agency for Research on Cancer (IARC) as Group 2B, possibly carcinogenic to humans, based on evidence in animals.Acetaldehyde is a respiratory tract carcinogen in experimental animals, especially of the nasal mucosa in rats and of the larynx in hamsters.
  There is inadequate evidence for the carcinogenicity of acetaldehyde in humans. One small study of workers manufacturing several types of aldehydes found increased risk of bronchial tumours, but workers were exposed to many other chemicals in addition to acetaldehyde.Three other studies on the carcinogenicity of alcoholic beverages found that people who developed cancer after heavy alcohol use had genetic differences and higher concentrations of acetaldehyde in their blood compared to those who didn't develop cancer.Further study is required to establish a causal relationship.
  Acetaldehyde can cause respiratory and eye irritation and in severe cases, lung edema. It also exacerbates the effects of alcohol and is a central nervous system depressant.;

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