Name | Benzaldehyde |
Synonyms | Benzaldehyde BENZALADEHYDE benzaldehydeffc Benzaldehyde FFC Benzene methylal benzoic aldehyde artificialalmondoil Benzene carbaldehyde Artificial Almond Oil NATURAL BENZALADEHYDE Artificial bitter almond oil Artifical essential oil of almond |
CAS | 100-52-7 |
EINECS | 202-860-4 |
InChI | InChI=1/C7H6O/c8-6-7-4-2-1-3-5-7/h1-6H |
InChIKey | HUMNYLRZRPPJDN-UHFFFAOYSA-N |
Molecular Formula | C7H6O |
Molar Mass | 106.12 |
Density | 1.044 g/cm3 at 20 °C (lit.) |
Melting Point | -26 °C (lit.) |
Boling Point | 178-179 °C (lit.) |
Flash Point | 145°F |
JECFA Number | 22 |
Solubility | H2O: soluble100mg/mL |
Vapor Presure | 4 mm Hg ( 45 °C) |
Vapor Density | 3.7 (vs air) |
Appearance | neat |
Color | Pale yellow |
Odor | Like almonds. |
Merck | 14,1058 |
BRN | 471223 |
pKa | 14.90(at 25℃) |
PH | 5.9 (1g/l, H2O) |
Storage Condition | Store below +30°C. |
Stability | Stable. Combustible. Incompatible with strong oxidizing agents, strong acids, reducing agents, steam. Air, light and moisture-sensitive. |
Sensitive | Air Sensitive |
Explosive Limit | 1.4-8.5%(V) |
Refractive Index | n20/D 1.545(lit.) |
Physical and Chemical Properties | density 1.045 |
Use | Important chemical raw materials, used in the production of lauric aldehyde, lauric acid, phenylacetaldehyde and benzyl benzoate, etc., also used as Spices |
Hazard Symbols | Xn - Harmful![]() |
Risk Codes | 22 - Harmful if swallowed |
Safety Description | 24 - Avoid contact with skin. |
UN IDs | UN 1990 9/PG 3 |
WGK Germany | 1 |
RTECS | CU4375000 |
FLUKA BRAND F CODES | 8 |
TSCA | Yes |
HS Code | 2912 21 00 |
Hazard Class | 9 |
Packing Group | III |
Toxicity | LD50 in rats, guinea pigs (mg/kg): 1300, 1000 orally (Jenner) |
A colorless or pale yellow, volatile oily liquid with a strong refractive index, with a bitter almond odor and an aromatic odor when burned. The relative density was 1. 0415. Refractive index 5455. Melting Point -26 °c. Freezing point -56 °c. Boiling point 179 °c. Flash point (closed cup) 64.5 °c. Spontaneous ignition point 192. Flammable. Oxidation to benzoic acid in air. With ethanol, ether, volatile oil and volatile oil immiscible, slightly soluble in water.
Medicine, dye, Fragrance Intermediates, mainly used in the manufacture of lauric acid, lauric aldehyde, green and so on.
FEMA | 2127 | BENZALDEHYDE |
pH indicator color change ph range | 5.9 |
freezing point | -56 ℃ |
LogP | 1.4 at 25℃ |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Overview | Benzaldehyde is also called benzoaldehyde. It is the organic compound formed after the hydrogen of benzene is replaced by an aldehyde group. Benzaldehyde is the simplest, and it is also the most commonly used aromatic aldehyde in industry. It is a colorless liquid at room temperature with a special almond smell. Benzaldehyde is a compound formed by directly connecting the aldehyde group with the phenyl group. Because it has a fragrance similar to bitter almond, it was once called bitter almond oil. Benzaldehyde is widely found in the plant kingdom, especially in Rosaceae plants, mainly in the form of glycosides in the stem bark, leaves or seeds of plants, such as amygdalin in bitter almonds, cherries, laurel leaves, peach pit. Benzaldehyde naturally exists in essential oils such as bitter almond oil, Huoxiang oil, hyacinth oil, ylang ylang oil, etc. The compound also exists in the form of glycosides (amygdalin, Amygdalin) in nuts and nuts. The chemical properties of benzaldehyde are similar to fatty aldehydes, but they are also different. Benzaldehyde cannot reduce Feilin reagent; when reducing benzaldehyde with the reagent used in reducing fatty aldehyde, in addition to the main product benzyl alcohol, some tetra-substituted o-glycol compounds and diphenyl ethylene glycol are also produced. In the presence of potassium cyanide, two molecules of benzaldehyde generate benzoin by giving hydrogen atoms. Benzaldehyde can also undergo electrophilic substitution reaction on the aromatic core, which mainly generates meta-substitution products. For example, the main product during nitration is m-nitrobenzaldehyde. Today benzaldehyde is mainly prepared from toluene through different routes. |
how to identify benzaldehyde? | can be identified by appearance and properties: pure product is colorless liquid, industrial product is colorless to light yellow liquid, with bitter almond smell. at this step, it can be basically concluded that it is benzaldehyde. moreover, it is slightly soluble in water and miscible in ethanol, ether, benzene and chloroform. |
use | benzaldehyde is an important raw material for medicine, dye, perfume and resin industry, and can also be used as solvent, plasticizer and low temperature lubricant. In the fragrance industry, it is mainly used to blend edible flavors, and a small amount is used in daily chemical flavors and tobacco flavors. Although widely used as commercial food condiments and industrial solvents, the main use of benzyl alcohol is still used to synthesize various other compounds from pharmaceuticals to plastic additives. Benzyl alcohol is also an important intermediate product in the production of perfumes, fragrances and the synthesis of certain aniline dyes. The synthesis of mandelic acid uses benzaldehyde as the initial reagent: hydrocyanic acid first reacts with benzaldehyde, and the product mandelonitrile is then hydrolyzed to obtain racemic mandelic acid. Glaciologists LaChepelle and Stillman reported in 1966 that benzaldehyde and heptanal inhibit the crystallization of ice, thereby preventing the formation of Depth Hoar. This treatment prevents avalanches due to unstable snow cover. However, this compound destroys vegetation and pollutes water sources, and has not been widely used for this purpose. Important chemical raw materials, used to make lauraldehyde, lauric acid, phenylacetaldehyde and benzyl benzoate, etc., are also used as spices GB 2760-1996 regulations are temporarily allowed to use edible spices. It is mainly used to prepare almond, cherry, peach, nut and other flavors with a dosage of up to 40%. As an flavoring agent for canned cherries in sugar water, 3ml per kg of sugar water is added. Intermediates in medicine, dyes, and spices. Used in the production of oxybenzaldehyde, lauric acid, lauraldehyde, green, benzyl benzoate, benzylidene aniline, benzylidene acetone, etc. Used to blend soap flavors, edible flavors, etc. It can be used as a special head fragrance and used in small amounts in floral formulations, such as lilac, prynne, jasmine, violet, acacia, sunflower, sweet bean flower, plum blossom, orange blossom, etc. It is also available in soap. It can also be used as a edible spice in almonds, berries, cream, cherries, coconuts, apricots, peaches, big walnuts, big plums, vanilla beans, spice and other flavors. Wine flavors such as rum and brandy are also used. Benzaldehyde is an intermediate of herbicide wild swallow blight and plant growth regulator anti-inverted amine. Used as a reagent for the determination of ozone, phenols, alkaloids and methylene beside carboxyl groups It is an important raw material for the medicine, dye, perfume and resin industries. It can also be used as a solvent, plasticizer and low-temperature lubricant. Organic synthesis, solvent, determination of ozone and methylene beside carbonyl groups, verification of phenols and alkaloids, and preparation of fragrances. |
preparation | benzaldehyde can be prepared by a variety of ways. In industry, toluene is mainly oxidized by air or oxygen under the action of catalysts (vanadium pentoxide, tungsten trioxide or molybdenum trioxide); or toluene is chlorinated to benzyl chloride under light, and then hydrolyzed and oxidized; It can also be chlorinated to dichloromethyl benzene and rehydrolyzed. In the industry, benzene is also used as raw material to react with carbon monoxide and hydrogen chloride under pressure and aluminum trichloride. Benzaldehyde is prepared by catalytic reduction of benzoyl chloride in the laboratory. The main current preparation route is liquid chlorination or oxidation of toluene. The preparation methods that are eliminated include incomplete oxidation of benzyl alcohol, alkaline hydrolysis of benzoyl chloride, and addition of benzene and carbon monoxide. |
Related reactions | Benzaldehyde can be oxidized to a white benzoic acid solid with an unpleasant smell and crystallized on the inner wall of the container. Benzyl alcohol can be prepared by hydrogenating benzaldehyde, or it can be obtained by self-redox of benzaldehyde in an alcohol solution of potassium hydroxide (the products are potassium benzoate and benzyl alcohol). Benzaldehyde reacts with anhydrous sodium acetate and acetic anhydride to produce cinnamic acid. The alcohol solution of potassium cyanide can be used to catalyze the condensation of benzaldehyde to form benzoin. Benzaldehyde is disproportionated in concentrated alkali solution (Conicaro reaction, Cannizarro reaction): one molecule of aldehyde is reduced to the corresponding alcohol, and the other molecule of aldehyde is oxidized to carboxylate at the same time. The speed of this reaction depends on the substituents on the aromatic ring. |
toxicity | this product has certain irritation effect on eyes and respiratory mucosa. Due to its low volatility, its stimulating effect is not enough to cause serious harm. First aid measures Skin contact: Remove contaminated clothing and rinse with flowing water. Eye contact: Lift the eyelids and rinse with flowing water or saline. Medical treatment. Inhalation: Detach from site to fresh air. If breathing is difficult, give oxygen. Medical treatment. Ingestion: Drink enough warm water to induce vomiting. Medical closed operation should be fully exhaust. Respiratory system protection: When the concentration in the air exceeds the standard, you must wear a self-priming filter gas mask (half mask). An air respirator should be worn during emergency rescue or evacuation. Eye protection: Wear chemical safety glasses. Body protection: wear anti-toxin penetration work clothes. Hand protection: wear rubber oil-resistant gloves. Other protection: Smoking is strictly prohibited at the work site. After work, shower and change. Regular physical examination ADI 0~5 mg/kg(FAO/WHO-1994). LD501.3g/kg (rat, oral). GRAS(FDA,§ 182.60,2000). |
boiling point of benzaldehyde in reduced pressure distillation | boiling point of benzaldehyde will decrease under reduced pressure. Under normal circumstances, 178 ℃, decompression to 0.1mpa, the boiling point of benzaldehyde is about 110 ℃. Of course, it is an oil bath. The water bath can only be reduced to 100 degrees before decompression, and its boiling point will not be reduced below 100 degrees. |
refractive index and relative density | aroma: has a fragrance similar to bitter almond. Boiling point: 178 ℃. Relative density: 1.0415(10/4 ℃). Refractive index: 1.544-1.547. |
content analysis | according to aldehyde determination method (OT-6). The amount of sample taken is 1g. The equivalent factor (e) in the calculation is 53.06. Or as determined by gas chromatography (GT-10-4) non-polar column method. |
usage limit | FEMA(mg/kg): soft drink 36; Cold drink 42; Candy 120; Baked food 110; Pudding 160; Gum sugar 840 wine 50~60. |
production method | its preparation method is to chlorinate toluene under light to obtain mixed benzyl chloride (including C6H5CH2Cl,C6H5CHCl2 and C6H5CCl3), put the mixed benzyl chloride into the reaction kettle, add a small amount of zinc oxide and zinc phosphate mixture catalyst, drop water into the enamel kettle at 125~135 ℃, and the reaction starts immediately, after adding water for about 10h, the reaction is completed, soda ash is added at 65 ℃ for neutralization, the neutralization solution is hydrolyzed with soda ash in a hydrolysis pot, and refluxed for 8h. when the oil layer contains side chain chlorine <0.1%, the reaction is over, steam distillation is carried out, benzaldehyde is steamed out with water, and the product is obtained by stratification and rectification. Benzaldehyde is widely found in plants, especially in Rosaceae plants. It mainly exists in the form of glycosides in the stem bark, leaves or seeds of plants, such as amygdalin in bitter almonds. There are two main types of industrial production methods for benzaldehyde: toluene and benzene are used as raw materials. Laboratory preparation can also use catalytic (palladium/barium sulfate) to reduce benzoyl chloride. 1. Toluene chlorination and rehydrolysis method uses toluene as raw material and chlorinated under light to obtain mixed benzyl chloride. Raw material consumption quota: toluene 1700kg/t, chlorine 3000kg/t, soda ash 1500kg/t. 2. Benzyl alcohol oxidation method, benzyl chloride is hydrolyzed to obtain benzyl alcohol, and then oxidized to obtain benzaldehyde. 3. Benzaldehyde is an intermediate product of toluene oxidation to benzoic acid. Toluene → benzyl alcohol → benzaldehyde → benzoic acid. 4. Benzene is used as raw material to react with carbon monoxide and hydrogen chloride under pressure and aluminum trichloride. The content of industrial benzaldehyde is above 98.5%. It is made by catalytic oxidation of toluene with molybdenum oxide as catalyst or by ozone oxidation of styrene. It is obtained by reacting benzyl chloride or toluene chloride with lime. Using thiourea as a reducing agent, cinnamon oil (containing cinnamaldehyde 80%) is ozonized to obtain about 62% benzaldehyde, which is a natural product. |
category | flammable liquid |
toxicity classification | poisoning |
acute toxicity | oral-rat LD50: 1300 mg/kg; Oral-mouse LD50: 2800 mg/kg |
stimulation data | skin-rabbit 500 mg/24 hours moderate |
explosive hazard characteristics | strong reducing agent, which reacts violently with oxidant; irritation of skin, dermatitis caused by local contact |
flammability hazard characteristics | central nervous depression and even convulsion of food; Combustible in case of open flame, high temperature and strong oxidant; Combustion emission stimulates smoke |
storage and transportation characteristics | complete packaging, light and light; warehouse ventilation, away from open flames, high temperature, separate storage from oxidant |
fire extinguishing agent | foam, carbon dioxide, dry powder, mist water |
occupational standard | TWA 5 mg/m3; STEL 10 mg/m3 |
auto-ignition temperature | 374 °F |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |