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Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent.
Benzaldehyde is the simplest aromatic aldehyde and one of the most industrially useful.
Benzaldehyde is a colorless liquid with a characteristic almond-like odor.
CAS Number: 100-52-7
EC Number: 202-860-4
IUPAC Name: Benzenecarbaldehyde
Chemical Formula: C7H6O
Other names: benzaldehyde, 100-52-7, Benzoic aldehyde, Phenylmethanal, Benzenecarboxaldehyde, Benzenecarbonal, Benzenemethylal, Benzaldehyde FFC, Benzene carbaldehyde, Benzene carboxaldehyde, benzanoaldehyde, Benzylaldehyde, Benzoyl hydride, NCI-C56133, Benzoic acid aldehyde, FEMA No. 2127, Caswell No. 076, Phenylformaldehyde, Benzaldehyde (natural), NSC 7917, Benzadehyde, Benzyaldehyde, CCRIS 2376, HSDB 388, NSC-7917, EINECS 202-860-4, UNII-TA269SD04T, Benzaldehyde [NF], EPA Pesticide Chemical Code 008601, Benzaldehyde-formyl-d, TA269SD04T, DTXSID8039241, CHEBI:17169, AI3-09931, Benzaldehyde-alpha-d1, MFCD00003299, Benzaldehyde, methyl-, Benzaldehyde-carbonyl-13C, CHEMBL15972, DTXCID90134, NSC7917, EC 202-860-4, Phenylmethanal benzenecarboxaldehyde, Benzaldehyde (NF), NCGC00091819-01, NCGC00091819-02, BENZALDEHYDE (II), BENZALDEHYDE [II], BENZALDEHYDE (MART.), BENZALDEHYDE [MART.], benzaldehyd, Benzaldhyde, BENZALDEHYDE (USP IMPURITY), BENZALDEHYDE [USP IMPURITY], BDBM50139371, CAS-100-52-7, FENTANYL IMPURITY E (EP IMPURITY), FENTANYL IMPURITY E [EP IMPURITY], TRIBENOSIDE IMPURITY C (EP IMPURITY), TRIBENOSIDE IMPURITY C [EP IMPURITY], BENZYL ALCOHOL IMPURITY A (EP IMPURITY), BENZYL ALCOHOL IMPURITY A [EP IMPURITY], FENTANYL CITRATE IMPURITY E (EP IMPURITY), FENTANYL CITRATE IMPURITY E [EP IMPURITY], AMFETAMINE SULFATE IMPURITY D (EP IMPURITY), AMFETAMINE SULFATE IMPURITY D [EP IMPURITY], UN1990, BENZALKONIUM CHLORIDE IMPURITY B (EP IMPURITY), BENZALKONIUM CHLORIDE IMPURITY B [EP IMPURITY], GLYCOPYRRONIUM BROMIDE IMPURITY F (EP IMPURITY), GLYCOPYRRONIUM BROMIDE IMPURITY F [EP IMPURITY], HYDROUS BENZOYL PEROXIDE IMPURITY A (EP IMPURITY), HYDROUS BENZOYL PEROXIDE IMPURITY A [EP IMPURITY], benzaidehyde, benzaldehvde, benzaldehye, benzaldeyde, BENZOYLL PEROXIDE HYDROUS IMPURITY A (EP IMPURITY), BENZOYLL PEROXIDE HYDROUS IMPURITY A [EP IMPURITY], C7H6O, phenyl-methanone, Benzene methylal, Aromatic aldehyde, Benzoylwasserstoff, (phenyl)methanone, benzenecarbaldehyde, Benzaldehyde,(S), PhCHO, Benzene carcaboxaldehyde, 2vj1, WLN: VHR, BENZALDEHYDE [MI], SCHEMBL573, BENZALDEHYDE [FCC], BENZALDEHYDE [FHFI], BENZALDEHYDE [HSDB], BENZALDEHYDE [VANDF], ghl.PD_Mitscher_leg0.170, 55279-75-9, BENZALDEHYDE [USP-RS], Benzaldehyde, AR, >=99%, Benzaldehyde, LR, >=99%, BIDD:ER0249, BDBM60953, Benzaldehyde, analytical standard, Ald3-H_000012, Benzaldehyde, >=98%, FG, FCC, Ald3.1-H_000160, Ald3.1-H_000479, Ald3.1-H_000798, Tox21_113069, Tox21_113244, Tox21_200634, s5574, STL194067, Benzaldehyde, for synthesis, 95.0%, AKOS000119172, Benzaldehyde [UN1990] [Class 9], CCG-266041, NA 1989, Benzaldehyde, purum, >=98.0% (GC), Benzaldehyde, ReagentPlus(R), >=99%, NCGC00091819-03, NCGC00258188-01, PS-11959, Benzaldehyde, natural, >=98%, FCC, FG, DB-023673, B2379, Benzaldehyde, SAJ special grade, >=98.0%, NS00008510, Benzaldehyde, Vetec(TM) reagent grade, 98%, Benzaldehyde 1000 microg/mL in Dichloromethane, Benzaldehyde 2000 microg/mL in Dichloromethane, Benzaldehyde, puriss. p.a., >=99.0% (GC), C00193, C00261, D02314, A800226, Q372524, SR-01000944375, Benzaldehyde, purified by redistillation, >=99.5%, SR-01000944375-1, F1294-0144, Flavor and Extract Manufacturers' Association No. 2127, InChI=1/C7H6O/c8-6-7-4-2-1-3-5-7/h1-6, Benzaldehyde, European Pharmacopoeia (EP) Reference Standard, Benzaldehyde, United States Pharmacopeia (USP) Reference Standard, Benzaldehyde, Pharmaceutical Secondary Standard; Certified Reference Material
The primary component of bitter almond oil, benzaldehyde can be extracted from a number of other natural sources.
Synthetic benzaldehyde is the flavoring agent in imitation almond extract, which is used to flavor cakes and other baked goods
Benzaldehyde appears as a clear colorless to yellow liquid with a bitter almond odor.
Flash point near 145°F. More denser than water and insoluble in water.
Hence sinks in water.
Vapors are heavier than air. The primary hazard is to the environment.
Immediate steps should be taken to limit spread to the environment.
Easily penetrates the soil to contaminate groundwater and nearby waterways.
Used in flavoring and perfume making.
Benzaldehyde (C6H5CHO), the simplest representative of the aromatic aldehydes, occurring naturally as the glycoside amygdalin.
Prepared synthetically, it is used chiefly in the manufacture of dyes, cinnamic acid, and other organic compounds, and to some extent in perfumes and flavouring agents.
Benzaldehyde was first extracted in 1803 by the French pharmacist Martrès. His experiments focused on elucidating the nature of amygdalin, the poisonous material found in bitter almonds,
the fruit of Prunus dulcis. Further work on the oil by Pierre Robiquet and Antoine Boutron-Charlard, two French chemists, produced benzaldehyde.
In 1832, Friedrich Wöhler and Justus von Liebig first synthesized benzaldehyde.
Benzaldehyde is readily oxidized to benzoic acid and is converted to addition products by hydrocyanic acid or sodium bisulfite. It undergoes simultaneous oxidation and reduction with alcoholic potassium hydroxide (a Cannizzaro reaction), giving potassium benzoate and benzyl alcohol; with alcoholic potassium cyanide, it is converted to benzoin; with anhydrous sodium acetate and acetic anhydride, it gives cinnamic acid.
Benzaldehyde is a colourless liquid with an odour of almond oil. It has a melting point of −26 °C (−14.8 °F) and a boiling point of 179 °C (354.2 °F). It is only slightly soluble in water and is completely soluble in ethanol and diethyl ether.
Production
As of 1999, 7000 tonnes of synthetic and 100 tonnes of natural benzaldehyde were produced annually. Liquid phase chlorination and oxidation of toluene are the main routes. Numerous
other methods have been developed, such as the partial oxidation of benzyl alcohol, alkali hydrolysis of benzal chloride, and the carbonylation of benzene.
A significant quantity of natural benzaldehyde is produced from cinnamaldehyde obtained from cassia oil by the retro-aldol reaction: the cinnamaldehyde is heated in an aqueous/alcoholic solution between 90 °C and 150 °C with a base (most commonly sodium carbonate or bicarbonate) for 5 to 80 hours, followed by distillation of the formed benzaldehyde. This reaction also yields acetaldehyde. The natural status of benzaldehyde obtained in this way is controversial.
"Site-specific nuclear magnetic resonance spectroscopy", which evaluates 1H/2H isotope ratios, has been used to differentiate between naturally occurring and synthetic benzaldehyde.
Occurrence
Benzaldehyde and similar chemicals occur naturally in many foods. Most of the benzaldehyde that people eat is from natural plant foods, such as almonds.
Almonds, apricots, apples, and cherry kernels contain significant amounts of amygdalin. This glycoside breaks up under enzyme catalysis into benzaldehyde, hydrogen cyanide and two
equivalents of glucose.
Description
Benzaldehyde is an organic compound, and is synthetized by the way that the hydrogen of benzene is substituted by aldehyde. It is the most simple, and also the most commonly used industrial aromatic aldehyde. It is a colorless liquid at room temperature and has a special almond odor. Benzaldehyde is a compound that aldehyde is directly linked to the phenyl group, because it has a similar bitter almond flavor. Benzaldehyde widely exists in plant, especially in the Rosaceae plants.
It is mainly in the form of glycosides in plant stem bark, leaves or seeds, such as amygdalin, bitter almond, cherry, laurel, peach. Benzaldehyde is naturally in bitter almond oil, patchouli oil, hyacinth oil, cananga oil. The compound is also in the nutlets and nuts, and exists in the form of Amygdalin, which is combination of glycosides. The chemical properties of Benzaldehyde is similar to that of aliphatic aldehydes, but It is also different.
Benzaldehyde cannot reduce fehling reagent. When the reducing fat is used to reduce the benzaldehyde, the main products are benzene methanol, four substituted for the ortho-glycol and two-phenyl ethylene glycol. In the presence of potassium cyanide, two molecules of benzaldehyde form benzoin by acceptance the hydrogen atom. The substitution reaction in aromatic nucleus of benzaldehyde is mainly the meta-position product.
For example, the main product is the m-nitrobenzaldehyde , when benzaldehyde is nitrated.
Benzaldehyde is an organic compound, and is synthetized by the way that the hydrogen of benzene is substituted by aldehyde. It is the most simple, and also the most commonly used industrial aromatic aldehyde. It is a colorless liquid at room temperature and has a special almond odor. Benzaldehyde is a compound that aldehyde is directly linked to the phenyl group, because it has a similar bitter almond flavor. Benzaldehyde widely exists in plant, especially in the Rosaceae plants.
It is mainly in the form of glycosides in plant stem bark, leaves or seeds, such as amygdalin, bitter almond, cherry, laurel, peach. Benzaldehyde is naturally in bitter almond oil, patchouli oil, hyacinth oil, cananga oil. The compound is also in the nutlets and nuts, and exists in the form of Amygdalin, which is combination of glycosides. The chemical properties of Benzaldehyde is similar to that of aliphatic aldehydes, but It is also different.
Benzaldehyde cannot reduce fehling reagent. When the reducing fat is used to reduce the benzaldehyde, the main products are benzene methanol, four substituted for the ortho-glycol and two-phenyl ethylene glycol. In the presence of potassium cyanide, two molecules of benzaldehyde form benzoin by acceptance the hydrogen atom. The substitution reaction in aromatic nucleus of benzaldehyde is mainly the meta-position product. For example, the main product is the m-nitrobenzaldehyde , when benzaldehyde is nitrated.
Chemical Properties
Benzaldehyde is a colorless to yellow, oily liquid with an odor of bitter almonds. Benzaldehyde is commercially available in two grades: (i) pure benzaldehyde and (ii) and double-distilled benzaldehyde. The latter has applications in the pharmaceutical, perfume, and fl avor industries. Benzaldehyde may contain trace amounts of chlorine, water, benzoic acid, benzyl chloride, benzyl alcohol, and/or nitrobenzene. Benzaldehyde is ignited relatively easily on contact with hot surfaces. This has been attributed to the property of very low auto-ignition temperature.
Benzaldehyde also undergoes autoxidation in air and is liable to self-heat. Benzaldehyde exists in nature, occurring in combined and uncombined forms in many plants. Benzaldehyde is also the main constituent of the essential oils obtained by pressing the kernels of peaches, cherries, apricots, and other fruits. Benzaldehyde is released into the environment in emissions from combustion processes, such as gasoline and diesel engines, incinerators, and wood burning.
It is formed in the atmosphere through photochemical oxidation of toluene and other aromatic hydrocarbons.
Benzaldehyde is corrosive to gray and ductile cast iron (10% solution), and all concentrations of lead. However, pure benzaldehyde is not corrosive to cast iron. Benzaldehyde does not attack most of the common metals, like stainless steels, aluminum, aluminum bronze, nickel and nickel-base alloys, bronze, naval brass, tantalum, titanium, and zirconium.
On decomposition, benzaldehyde releases peroxybenzoic acid and benzoic acidBenzaldehyde is used in perfumes, soaps, foods, drinks, and other products; as a solvent for oils, resins, some cellulose ethers, cellulose acetate, and cellulose nitrate. The uses of benzaldehyde in industries are extensive.
For instance, in the production of derivatives that are employed in the perfume and fl avor industries, like cinnamaldehyde, cinnamyl alcohol, cinnamic acid, benzylacetone, and benzyl benzoate, in the production of triphenylmethane dyes and the acridine dye, benzofl avin; as an intermediate in the pharmaceutical industry, for instance, to make chloramphenicol, ephedrin, and ampicillin, as an intermediate to make benzoin, benzylamine, benzyl alcohol, mandelic acid, and 4-phenyl-3-buten-2-one (benzylideneacetone), in photochemistry, as a corrosion inhibitor and dyeing auxiliary, in the electroplating industry, and in the production of agricultural chemicals
Occurrence
Present as cyanuric glucoside (amygdalin) in bitter almond, peach, apricot kernel and other Prunus species; amygdalin is also present in various parts of the following plants: Sambucus nigra, Chrysophyllum arlen, Anacyclus officinarnm, Anacyclus pedunculatus, Davallia brasiliensis, Lacuma deliciosa, Lacuma multiflora and others; free benzaldehyde has been reported found in several essential oils: hyacinth, citronella, orris, cinnamon, sassafras, labdanum and patchouli.
Reported found in strawberry jam, leek (raw) (Allium porrum L.), crispbread, Camembert, Gruyere de Comte, provolone cheeses, black tea, salted and pickled plum, cooked trassi, Bantu beer, red sage (Texas sage) (S. coccinea Juss. Ex Murr.), arrack, scallop, hog plum (Spondias mombins L.), chekur (Alpinia sessilis Kon. = Kaemferia galanga) and other natural sources.
Uses
Benzaldehyde is used as an intermediatein the production of flavoring chemicals,such as cinnamaldehyde, cinnamalalcohol,and amyl- and hexylcinnamaldehyde for perfume,soap, and food flavor; synthetic penicillin,ampicillin, and ephedrine; and as araw material for the herbicide Avenge. Itoccurs in nature in the seeds of almonds,apricots, cherries, and peaches. It occurs intrace amounts in corn oil.
Manufacture of dyes, perfumery, cinnamic and mandelic acids, as solvent; in flavors.
Benzaldehyde is a flavoring agent which is liquid and colorless, and has an almond-like odor. it has a hot (burning) taste. it is oxidized to benzoic acid when exposed to air and deteriorates under light. it is miscible in volatile oils, fixed oils, ether, and alcohol; it is spar- ingly soluble in water. it is obtained by chemical synthesis and by natural occurrence in oils of bitter almond, peach, and apricot kernel. it is also termed benzoic aldehyde.
Definition
A yellow organic oil with a distinct almondlike odor. Benzenecarbaldehyde undergoes the reactions characteristic of aldehydes and may be synthesized in the laboratory by the usual methods of aldehyde synthesis. It is used as a food flavoring and in the manufacture of dyes and antibiotics, and can be readily manufactured by the chlorination of methylbenzene and the subsequent hydrolysis of (dichloromethyl) benzene: C6H5CH3 + Cl2 →C6H5CHCl2 C6H5CHCl2 + 2H2O →C6H5CH(OH)2+ 2HCl C6H5CH(OH)2 →C6H5CHO + H2O.
Preparation
Benzaldehyde is prepared by hydrolysis of benzal chloride, for example, in acidic media in the presence of a catalyst such as ferric chloride or in alkaline media with aqueous sodium carbonate. Part of the commercially available benzaldehyde originates from a technical process for phenol. In this process, benzaldehyde is a by-product in the oxidation, in air, of toluene to benzoic acid.
Highly toxic.
Health Hazard
Benzaldehyde exhibited low to moderate toxicityin test animals, the poisoning effectdepending on dosage. Ingestion of 50–60 mLmay be fatal to humans. Oral intake of a largedose can cause tremor, gastrointestinal pain,and kidney damage. Animal experimentsindicated that ingestion of this compoundby guinea pigs caused tremor, bleeding fromsmall intestine, and an increase in urine volume;in rats, ingestion resulted in somnolenceand coma.
A 500-mg amount for a 24-hour periodresulted in moderate skin irritation in rabbits.Because of its low toxicity, high boilingpoint, and low vapor pressure, the healthhazard to humans from exposure to benzaldehydeis very low.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
Chemical Reactivity
Reactivity with Water: No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Pharmacology
Benzaldehyde significantly inhibited peptic activity in artificial gastric juice in vitro (20-45% inhibition) and in vivo to the extent of 87% in normal healthy persons and ulcer patients (Kleeberg, 1959). As a freshly prepared 1:500 solution, it exerted a marked antispasmodic effect, relaxing the tonus and inhibiting contractions of various isolated smooth muscles of dog, cat, rat, rabbit, mouse, guinea-pig, pig and frog and of a few human tissues. Injected into rabbits and other animals it produced a marked relaxation of the intestines and urinary bladder and marked vasodilation of the splanchnic vessel. Injection of 4 ml of a 5% solution iv into a cat caused a fall in blood pressure and slowing of respiration. In dogs, 1 ml injected iv or sc or 2 ml/kg given orally produced only a slight slowing of respiration.
Injection of larger doses iv produced only a drop in blood pressure, slight slowing of respiration and inhibition of intestinal contractions, with vasodilation of the splanchnic vessel. In rabbits, iv injection of 20 ml of a 0-2% solution did not produce dangerous results. Large injected doses of benzaldehyde exert their mosjt important toxic effects on the medulla, with slowing or paralysis of respiration. In the intact animal, the heart is very little affected; but benzaldehyde acts as a muscular depressant on isolated frog heart (Macht, 1922).
Treatment of isolated rat striated muscle for 1-5 min with 30 mM-benzaldehyde increased the rate of propagation of contractures and the rate of structural breakdown of injured striated muscle fibres. After more prolonged application (for 30 min), the rapid propagation of contracture continued but the structural breakdown was inhibited (Busing, 1972).
Benzaldehyde possessed definite local anaesthetic properties in the sciatic nerves of cats, dogs and frogs, in the eyes of rabbits and dogs (accompanied by irritation) and in the skin of frogs, but was considered unsuitable for practical use because of its rapid oxidation to benzoic acid (Macht, 1922).
In a study of the toxic effects of cherry laurel water on mice and on isolated rat intestine, benzaldehyde was found to aid in the detoxication of HCN by the formation of C6H5?CH(OH)?CN (Lanza & Conte, 1964).
Benzaldehyde did not act as a cross-linking (tanning) agent for corium and aorta, since in a 015 M solution it did not increase the observed in vitro hydrothermal shrinkage temperatures of goat skin and human, bovine and canine aortae (Milch, 1965).
The intestinal absorption-rate coefficients of benzaldehyde and related compounds were determined by perfusion of aqueous solutions through the small intestines of anaesthetized rats (Nogami, Hanano & Yamada, 1968).
No changes in gastric motor patterns, including gastric motility, were observed in rats after inhalation of "toxic levels" (not specified) of benzaldehyde from a liquid sample placed in a test chamber using recirculated air, or from a saturated paper applied to the trachea (Roth & Tansy, 1972).
