Description
Benzaldehyde is an organic compound and is synthesized by replacing the hydrogen in benzene with an aldehyde. It is the simplest industrial aromatic aldehyde and also the most commonly used. It is a colorless liquid at room temperature and has a characteristic almond odor. Benzaldehyde is a compound that has the aldehyde attached directly to the phenyl group because it tastes like bitter almond. Benzaldehyde is common in plants, particularly Rosaceae plants. It is mainly in the form of glycosides in the bark of the plant's stem, leaves or seeds, such as amygdalin, bitter almond, cherry, bay leaf, peach. Benzaldehyde is naturally present in bitter almond oil, patchouli oil, hyacinth oil, cananga oil. The compound is also found in nutlets and nuts and exists in the form of amygdalin, a combination of glycosides. The chemical properties of benzaldehyde are similar to, but different from, those of aliphatic aldehydes. Benzaldehyde cannot reduce the missing reagent. When reducing fat is used to reduce benzaldehyde, the main products are benzeneethanol replacing orthoglycol by four and diphenylethylene glycol. In the presence of potassium cyanide, two molecules form benzaldehyde by adding a hydrogen atom to benzoin. The substitution reaction on the aromatic nucleus of benzaldehyde is mainly the product of the meta position. For example, when benzaldehyde is nitrated, the major product is m-nitrobenzaldehyde.
structure of benzaldehyde
chemical properties
O benzaldeído é o principal componente característico do óleo de amêndoa amarga. Encontrado em muitos outros óleos essenciais, é um líquido incolor com odor de amêndoa amarga. Na ausência de inibidores, o benzaldeído sofre auto-oxidação para formar o ácido perbenzóico, que reage com uma segunda molécula de benzaldeído para formar o ácido benzóico. A hidrogenação do benzaldeído dá álcool benzílico, a condensação com aldeídos alifáticos leva a outras fragrâncias ou seus intermediários insaturados. Os ácidos aralifáticos insaturados são obtidos pela reação de Perkin, por exemplo, a reação com anidrido acético para formar ácido cinâmico.
Benzaldehyde is used in flavoring compositions because of its bitter almond smell. It is the starting material for a large number of fragrances and araliphatic aromas.
Used
1. O benzaldeído é uma matéria-prima importante para as indústrias de medicamentos, corantes, perfumes e resinas. Também pode ser usado como solvente, plastificante e lubrificante de baixa temperatura. Essencialmente, é usado principalmente para o desenvolvimento de sabores de alimentos. Uma pequena quantidade de benzaldeído é usada diariamente para dar sabor e aroma ao tabaco. Embora o álcool benzílico seja amplamente utilizado como aromatizante comercial de alimentos e solvente industrial, o álcool benzílico ainda é usado principalmente para sintetizar uma variedade de outros compostos, desde produtos farmacêuticos até aditivos plásticos. O álcool benzílico é um intermediário importante na fabricação de perfumes, especiarias e alguns corantes de anilina.
Mandelic acid was synthesized using benzaldehyde as the starting reagent: first, hydrocyanic acid reacts with benzaldehyde, then mandelonitrile hydrolyses to form racemic mandelic acid. Glaciologists LaChepelle and Stillman reported in 1966 that ice crystallization is inhibited by benzaldehyde and aldehyde ice to prevent the formation of thick frost (deep frost). This process can prevent a snow slide caused by snow pack instability. However, this compound has not been widely used due to the destruction of vegetation and polluted water sources.
2. It is mainly used to prepare flavors such as almond, cherry, peach, nut, etc., the amount is up to 40%. Canned cherry syrup as flavoring agent, added amount of sugar 3ml/kg.
3. Pharmaceuticals, colorants, seasoning intermediates. For the production of oxygen-based formaldehyde benzene, lauric acid, lauric acid aldehyde, malachite, benzyl benzoate, benzyl aniline and benzylidene acetone etc. Used to combine soap flavor, edible essence, etc.
4. As a special aroma head, it is used as a trace formula for fragrances such as lilac, white, violet, jasmine, acacia, sunflower, sweet plum, orange blossom, tofu pudding, etc. It is also used in soap. It can also be used as an edible seasoning for almonds, coconut cream, berries, cherries, apricots, peaches, plums, walnuts and vanilla pods with a spicy flavor. Wine with aromas such as rum, brandy, etc.
5. Benzaldehyde is an intermediate of herbicide resistance, plant growth regulator and antiamine.
6. Usado como reagente para determinar ozônio, fenol, alcaloide e metileno. Usado na preparação de especiarias.
Production
O benzaldeído pode ser produzido de várias maneiras.
- Obtained from natural essential oils by fractionation.
- Ozone oxidation and thiourea reduction reaction of natural cinnamon oil (contains at least 80% cinnamaldehyde component)
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- Catalytic oxidation of toluene
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- Hydrolyze dichloromethane under alkaline conditions.
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reactions
Benzaldehyde can be slowly oxidized to benzoic acid in air, so a small amount of hydroquinone is often added to prevent its oxidation.
There is no α-H atom in the benzaldehyde molecule. Under the action of concentrated alkali, a disproportionation reaction may occur (Cannizarro reaction):
When benzaldehyde is heated in the presence of a cyanide ion catalyst, bimolecular condensation occurs:
chemical properties
Benzaldehyde is a colorless to yellow oily liquid with a bitter almond odor. Benzaldehyde is commercially available in two grades: (i) pure benzaldehyde and (ii) double-distilled benzaldehyde. The latter is used in the pharmaceutical, perfume and aroma industries. Benzaldehyde may contain traces of chlorine, water, benzoic acid, benzyl chloride, benzyl alcohol and/or nitrobenzene. Benzaldehyde ignites relatively easily on contact with hot surfaces. This was attributed to the very low auto-ignition temperature property. Benzaldehyde is also subject to self-oxidation in air and tends to self-heat. It is used as a food flavoring and in the manufacture of dyes and antibiotics, and can be easily prepared by the chlorination of methylbenzene and the subsequent hydrolysis of (dichloromethyl)benzene: C6H5CH3 + Cl2 → C6H5CHCl2C6H5CHCl2 + 2H2O → C6H5CH(OH)2+ 2HCl C6H5CH( OH)2 →C6H5CHO + H2O.
To appear
Benzaldehyde occurs naturally and occurs in many plants in combined and uncombined forms. It is also the main component of essential oils obtained by pressing the pits of peaches, cherries, apricots and other fruits. Benzaldehyde is released into the environment through emissions from combustion processes such as gasoline and diesel engines, incinerators and wood burning. It is formed in the atmosphere by the photochemical oxidation of toluene and other aromatic hydrocarbons.
Usado
Manufacture of dyes, perfumery, cinnamic and mandelic acids as solvents; with aromas.
Used
Benzaldehyde is used as an intermediate in the manufacture of flavor chemicals such as cinnamaldehyde, cinnamyl alcohol and amyl and hexyl cinnamaldehyde for perfumes, soaps and food flavorings. synthetic penicillin, ampicillin and ephedrine; and as a raw material for the Avenge herbicide. It occurs naturally in the seeds of almonds, apricots, cherries and peaches. It is found in small amounts in corn oil.
Used
Benzaldehyde is a colorless liquid flavoring compound with an almond odor. it has a pungent (burning) taste. it is oxidized in air to benzoic acid and decomposes under light. it is miscible with volatile oils, fixed oils, ether and alcohol; it is sparingly soluble in water. It is obtained by chemical synthesis and occurs naturally in bitter almond, peach and apricot kernel oils. it is also referred to as benzoic aldehyde.
Preparation
Por exemplo, o benzaldeído é produzido pela hidrólise do cloreto de benzal em meio ácido na presença de um catalisador como cloreto férrico ou em meio alcalino com carbonato de sódio aquoso. Parte do benzaldeído disponível comercialmente vem de um processo técnico para o fenol. Neste processo, o benzaldeído é um subproduto da oxidação ao ar do tolueno em ácido benzóico.
Definition
ChEBI: Benzaldehyde is an arenocarbaldehyde composed of benzene with a single formyl substituent; the simplest aromatic aldehyde and the family tree of the benzaldehyde class. It plays a role as a flavor, fragrance, olfactory receptor agonist, plant metabolite, EC 3.5.5.1 inhibitor (Nitrilase) and EC 3.1.1.3 inhibitor (triacylglycerol lipase).
reactions
Benzaldehyde reacts with many chemicals in a remarkable way: (1) with ammonium silver nitrate ("Tollen's solution") to form metallic silver, either as a black precipitate or as a mirror film adhered to glass (reduces but not alkaline copper solution). , "Solution failed"); (2) with rosaniline (fuchsin, magenta) decolorized by sulfuric acid ("Schiff's solution"), restoring the pink color of rosaniline; (3) with NaOH solution giving benzyl alcohol and sodium benzoate; (4) with NH4OH, gives tribenzaldeamine (hydrobenzamide, (C6H5CH)3N2), white solid, mp 101 °C, (5) with aniline, gives benzylidene aniline ("Schiff's base", C6H5CH:NC6H5); (6) with sodium cyanide in alcohol to give benzoin C6H5·CHOHCOC6H5, white solid, m.p. 133°C; (7) with hydroxylamine hydrochloride to give benzaldoxime C6H5CH:NOH, white solids, antioxime, mp 35°C, syn-oxime, mp 130°C; (8) with phenylhydrazine gives benzaldehyde phenylhydrazone C6H5CH:NNHC6H5 pink solid, m.p. 156°C; (9) with concentrated HNO3 gives metanitrobenzaldehyde NO2 C6H4CHO, white solid, m.p. 58°C; (10) with concentrated H2SO4 gives methabenzaldehyde sulfonic acid C6H4CHO (SO3H)2, (11) with anhydrous sodium acetate and acetic anhydride at 180 °C gives sodium benzoate C6H5CHOONa (12) with sodium bisulfite gives benzaldehyde sodium bisulfite C6H5CHOHSO3Na, a white solid, from benzaldehyde easily by treatment can be obtained with sodium carbonate solution; (13) with acetaldehyde slightly alkalized with NaOH gives cinnamaldehyde C6H5CH:CHCHO, (14) with phosphorus pentachloride gives benzylidine chloride C6H5CHCl2.
taste thresholds
Detection: 100ppb at 4.6ppm; Detection: 330ppb at 4.1ppm.
limiares de gosto
Taste characteristics at 50 ppm: sweet, oily, nutty, cherry, nutty and woody
Summary Reference(s)
Chemical and Pharmaceutical Bulletin, 12, p. 403, 1964
Das Journal of Organic Chemistry, 58, p. 4732, 1993DOI: 10.1021/jo00069a043
Comunicações Sintéticas, 16, p. 43, 1986DOI: 10.1080/00397918608057686
general description
Benzaldehyde appears as a clear, colorless to yellow liquid with a bitter almond odor. Flash point close to 145°F. Denser than water and insoluble in water. Then, sink into the water. Vapors are heavier than air. The main danger is in the environment. Immediate actions must be taken to limit environmental spread. Easily penetrates the soil, contaminating groundwater and nearby water courses. Used in the production of flavors and perfumes.
Air and water reactions
Oxida-se no ar para formar ácido benzóico, que é moderadamente tóxico se ingerido. Não solúvel em água.
reactivity profile
A non-toxic, flammable liquid reacts with oxidizing reagents. Benzaldehyde must be covered with an inert gas at all times, since benzaldehyde is easily oxidized to benzoic acid in air [Kirk-Othmer, 3rd Ed., Vol. 3, No. 3, 1978, p. 736]. In contact with strong acids or bases, benzaldehyde undergoes an exothermic condensation reaction [Sax, 9th ed., 1996, p. 327]. A vigorous reaction was observed in contact with peroxyacids (peroxyformic acid) [DiAns, J. et al., Ber., 1915, 48, p. 1136]. An explosion occurred when pyrrolidine, benzaldehyde and propionic acid were heated to form porphyrins.
Danger
highly toxic.
health hazard
Benzaldehyde showed low to moderate toxicity in test animals, the poisoning effect was dose dependent. Ingestion of 50–60 ml can be fatal for humans. Taking a large dose by mouth can cause tremors, gastrointestinal pain, and kidney damage. Animal experiments showed that ingestion of this compound caused tremors, small intestinal bleeding, and increased urine volume in guinea pigs; in rats, ingestion resulted in drowsiness and coma.
LD50 value, oral (guinea pig): 1000 mg/kg
LD50 value, oral (rats): 1300 mg/kg
A dose of 500 mg over a 24 hour period caused moderate skin irritation in rabbits. Due to its low toxicity, high boiling point and low vapor pressure, the risk to human health from exposure to benzaldehyde is very low.
fire risk
HIGHLY FLAMMABLE: Easily ignited by heat, sparks or flame. Vapors can form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They spread through the soil and accumulate in low or narrow areas (sewer, basement, tank). Vapor explosion hazard indoors, outdoors or in sewers. Drainage to sewers may present a fire or explosion hazard. Containers may explode if heated. Many liquids are lighter than water.
Flammability and Explosiveness
Non flammable
reatividade química
Reactivity with water: No reaction; Reactivity with Common Materials: No reactions; Stability during transport: Stable; Neutralizing agent for acids and bases: Not relevant; Polymerization: Not relevant; Polymerization inhibitor: Not relevant.
pharmacology
Benzaldehyde significantly inhibited peptic activity in artificial gastric juice in vitro (20-45% inhibition) and in vivo by 87% in normal healthy subjects and ulcer patients (Kleeberg, 1959). As a freshly prepared 1:500 solution, it exerted a marked antispasmodic effect, relaxed tone, and inhibited the contractions of various isolated smooth muscles from dogs, cats, rats, rabbits, mice, guinea pigs, pigs, and frogs, and some human tissues. Injected into rabbits and other animals, it produced marked relaxation of the bowel and urinary bladder and marked vasodilation of the splanchnic vessels. Intravenous injection of 4 ml of a 5% solution into a cat caused blood pressure to drop and breathing to slow. In dogs, 1 ml injected iv or sc or 2 ml/kg given orally resulted in only a slight slowing of respiration. Injection of higher iv doses caused only a reduction in blood pressure, a slight slowing of respiration and inhibition of intestinal contractions with vasodilation of splanchnic vessels. In rabbits, iv injection of 20 ml of a 0-2% solution did not produce dangerous results. Large injected doses of benzaldehyde exert their main toxic effects on the medulla, with slowing or paralysis of breathing. In the intact animal, the heart is very little affected; but benzaldehyde acts as a muscle depressant in isolated frog heart (Macht, 1922). Treatment of isolated rat striated muscle for 1-5 minutes with 30 mM benzaldehyde increased the rate of propagation of contractures and the rate of structural degradation of injured striated muscle fibers. After prolonged use (for 30 min), the rapid spread of contracture continued, but structural degradation was inhibited (Busing, 1972).
Benzaldehyde had marked local anesthetic properties in the sciatic nerve of cats, dogs and frogs, in the eyes of rabbits and dogs (with 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 laurel cherry water in mice and isolated rat intestines, benzaldehyde was found to aid in HCN detoxification through the formation of C6H5?CH(OH)?CN (Lanza & Conte, 1964) .
Benzaldehyde did not act as a crosslinker (tanning agent) for the chorion and aorta because, in a 0.15 M solution, it did not increase the hydrothermal shrinkage temperatures of goat skin and human, bovine, and canine aorta observed in vitro (Milch, 1965) .
Intestinal absorption coefficients of benzaldehyde and related compounds were determined by infusing aqueous solutions through the small intestine of anesthetized rats (Nogami, Hanano & Yamada, 1968).
No changes in gastric motor function, including gastric motility, were observed in rats after inhalation of "toxic concentrations" (unspecified) of benzaldehyde from a liquid sample placed in a forced air test chamber or from a saturated paper placed in the trachea, noted (Roth & Tansy, 1972).
Benzaldehyde at a concentration of 0-1 mmol/l caused a 16% decrease in the frequency of electrical discharges in the organs of the mormyrid electric fish Gnathonemus moori (Walsh & Schopp, 1966).
security profile
Poisoning by ingestion and intraperitoneal administration. Moderately toxic by subcutaneous administration. an allergen. It acts as a weak local anesthetic. Local contact can cause contact dermatitis. It causes central nervous system depression in small doses and convulsions in larger doses. A skin irritant. Questionable carcinogen with experimental tumorigenic data. Reported mutation data. Flammable liquid. For firefighting, use water (can be used as a blanket), alcohol, foam, chemical powder. A powerful reducing agent. Reacts violently with peroxyformic acid and other oxidizing agents. See also ALDEHYDE.
synthesis
Natural benzaldehyde is obtained from botanical sources by extraction and subsequent fractional distillation; synthetically from benzyl chloride and lime or by oxidation of toluene
possible exposure
In the manufacture of perfumes, dyes and cinnamic acid; as a solvent; with aromas.
metabolism
Benzaldehyde was among 300 volatile compounds found in the urine of ten adults. It is commonly converted to hippuric acid in vivo. In rabbits and dogs, hippuric acid appears to be the only metabolite with virtually no benzoyl glucuronide formation. In rabbits, the conversion of benzaldehyde to benzoic acid follows first-order kinetics.
store
Benzaldehyde should be stored in a tightly closed container and protected from physical damage. Storage of the chemical outdoors or in a segregated area is preferred, while indoor storage should be in a standard room or cupboard for storing flammable liquids. Benzaldehyde must be kept separate from oxidizing materials. In addition, storage and use areas must be non-smoking areas. Containers made with this material can be dangerous when empty, as they retain product residues (vapors, liquids); Observe all warnings and precautions listed for the product
shipping
UN1990 Benzaldehyde, hazard class: 9; Tags:9—Miscellaneous Hazardous Material.
cleaning methods
Para reduzir sua taxa de oxidação, o benzaldeído geralmente contém aditivos como hidroquinona ou catecol. Pode ser purificado por meio de seu composto de adição de bissulfito, mas a destilação (sob nitrogênio a pressão reduzida) geralmente é suficiente. Antes da destilação, é lavado com NaOH ou Na2CO3 a 10% (até que não haja mais emissão de CO2), depois com Na2SO3 e H2O saturados, seguido de secagem com CaSO4, MgSO4 ou CaCl2. [Beilstein 7 IV 505.]
incompatibilidades
Reacts with air to form explosive peroxides. Reacts violently with performic acid, oxidants, aluminum, iron, alkalis and phenols causing risk of fire and explosion. May spontaneously ignite if absorbed into high surface area combustible material or otherwise spread over large areas. Reacts with rust, amines, alkalis, strong bases, reducing agents such as hydrides and active metals.
garbage disposal
Combustão; adicione solvente inflamável e pulverize no incinerador com pós-combustor.
Precautions
Workers should be careful when using benzaldehyde due to the risk of self-inflammation. May spontaneously ignite if absorbed by rags, scouring pads, clothing, sawdust, diatomaceous earth, activated carbon, or other large area materials in the workplace. Workers should avoid handling the chemical and should not cut, drill, or weld on or near the container. Exposure of benzaldehyde to air, light, heat, hot surfaces such as hot pipes, sparks, open flames and other sources of ignition should be avoided. Workers must wear appropriate personal protective clothing and equipment