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Send EmailE210, Benzoic acid, Benzyl acid, 65-85-0
CAS: 65-85-0
Molecular Formula: C7H6O2
Names and Identifiers
| Name | Benzoic acid |
| Synonyms | 210 benzoate a 1 (acid) Benzyl acid Benzoic acid SS Benzoic Acid Acide benzoique 4-Carboxypolystyrene Benzoic acid, USP Grade Benzoic aBenzoic acidcid Mefenamic Acid Impurity D Industrial-use benzoic acid Benzoic-12C7 acid, 13C-depleted Melting point standard benzoic acid Glycopyrronium Bromide EP Impurity D |
| CAS | 65-85-0 |
| EINECS | 200-618-2 |
| InChI | InChI=1/C7H6O2/c8-7(9)6-4-2-1-3-5-6/h1-5H,(H,8,9)/p-1 |
| InChIKey | WPYMKLBDIGXBTP-UHFFFAOYSA-N |
Physico-chemical Properties
| Molecular Formula | C7H6O2 |
| Molar Mass | 122.12 |
| Density | 1.08 |
| Melting Point | 121-125°C(lit.) |
| Boling Point | 249°C(lit.) |
| Flash Point | 250°F |
| JECFA Number | 850 |
| Water Solubility | Slightly soluble. 0.34 g/100 mL |
| Solubility | Slightly soluble in water, soluble in ethanol, methanol, ether, chloroform, benzene, toluene, carbon disulfide, carbon tetrachloride and turpentine. |
| Vapor Presure | 10 mm Hg ( 132 °C) |
| Vapor Density | 4.21 (vs air) |
| Appearance | White crystalline powder |
| Color | White to yellow-beige to orange |
| Merck | 14,1091 |
| BRN | 636131 |
| pKa | 4.19(at 25℃) |
| PH | 3.66(1 mM solution);3.12(10 mM solution);2.6(100 mM solution); |
| Storage Condition | 2-8°C |
| Stability | Stable. Combustible. Incompatible with strong bases, strong oxidizing agents, alkalies. |
| Sensitive | Easily absorbing moisture |
| Refractive Index | 1.504 |
| MDL | MFCD00002398 |
| Physical and Chemical Properties | Scaly or needle-like crystals. Has the odor of benzene or formaldehyde. slightly soluble in water, soluble in ethanol, methanol, ether, chloroform, benzene, toluene, carbon disulfide, carbon tetrachloride and turpentine. |
| Use | It is used in the production of medicines, dye carriers, plasticizers, spices and food preservatives, and also used in the performance improvement of alkyd resin coatings; It is used as an intermediate for pharmaceuticals and dyes, and is used in the preparation of plasticizers and perfumes, etc, also as a rust inhibitor for iron and steel equipment |
Risk and Safety
| Risk Codes | R22 - Harmful if swallowed R36 - Irritating to the eyes R42/43 - May cause sensitization by inhalation and skin contact. R36/37/38 - Irritating to eyes, respiratory system and skin. R40 - Limited evidence of a carcinogenic effect R63 - Possible risk of harm to the unborn child R43 - May cause sensitization by skin contact R23/24/25 - Toxic by inhalation, in contact with skin and if swallowed. R45 - May cause cancer R41 - Risk of serious damage to eyes R37/38 - Irritating to respiratory system and skin. R20/21/22 - Harmful by inhalation, in contact with skin and if swallowed. R48/23 - R38 - Irritating to the skin R67 - Vapors may cause drowsiness and dizziness R37 - Irritating to the respiratory system |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S37/39 - Wear suitable gloves and eye/face protection S24 - Avoid contact with skin. S22 - Do not breathe dust. S36/37 - Wear suitable protective clothing and gloves. S24/25 - Avoid contact with skin and eyes. S23 - Do not breathe vapour. S53 - Avoid exposure - obtain special instructions before use. S36 - Wear suitable protective clothing. S63 - S39 - Wear eye / face protection. |
| UN IDs | UN 3077 9/PG 3 |
| WGK Germany | 1 |
| RTECS | DG0875000 |
| FLUKA BRAND F CODES | 21 |
| TSCA | Yes |
| HS Code | 2916 31 00 |
| Hazard Note | Harmful |
| Toxicity | LD50 orally in Rabbit: 1700 mg/kg LD50 dermal Rabbit > 5000 mg/kg |
Upstream Downstream Industry
| Raw Materials | Cobalt naphtenate Toluene |
| Downstream Products | 3,5-Dihydroxybenzoic acid 3,5-Diaminobenzoic acid Potassium benzoate 3-Hydroxybenzoic acid Benzoyl chloride Methyl benzoate Benzyl benzoate |
Nature
colorless monoclinic plate-like or lobular crystals. lg the product is dissolved in 2. 3mL cold ethanol, 1.5mL boiling ethanol, 4.5ml chloroform, 3mL ether, 3mL acetone, 30mL carbon tetrachloride, 10ml benzene, 30mL carbon disulfide, 23mL turpentine. Soluble in hot water, slightly soluble in petroleum ether. Heat to sublimation above 100 °c. Risk of combustion.
Preparation Method
toluene is obtained by oxidation under the action of a catalyst.
Standard
This product contains C7H602 not less than 99.0%.
Trait
- This product is white mercerized scale or needle-like crystal or crystalline powder; Light; Odorless or slightly odorless; Slightly volatile in hot air; Acidic reaction in aqueous solution.
- This product is soluble in ethanol, chloroform or ether, soluble in boiling water, slightly soluble in water.
melting point
The melting point of this product (General 0612) is 121~124.5°C.
Use
reagents for the detection of manganese, mercury, nickel, magnesium, titanium, tungsten, uranium, nitrate and nitrite. For the separation of trivalent and tetravalent ions (such as iron, aluminum, chromium, etc.).
Differential diagnosis
- take about 0.2g of this product, add 0.4% sodium hydroxide solution 15ml, shake, filter, add 2 drops of ferric chloride test solution to the filtrate, and generate ochre precipitate.
- The infrared absorption spectrum of this product should be consistent with that of the control (Spectrum set 233).
Safety
rat oral LD50:2530mg/kg. Mild skin irritation. Its vapor causes irritation to the upper respiratory tract, eyes and skin. Under normal circumstances, there is no obvious harm to contact. Store in a cool, ventilated warehouse. Keep away from fire and heat source. Protection from direct sunlight. Keep the container sealed. Should be stored separately from the oxidant, alkali.
Exam
clarity and color of ethanol solution
Take 5.0g of this product, add ethanol to dissolve and dilute to 100ml, the solution should be clear and colorless.
halides and halogens
- take 6.7g of this product and put it in a 100ml measuring flask, add 40ml of 1 mol/L sodium hydroxide solution and 50ml of ethanol to dissolve, dilute with water to the scale, and shake well. Take 10ml of the above solution, add 7.5ml of 2mol/L sodium hydroxide solution and 0.125g of nickel-aluminum alloy, put it on a water bath and heat it for 10 minutes, let it cool, filter, and put the filtrate into a 25ml measuring flask, the filtrate was washed 3 times with 2ml of ethanol each time, washed with A human filtrate, and diluted to the mark with water as solution A. A blank solution was prepared as solution B in the same manner. (The Glass instrument used in this experiment must be soaked with 500g/L nitric acid solution overnight before use, washed with water and filled with water to ensure that no chlorine element.)
- Take solution A, solution B and standard chloride solution [take 0.132%(W/V) sodium chloride solution lm l for precision measurement, put it in A volumetric flask, and dilute it to the scale with water, add ammonium ferric sulfate solution (30g of ammonium ferric sulfate, 40ml of nitric acid) to the flask (10ml of water), then dilute to 100ml with water and filter. The liquid should be kept in the dark) 5ml, shake well, add 2ml of nitric acid Dropwise (with shaking), and then add mercury thiocyanate solution (take Mercury thiocyanate 0.3g), absolute ethanol was added to dissolve into 100ml, which was obtained. This solution was used within 7 days after preparation) 5ml, shaken, diluted to the scale with water, and placed in a water bath at 20°C for 15 minutes. UV-Vis spectrophotometry (General rule 0401), respectively, at the wavelength of 460nm in solution A (solution B blank) and standard chloride solution (water blank) the absorbance of solution A shall not be greater than that of the standard chloride solution (0.03%).
easy oxide
take 100ml of water and add 1.5 of sulfuric acid. After boiling, add appropriate amount of potassium permanganate titration solution (0.02mol/L) Dropwise until the pink color does not disappear for 30 seconds, hot add this product 1.0g, dissolved, add potassium permanganate titration solution (0.02mol/L )0.25, should be pink, and in 15 seconds does not disappear.
easy carbide
take 0.5g of this product, add sulfuric acid [containing H2S04 94.5% ~ 95.5% (g/g)]5ml shake, place for 5 minutes, and compare with the yellow No. 2 Standard Colorimetric solution, not deeper.
ignition residue
not more than 0.1% (General rule 0841).
Heavy metals
take this product l. After dissolving with 22ml of ethanol, add 2ml of acetate buffer (pH 3.5) and an appropriate amount of water to make 25ml, which shall be checked according to law (General Principles 0821, first method), heavy metals should not be more than 10 parts per million.
Content determination
take this product about 0.25g, precision weighing, add neutral dilute ethanol (phenolphthalein indicator solution neutral) 25ml dissolved, add phenolphthalein indicator solution 3 drops, with sodium hydroxide titration solution (O.lmol/L) titration. Each 1 ml of sodium hydroxide titration solution (0.1 mol/L) corresponds to 12.21mg of C7H602.
Category
Disinfection antiseptic.
Storage
sealed storage.
Reference Information
| FEMA | 2131 | BENZOIC ACID |
| Henry's Law Constant | (x 10-8 atm?m3/mol):7.02 (calculated, U.S. EPA, 1980a) |
| Overview | benzoic acid, also known as benzoic acid, has the molecular formula C6H5COOH, the simplest aromatic acid in which the carboxyl group is directly attached to the carbon atom of the benzene ring is a compound in which a hydrogen on the benzene ring is replaced by a carboxyl group (-COOH). It is a colorless, tasteless crystal. The melting point is 122.13 ℃, the boiling point is 249 ℃, and the relative density is 1.2659(15/4 ℃). At 100 deg C when the rapid sublimation, its vapor has a strong irritation, easy to cause Cough after inhalation. Slightly soluble in water, soluble in ethanol, ether, chloroform, benzene, toluene, carbon disulfide, carbon tetrachloride and turpentine and other organic solvents. It widely exists in nature in the form of free acid, ester or derivative thereof, for example, it exists in the form of free acid and benzyl ester in benzoin; in the leaves and bark of some plants in free form; In essential oils in the form of methyl or benzyl esters; In the urine of horses in the form of its derivative hippuric acid. Benzoic acid is a weak acid, stronger than fatty acids. Their chemical properties are similar, can form salts, esters, acid halides, amides, anhydrides, etc., are not easy to be oxidized. The benzene ring of benzoic acid can be electrophilic substitution reaction, mainly to obtain meta substitution. |
| discovery process | benzoic acid was discovered in the sixteenth century. In 1556, Nostradamus was the first to describe the retorting effect of benzoin; Later, it was discovered in 1560 and 1596, respectively, by Alexius Pedemontanus and brastoid. In 1875, Salkowski discovered the antifungal potency of benzoic acid, so that benzoic acid was used for long-term preservation of berries. |
| solubility | solubility in 0.18g water: 4 ℃,0.27g;18 ℃, g;20 ℃,0.29g;25 °c, 0.34g;30 °c, 0.42g;40 °c, 0.6g;50 °c, 0.95g;60 °c, 1.2g;75 °c, 2.2g;80 C, 2.75g;90 C, 4.6g;95 C, 6.8g. |
| Application | benzoic acid is usually used as a drug or preservative, which can inhibit the growth of fungi, bacteria and mold, it is usually applied to the skin for the treatment of dermatophytes. For synthetic fibers, resins, coatings, rubber, tobacco industry. The original benzoic acid is from the dry distillation or alkaline water hydrolysis of benzoic acid, can also be prepared by the hydrolysis of hippuric acid. Industrially, benzoic acid is prepared by oxidizing toluene with air in the presence of cobalt, manganese and other catalysts; Or by hydrolysis and decarboxylation of phthalic anhydride. Benzoic acid and its sodium salt can be used as a bacteriostatic agent for latex, toothpaste, jam or other foods, and can also be used as a mordant for dyeing and printing. |
| preparation | Industrial preparation at present, benzoic acid is mainly produced by liquid phase air oxidation of toluene in industry. The process is based on the reaction of cobalt naphthenate as Catalyst, the reaction temperature is 140-160 deg C and operating pressure 0.2-0.3MPa to form benzoic acid. After the reaction, toluene was distilled off, and the product was distilled under reduced pressure and recrystallized. This process utilizes inexpensive raw materials and has a high yield, and thus is a method mainly used in industry. Laboratory preparation method main reaction: 1. Toluene potassium permanganate water-potassium benzoate potassium hydroxide manganese dioxide water (the front water is to provide the reaction environment) 2. Potassium benzoate concentrated hydrochloric acid-benzoic acid drug and dosage: toluene 1.5g(1.7ml,0.016mol), potassium permanganate 5g(0.032mol), ten six alkyl three methyl ammonium bromide 0.1g experimental operation: with ml round bottom flask. Install the reflow device. To the reaction flask were added 5g of potassium permanganate, 0.1g of decahexyltrimethylammonium bromide, 1.7ml of toluene and 50ml of water, respectively, and the mixture was heated to boiling with stirring (vigorous stirring, vigorous boiling) to keep the reactant solution boiling smoothly. When a large amount of brown precipitate was formed, the purple color of potassium permanganate became lighter or disappeared, and the toluene layer disappeared, the reaction was almost finished. The precipitate of manganese dioxide is filtered out, and the filtrate is acidified with concentrated hydrochloric acid to precipitate the precipitate of benzoic acid, and the crude product is obtained by Suction filtration. The crude product was recrystallized with water. It was dried in a boiling water bath, weighed and measured for its melting point. |
| effect | benzoic acid and its sodium salt sodium benzoate is a very commonly used food preservative. Under acidic conditions, the inhibition of yeast and mold, pH value of 3 when the antibacterial force is strong, and pH 6 on a lot of mold effect is very poor, therefore, the optimum pH value of its bacteriostasis is 2.5-4.0. In the food industry with plastic bottled fruit and vegetable juice concentrate, the maximum use should not exceed 2.0g/kg; In the jam (not including cans), fruit juice (flavor) beverages, soy sauce, the maximum usage amount of vinegar is 1.0g/kg; The maximum usage amount of soft candy, wine and fruit wine is 0.8g/kg; The maximum usage amount of low salt pickles, sauce and preserved fruit is 0.5g/kg; the maximum amount used in carbonated beverages was 0.2g/kg. Because of the solubility of benzoic acid is small, the use of fully stirred, or dissolved in a small amount of hot water or ethanol. When it is used in the concentrated fruit juice used in the cool drink, the sodium salt of benzoic acid is commonly used because it is easy to volatilize with water vapor. Benzoic acid is a common preservative in the food industry, but it is not allowed to be added to dairy products. In general, benzoic acid is considered safe. But for some special populations, including infants and young children, long-term intake of benzoic acid may also cause asthma, urticaria, Metabolic Acidosis and other adverse reactions. Benzoic acid is also used as a flavoring agent for fruit juice beverages. Can be used as a cream fragrance into the fragrance. It can also be used in chocolate, lemon, orange, Berry, nut, preserved fruit and other food flavors. Tobacco flavor is also commonly used. In addition, benzoic acid is also used as raw materials for the production of pesticides, dyes, pharmaceuticals, mordant and plasticizers, modifiers of polyamide resins and alkyd resins, and rust inhibitors for iron and steel equipment. |
| Use method of food additive | 1. The antibacterial activity of benzoic acid in molecular state is higher than that in ionic state, so when PH is less than 4, high antibacterial activity, the minimum inhibitory concentration of 0.015%-0.1%. However, its solubility decreases in acidic solution, so it does not rely solely on increasing the acidity of the solution to improve its antibacterial activity. The optimum bacteriostatic PH of benzoic acid was 2.5~4.0. 2, due to the low solubility of benzoic acid to water, so the actual is to add the right amount of sodium carbonate or sodium bicarbonate, with more than 90 degrees Celsius hot water dissolution, it is converted into sodium benzoate and then added to the food. If benzoic acid must be used, it can be dissolved in a suitable amount of ethanol before application. 3, because the solubility of benzoic acid to water is lower than that of sodium benzoate, so when using sodium benzoate in acidic food, attention should be paid to prevent the precipitation caused by the conversion of sodium benzoate into benzoic acid and reduce its use effect. 4, 1g of benzoic acid is equivalent to 1.18g of sodium benzoate; 1g of sodium benzoate is equivalent to 0.847G of benzoic acid 5, benzoic acid in soy sauce, cool drinks can be used together with P-Hydroxybenzoic acid esters and synergistic. Dosage: 1, China's "health standards for the use of food additives" (GB2760-1996): carbonated beverages, the maximum use of 0.2g/kg; Low salt pickles, sauce, preserved fruit, 0.5g/kg; wine, fruit wine, soft candy, 0.8g/kg; Soy sauce, vinegar, Jam (excluding cans), fruit juice (flavor) Beverage type, 1.0g/kg; Food industry plastic bottled concentrated fruit and vegetable juice, 2g/kg; Fruit juice (fruit flavor) ice, 1.0g/kg (mixed or used alone). When benzoic acid and sodium benzoate are used at the same time, the maximum amount of benzoic acid shall not be exceeded. 2, the actual use of reference: benzoic acid and sodium benzoate commonly used in the preservation of highly acidic fruits, berries, fruit juice, jam, beverage syrup and other acidic foods, can be combined with low temperature sterilization, synergistic effect. Different countries to allow the use of this product in food and its use concentration is different |
| pharmacological effects | [pharmacodynamics] This product is Disinfection preservative, with antibacterial effect; In acidic environment, 0.1% concentration has antibacterial effect. Usually lower pH value is better, such as pH 3.5, 0.125% concentration can kill staphylococcus in 1 hours. The effect is weakened in alkaline environment. External use can resist superficial fungal infection. The concentration of 0.05-0.1% added to pharmaceutical preparations or food as a preservative, can inhibit the growth of bacteria and fungi. [Pharmacokinetics] oral rapid absorption from the digestive tract, combined with glycine in the liver to form hippuric acid, which is quickly excreted from the urine within 12 hours, in the first 4 hours that amount to 97%. If the oral dosage is large, part of the benzoylglucuronic acid that can be coupled is excreted from the urine. [Indications] for superficial fungal infections, such as Tinea corporis, tinea Manus and tinea pedis; Also used as food and pharmaceutical preparations of preservatives. [Usage and dosage] This product is often 6 ~ 12% concentration and salicylic acid formulated tincture or ointment treatment of superficial skin fungal infections. External application of skin lesions, 2 times a day, as a preservative in pharmaceutical preparations and food, the effective concentration of 0.05-1%. [Adverse reactions] Oral can occur asthma, urticaria and angioedema and other allergic reactions. Contact dermatitis may occur when applied externally. Higher doses of oral can cause salicylate-like reactions. |
| harm | benzoic acid, commonly known as benzoic acid, is involved in metabolism in the body, does not accumulate, and has low toxicity. If excessive consumption of benzoic acid, the body's liver and kidneys will be damaged. The maximum safe use of benzoic acid in carbonated beverages is 5 mg/kg body weight, so the maximum daily limit is 300mg, the maximum amount of benzoic acid used for carbonated beverages is 0.2g/kg, so it is safe to drink a beverage of 1.5kg per day. It is highly toxic to microorganisms, but the toxicity of its sodium salt is very low. The daily oral administration of 0.5g or less is not toxic to the human body, and even the dosage is not more than 4G is not harmful to health. In human and animal tissues can be combined with the protein components of glycine detoxification, the formation of hippuric acid with urine excretion. The crystal or dust of benzoic acid has a stimulating effect on the skin, eyes, nose, throat, etc. Even its sodium salt, if taken in large amounts, can cause damage to the stomach. The operator should wear protective gear. Should be stored in a dry and ventilated place, moisture-proof, heat-proof, away from fire. |
| determination method of sorbic acid and benzoic acid in food | 1, principle: After sample acidification, extract sorbic acid and benzoic acid with ether, the separation and determination were carried out by gas chromatography with hydrogen flame ionization detector, and the quantification was compared with the standard series. 2, reagent: ether: does not contain peroxide, petroleum ether: boiling range 30~60 ℃, hydrochloric acid, anhydrous sodium sulfate, hydrochloric acid (1+1): Take 100mL hydrochloric acid, dilute to 200mL with water, sodium chloride acidic solution (40g/L): sodium chloride solution (40g/L) with a small amount of hydrochloric acid (1+1) acidification, sorbic acid, benzoic acid standard solution: accurately weigh the sorbic acid, 0.2000g each of benzoic acid was placed in a mL volumetric flask, dissolved in a petroleum ether-diethyl ether (3+1) mixed solvent and diluted to the mark. This solution per ml equivalent to 2.0mg of sorbic acid or benzoic acid, sorbic acid, benzoic acid standard use liquid: absorb the right amount of sorbic acid, benzoic acid standard solution, with petroleum ether-ether (3+1) the mixed solvent is diluted to 50,100,150,200,250mg of sorbic acid or benzoic acid per ml. 3, instrument: Gas Chromatograph: with hydrogen flame ionization detector. 4, analysis steps: 5.1 Sample extraction weigh g pre-mixed sample, place in 25ml measuring cylinder with plug, add hydrochloric acid (1+1), acidify with 15,10ml of ether was extracted twice with shaking for 1min each time, and the upper ether extract was drawn into another 25ml measuring cylinder with a plug. The ether extracts were combined. Wash twice with 3ml of an acidic solution of sodium chloride (40g/L), stand for 15min, and filter the ether layer through anhydrous sodium sulfate into a 25ml volumetric flask with a dropper. Add ether to the scale and mix well. Accurately take 5ml of ether extract into 5ml of test tube with plug and scale, let it dry on 40 ℃ water bath, add 2ml of petroleum ether-ether (3+1) mixed solvent to dissolve residue, and reserve. 5.2 chromatographic reference conditions: 5.2.1 column: glass column, inner diameter 3mm, length 2m, inside coated with 5%(m/m)DEGS +1%(m/m) h3PO4 fixative 60-80 mesh Chromosorb W AW. 5.2.2 flow rate: the carrier gas is nitrogen, 50mL/min (the ratio of nitrogen to air and hydrogen is selected according to the optimal ratio of each instrument type). 5.2.3 temperature: Injection Port 230 deg C; Detector 230 deg C; Column temperature 170 deg C. 5.3 determination of sample 2μL standard series of each concentration standard used in the liquid gas chromatograph, can be measured at different concentrations of sorbic acid, benzoic acid peak height, the concentration of abscissa, the corresponding peak height value for the ordinate, A standard curve was drawn. |
| Use | use as chemical reagent and preservative benzoic acid is an important acid-based food preservative. Under acidic conditions, it has inhibitory effect on mold, yeast and bacteria, but weak effect on acid-producing bacteria. The optimum pH value of bacteriostasis is 2.5~4.0, and it is advisable to lower than the pH value of 4.5~5.0. In the food industry with plastic bottled fruit and vegetable juice concentrate, the maximum use should not exceed 2.0g/kg; In the jam (not including cans), fruit juice (flavor) beverages, soy sauce, the maximum usage amount of vinegar is 1.0g/kg; The maximum usage amount of soft candy, wine and fruit wine is 0.8g/kg; The maximum usage amount of low salt pickles, sauce and preserved fruit is 0.5g/kg; the maximum amount used in carbonated beverages was 0.2g/kg. Because benzoic acid is slightly soluble in water, it can be dissolved by using a small amount of ethanol. benzoic acid is an important acid-based feed preservative. Under acidic conditions, it has inhibitory effect on mold, yeast and bacteria, but weak effect on acid-producing bacteria. The optimum PH for bacteriostasis is 2.5-4.0, generally less than PH4.5-5.0 is appropriate. preservatives; Antimicrobial agents. Because of the solubility of benzoic acid is small, the use of fully stirred, or dissolved in a small amount of hot water or ethanol. When it is used in the concentrated fruit juice used in the cool drink, the sodium salt of benzoic acid is commonly used because it is easy to volatilize with water vapor. 1g of the sodium salt corresponds to 0.847g of benzoic acid. It is commonly used as a fixative or preservative. It is also used as a flavor-retaining agent for fruit juice beverages. Can be used as a cream fragrance into the fragrance. It can also be used in chocolate, lemon, orange, Berry, nut, preserved fruit and other food flavors. Tobacco flavor is also commonly used. benzoic acid and its sodium salt are important preservatives in food. Inhibition of yeast and mold under acidic conditions, When the pH value is 3, the antibacterial power is strong, and when the pH value is 6, the effect on many molds is very poor, so the optimum pH value of the antibacterial is 2.5-4.0. Benzoic acid is mainly used in the production of sodium benzoate food preservatives, dye intermediates, pesticides, plasticizers, mordant, pharmaceuticals, spices, but also can be used as a modifier of alkyd resin and polyamide resin, for the production of polyester raw material terephthalic acid and used as iron and steel equipment rust inhibitor. It is mainly used for anti-fungal and Disinfection anti-corrosion It is used for the production of medicine, dye carrier, plasticizer, perfume and food preservative, etc. It is also used for the performance improvement of alkyd resin coatings; used as pharmaceutical and dye intermediates, for the preparation of plasticizers and spices, etc., but also as iron and steel equipment rust inhibitor alkali quantitative standard. Iodine quantitative standard. Calorific value standard. Aluminum, boron, cerium, copper, iron, lead, manganese, mercury, nickel, nitrate, nitrite, silver, titanium, tungsten and vanadium. Determination of aluminium, copper, iron, titanium and uranium. Organic microanalysis standards for the determination of carbon, hydrogen, oxygen and relative molecular mass. Organic analysis was also used for benzoylation. |
| production method | is initially prepared by dry distillation of benzoin gum or hydrolysis with alkaline water, and can also be prepared by hydrolysis of hippuric acid. The industrial production methods of benzoic acid are toluene liquid phase air oxidation method, benzyl trioxychloride hydrolysis method and phthalic anhydride decarboxylation method three, and the toluene liquid phase air oxidation method is the most common. Toluene and air are introduced into a reactor containing a cobalt naphthenate catalyst, and the reaction is carried out at a reaction temperature of 140-160 ℃ and an operating pressure of 0.2-0.3MPa to form benzoic acid, the crude benzoic acid was distilled off from the unreacted toluene, and then recrystallized under reduced pressure to obtain the finished product. The final product obtained by the method of decarboxylation of phthalic anhydride is not easy to be refined, and the production cost is high, and it is only used in the manufacturing process of small quantities of pharmaceuticals and other products. Products of the toluene chlorination process are not suitable for use in food. Benzoic acid with industrial, food, medicine and other different specifications. Food Grade should comply with the GB1901-80, the content of more than 99.5%, the melting point of 121-123 ℃, and easy oxides, easy carbide, chlorine compounds, burning residue, heavy metals, arsenic content and other quality indicators are specified. Raw material consumption quota: toluene 1140kg/t, cobalt naphthenate 4kg/t. In addition, benzoic acid can be produced by the production of benzaldehyde from toluene. obtained by direct liquid phase oxidation of toluene. It is obtained by decarboxylation of phthalic acid with lead oxide, zinc oxide and the like as catalysts. Chlorination of toluene to trichlorotoluene, and then hydrolyzed with milk of lime and iron powder obtained. Although benzoic acid can be prepared by chlorination of toluene and decarboxylation of phthalic acid, the liquid phase catalytic air oxidation of toluene as raw material is widely used in industrial production at home and abroad. Toluene and air dissolved in the catalyst (cobalt naphthenate, cobalt naphthenate or cobalt acetate) are continuously pumped into the oxidation Tower (or kettle), respectively, further, benzoic acid is produced by oxidation at a temperature of 140 to 165 ° C. And a pressure of 0.3 to 0.4MPA. The tail gas at the top of the column is recovered by condensation and activated carbon adsorption, and then vented. After the reaction liquid in the column is often pressurized and pre-distilled to recover unreacted light components such as toluene, benzyl alcohol and benzaldehyde, then the benzoic acid is distilled under reduced pressure; The recovered toluene and the like are returned to the oxidation tower, The single-pass conversion of toluene can be controlled at more than 35%. Domestic consumption of benzoic acid per ton of toluene 1025-1500kg, cobalt naphthenate about 4kg; Foreign consumption of toluene per ton of 820kg. Although benzoic acid can be prepared by chlorination of toluene and decarboxylation of phthalic acid, the liquid phase catalytic air oxidation of toluene as raw material is widely used in industrial production at home and abroad. Toluene and air dissolved in the catalyst (cobalt naphthalate, cobalt naphthenate or cobalt acetate) are continuously pumped into the oxidation Tower (or kettle), respectively, benzoic acid is produced by oxidation at 140-165 °c and a pressure of 0.3-0.4MPa. The tail gas at the top of the column is recovered by condensation and activated carbon adsorption, and then vented. After the reaction liquid in the column is often pressurized and pre-distilled to recover unreacted light components such as toluene, benzyl alcohol and benzaldehyde, then the benzoic acid was distilled under reduced pressure. The recovered toluene and the like were returned to the oxidation Tower, and the single-pass conversion rate of toluene could be controlled to be above 35%. Domestic consumption of benzoic acid per ton of toluene 1025 ~ 1500kg, cobalt naphthenate about 4kg; Foreign consumption of toluene per ton of 820kg. 2C6CH5CH3+3O2 [cobalt salt] → 2C6H5COOH |
| category | flammable solid |
| toxicity grade | poisoning |
| Acute toxicity | oral-rat LD50: 1700 mg/kg; Oral-mouse LD50: 1940 mg/kg |
| stimulation data | Skin-rabbits 500 mg/24 h mild; eye-rabbit 100 mg severe |
| explosive hazard characteristics | reacts strongly with oxidant; Its powder burns rapidly in oxygen |
| flammability hazard characteristics | open flame, flammable when heated; Combustion-induced smoke |
| storage and transportation characteristics | ventilation and low temperature drying; Separate storage with oxidant |
| extinguishing agent | dry powder, carbon dioxide, water mist |
| spontaneous combustion temperature | 570°C |
