|Company Name:||Jonny pharmaceutical co.,ltd Gold|
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|Company Name:||J & K SCIENTIFIC LTD. |
|Company Name:||Alfa Aesar |
|Benzoic acid Chemical Properties|
|mp ||121-125 °C(lit.)|
|bp ||249 °C(lit.)|
|vapor density ||4.21 (vs air)|
|vapor pressure ||10 mm Hg ( 132 °C)|
|refractive index ||1.504|
|Fp ||250 °F|
|storage temp. ||Store at RT.|
|Water Solubility ||Slightly soluble. 0.34 g/100 mL|
|Stability:||Stable. Combustible. Incompatible with strong bases, strong oxidizing agents, alkalies.|
|CAS DataBase Reference||65-85-0(CAS DataBase Reference)|
|NIST Chemistry Reference||Benzoic acid(65-85-0)|
|EPA Substance Registry System||Benzoic acid(65-85-0)|
|Benzoic acid Usage And Synthesis|
|Summary||The molecular formula of benzoic acid is C6H5COOH, carboxyl is directly connected with the carbon atom on the benzene ring of the simplest aromatic acid, is a hydrogen in benzene ring by the substitution of the carboxyl group (- COOH) compound formation. It is colorless, lamellar crystal, odorless. Melting point is 122.13℃, boiling point is 249℃. The relative density is 1.2659 (15 / 4 ℃). The rapid sublimation at 100 ℃, the steam has a strong irritant, can cause cough after inhalation. It is slightly soluble in water, soluble in ethanol, ether, chloroform, benzene, toluene, CS2, CCl4 and turpentine organic solvent. As the free acid, ester or its derivatives in the form of widespread in nature, for example, in the benzoin gum is existence in the form of free acid and benzyl ester; it is in the free form in some plant leaves and stem bark; and exists in form of methyl and benzyl ester in the essential oils; exists in form of the derivatives of hippuric acid in the horse urine. Benzoic acid is weak, and stronger than fatty acids. Their chemical properties are similar, can form salt, ester, amide anhydride, acyl halide, etc., are not easy to be oxidized. Benzene of benzoic acid occurred electrophilic substitution reaction, mainly by m-substituted. Benzoic acid is often used as drug or the use of preservative, anti fungal, bacterial, fungal growth, medicinal is painted on the skin, used to treat ringworm of the skin disease. It is used for synthetic fiber, resin, paint, rubber, tobacco industry. Initially benzoic acid is obtained by an interest gum distillation or alkaline hydrolysis and by hippurate hydrolysis. In industrial, benzoic acid is obtained in cobalt, manganese catalyst by air oxidation of toluene; or by phthalic anhydride hydrolysis decarboxylation of benzoic acid and its sodium salt can be used as latex, toothpaste, jam or other food antimicrobial agent, also can be used for dyeing and mordant.
|Discovery History||Benzoic acid was found in the 16th century. In 1556, Nostradamus first described carbonization effect of benzoin; After the Alexius Pedemontanus and Brian blessed decipher were discovered in 1560 and 1596. In 1875, the salkowski discovered the antifungal potency of benzoic acid, so benzoic acid is used for long term preservation cloudberry.|
|solubility||The solubility of 100g is: 4 ℃, 0.18g; 18 ℃, 0.27g; 20 ℃, 0.29g; 25℃, , 0.34g; 30 ℃, 0.42g; 40 ℃, 0.6g; 50℃, 0.95g; 60 ℃, 1.2g; 75 ℃, 2.2g; 80 ℃, 2.75g; 90 ℃, 4.6g; 95℃, 6.8g.|
|Preparation||Industrial preparation method |
The industrial benzoic acid is mainly by toluene liquid phase air oxidation preparation. The process was with cobalt naphthenate as catalyst, in response to temperature is 140 - 160 ℃ and operating pressure is 0.2 - 0.3MPa and response generation benzoic acid. Reaction after steaming to toluene, and vacuum distillation and recrystallization to obtain the product. The process uses cheap raw materials, high yield. Therefore, it is industrial uses mainly the method.
Laboratory preparation method of the main reaction:
1.C6H5CH3+ KMnO4+H2O -C6H5 COOK+KOH+MnO2+H2O(water in fron of the manganese dioxide is supplied with water reaction environment)
2.C6H5 COOK+HCl--C6H5 COOH
Drug and dosage:
Toluene 1.5g (1.7ml, 0.016mol), potassium permanganate 5g (0.032mol), CTAB(cetyl trimethyl ammonium bromide) 0.1g.
With 100 ml round bottom flask. Install a refluxing device. add 5g potassium permanganate, 0.1g of hexadecyl trimethyl ammonium bromide, 1.7 ml of toluene and 50 ml of water to the reaction flask, stir heated boiling (vigorous stirring, violent boiling), keep the reactant solution stable boiling.
When large amounts of brown precipitate, potassium permanganate purple shallow or disappeared, the toluene layer disappeared, reaction has basically ended. Filter out of manganese dioxide precipitation, landfill leachate by concentrated hydrochloric acid, precipitation of benzoic acid precipitation, filtering to the crude product.
The crude product water recrystallization. In a boiling water bath for drying, weighing, measuring the melting point.
|Effect||Benzoic acid and sodium benzoate are commonly used food preservative. In acidic conditions, it has inhibitory effect on yeast and mold. When pH value is 3 antibacterial strength, when pH was 6 for a lot of mould effect is very poor, so the inhibition the optimum pH value is 2.5-4.0. In the food industry with plastic barrels concentrated fruit and vegetable juice, the maximum usage shall not exceed 2.0g/kg; in the jam (not including canned), fruit juice (taste) drinks, soy sauce, vinegar in the maximum amount is 1.0g/kg; in Wine, candy, wine in the maximum amount of 0.8g/kg in the low salt; pickles, sauces, candied fruit, use the largest 0.5g/kg in carbonate; use the largest beverage 0.2g/kg. because of solubility of benzoic acid, when used will be stirring, or dissolved in a small amount of hot water or ethanol. The use of concentrated fruit juice in the soft drink used for benzoic acid easily volatile with steam, it is commonly used in the sodium salt. Benzoic acid in food industry is a common preservative in dairy products, but not allowed to be added. In general, benzoic acid is considered to be safe. But for some special populations, including infants, long-term intake of benzoic acid may lead to asthma, urticaria, metabolic acidosis and other adverse reactions. Paul deodorant benzoic acid is also used as a beverage. As the cream sweet perfume fragrance. Can also be used for chocolate, lemon, orange, sub berries, nuts, candied fruit and other edible flavor type. Tobacco flavor also commonly used. In addition of benzoic acid is also used as a pesticide, medicine, dye, mordant and plasticizer agent for the production of raw materials, polyamide resin and alkyd resin modifying agent and steel equipment anti rust agent.|
|The method of use of food additives||1.the antibacterial activity of benzoic acid molecule was higher than that of the ions, so When pH is less than 4, antibacterial activity is high, the minimum inhibitory concentration is 0.015%-0.1%. but in acidic solution in the solubility decreased, so do not rely solely on the improvement of the solution of acid to improve its antibacterial activity. Benzoic acid of optimum antibacterial is pH 2.5 ~ 4.|
2.Due to the low solubility of benzoic acid in water, so the actual is added just the right amount of sodium carbonate or sodium bicarbonate, with more than 90℃ dissolved in hot water, making it into benzoic acid sodium then added to the food. If you must use of benzoic acid, first with the amount of dissolved in ethanol before use.
3.because the solubility of benzoic acid in water is lower than sodium benzoate , so the use of sodium benzoate in acidic foods should pay attention to prevent the transformation of sodium benzoate into benzoic acid caused by precipitation and reduce the effect of its use.
4.1g benzoic acid is equivalent of 1.18g sodium benzoate and 1g sodium benzoate is equivalent to 0.847g benzoic acid.
5.benzoic acid in soy sauce, in soft drinks can be used together with p-hydroxybenzoic acid esters and have efficiency.
1.China < food additives hygiene standards > (GB2760-1996) provisions: carbonated drinks, maximum usage was 0.2g/kg; low salt pickles, sauces, candied fruit, 0.5 g / kg, wine, fruit wine, candy, 0.8 g / kg separately; soy sauce, vinegar, jam (excluding canned), (taste) juice drinks, 1.0, food industrial plastic drums of concentrated fruit and vegetable juice, 2G / kg; juice (fruit) ice, 1.0 g / kg (mixed or used alone). Benzoic acid and sodium benzoate and use, with benzoic acid meter shall not exceed the maximum amount of use.
2.the actual use of reference: benzoic acid and sodium benzoate commonly used in preservation of high acid fruit, berries, fruit juice, jam, syrup drinks and other acidic food, combined with low temperature sterilization, play a synergistic role. Different countries for permission to use the product of the food and the using concentration of different.
|Pharmacological action||[pharmacodynamics] this product is antiseptic, with anti bacteria effect; in the acidic environment, 0.1% concentration of the bacteriostatic effect. Lower effect of PH value is usually better, such as pH 3.5, concentrations of 0.125% within 1 hour can kill Staphylococcus. In alkaline environment weakened. For external use can anti superficial fungal infection. 0.05 - 0.1% concentration added to drugs or food preservatives, inhibit bacterial and fungal growth. |
[pharmacokinetics] oral rapidly absorbed from the digestive tract, combination with glycine in the liver form hippuric acid, the latter in 12 hours quickly from the urine discharge, in the first 4 hours reached dosage 97%. Such as oral dose, some can be coupled benzoyl gluconic acid in the urine leakage.
[indications] Used for superficial fungal infections, such as tinea corporis, tinea manuum and tinea pedis; also used as food and medicine preservatives.
[usage] this product with 6 ~ 12% concentration of salicylic acid and formulated into tincture or ointment in the treatment of skin superficial fungal infection. Coated with skin lesions, 2 times a day, as a pharmaceutical preparations and food preservative, effective concentration of 0.05 - 1%.
[Adverse reaction]Oral asthma, urticaria and angioedema and other allergic reactions can occur. Coated with contact dermatitis. Larger doses can cause oral salicylates like reaction.
The above information is edited by the chemicalbook Han Ya.
|Hazard||Benzoic acid accumulation is less, low toxicity in the body involved and metabolism. If the excessive consumption of benzoic acid, the body's liver and kidney will be jeopardized. Maximum safety of carbonated drinks of benzoic acid usage is 5mg / kg of body weight, then calculated according to the weight of 60kg, daily limit is 300mg, benzoic acid for carbonated drinks, the maximum amount of use is 0.2g/kg, then drank 1.5kg of beverage is safe.|
It has strong toxic effects on microorganisms, but the toxicity of the sodium salt is very low. A daily dose of 0.5g, has no toxicity to the body , even in an amount of not more than 4g of health also has no harm. In human and animal tissues it can bind with protein components of the glycine and detoxification, formed hippuric acid excreted in the urine. Benzoic acid crystallites or dust on the skin, eyes, nose, and throat has stimulating effect. Even if its sodium salt, if you take a lot, also can damage to the stomach. The operator should wear protective equipment. Need to be stored in a dry and ventilated place moisture, heat, away from the fire source.
|The maximum amount of food additives permitted maximum allowable residue limits|
|The method for determination of benzoic acid and Sorbic acid in food||1.The Principle: After samples were acidification, sorbic acid, benzoic acid were extracted with ether, were separated and determined by flame ionization detector of gas chromatography, quantitative comparison with the standard series. |
2.reagents: peroxide free ether: petroleum ether: boiling range is 30 to 60 ℃, hydrochloric acid, anhydrous sodium sulfate, hydrochloric acid (1 + 1): take 100mL hydrochloric acid, diluted with water to 200mL, sodium chloride acid solution (40g/L): sodium chloride solution (40g/L) with a small amount of hydrochloric acid (1 + 1) acid, sorbic acid, benzoic acid standard solution: weigh the sorbic acid, benzoic acid, 0.2000g, separately to a 100mL volumetric flask, with petroleum ether ether (3 + 1) mixed solvent dissolved and diluted to the scale. This solution is equivalent to 2.0mg per milliliter of sorbic acid and benzoic acid, sorbic acid, use benzoic acid standard solution: learn the amount of sorbic acid, benzoic acid standard solution with petroleum ether and ether (3 + 1) mixed solvent diluted to the equivalent of 50, 100, 150, 200, 250mg/ml of sorbic acid or benzoic acid.
3.Instrument: gas chromatography with flame ionization detector.
Weigh 2.50g beforehand mixed samples with cylinder plug in 25mL,add 0.5 ml of hydrochloric acid (1 + 1) acidification, extract twice with ether 15,10mL, each vibration shake 1 min, upper ether extract inhalation another 25ml stoppered cylinder. The combined ether extracts. With 3ml sodium chloride acid solution (40g / L) were washed twice and rest for 15 minutes, with a dropper the ether layer through the filter of anhydrous sodium sulfate into 25ml volumetric flask. with diethyl ether to volume, and mixed. Imbibe 5ml of ether extract in 5 ml with plug in a graduated test tube and placed 40℃ water bath on the volatile dry, add 2 ml of petroleum ether - ether (3 + 1) mixed solvent residue, spare.
4.2The reference of chromatographic conditions:
4.2.1Column: glass column, diameter 3mm, length 2m, built-in coated with 5% (m/m) DEGS + 1% (m/m) H3PO4 stationary liquid 60 ~ 80 mesh Chromosorb WAW.
4.2.2Flow rate: carriergaswasnitrogen, 50mL/min (nitrogen and air, hydrogen ratio according to the different types of instruments to choose their optimal ratio).
4.2.3 Inlet temperature: 230℃; detector 230℃; the column temperature was 170 ℃.
Sample of 2 L standard series in the concentration of standard solution into gas chromatography, can be measured with different concentration of sorbic acid, benzoic acid peak, with concentration as abscissa and the corresponding peak value as the ordinate, drawing the standard curve.
|Chemical property||Scaly or needle like crystals. With the smell of formaldehyde or benzene. Slightly soluble in water, soluble in ethanol, methanol, diethyl ether, chloroform, benzene, toluene, CS2, CCl4 and turpentine.
|Application||1. Used as a chemical reagent and preservative.|
2. Benzoic acid is important type food preservative. Under acidic conditions, It has inhibitory effects to mold, yeast and bacteria , but the effect is weak acid producing bacteria. The most appropriate antimicrobial pH values is ranging from 2.5 to 4, generally lower, the pH value is appropriate from 4.5 to 5. In the food industry with plastic barrels concentrated fruit and vegetable juice, the maximum use amount shall not be over 2.0g / kg; in jam (excluding canned), (taste) juice drink, soy sauce, vinegar in the maximum dose of 1.0g/kg; in soft candy, wine, wine in the maximum dose of 0.8 g / kg separately; in the low salt pickled vegetables, the sauce, candied fruit, maximum dose is 0.5 g / kg; in carbonated drinks in the largest amount of use is 0.2g/kg. due to benzoic acid, slightly soluble in water, its use can be a small amount of ethanol enable dissolved.
3.Preservative; anti microbial agents.
Due to the low solubility of benzoic acid and use shall be stirring, or dissolved in a small amount of hot water or ethanol. When used in the soft drink with fruit juice concentrate, for benzoic acid easy volatile with the water vapor, so often used in the sodium salt, besides the above sodium equivalent to benzoic acid 0.847g.
4.Often used as a fixative agent or preservative. Also used as a fruit juice aroma conservation agents. As a perfume with perfume fragrance. Can also be used for chocolate, lemon, orange, berries, nuts, candied fruit type edible essence. Tobacco flavor is also commonly used.
5.Benzoic acid and its sodium salt are food preservatives. Under acidic conditions, it has inhibition of yeasts and molds. When pH 3, antibacterial strength and when pH 6, many fungi effect is very poor, so the antibacterial optimum pH is 2.5-4.0. Benzoic acid is mainly used for the production of sodium benzoate preservatives, dyes intermediates, pesticides, plasticizers, mordant, medicine, spice and also can be used as alkyd resin and polyamide resin modifier for the production of polyester, terephthalic acid and used equipment, iron and steel anti rust agent.
6.Mainly used for antifungal and antiseptic.
7.Used in medicine, dye carriers, plasticizer, spices and food preservatives such as production, and can also be used to paint of alkyd resin performance improvement; used as pharmaceutical and dye intermediates, used for the preparation of plasticizer and spices etc., as well as equipment, iron and steel anti rust agent.
|Methods of production||1.It is initially from gum benzoin carbonization or alkaline hydrolysis , also by hippurate hydrolysis. In industrial, production method of benzoic acid is three, including in liquid phase oxidation of toluene, benzyl chloride hydrolysis and phthalic anhydride off carboxyl method , and toluene liquid phase air oxidation method are the most common. Toluene and air were vent into a container of cobalt naphthenate catalyst reactor. In reaction temperature 140-160℃, operating pressure is 0.2-0.3MPa conditions, then reaction to benzoic acid. After steaming to unreacted toluene to crude benzol acid, again by vacuum distillation and recrystallization to obtain the finished product. With phthalic anhydride off carboxyl method and the resulting product is not easy to be refined, and the production cost is high, only used in small quantities of pharmaceutical products in the manufacturing process. Toluene chlorination products are not suitable for application in food. The benzoic acid for industrial use, food, medicine with different specifications. Food grade should conform to the GB1901-80, content above 99.5%, melting point is 121-123℃, and oxides, carbides, chlorinated compounds, the burning residue, heavy metal and arsenic content for the provisions were stipulated. Raw materials consumption quota: toluene 1140kg/t, cobalt naphthenate 4kg/t. in addition, the production method which use toluene to benzaldehyde can be by-product benzoic acid.|
2.Derived directly from toluene liquid-phase oxidation.
It is from the adjacent benzene two formic acid to lead oxide, zinc oxide as catalyst and decarboxylation.
It is by the chlorination of toluene into three chloro toluene, then lime and powder hydrolysis.
3.Benzoic acid, although by toluene chlorination and phthalic acid decarboxylation process, but industrial production methods which are widely used at home and abroad for toluene as the raw materials of the liquid phase catalytic air oxidation method.
Dissolved toluene (NAI acid cobalt, cobalt or cobalt acetate) catalyst and air were continuously pumped into oxidation tower (or kettle) and again 140-165℃ and 0.3-0.4MPa pressure oxidation generating benzoic acid. Tower tail gas condensation and activated carbon adsorption process for the recovery of toluene vent; tower reactor liquid pressure fore running recovering unreacted toluene, benzyl alcohol and benzaldehyde light components, vacuum distillation to benzoic acid; recovery of toluene returned to the oxidation tower, toluene one-way conversion rate can be controlled in more than 35%.
Domestic consumption per ton of benzoic acid was toluene 1025-1500kg, cobalt naphthenate about 4kg; toluene consumption per ton 820kg at abroad.
|Chemical Properties||white crystals or powder|
|Acute toxicity||Oral rat LD50: 1700 mg / kg; oral LD50: 1940 mg / kg in mice
|Stimulus data||Rabbit skin - 500 mg /24 hours, mild; rabbit eyes - 100 mg, severe
|Explosive hazard characteristics||With the oxidant react; the powder combustion in oxygen rapidly
|Combustible hazard characteristics||Fire, heat is flammable; combustion smoke stimulation.
|Storage and transportation characteristics||Low temperature drying ventilation; stored separatelyoxidizing agent.
|Fire extinguishing agent||Dry powder, carbon dioxide, water mist.
|General Description||A white crystalline solid. Slightly soluble in water. The primary hazard is the potential for environmental damage if released. Immediate steps should be taken to limit spread to the environment. Used to make other chemicals, as a food preservative, and for other uses.|
|Air & Water Reactions||Vapor from molten Benzoic acid may form explosive mixture with air. The finely powdered dry acid is a significant dust explosion hazard [Bretherick, 5th ed., 1995, p. 884]. In air very rapid combustion occurs [Wilson, L.Y. et al., J. Chem. Ed., 1985, 62(10), p. 902]. Slightly soluble in water.|
|Reactivity Profile||At high temperature Benzoic acid can react with oxidizing reagents.|
|Health Hazard||Dust may be irritating to nose and eyes. At elevated temperatures, fumes may cause irritation of eyes, respiratory system, and skin.|
|Fire Hazard||Behavior in Fire: Vapor from molten Benzoic acid may form explosive mixture with air. Concentrated dust may form explosive mixture.|
|Benzoic acid Preparation Products And Raw materials|