Name | 4-Hydroxybenzaldehyde |
Synonyms | PHBA 4-Hydroxy benzaldehy 4-Hydroxybenzaldehyde p-Hydroxybenzaldehyde 4-hydroxy benzaldehyde p-hydroxy benzaldehyde Hydroxybenzaldehyde, p- HYDROXYBENZALDEHYDE, 4-(RG) 4-HYDROXYBENZALDEHYDE FOR SYNTHESIS |
CAS | 123-08-0 |
EINECS | 204-599-1 |
InChI | InChI=1/C7H6O2/c8-5-6-1-3-7(9)4-2-6/h1-5,9H |
InChIKey | RGHHSNMVTDWUBI-UHFFFAOYSA-N |
Molecular Formula | C7H6O2 |
Molar Mass | 122.12 |
Density | 1,129 g/cm3 |
Melting Point | 112-116 °C (lit.) |
Boling Point | 191°C 50mm |
Flash Point | 174°C |
JECFA Number | 956 |
Water Solubility | 13 g/L (30 ºC) |
Solubility | Soluble in ethanol, ether, acetone, ethyl acetate, slightly soluble in water (solubility is 1.38g/100ml in water at 30.5°C), soluble in benzene (solubility is 3.68 g/ml in benzene at 65°C). |
Vapor Presure | 0.004Pa at 25℃ |
Appearance | Colorless crystalline powder |
Color | light yellow to light brown |
Merck | 14,4811 |
BRN | 471352 |
pKa | 7.61(at 25℃) |
Storage Condition | Store below +30°C. |
Stability | Hygroscopic |
Sensitive | Air Sensitive |
Refractive Index | 1.5105 (estimate) |
MDL | MFCD00006939 |
Physical and Chemical Properties | melting point 114-118°C |
Use | It is used as an important intermediate for medicine, perfume and pesticide, and is used for the synthesis of hydroxyaminobenzylpenicillin, trimethoxybenzaldehyde, trimethoxybenzaldehyde and other drugs |
Hazard Symbols | Xi - Irritant |
Risk Codes | R36/37/38 - Irritating to eyes, respiratory system and skin. |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. S24/25 - Avoid contact with skin and eyes. S37/39 - Wear suitable gloves and eye/face protection |
WGK Germany | 2 |
RTECS | CU6475000 |
TSCA | Yes |
HS Code | 29124900 |
Hazard Note | Irritant/Air Sensitive |
Toxicity | LD50 orally in Rabbit: 2250 mg/kg |
Raw Materials | Sodium hydroxide Hydrochloric acid Oxygen |
Downstream Products | 2,6-dibromo-4-cyanophenyl octanoate 4-(4-hydroxyphenyl)-2-butanone |
colorless crystalline powder with a relative density of 129 and a melting point of 115-116 °c. Soluble in ethanol, ether, acetone, ethyl acetate, slightly soluble in water, soluble in benzene. Easy sublimation.
It is used in the synthesis of bezafibrate and Dujuan in medicine.
FEMA | 3984 | 4-HYDROXYBENZALDEHYDE |
LogP | 1.3 at 23℃ |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
introduction | p-hydroxybenzaldehyde is an important intermediate in organic synthesis and is widely used in fine chemical products such as medicine, perfume, electroplating, food and pesticide. |
morphology and smell | p-hydroxybenzaldehyde is a light yellow or white-like crystal with a slight aromatic smell. |
use | p-hydroxybenzaldehyde is used in the perfume industry to synthesize vanillin, ethyl vanillin, syringaldehyde, anisaldehyde and forpone etc. used for the synthesis of medicine and organic compounds used as an important intermediate of medicine, perfume, pesticide, used for the synthesis of amoxicillin, trimethoxy benzaldehyde and other drugs This product is an intermediate of medicine, perfume, liquid crystal. P-hydroxybenzaldehyde is used to produce antibacterial synergists TMP (trimethoprim), amoxicillin, amoxicillin, artificial gastrodia, rhododendron, bezafibrate, esmolol; used in the production of spices anisaldehyde, vanillin, ethyl vanillin, raspberry ketone. The key raw material for the production of p-hydroxyphenylsidonic acid (p-hydroxyphenylsidine is a key intermediate for the new generation of semi-synthetic penicillium oxyampicillin). It is also a key intermediate raw material for the production of pesticide-bromobenzonitrile. p-hydroxybenzaldehyde is an important intermediate in pharmaceutical industry and perfume industry used as an important intermediate in medicine, perfume and pesticide, and used in the synthesis of hydroxybenzylpenicillin, trimethoprim, trimethoxybenzaldehyde and other drugs. High molecular polymers and pharmaceutical raw materials. Used as raw material for polymers and medicines |
Hydroxybenzaldehyde isomers | Hydroxybenzaldehyde has 3 isomers, namely o-hydroxybenzaldehyde, p-hydroxybenzaldehyde and m-hydroxybenzaldehyde, p-hydroxybenzaldehyde is also known as p-formaldehyde phenol. Those precipitated from the water are white to light yellow needle-like crystals. It has an aromatic smell. It can be sublimated without decomposition under normal pressure. Molecular weight 122.12. Melting point 115~116 ℃. Relative density 1.129 (130/4 ℃). The refractive index 1.5705(130 ℃). Slightly soluble in water and benzene, easily soluble in ethanol, ether, acetone, ethyl acetate, the solubility in water at 30.5 ℃ is 1.38, and the solubility in benzene at 65 ℃ is 3.68. Mice were injected intraperitoneally with LD50500mg/kg. p-hydroxybenzaldehyde is an important intermediate in medicine, perfume, and liquid crystal. It can react with dimethyl sulfate to produce anisaldehyde, and react with acetaldehyde to produce p-hydroxycinnamaldehyde, and further oxidation can produce cinnamic acid. This product can be directly oxidized to produce p-hydroxybenzoic acid, reduced to p-hydroxybenzyl alcohol, etc., which can be used as spices; pharmaceutical intermediates; liquid crystal raw materials; other organic synthesis intermediates, which have a wide range of uses. In addition to being directly used as a spice, m-hydroxybenzaldehyde is also used as an intermediate for making other spice; pharmaceutical raw materials to produce dehydroxyepinephrine hydrochloride, epinephrine, quinine, etc.; nickel-plated brightener; chemical analysis Reagents (quantitative analysis of sugar); photographic emulsions and fungicides, etc. O-hydroxybenzaldehyde, also known as salicylaldehyde, is a colorless and transparent oily liquid with a special smell and bitter almond taste. It is chemically active and can undergo substitution, condensation, oxidation, Wittig reactions, etc. It is orange-red when it reacts with sulfuric acid, and can form colored chelates with metal ions. In case of ferric chloride solution, it appears purple. Can be reduced to salicylic alcohol. It is mainly used as raw materials for producing spices "coumarin" and "dihydrocoumarin", preparing violet spices, and can also be used as fungicides. preparation method of p-hydroxybenzaldehyde: phenol is used as raw material to react chloroform with phenol sodium salt at 60 ℃. Or phenol and chloroacetaldehyde are condensed under the catalysis of potassium carbonate, and then decomposed by sodium methoxide. It is also possible to pass dry hydrogen chloride into the mixture of phenol and hydrocyanic acid under the aluminum trichloride catalyst, and then decompose it in ice water to produce p-hydroxybenzaldehyde. |
laboratory method for preparing p-hydroxybenzaldehyde | 1, using phenol and chloroform as raw materials, heating in alkaline solution, performing Reimer-Tiemann reaction, and generating p-hydroxybenzaldehyde [1] and a small amount of salicylaldehyde (o-hydroxybenzaldehyde). 2. Using phenol and hydrogen cyanide as raw materials, under the catalysis of aluminum trichloride, it reacts with anhydrous hydrogen chloride to generate imine hydrochloric acid of p-hydroxybenzaldehyde, which is then hydrolyzed to obtain p-hydroxybenzaldehyde [1]. The solvent for the reaction can be benzene, chlorobenzene, and chloroalkanes; zinc cyanide can also be used instead of hydrogen cyanide. 3, phenol and trichloroacetaldehyde are condensed under the catalysis of potassium carbonate, and then in dimethylformamide, by sodium methoxide decomposition, can be prepared. 4, using p-cresol as raw material, reacting with acetic acid to generate p-toluene acetate, and then chlorination and hydrolysis can produce p-hydroxybenzaldehyde. 5, using p-nitrotoluene as raw material, reacting with sodium polysulfide under the action of a catalyst, reducing to generate p-aminobenzaldehyde, diazotization reaction with sodium nitrite in sulfuric acid to generate diazonium salt, and then hydrolyze at 100~110 ℃ to prepare p-hydroxybenzaldehyde [1]. |
production method | there are many process routes for the production of p-hydroxybenzaldehyde. at present, industrial production mainly includes phenol, p-cresol, p-nitrotoluene and other raw materials. 1. Phenol method Phenol method is divided into Reimer-Tiemann reaction, Gattermann reaction, phenol-chloral route, phenol-glyoxylic acid route, phenol-formaldehyde route and other synthesis process routes. The process of phenol method is characterized by easy availability of raw materials, simple manufacturing process, but low yield and high cost. (1)Reimer-Tiemann reaction phenol and chloroform in alkaline aqueous solution, heating at 60-100 ℃ for 2-4h, at the same time to generate p-hydroxybenzaldehyde and o-hydroxybenzaldehyde (commonly known as salicylaldehyde), the total yield of about 50%, the highest yield of p-hydroxybenzaldehyde is only 17%. This process is mainly used to synthesize salicylaldehyde and p-hydroxybenzaldehyde as a by-product, but it is one of the main existing process production methods. The conversion rate of raw materials and product yield of this process are very low, and a large amount of tar is produced. Chloroform must be excessive, unreacted phenol is not easy to recover, and product separation and purification are difficult. Therefore, it is necessary to vigorously develop new high-efficiency catalysts, improve the selectivity of the reaction, and develop simple and efficient product separation and purification methods in order to reduce costs and improve product yield. (2)Gattermann the reaction of phenol and HCN, in the presence of AlCl3, the introduction of dry HCl, catalytic reaction, and decomposition in ice water, to obtain p-hydroxybenzaldehyde, the product yield is higher. If zinc cyanide is used instead of HCN, the yield is almost theoretical. The selectivity of this process product is high, but the disadvantage is that the cyanide is toxic, the operation technology is high, and the difficulty is high; the second is that due to the use of anhydrous operation, the reaction equipment is strict and the cost is high; the third is that a small amount of salicylaldehyde is accompanied by It is difficult to separate and purify the product, which limits large-scale production. 2. The process of producing p-hydroxybenzaldehyde by p-nitrotoluene method is divided into three steps: redox, diazotization and hydrolysis. (1) p-nitrotoluene redox p-nitrotoluene is simultaneously redox with sodium polysulfide to obtain p-aminobenzaldehyde. The specific technological process is as follows: p-nitrotoluene, ethanol solvent and surfactant (such as OP Tween, etc.) are uniformly mixed according to the mass ratio of 1:5:0.02-0.04, sodium polysulfide aqueous solution is added dropwise at 80-85 ℃, and the reaction is 2-3h. The product is distilled with water steam to remove p-nitrotoluene and p-aminotoluene. In the extraction with ether to obtain p-aminobenzaldehyde. The conversion rate and yield of the reaction are above 90%. Sodium polysulfide can be prepared from sodium hydrosulfide, caustic soda and sulfur. (2) diazotization and hydrolysis p-aminobenzaldehyde is treated with 40% sulfuric acid, 30% sodium nitrite solution is added at 0-3 ℃, the reaction is about 30min, and the excess sodium nitrite is decomposed with a small amount of urea to obtain p-aminobenzaldehyde diazonium salt solution. The solution was hydrolyzed in the presence of sulfuric acid at 80-85 ℃ for about 30min. The product was extracted, purified and dried to obtain p-hydroxybenzaldehyde with a yield of more than 90%. The advantages of this process are that the raw materials are cheap, but the disadvantages are that the process route is long, the equipment is huge, and the intermediate product is toxic to aminobenzaldehyde, the diazotization reaction temperature is low, and the freezing conditions are high. At present, the domestic Shanxi Qixian fine plant adopts this process to produce p-hydroxybenzaldehyde. 3. p-cresol catalytic oxidation method This process is to directly oxidize p-cresol with air or oxygen to synthesize p-hydroxybenzaldehyde under the action of a catalyst. In the 1980s, Japan, the United States, and Germany conducted in-depth research and reports on this route. In the late 80 s and early 90 s, several domestic research and production units in Jiangsu, Shanghai, Dalian and other places also researched and developed this process and used it in industrial production. The specific process flow is as follows: p-cresol, sodium hydroxide and methanol are added into a stainless steel pressure kettle, stirred until completely dissolved, cobalt acetate is added to seal the reaction kettle, and oxygen is introduced at 55 ℃ to keep the pressure in the kettle at 1.5MPa for 8-10h. During the reaction, the oxygen passing rate is strictly controlled, and a coil cooling system is provided in the kettle. When the temperature rises, the kettle jacket can pass cooling water, at this time, the coil began to pass cooling water, strictly control the total amount of oxygen, and keep the temperature in the kettle at about 60 ℃. At the end of the reaction, the material is put into the initial steam kettle, the solvent methanol is distilled for recycling, and hydrochloric acid is added to dissolve in water for salting out. The solid-liquid material is filtered by a centrifuge, and the obtained solid is put into a vacuum oven and dried at about 60 ℃ for 3-5h to obtain p-hydroxybenzaldehyde with a content greater than 98%. |
spontaneous combustion temperature | 450°C |