Background and overview[1][2]
4-Ethylphenol is also called p-hydroxyethylbenzene. Those precipitated from water are white needle crystals. Has a strong woody smell. Insoluble in water, soluble in ethanol, ether, acetone, benzene and common organic reagents. Rat oral LD50270mg/kg. Naturally found in eggs, cranberries, pork, whiskey, coffee, etc., 4-ethylphenol is often used to prepare whiskey, rum, smoked pork, ham, used in baked goods, and also used as food Spice, it is also an intermediate of pesticides and can be used to produce a series of high-end, low-toxicity, low-residue pesticides; it is also used as an anti-aging agent, surfactant, and non-ionic emulsifier for rubber and plastics. agents, organic synthesis intermediates and chemical reagents. 4-Ethylphenol is an excellent model for studying the interaction between phenol structure and multi-carbon chains.
Structure[1, 3]
Purpose[1-3]
4-Ethylphenol can be used as a spice. It is an edible spice allowed by my country’s GB2760-1996 regulations and is used in baked goods and margarine. If there is research and development of a blended purple potato flavor, including the following weight The raw material composition is: 0.01 to 2 parts of isobutyraldehyde, 0.01 to 2 parts of isovaleraldehyde, 0.01 to 2 parts of acetic acid, 0.1 to 5 parts of isoamyl alcohol, 0.05 to 2 parts of hexanal, and 0.01 to 5 parts of 2-heptanone. , 0.01 to 5 parts of heptanaldehyde, 0.01 to 0.5 parts of 4-ethylphenol, 0.01 to 5 parts of methyl hexanoate, 0.01 to 5 parts of benzaldehyde, 0.01 to 5 parts of hexanoic acid, 0.01 to 5 parts of 2-octanone, 0.01 to 5 parts of ethyl hexanoate, 0.01 to 5 parts of ethyl caprylate, 0.005 to 2 parts of 2-undecanone, etc., as well as auxiliary materials. The provided essence has the characteristic flavor of roasted purple potatoes, and when added to the heat-processed purple potato products, it can continue to provide the unique sensory flavor of purple potatoes.
4-Ethylphenol can also be used to prepare plastic antioxidants, such as 2,6-di-tert-butyl ethylphenol; to prepare rubber anti-aging agents, such as 2,2′-methylenebis(4-ethylphenol) (6-tert-butyl)phenol; also used as raw material for PVP, surface treatment agent, epoxy resin curing agent, photosensitive materials, medicine, pesticides and dyes.
Preparation [4-5]
Method 1: A method for preparing 4-ethylphenol by catalytic pyrolysis of biomass using a palladium catalyst.
Using biomass as raw material, mechanically mix biomass and palladium catalyst according to the mass ratio of (10:1) ~ (1:3), and then perform rapid pyrolysis at 250 ~ 380°C under anaerobic conditions , after condensing the pyrolysis gas, a liquid product rich in 4-ethylphenol can be obtained. The biomass raw material is grass biomass.
The palladium-based catalyst includes a carrier and palladium metal supported on the carrier. The specific preparation method is as follows: first, weigh a certain mass of palladium nitrate and dissolve it in deionized water. After it is completely dissolved, add a certain amount of palladium nitrate to the solution. amount of catalyst carrier, slowly drip ammonia water under stirring conditions until the pH value reaches 9 to 10, continue stirring at room temperature for 12 hours and then filter, the filter cake is dried at 100°C, and finally the solid obtained after drying is kept at a certain Reduction in a hydrogen atmosphere at reduction temperature yields a palladium-loaded solid catalyst.
Method 2: A method for preparing 4-:ethylphenol through activated carbon catalytic pyrolysis of sugarcane bagasse.
Using sugarcane bagasse as raw material and activated carbon as catalyst, the bagasse and activated carbon catalyst are mechanically mixed according to the mass ratio of (10:1) to (1:5), and then mixed under a hydrogen atmosphere at 240 to 410°C. Rapid pyrolysis, the pyrolysis reaction time is less than 50 seconds, and a liquid product rich in 4-ethylphenol can be obtained after condensing the pyrolysis gas. The activated carbon catalyst is activated carbon prepared from biomass through a steam activation method. The specific preparation method is as follows: the biomass raw material is crushed to a particle size of less than 1 mm, first carbonized and cooled under an inert atmosphere; the carbonized material is Activated in a water vapor atmosphere; activated carbon is obtained after cooling. Using biomass-based steam-activated activated carbon as a catalyst, a liquid product rich in 4-ethylphenol was prepared by catalytic pyrolysis of sugarcane bagasse in a hydrogen atmosphere.
It should be noted that activated carbon obtained by other activation methods (such as activated carbon obtained by chemical activation such as ZnCl2, H3PO4 and KOH, activated carbon obtained by physical activation methods such as CO2)Activated carbon) does not have this catalytic effect. Only activated carbon obtained by water vapor activation method has this catalytic effect. However, relying solely on activated carbon to catalyze the pyrolysis of sugarcane bagasse, the yield and selectivity of 4-ethylphenol are very limited. The biggest beneficial effect of this method is to use hydrogen as the reaction gas, relying on its synergistic effect with the activated carbon catalyst to greatly increase the yield and selectivity of 4-ethylphenol.
As a hydrogen source, hydrogen can be used as an effective hydrogen donor to react with 4-vinylphenol and its precursor under the catalysis of activated carbon to selectively generate 4-ethylphenol. Using activated carbon catalyst alone, the lack of a sufficiently effective hydrogen donor in the pyrolysis system limits the production of 4-ethylphenol; using hydrogen alone cannot react with 4-vinylphenol and its precursors in the pyrolysis system , it is impossible to promote the generation of 4-ethylphenol; when hydrogen and activated carbon are used together, there is basically no ability to deal with various complex unsaturated (containing C=C bonds) pyrolysis products generated during the pyrolysis of biomass. The catalytic hydrogenation effect shows excellent catalytic hydrogenation effect only for 4-vinylphenol and its precursors, thus enabling the selective preparation of 4-ethylphenol.
Based on this characteristic, the yield and selectivity of 4-ethylphenol produced by using activated carbon to catalyze the pyrolysis of sugarcane bagasse under a hydrogen atmosphere are much higher than those previously reported for the catalytic pyrolysis of sugarcane bagasse under a nitrogen atmosphere. The yield and selectivity of preparing 4-ethylphenol are increased by at least 1.5 times, and the selectivity is also significantly improved accordingly. Since the purity of 4-ethylphenol in the liquid product is very high, its subsequent separation and purification is relatively simple. In addition, the mixture of coke and activated carbon catalyst formed by the pyrolysis of sugarcane bagasse can be activated by water vapor to obtain activated carbon, which can then be used to prepare 4-ethylphenol.
Main reference materials
[1] Practical Fine Chemical Dictionary
[2] Theoretical calculation and experimental study of monochromatic resonance two-photon ionization spectroscopy of ethylphenol
[3] CN201810820338.X A blended purple potato flavor and its preparation method
[4] CN201410558325.1 A method for preparing 4-ethylphenol through catalytic pyrolysis of biomass
[5] CN201710127516.6 A method for preparing 4-ethylphenol through activated carbon catalytic pyrolysis of sugarcane bagasse
