Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/11—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms
  • C07C37/16—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms by condensation involving hydroxy groups of phenols or alcohols or the ether or mineral ester group derived therefrom
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
  • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
  • C07C37/88—Use of additives, e.g. for stabilisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C39/00—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring
  • C07C39/24—Halogenated derivatives
  • C07C39/367—Halogenated derivatives polycyclic non-condensed, containing only six-membered aromatic rings as cyclic parts, e.g. halogenated poly-hydroxyphenylalkanes

Definitions

• This disclosure relates to methods of making benzylated phenols.
• Benzylated phenols in particular ortho-benzylated phenols, are valuable as antioxidants and chemical intermediates.
• benzyl phenol is produced by treating phenol with benzyl chloride or benzyl alcohol in the presence of strong acids (e.g., aluminum chloride, zinc chloride, and sulfuric acid).
• strong acids e.g., aluminum chloride, zinc chloride, and sulfuric acid.
• 2-benzyl, 2,4-dibenzyl and 2,6-dibenzyl phenols are produced by heating phenol with sodium hydroxide in toluene and reacting it with benzyl chloride.
• benzyl alcohol can be reacted with p-cresol using an aluminum chloride catalyst to make dibenzyl-p-cresol.
• Vapor phase benzylation of phenols having un-substituted ortho position with benzyl alcohol in contact with an activated alumina catalyst is also known.
• a method of making benzylated phenols comprises contacting a phenol and a benzyl alcohol with a basic metal oxide catalyst at a temperature sufficient to maintain each of the phenol and the benzyl alcohol in a vapor phase.
• the phenol has at least one hydrogen located ortho to the phenolic hydroxyl .
• Combination includes mixtures, copolymers, reaction products, blends, composites, and the like.
• benzylated phenols e.g., 2,6-dibenzylphenol
• high selectivity e.g., 80% to 90%
• a temperature of 300 0 C to 600 0 C can be employed, or, more specifically, a temperature of 350 0 C to 450 0 C.
• Selectivity is defined as 100 X (all ortho benzyl products )/(total products).
• the method is applicable to a broad range of phenols.
• a phenol is used to generically describe all aromatic hydroxy compounds having at least one hydroxy group bonded to an aromatic ring.
• the phenol used in the method has at least one hydrogen located ortho to the phenolic hydroxyl group. Further, the phenol is selected such that it is capable of being heated to a temperature sufficient to convert it to the vapor phase without excessive decomposition.
• suitable phenols include phenol, o-cresol, p-cresol, 4-ethyl phenol, 4-phenyl phenol, alpha-naphthol, beta-naphtliol, 4-chlorophenol, 2-chlorophenol, 2,4-dichlorophenol, 4-bromophenol, hydroquinone, 4-methoxyphenol, 4-ethoxyphenol, and the like, as well as combinations comprising at least one of the foregoing.
• Particular suitable phenols include the compound phenol, C 6 HsOH, and mono lower alkyl derivatives thereof such as p-cresol, o-cresol, p-ethylphenol, p-n-butylphenol, and the like. More particularly, in one embodiment the phenol is the compound phenol.
• benzyl alcohol broadly describes a class of compounds having the formula I:
• R 1 can be a hydrogen or an alkyl group having 1 to 5 carbons.
• the Ar represents a monocyclic or polycyclic aromatic group that can be unsubstituted or can be substituted with groups such as alkyl, halogen, alkoxy, and the like.
• Suitable benzyl alcohols include p-methylbenzyl alcohol, p-ethylbenzyl alcohol, o- methylbenzyl alcohol, p-isobutylbenzyl alcohol, p-chlorobenzyl alcohol, 2,4- dichlorobenzyl alcohol, o-bromobenzyl alcohol, p-methoxybenzyl alcohol, p- ethoxybenzyl alcohol, and the like, as well as combinations comprising at least one of the foregoing.
• the benzyl alcohol comprises the compound benzyl alcohol, C 6 H 5 CH 2 OH.
• a wide amount of benzyl alcohol per mole of phenol can be employed in the reaction.
• the amount of benzyl alcohol per mole of phenol can be 0.2 moles to 10 moles.
• the amount of benzyl alcohol can be greater than or equal to 1 mole of benzyl alcohol per mole of phenol, or, more specifically, greater than or equal to 2 moles of benzyl alcohol per mole of phenol.
• the amount of benzyl alcohol can be less than or equal to 5 moles of benzyl alcohol per mole of phenol, or, more specifically, less than or equal to 3 moles of benzyl alcohol per mole of phenol.
• the amount of benzyl alcohol per mole of phenol when di-benzylation is desired is 1 mole to 3 moles, or, more specifically, 1.5 moles to 2.5 moles.
• high yields (e.g., greater than or equal to 40%) of 2,6-dibenzylphenol are obtained when the amount of benzyl alcohol per mole of phenol is 2 moles to 5 moles, or, more specifically, 3 moles to 4 moles.
• the amount of benzyl alcohol per mole of phenol is 0.2 moles of 3 moles, or, more specifically, 0.5 mole to 1 mole.
• the catalyst employed in the method includes, as a main constituent, at least one basic metal oxide.
• Suitable metals for the basic metal oxide include iron, magnesium, calcium, barium, and strontium.
• the basic metal oxide can be obtained from a basic metal oxide precursor comprising a magnesium reagent, an iron reagent, or combinations comprising at least one of the foregoing. Any magnesium reagent that yields magnesium oxide can be used. Likewise, any iron reagent that yields iron oxide can be used.
• Suitable magnesium reagents include, but are not limited to, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium, basic magnesium carbonate, and mixtures comprising at least one of the foregoing.
• the magnesium reagent is generally in the form of a powder.
• the magnesium reagents have an average particle size (as determined by measuring across the major diameter (i.e., the longest diameter) of each particle) of 5 micrometers to 50 micrometers, particularly 10 micrometers to 30 micrometers.
• iron reagents used for the preparation of the catalyst include, but are not limited to, ferric nitrate, ferric sulfate, ferric chloride, ferrous nitrate, ferrous sulfate, and ferrous chloride.
• the iron reagent comprises ferric nitrate.
• the iron oxides can be in any form.
• suitable forms of iron oxides include, but are not limited to, FeO, Fe 2 O 3 , Fe 3 O 4 , and mixtures comprising at least one of the foregoing.
• the catalyst is formed by dry-blending the basic metal oxide precursor with at least one filler, and an optional pore former.
• dry blending refers to the general technique in which the individual ingredients are initially mixed together in the dry state, without resorting to any "wet” techniques, such as suspension blending or precipitation. Any type of mechanical mixer or blender can be used, such as a ribbon blender.
• filler is inclusive of, but not limited to, lubricants, binders, and fillers.
• the total amount of filler present in the catalyst composition can be less than or equal to 20% by weight, based on the total weight of filler and basic metal oxide precursor. In some embodiments, the total amount of filler is less than or equal to 10% by weight.
• fillers used in the catalyst composition include graphite and polyphenylene ether (PPE). In some embodiments the polyphenylene ether is used in an amount of less than or equal to 10% by weight, based on the total weight of the fillers and basic metal oxide precursor. In some embodiments the graphite is employed in an amount less than or equal to 5% by weight.
• the optional pore former is a substance capable of aiding the formation of pores in the catalyst.
• suitable pore formers include, but are not limited to waxes and polysaccharides.
• the waxes can include paraffin wax, polyethylene wax, microcrystalline wax, montan wax, and the like, as well as combination comprising at least one of the foregoing.
• the polysaccharide can include cellulose, carboxyl methyl cellulose, cellulose acetate, starch, walnut powder, citric acid, polyethylene glycol, oxalic acid, stearic acid, and the like, as well as combinations comprising at least one of the foregoing.
• anionic and cationic surfactants generally long chain (C 1O-28 ) hydrocarbons containing neutralized acid species (e.g., carboxylic acid, phosphoric acid, and sulfonic acid species).
• the optional pore former is employed in an amount sufficient to provide an average pore diameter of 50 angstroms to 300 angstroms after calcination, or, more specifically, 100 angstroms to 300 angstroms after calcination.
• the pore former can be present in an amount of 0.5 wt.% to 50 wt.%, based on a total weight of basic metal oxide precursor, filler, and pore former. Within this range, the pore former can be present in an amount less than or equal to 40 wt.%, or, more specifically, less than or equal to 30 wt.%. Also within this range, the pore former can be present in amount greater than or equal to 2 wt.%, or, more specifically, greater than or equal to 5 wt.%.
• the catalyst has a bimodal distribution of pores.
• first and smaller diameter pore distribution is obtained from the basic metal oxide precursor during the calcination process, i.e. these pores are of similar dimension to those obtained from calcination of the basic metal oxide precursor not containing the pore former.
• the second and larger diameter pore distribution is believed to be the result of the addition and calcination of the pore former reagent itself, i.e. these pore diameters would not be found in substantial quantities after calcination of a basic metal oxide precursor not containing the pore former.
• the bimodal distribution of pores has a first distribution of pores in which the first distribution has an average pore diameter less than 100 angstroms and a second distribution of pores in which the second distribution has an average diameter greater than or equal to 100 angstroms and less than or equal to 500 angstroms.
• the blended, solid catalyst composition is in the form of a powder.
• the powder usually has a bulk density of 0.1 grams per cubic centimeter (g/cm 3 ) to 0.5 g/cm 3 , or, more specifically, 0.25 g/cm 3 to 0.5 g/cm 3 .
• the powder then generally undergoes further processing prior to being shaped into a desired form. For example, the power can be sieved (to obtain a more narrow particle distribution), milled, compressed, and the like, hi most embodiments, the catalyst composition is deaerated after dry-blending, and prior to additional processing. Deaeration further increases the bulk density of the material by forcibly removing entrained gas (primarily air) from within the powder.
• the catalyst can be formed into any desired shape.
• the catalyst may be compressed into a pellet or "tablet", which can be accomplished by pelletizing equipment, including, but not limited to that equipment described in U.S. Patent 4,900,708.
• the shaped catalyst composition is then calcined. Calcination is usually carried out by heating the catalyst at a temperature sufficient to convert the basic metal oxide precursor to basic metal oxide, which is the active species in the catalyst. Calcination increases the surface area of the catalyst.
• the calcination temperature can vary depending on the metal precursor, but is generally 350 °C to 600 °C.
• the calcination atmosphere can be oxidizing, inert, or reducing.
• the catalyst can be calcined at the beginning of the benzylation reaction. In other words, calcination can take place in the presence of the feed materials, e.g., phenol and benzyl alcohol.
• the surface area of the catalyst pellets can be 50 square meters per gram (m 2 /g) to 300 m /g, or, more specifically, 120 square meters per gram (m /g) to 200 m /g, based on BET (Brunauer, Emmett, and Teller) analysis.
• the uncalcined pellets have pellet density of 1.3 g/cm 3 to 2.1 g/cm 3 . Within this range, the pellets have a pellet density of greater than or equal to 1.4 g/cm 3 , particularly greater than or equal to 1.6 g/cm 3 . Also within this range, the pellets have a pellet density of less than or equal to 2.0 g/cm 3 , particularly less than or equal to 1.9 g/cm 3 .
• the catalyst pellets have a surface area to volume ratio of 950 square meters per cubic meter (m7m ) to 4000 m /m . Within this range, the catalyst pellets particularly have a surface area to volume ratio greater than or equal to 1100 m 2 /m 3 and more particularly greater than or equal to 1300 m 2 /m 3 . Also within this range, the catalyst pellets have a surface area to volume ratio less than or equal to 3800 m /m and more particularly less than or equal to 3000 m /m .
• the catalyst pellets have an aspect ratio of 0.7 to 1.0. Within this range, the aspect ratio is particularly greater than or equal to 0.72 and more particularly greater than or equal to 0.75. Also within this range, the aspect ratio is particularly less than or equal to 0.95 and more particularly less than or equal to 0.90. Aspect ratio is herein defined as the ratio of length to diameter or length to width.
• the phenol having at least one position ortho to its phenolic hydroxyl group un-substituted except for hydrogen and the benzyl alcohol are introduced into a vessel containing the catalyst (herein after "catalyst bed" for ease in discussion).
• the temperature of the catalyst bed is maintained at a temperature sufficient to maintain the reactants in a vapor phase (e.g., a temperature of 300°C to 600 0 C).
• the reaction proceeds at atmospheric pressure, but pressures above or below can also be used.
• This reaction can also be carried out in the presence of water vapor.
• the water vapor can be present in an amount of 1 wt.% to 35 wt.%, based on a total weight of the reactants, or, more specifically, 5 wt.% to 25 weight%.
• the method allows for a selectivity of greater than or equal to 80% of ortho benzylated products (e.g., ortho and 2,6-dibenzyl phenols), or, more specifically, a selectivity of greater than or equal to 85%. In some embodiments, the selectivity is greater than or equal to 99%.
• ortho benzylated products e.g., ortho and 2,6-dibenzyl phenols
• the selectivity is greater than or equal to 99%.
• embodiments are disclosed where essentially no byproducts are produced. For example, less than or equal to 1 wt.% of the total weight of the reaction products are byproducts (e.g., benzyl ethers, meta or para benzyl phenol). While benzaldehyde may be produced it can be recycled to form ortho benzylated products.
• the catalyst includes iron oxide, 15 wt.% orthobenzyl phenol is produced, based on the total weight of the reaction products.
• calcined sample was subjected to surface area and porosity measurement using a Micromeritics 2010 analyzer.
• the pore size distribution and surface area were obtained from the nitrogen desorption isotherm.
• the overall average pore diameter was 120 angstroms to 180 angstroms.
• the pore volume was 0.5 cubic centimeters per gram (cc/g) to 0.7 cc/g.
• the surface area was 100 m /g to 250 m /g.
• a packed bed reactor was loaded with 5 cubic centimeters (cc) of magnesium carbonate pellets, having an average particle size of 1000 micrometers to 1400 micrometers.
• This catalyst was calcined in-situ for 16 to 22 hours at 390° C at a rate of 0.2 to 5°C/min under 0.06 to 0.24 (10) g of nitrogen/hr/g of catalyst. All the reactions were performed under atmospheric pressure. After calcination, the temperature was increased from 390 0 C to 475°C within two hours under nitrogen atmosphere. After 15 minutes of attaining this temperature, a feed mixture was introduced at 0.12 cc/min.
• the feed contained 16.21 wt.% phenol, 74.48 wt.% benzylalcohol, and 9.31 wt.% water (4:1 molar ratio of benzylalcohol to phenol).
• the benzylation reaction was carried out under isothermal condition for a period of 24 hours.
• the yields of reaction products such as ortho benzylphenol, 2,6 dibenzylphenol, benzaldehyde and unconverted phenols and benzylalcohol were monitored over the period of 20 hours.
• the conversion measured was based on area percent peaks reported by gas chromatography. The results were shown in Table 1.
• This Example illustrates that the yield of ortho-benzylated phenols was greater than 50%, or, more specifically, greater than 60%, when a 4 to 1 molar ratio of benzyl alcohol to phenol was used. More particularly, the yield of 2,6-dibenzyl phenol was greater than or equal to 40%.
• the reaction demonstrated 83% selectivity for ortho- benzylated phenols with the only other significant product being benzaldehyde which can be recycled to the reaction to produce further product.
• the method uses low cost basic catalyst such as magnesium carbonate, which can be in-situ converted to magnesium oxide.
• the resultant reaction products include minimal undesired products, such as para and meta benzylphenol.
• reactions employing the catalyst described herein have 13.5% byproduct (only benzaldehyde) compared to 50% byproducts when the same reaction is carried out using alpha alumina.
• the method allows for a relatively low cost catalyst to be employed, while allowing for high selectivity to ortho-benzylated phenols. Accordingly, a reduction in separation costs can be realized. Further, this method allows for a continuous method to be employed, which can increase production compared to batch methods. The method does not employ acids that can cause corrosion to or increased cost of process equipment.

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• 2006
  • 2006-08-08 KR KR1020087007684A patent/KR20080044891A/ko not_active Application Discontinuation
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