It was found that the composition of the products depended on the ratio of starting materials. Hydrothermal alkylation of phenols with alcohols in diluted acids. The methodology is more efficient than previous methods since harsh conditions such as higher temperatures and longer reaction times are avoided. Continuous phenol alkylation process chevron research. Friedelcrafts alkylation involves the alkylation of an aromatic ring with an alkyl halide using a strong lewis acid, such as aluminium chloride, ferric chloride, or other mx n reagent, as catalyst. Intramolecular phenol dearomatization is one of the most straightforward method for synthesizing spirocyclohexadienones. Computational studies of the mechanism of pdcatalyzed. Friedelcrafts alkylation has been hypothesized to be reversible.
Sep 24, 2006 the alkylation of phenol, hydroquinone and paminophenol is performed by phase transfer catalysis without solvent. This reaction is promoted by having an excess of catalyst present, either a lewis acid such. Alkylation of phenol provides many industrial intermediates such as agrochemicals and polymers. The alkylation of phenol is of great industrial importance. The e ect of the phenol to benzyl alcohol ratio and the time of reaction on the phenol conversion. The phenacyl bromide was firstly chosen as oalkylation reagent. A mechanistic view the current work utilizes the ab initio density functional theory dft to develop a molecular level of the. Other alkylations are the alkylation of phenol, derivatives of which are used as raw materials for the production of resins, herbicides, insecticides, and other chemicals, and alkylation of. Our calculations conclude that oalkylation to form the phenolic ether is the most energetically favorable in the neutral condition. However, phenol esters also undergo a fries rearrangement under friedelcrafts conditions to produce the calkylated, hydroxyarylketones.
Mechanism of phenol alkylation in zeolite hbea using in situ solidstate nmr spectroscopy. This improvement comprises using as c an aryl sulfonic acid selected from the class of highly acidic aryl sulfonic acids having a k value of at least 3. Alkylation of benzene with isopropanol on mixed oxides7 and benzoylation. Abstract cesium carbonate mediated oalkylation of phenols was carried out under mild conditions to give the corresponding phenol ethers exclusively. Alkylation of benzene by propylene to cumene 173 6 6. Synthesis of aryl alkyl ethers by alkylation of phenols.
By using bronsted acidic triflate ionic liquids containing the. Organic base catalyzed oalkylation of phenols under solvent. The purpose of this experiment was to conduct a substitution reaction which can be used to construct from two sample parts. Some 450,000 tonnes of alkylated products like tertiary butylphenols are used in the industry per year. Acidcatalyzed liquidphase alkylation of phenol with branched and linear olefin isomers. Kinetic characterisation of zeolite catalysts using. Alkylation of phenol with other alkenes and cresols alkylations were successfully catalysed by. The catalyst is modeled with the benzene sulfonic acid, and the effect of this acid on olefins such as isopropene ipr and tributene tbu in a phenol solution. Liquid phase alkylation of anisole and phenol catalyzed by. Friedelcrafts reaction of phenol chemistry stack exchange. The segmented flow that is generated within the flow system is able to afford the desired ethers in high yield and in very short times.
Today, the cumene is used almost exclusively for manufacturing phenol and acetone. The possibility of product 1 being formed is higher than the probability of formation of product 2. Alternatively, the dioxaborin, when reacted with an alkylthiol or an alcohol in the presence of an acid, gave the corresponding orthoalkylthiomethyl or. This invention relates to the reaction of a phenolic compound with a compound capable of yielding an alkyl radical. Linear alkylphenols from olefins can be made by reaction at 260425 c without added catalyst. The alkylation of phenol, hydroquinone and paminophenol is performed by phase transfer catalysis without solvent.
The principal products were chromanetype ethers with an equimolar ratio of starting materials and an excess of phenol. Then the mixture of phenol, phenacyl bromide, dabco and anhydrous k 2 co 3 was grinded in a mortar. Chapter 3 friedelcrafts alkylation of phenol using ionic. The friedelcrafts reaction open computing facility.
Aqueousmediated nalkylation of amines full paper but the reaction rate is slow and it requires a longer reaction time 810 h. The general mechanism for tertiary alkyl halides is shown below. Friedeicrafts alkylation is an important means of attaching alkyl chains to aromatic rings and hence is a key reaction in organtc chemistry. Continuous phenol alkylation process chevron research company. The formation reaction mechanism includes an unexpected highly selective ortho aromatic electrophilic substitution on phenol, operated by ptcleta1c2h4ornn, r me or ph, and a final cyclization step. The alkylate formed has a high octane value and can typically boost the octane of the gasoline pool by 0. Phosphorous acidcatalyzed alkylation of phenols with. It was found that a new substance appeared several minutes later with the disappearance of reactants upon tlc plate.
Summary of limitations of friedelcrafts alkylations. The methodology is more efficient than previous methods since harsh conditions such as higher. Mechanism of phenol alkylation in zeolite hbea using in situ. Solvent free liquidphase alkylation of phenol over solid. Alkylation of phenol materials and process simulation center. Mechanism of phenol alkylation in zeolite hbea using in. Phasetransfer catalysis under continuous flow conditions. Pdf alkylation of phenol with olefins in the presence of sulphuric. Synthesis of aryl alkyl ethers by alkylation of phenols with quaternary ammonium salts.
The longchain alkylphenols are prepared by alkylation of phenol with alkenes. Improvement in a method for producing paraalkylated phenols comprising reacting a a phenol and b an alkylating agent in the presence of c an alkylation catalyst and resulting product. A typical example of diluted acid promoted alkylation of phenol with benzyl alcohol. Some of the existing aqueous alkylation procedures are not successful because of the rapid hydrolysis of the alkylbenzylic halides under strongly basic conditions csoh, naoh, k 2co 3 koh, etc. Lewis acids are particularly suited for c alkylation. For example, the contribution of alkyl phenyl ether rearrangement to c. Kinetic characterisation of zeolite catalysts using cracking, alkylation and other chemical reactions dmitry b. For example, the contribution of alkyl phenyl ether rearrangement to calkylation has been controversially discussed.
The thermal alkylation of phenol with olefins anderson. Nonylphenol np is the commercial description for a complex mixture of ninecarbon alkylchain substituted phenols. Our calculations conclude that o alkylation to form the phenolic ether is the most energetically favorable in the neutral condition. Pdf highly selective metal mediated orthoalkylation of. A h3po3catalyzed alkylation of phenols with alkenes is achieved in a facile, efficient, and selective manner. The alkylation of phenol with alcohols and olefins is an important process used in industrial scale. Selective alkylation of phenols using solid catalysts white rose. Alkylated phenols are widely used as additives in gasoline, lubricants and surfactants. Alkylation of aluminum phenolate by nerol and of phenol by nerol in the presence of the organoaluminum compounds aluminum phenolate and aluminum isopropylate was studied.
Mar 21, 2012 o alkylation of phenol compounds was performed in a continuous flow apparatus under biphasic liquidliquid conditions and promoted by tetrabutylammonium bromide tbab as a phasetransfer catalyst. A mechanistic view the current work utilizes the ab initio density functional theory dft to develop a molecular level of the mechanistic understanding on. The product will be purified by crystallization, a common purification technique in organic chemistry. The main purpose of using alcl3 is to polarise the halo alkane bondalkylation. The phenacyl bromide was firstly chosen as o alkylation reagent. Phenol alkylation with cyclohexanol sets in only after a. Tanmoy patra, firdaus parveen, sreedevi upadhyayula. The latter could be reduced to the corresponding orthoalkylphenol with tertbutylamine borane in the presence of aluminum chloride.
Alkylation of phenol with tertbutyl alcohol catalysed by. Vinyl or aryl halides do not react their intermediate carbocations are too unstable alkylation reactions are prone to carbocation rearrangements deactivated benzenes are not reactive to friedelcrafts conditions, the benzene needs to be as or more reactive than a monohalobenzene see. Pdf alkylation of phenol with olefins in the presence of. Phenol alkylation abigail sanders anna katherine edmondson introduction. Do phenols undergo friedel crafts alkylation reaction when. Jan 24, 2006 the current work utilizes the ab initio density functional theory dft to develop a molecular level of the mechanistic understanding on the phenol alkylation in the presence of a cationexchange resin catalyst, amberlyst15. Kinetic characterisation of zeolite catalysts using cracking. Homogenous acid catalysts such as hf, h 2 so 4, alcl 3, or bf 3 are commonly used in friedelcrafts. The current work utilizes the ab initio density functional theory dft to develop a molecular level of the mechanistic understanding on the phenol alkylation in the presence of a cationexchange resin catalyst, amberlyst15. The catalyst preparation method, its characterization and reusability, were reported. The alkylation of carboxylic acids with alcohols in acidic. Alkylation of phenol has an additional complication because of the possibility of the olefin attack to the phenolic oxygen oalkylation leading to ether formation beside the usual alkylation at the aromatic ring calkylation. However, under certain conditions, it is possible to form product 2 as well.
Abstract cesium carbonate mediated o alkylation of phenols was carried out under mild conditions to give the corresponding phenol ethers exclusively. For alkylation at carbon, the electrophilicity of alkyl halides is enhanced by the presence of a lewis acid such as aluminium trichloride. C alkylation can also be effected by alkenes in the presence of acids. This reaction allowed for the formation of alkyl benzenes from alkyl halides, but was plagued with unwanted supplemental activity that. The product 1 is formed by the oalkylation of the phenolate anion, while product 2 is formed via calkylation of the phenolate anion. Us3932537a us05496,312 us49631274a us3932537a us 3932537 a us3932537 a us 3932537a us 49631274 a us49631274 a us 49631274a us 3932537 a us3932537 a us 3932537a authority us united states prior art keywords phenol acid alkylation catalyst ortho process prior art date 19710909 legal status the legal status is an assumption and is not a legal. Chem 1650 phenol alkylation phenol alkylation abigail. In 2010, we reported a synthetic method of spirocyclohexadienones using an pdcatalyzed intramolecular ipsofriedelcrafts allylic alkylation of phenols. Pdf alkylphenols have been synthesised in high yield by the alkylation of phenol with olefins c6c8 in the presence of sulphuric acid. In the catalytic alkylation of phenols wherein there is formed a catalyst phase containing dissolved monoalkylated phenol and unreacted phenol, the improvement which comprises removing said catalyst phase from the alkylating zone and extracting the monoalkylated phenol therefrom by contacting the catalyst phase with a selective solvent. Generally, transition metalcatalyzed allylic alkylation using phenolic nucleophiles occurs on the oxygen atom to. The european union has implemented sales and use restrictions on certain applications in which nonylphenols are used because of.
Mechanistic insights into solvent induced alkylation of p cresol with tert butyl alcohol using bronsted acidic ionic liquids. Mechanistic aspects of alkylation of a general carboxylic acid. Apr 09, 2011 the product 1 is formed by the o alkylation of the phenolate anion, while product 2 is formed via c alkylation of the phenolate anion. The catalyst is modeled with the benzene sulfonic acid, and the effect of this acid on olefins such as isopropene ipr and tributene tbu in a phenol solution mimics. It is more particularly concerned with the reaction of a phenol with an alkylating agent in the presence of a phenol alkylation catalyst by a process which increases the yield of monoalkylated product and suppresses the production of polyalkylated phenol. We were able, for the first time, to synthesize and characterize pt derivatives with a structural shape similar to vitamin e, having a metallachromane core. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene or their equivalents. Upon oxidation of cumene isopropylbenzene in presence of air, we obtain cumene hydroperoxide.
It was found that orthosubstitution of the aromatic ring occurred primarily. C alkylation is a process for the formation of carboncarbon bonds. The reaction products were isolated and characterized. This is an example of the synthesis of the reaction. Amberlyst15, dowex50wx2 and dowex50wx4 effectively catalyzed phenol o and c alkylation from 65 to 120 degrees c, giving high o alkylation selectivities in the presence of water, acetic acid and 1.
Other alkylations are the alkylation of phenol, derivatives of which are used as raw materials for the production of resins, herbicides, insecticides, and other chemicals, and alkylation of aromatic amines and pyridines. Isobutylene is commercially produced mostly from the dehydration of tert butyl alcohol or from the cracking of methyl tertbutyl ether mtbe. Highly selective aromatic alkylation of phenol and anisole by using. The mechanism involves an exothermic reaction between olefin and the benzene sulfonic acid to form ester followed by three reaction pathways leading to direct oalkylation, ocalkylation, and pcalkylation. Alkylation is the transfer of an alkyl group from one molecule to another. Us3359333a us571643a us57164366a us3359333a us 3359333 a us3359333 a us 3359333a us 571643 a us571643 a us 571643a us 57164366 a us57164366 a us 57164366a us 3359333 a us3359333 a us 3359333a authority us united states prior art keywords product phenol catalyst alkylation reaction prior art date 19620427 legal status the legal status is an assumption and is not a legal conclusion. Monoalkylphenols and dialkylphenols are used in the manufacture of antioxidants, uv absorbers and for the production of phenolic resins 8,9. The method is readily extendable to the alkylation of phenols with various alcohols. Alkylation of aromatics with alkanes ethane in principle, direct alkylation of benzene with ethane into ethylbenzene eb can be carried out over a bifunctional catalyst by coupling two reactions.
Us3359333a separation of bf3 catalyst from alkyl phenol. Feb 16, 2006 the mechanism involves an exothermic reaction between olefin and the benzene sulfonic acid to form ester followed by three reaction pathways leading to direct o alkylation, oc alkylation, and pc alkylation. So when we add this reactant mixture to the substrate which is phenol. The main purpose of using alcl3 is to polarise the halo alkane bond alkylation. Reaction of a phenol with an aldehyde in the presence of phenylboronic acid gives a 1,3,2benzodioxaborin. Alkylation of phenol with hexene1 in the presence of 94% sulphuric acid temperatur e 140 c, time of addition 2h, time of stirring. By proper choice of conditions, up to 95% monoalkylphenol having the phenol moiety attached at the 1. Alkylation units were installed in petroleum refineries in the 1930s, but the process became especially important during world war ii, when there was a great demand for aviation gasoline. It is now used in combination with fractional distillation, catalytic cracking, and isomerization to increase a refinerys yield of automotive gasoline.
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