The alkylation of phenol with alcohols and olefins is an important process used in industrial scale. 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. The purpose of this experiment was to conduct a substitution reaction which can be used to construct from two sample parts. Alkylation is the transfer of an alkyl group from one molecule to another. The phenacyl bromide was firstly chosen as o alkylation reagent. The method is readily extendable to the alkylation of phenols with various alcohols. The methodology is more efficient than previous methods since harsh conditions such as higher temperatures and longer reaction times are avoided. The alkylate formed has a high octane value and can typically boost the octane of the gasoline pool by 0. 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. The catalyst preparation method, its characterization and reusability, were reported. Pdf alkylation of phenol with olefins in the presence of sulphuric.
However, phenol esters also undergo a fries rearrangement under friedelcrafts conditions to produce the calkylated, hydroxyarylketones. 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. Alkylation of benzene with isopropanol on mixed oxides7 and benzoylation. C alkylation is a process for the formation of carboncarbon bonds. Tanmoy patra, firdaus parveen, sreedevi upadhyayula. In 2010, we reported a synthetic method of spirocyclohexadienones using an pdcatalyzed intramolecular ipsofriedelcrafts allylic alkylation of phenols.
For example, the contribution of alkyl phenyl ether rearrangement to c. Alkylation of benzene by propylene to cumene 173 6 6. Alternatively, the dioxaborin, when reacted with an alkylthiol or an alcohol in the presence of an acid, gave the corresponding orthoalkylthiomethyl or. Isobutylene is commercially produced mostly from the dehydration of tert butyl alcohol or from the cracking of methyl tertbutyl ether mtbe. 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. Alkylated phenols are widely used as additives in gasoline, lubricants and surfactants. It is now used in combination with fractional distillation, catalytic cracking, and isomerization to increase a refinerys yield of automotive gasoline. Kinetic characterisation of zeolite catalysts using. Homogenous acid catalysts such as hf, h 2 so 4, alcl 3, or bf 3 are commonly used in friedelcrafts. 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. The latter could be reduced to the corresponding orthoalkylphenol with tertbutylamine borane in the presence of aluminum chloride. Abstract cesium carbonate mediated oalkylation of phenols was carried out under mild conditions to give the corresponding phenol ethers exclusively. Synthesis of aryl alkyl ethers by alkylation of phenols with quaternary ammonium salts. Phasetransfer catalysis under continuous flow conditions.
Friedelcrafts reaction of phenol chemistry stack exchange. Computational studies of the mechanism of pdcatalyzed. Chapter 3 friedelcrafts alkylation of phenol using ionic. 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. For alkylation at carbon, the electrophilicity of alkyl halides is enhanced by the presence of a lewis acid such as aluminium trichloride. It was found that a new substance appeared several minutes later with the disappearance of reactants upon tlc plate.
Phenol alkylation with cyclohexanol sets in only after a. The e ect of the phenol to benzyl alcohol ratio and the time of reaction on the phenol conversion. Alkylation of phenol provides many industrial intermediates such as agrochemicals and polymers. 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. Chem 1650 phenol alkylation phenol alkylation abigail. 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. However, under certain conditions, it is possible to form product 2 as well.
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. A mechanistic view the current work utilizes the ab initio density functional theory dft to develop a molecular level of the. Friedeicrafts alkylation is an important means of attaching alkyl chains to aromatic rings and hence is a key reaction in organtc chemistry. Reaction of a phenol with an aldehyde in the presence of phenylboronic acid gives a 1,3,2benzodioxaborin. Mechanistic aspects of alkylation of a general carboxylic acid.
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. This reaction is promoted by having an excess of catalyst present, either a lewis acid such. Generally, transition metalcatalyzed allylic alkylation using phenolic nucleophiles occurs on the oxygen atom to. By proper choice of conditions, up to 95% monoalkylphenol having the phenol moiety attached at the 1. The product 1 is formed by the oalkylation of the phenolate anion, while product 2 is formed via calkylation of the phenolate anion. Friedelcrafts alkylation has been hypothesized to be reversible. It was found that orthosubstitution of the aromatic ring occurred primarily. Synthesis of aryl alkyl ethers by alkylation of phenols. Kinetic characterisation of zeolite catalysts using cracking. Oalkylation of phenol compounds was performed in a continuous flow apparatus under biphasic liquidliquid conditions and promoted by tetrabutylammonium bromide tbab as a phasetransfer catalyst.
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. Linear alkylphenols from olefins can be made by reaction at 260425 c without added catalyst. The alkylation of carboxylic acids with alcohols in acidic. Phenol can react via two pathways with acyl chlorides to give either esters, via oacylation, or hydroxyarylketones, via cacylation however, phenol esters also undergo a fries rearrangement under friedelcrafts conditions to produce the calkylated, hydroxyarylketones. 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. For example, the contribution of alkyl phenyl ether rearrangement to calkylation has been controversially discussed. Mechanistic insights into solvent induced alkylation of p cresol with tert butyl alcohol using bronsted acidic ionic liquids. The phenacyl bromide was firstly chosen as oalkylation reagent. 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. So when we add this reactant mixture to the substrate which is phenol.
The european union has implemented sales and use restrictions on certain applications in which nonylphenols are used because of. Organic base catalyzed oalkylation of phenols under solvent. 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. 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. Liquid phase alkylation of anisole and phenol catalyzed by.
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. Us3359333a separation of bf3 catalyst from alkyl phenol. Organic base catalyzed oalkylation of phenols under. A typical example of diluted acid promoted alkylation of phenol with benzyl alcohol. Mechanism of phenol alkylation in zeolite hbea using in situ solidstate nmr spectroscopy. 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.
Our calculations conclude that oalkylation to form the phenolic ether is the most energetically favorable in the neutral condition. The main purpose of using alcl3 is to polarise the halo alkane bond alkylation. Np is produced through the friedelcrafts alkylation of phenol with nonene, which, in the presence of an acid catalyst, preferentially alkylates at the. This is an example of the synthesis of the reaction. Sep 24, 2006 the alkylation of phenol, hydroquinone and paminophenol is performed by phase transfer catalysis without solvent. The alkylation of phenol, hydroquinone and paminophenol is performed by phase transfer catalysis without solvent.
A mechanistic view the current work utilizes the ab initio density functional theory dft to develop a molecular level of the mechanistic understanding on. Alkylation of phenol with tertbutyl alcohol catalysed by. The reaction products were isolated and characterized. Abstract cesium carbonate mediated o alkylation of phenols was carried out under mild conditions to give the corresponding phenol ethers exclusively. It was found that the composition of the products depended on the ratio of starting materials. Intramolecular phenol dearomatization is one of the most straightforward method for synthesizing spirocyclohexadienones. 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. Mechanism of phenol alkylation in zeolite hbea using in. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene or their equivalents. 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. Mechanism of phenol alkylation in zeolite hbea using in situ. Alkylation of phenol with hexene1 in the presence of 94% sulphuric acid temperatur e 140 c, time of addition 2h, time of stirring. Do phenols undergo friedel crafts alkylation reaction when. The alkylation of phenol is of great industrial importance.
A h3po3catalyzed alkylation of phenols with alkenes is achieved in a facile, efficient, and selective manner. The thermal alkylation of phenol with olefins anderson. C alkylation can also be effected by alkenes in the presence of acids. The longchain alkylphenols are prepared by alkylation of phenol with alkenes. Some 450,000 tonnes of alkylated products like tertiary butylphenols are used in the industry per year. 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. 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.
Kinetic characterisation of zeolite catalysts using cracking, alkylation and other chemical reactions dmitry b. Pdf highly selective metal mediated orthoalkylation of. The product will be purified by crystallization, a common purification technique in organic chemistry. 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. 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. Highly selective aromatic alkylation of phenol and anisole by using.
The methodology is more efficient than previous methods since harsh conditions such as higher. Aqueousmediated nalkylation of amines full paper but the reaction rate is slow and it requires a longer reaction time 810 h. Our calculations conclude that o alkylation to form the phenolic ether is the most energetically favorable in the neutral condition. Today, the cumene is used almost exclusively for manufacturing phenol and acetone. Monoalkylphenols and dialkylphenols are used in the manufacture of antioxidants, uv absorbers and for the production of phenolic resins 8,9. Friedelcrafts alkylation was first discovered by french scientist charles friedel and his partner, american scientist james crafts, in 1877. 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. Pdf alkylation of phenol with olefins in the presence of.
Then the mixture of phenol, phenacyl bromide, dabco and anhydrous k 2 co 3 was grinded in a mortar. This reaction allowed for the formation of alkyl benzenes from alkyl halides, but was plagued with unwanted supplemental activity that. Summary of limitations of friedelcrafts alkylations. This invention relates to the reaction of a phenolic compound with a compound capable of yielding an alkyl radical. Nonylphenol np is the commercial description for a complex mixture of ninecarbon alkylchain substituted phenols. Phenol alkylation abigail sanders anna katherine edmondson introduction. By using bronsted acidic triflate ionic liquids containing the.
Phosphorous acidcatalyzed alkylation of phenols with. The friedelcrafts reaction open computing facility. The principal products were chromanetype ethers with an equimolar ratio of starting materials and an excess of phenol. Continuous phenol alkylation process chevron research company. Lewis acids are particularly suited for c alkylation. The main purpose of using alcl3 is to polarise the halo alkane bondalkylation.
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. Pdf alkylphenols have been synthesised in high yield by the alkylation of phenol with olefins c6c8 in the presence of sulphuric acid. Continuous phenol alkylation process chevron research. Selective alkylation of phenols using solid catalysts white rose. The general mechanism for tertiary alkyl halides is shown below. Solvent free liquidphase alkylation of phenol over solid. 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. 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. Upon oxidation of cumene isopropylbenzene in presence of air, we obtain cumene hydroperoxide. The possibility of product 1 being formed is higher than the probability of formation of product 2.
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