Phenols alkylation with isobutene

The first reactions concerned (Simons and Archer, 27) alkylation of benzene with propylene to form isopropylbenzene, with isobutene to form f-butylbenzene and di-f-butylbenzene, and trimethylethylene to form amylbenzene. Later on (Simons and Archer, 28) studied these and other reactions in more detail and showed that high yields could be obtained and that the product was not contaminated with tars or other obnoxious impurities. It was shown that the products obtained with trimethylethylene were mono- and di-f-amylbenzene, that phenyl-pentane resulted from the use of pentene-2, and that cyclohexene produced cyclohexylbenzene. Cinnamic acid reacted with benzene (Simons and Archer, 29) to form /3-phenylpropionic acid and allyl benzene reacted with benzene to form 1,2-diphenylpropane. It is interesting to note that although allyl alcohol reacted with benzene to form 1,2-diphenylpropane, the intermediate in the reaction, allylbenzene, was isolated and identified. This shows that in this case the hydroxyl reacted at a more rapid rate than the double bond. Both di- and triisobutylene reacted with phenol (Simons and Archer, 30) at 0°, when using hydrogen fluoride containing only relatively small quantities of water, to form f-butyl-benzene, but diisobutylene with 70% hydrogen fluoride produced p-f-octylphenol. Cyclohexene reacted with toluene to form cyclohexyl-toluene and octene-1 rapidly reacted with toluene to form 2-octyltoluene (Simons and Basler, 31). 

Alkylation of phenols with isobutene has also been accomplished using a heterogeneous catalyst system comprising an aluminum phenoxide bonded to a solid polymeric resin having acidic functional... 

Phenol condensations. A cation-exchange resin is an excellent catalyst for the alkylation of phenol with isobutene." A mixture of phenol and the resin was stirred at 80° and isobutene was passed in over a period of 3 hrs. The temperature was... 

Solid acid catalysts, consisting of polysiloxane bearing alkylsulfonic acid groups (MCM-41), are comparable in their catalytic activity to those of the polystyrene-based cation exchange resins. These catalysts can be used in the preparation of para-Bisphenol-A by the alkylation of phenol with acetone. Other application of these catalysts lie in the alkylation of phenol with isobutene at 90-130 O . 

The alkylation of phenol was studied with isobutene in the temperature range from 90 - 130°C and high conversion was found as well as in the alkylation of a-methy 1-styrene with 2,3-dimethyl-1-butene. Finally, the catalytic hydrogenolysis of the model substance 1-phenyl-ethanol to ethylbenzene proceeds quantitatively at 30°C without addition of a soluble acid. 

Alkylation of phenols and phenol derivatives with olefins like isobutene, octene, and nonene to synthesize industrially very important alkylphenols, -cresols, or -xylenols is typically performed at temperatures between 80°C and 120°C. High yields and good selectivities are obtained at these temperatures by using Deloxan catalysts. The very good thermal stability of the Deloxan catalysts allows their use at even higher operating temperatures, like 110°C to 150°C, which results in a higher productivity. 

It is interesting to note, that in the alkylation of phenol with isobutene, a change in temperature seems also to change the course of the alkylation reaction with the polysiloxane based catalysts. The principal reaction pathways to the main substitution products (according to the theory for electrophilic substitution, only very small amounts of meta-alkylation products are observed) are given in fig. 5. 

Reaction pathways for the alkylation of phenol with isobutene... 

Industrial processes for which this kind of catalysts were originally used include the hydration of propene and the conversion of isopropanol into diisopropyl ether [36], the cleavage of ethers such as MTBE to produce pure isobutene [37] and the alkylation of phenol with isobutene and isobutene oligomers to afford p-t-butylphenol (as stabilizer for plastics) and isoalkylphenols (for detergents) (Scheme... 

Among the tertiary-butyl phenols, the o- and p-derivatives and 2,6-di-tert-butylphenol are commerically important. They are used in the production of antioxidants. o-tert-Butylphenol and 2,6-di-tert-butylphenol are produced by alkylation of phenol with isobutene at a reaction temperature of 100 °C in the presence of aluminum phenolate as catalyst. 

Alkylation with Alkenes. The alkylation of phenols by olefins and cyclo-olefins has been reviewed, in Russia Several papers on the alkylation of phenols have appeared. Thus, p-t-butyiphenol has been prepared with good selectivity by treatment of phenol with isobutene and a Lewis acid catalyst followed by HCIO4 as an isomerization catalyst. The ort/io-alkylation of phenol by alkenes can be improved by using Al(OPh)3 and an aluminosilicate catalyst.Much greater ortho-selectivity in the alkylation of phenol with 4-bromostyrene is obtained if aluminium diphenylphosphorodithioate rather than BF3-OEt2 or BF3-H3P04 is used as catalyst. Relative reactivities of the various ring positions towards... 

High activity associated with x = 0.5 composition demonstrates an optimum concentration of acid-base sites is needed for phenol adsorption and subsequent polarization of both phenol and isobutene as in the ease of other alkylations. It was proposed that in the phenol t-butylation, t-butyl carbocation ean attaek phenol from the adsorbed as well as from the gaseous state resulted in the formation of para t-butylated products such as 4-tBP and 2,4-tBP. The steric hindrance of t-butyl group prevents the sequential attack of t-butyl cation at ortho position for dialkylation and that demonstrated the negligible formation of 2,6-di-t-butyl phenol. 

The reaction apparently proceeds via dehydration of f-BuOH to generate isobutene, which reacts with phenol to form 2-isobutylphenols as anti-Markovnikov products. The hydroxy group presumably participates in the anti-Markovnikov alkylation and is further assisted by the increased water density.35... 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

Permutit Q are effective catalysts for the alkylation of phenols with alkenes such as propene, isobutene and 2,5-dimethyl-2-hexene, and alkyl halides and alcohols. ... 

UVA 2-hydroxy-4-octyloxybenzophenone 2-hydroxy-4-methoxybenzophenone 2-(2H-benzotriazol-2-yl)-p-cresol 2-(2H-benzotriazole-2-yl)-4,6-di-tert-pentylphenol 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetraethylbutyl)phenol 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazole-2-yl)-phenol 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy) phenol ethyl-2-cyano-3,3-diphenylacrylate HAS 1,3,5-tri-azine-2,4,6-triamine, N,N [1,2-ethane-diyl-bis[[[4,6-bis[butyl-(1,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl] imino]-3,1 -propanediyi] bis[N ,N -dibutyl-N ,N -bis(1,2,2,6,6-pentamethyl-4-piperidinyl)- bis(2,2,6,6-tetramethyl-4-piper-idyl) sebacate 2,2,6,6-tetramethyl-4-piperidinyl stearate N,N -bisformyl-N,N -bis-(2,2,6,6-tetramethyl-4-piperidinyl)-hexamethylendiamine alkenes, C20-24-.alpha.-, polymers with maleic anhydride, reaction products with 2,2,6,6-tet-ramethyl-4-piperidinamine 1,6-hexanediamine, N, N -bis(2,2,6,6-tetramethyl-4-piperidinyl)-, polymers with 2,4-di-ohloro-6-(4-morpholinyl)-1,3,5-triazine 1,6-hexanediamine, N,N -bis(2,2,6,6-tetramethyl-4-piperidinyl)-, polymers with morpholine-2,4,6-trichloro-1,3,5-triazine reaction products, methylated Phenolic antioxidants ethylene-bis(oxyethylene)-bis(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate) 2,6,-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5,-triazine-2-ylamino) phenol pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) 2-(1,1 -dimethylethyl)-6-[[3-(1,1 -dimethylethyl)-2-hydroxy-5-methylphenyl] methyl-4-methylphenyl acrylate isotridecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate 2,2 -ethylidenebis (4,6-di-tert-butylphenol) 2,2 -methylenebis(4-ethyl-6-tertbutylphenol) 3,5-bis(1,1-dimethyethyl)-4-hydroxy-benzenepropanoic acid, C13-15 alkyl esters phenol, 4-methyl-, reaction products with dicyclopen-tadiene and isobutene Phosphite trinonylphenol phosphite isodecyl diphenyl phosphite... 

Stabilizers UVA 2(2 -hydroxy-5-methylphenyl)benzotriazole Screener carbon black HAS bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-n-butyl-2-( 3,5-di-tert-bulyl-4-hydroxy-benzyl) malonate Phenolic antioxidants phenol, 4-methyl-, reaction products with dlcyclopentadiene and isobutene 2,6,-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5,-triazine-2-ylamino) phenol 2- (1,1 -dimethylethyl)-6-[[3-(1,1 -dimethylethyl)-2-hydroxy-5-methylphenyl] methyl-4-methylphenyl acrylate isotridecyl- 3- (3,5-di-tert-biAyl-4-hydroxyphenyl) propionate 3,5-bis(1,1-dimethyethyl)-4-hydroxy-benzenepropanoic acid. Cl 3-15 alkyl esters 2,2 -isobutylidenebis(2,4 imethylphenol) Amine nonylated diphenylamine Thiosynergist 2,2 -thiobis(6-tert-butyl-4-methylphenol) 4,6-bis(octylthiomethyl)-o-cresol ... 

---