Propylene Friedel-Crafts reaction

Friedel-Crafts. 2-Phenylpropanol results from the catalytic (AlCl, FeCl, or TiCl reaction of ben2ene and propylene oxide at low temperature and under anhydrous conditions (see Friedel-CRAFTS reactions). Epoxide reaction with toluene gives a mixture of 0-, m- and -isomers (75,76). 

Another important use of BCl is as a Ftiedel-Crafts catalyst ia various polymerisation, alkylation, and acylation reactions, and ia other organic syntheses (see Friedel-Crafts reaction). Examples include conversion of cyclophosphasenes to polymers (81,82) polymerisation of olefins such as ethylene (75,83—88) graft polymerisation of vinyl chloride and isobutylene (89) stereospecific polymerisation of propylene (90) copolymerisation of isobutylene and styrene (91,92), and other unsaturated aromatics with maleic anhydride (93) polymerisation of norhornene (94), butadiene (95) preparation of electrically conducting epoxy resins (96), and polymers containing B and N (97) and selective demethylation of methoxy groups ortho to OH groups (98). 

Cumene as a pure chemical intermediate is produced in modified Friedel-Crafts reaction processes that use acidic catalysts to alkylate benzene with propylene (see Alkylation Friedel-CRAFTSreactions). The majority of cumene is manufactured with a soHd phosphoric acid catalyst (7). The remainder is made with aluminum chloride catalyst (8). 

The importance of the solvent, in many cases an excess of the quatemizing reagent, in the formation of heterocyclic salts was recognized early. The function of dielectric constants and other more detailed influences on quatemization are dealt with in Section VI, but a consideration of the subject from a preparative standpoint is presented here. Methanol and ethanol are used frequently as solvents, and acetone,chloroform, acetonitrile, nitrobenzene, and dimethyl-formamide have been used successfully. The last two solvents were among those considered by Coleman and Fuoss in their search for a suitable solvent for kinetic experiments both solvents gave rise to side reactions when used for the reaction of pyridine with i-butyl bromide. Their observation with nitrobenzene is unexpected, and no other workers have reported difficulties. However, tetramethylene sulfone, 2,4-dimethylsulfolane, ethylene and propylene carbonates, and salicylaldehyde were satisfactory, giving relatively rapid reactions and clean products. Ethylene dichloride, used quite frequently for Friedel-Crafts reactions, would be expected to be a useful solvent but has only recently been used for quatemization reactions. ... 

Acrylonitrile is obtained from propylene and ammonia. 1,3-Butadiene is a petroleum hydrocarbon obtained from the C4 fraction of steam cracking. An overview on the issues of the production of butadiene is given in the literature (5). Styrene monomer is made by the dehydrogenation of ethylbenzene, which is obtained by the Friedel-Crafts reaction of ethylene and benzene. 

Epoxides have occasionally been used in Friedel-Crafts reactions, and some interesting stereochemical observations have been made in this context. Quite unlike secondary alcohols which give almost fully racemized product, it has been shown that optically pure propylene oxide with AlCh and benzene gives optically pure 2-phenyl-1-propanol with inversion of configuration at the cleaved center. AlBrs leads to much lower levels of optical purity it was demonstrated that both starting material and product are optically stable to the reaction conditions, and therefore partial racemization is intrinsic to the mechanism with AlBrs. It is nonetheless clear from these and other results that even powerful Lewis acids do not assure reaction via simple planar carbenium ions. 

Friedel-Crafts reaction catalysts like anhydrous aluminum chloride are readily soluble in the nitroalkanes. Solutions containing up to 50% aluminum chloride are easily prepared in nitroalkane solvents. These catalytically active complexes, AICI3-RNO2, can be isolated and used in solvents other than the nitroalkane. The reactants in the Friedel-Crafts reaction are often soluble in the nitroalkane reaction medium. Other catalysts like boron trifluoride (BF3), titanium tetrachloride (TiC ), and stannic tetrachloride (SnClj) are also soluble in the nitroalkane solvents. Reaction types which use nitroparaffins as solvents include alkylation of aromatics, acetylation of aromatics, halogenations, nitrations, and the reaction of olefins and hydrogen sulfide to yield mercaptans. Nitroparaffins are used with catalysts such as alkyl-metal (e.g., triethylaluminum, vanadium, or titanium) salts in the polymerization reactions of alkylene oxides, epichlorohydrin, propylene, butylene, vinyl chloride, and vinyl ethers. The nitroparaffin acts as an activator for the catalyst or can serve as the reaction solvent. 

Last isochormanic system drawn, l,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclo-penta-( )-2-benzopyran, which was developed in the middle 1960 (3) by Beets and Heer-inga from IFF is know also commercially as, e.g., Galaxolide, Abbalide. This molecule is S5mthesized as follows there is a condensation-cyclization stage of tert-smy alcohol and a-methyl styrene in acidic conditions to obtain the indane system, followed by a Friedel-Crafts reaction with propylene oxide to get the side chain. The side chain is finally closed to the isochromanic system using formaldehyde ... 

Hydroperoxidative synthesis 4 (Figure 12.4, middle) accounts for approximately 2.5 x 10 kg of hydroquinone production per year. p-Diisopropylbenzene is synthesized by zeolite-catalyzed Friedel-Crafts reaction of benzene or cumene with propylene or isopropanol. Air oxidation of p-diisopropyl-benzene proceeds at 90-100°C in an aqueous NaOH solution containing organic bases along with cobalt... 

In the reaction of Eq. 14.38, benzene can be functionalized with an alkene, catalyzed by Ir(acac)3. Because Ir-H insertion into the alkene is predominantly anti-Markownikoff, the linear alkyl tends to be obtained, for example, n-Pr not f-Pr from propylene. In the traditional Friedel-Crafts reaction, in contrast, an acid catalyst converts the alkene to a carbonium ion that attacks the arene.This produces branched alkyl substituents, for example, /-Pr not n-Pr from propylene, because carbonium ions are more stable in the order tertiary > secondary > primary. 

Cumene is an important intermediate in the manufacture of phenol and acetone. The feed materials are benzene and propylene. This is a Friedel-Crafts alkylation reaction catalyzed by solid phosphoric acid at 175-225 °C and 400-600 psi. The yield is 97% based on benzene and 92% on propylene. Excess benzene stops the reaction at the monoalkylated stage and prevents the polymerization of propylene. The benzene propylene ratio is 8-10 1. 

Reactions other than those of the nucleophilic reactivity of alkyl sulfates involve reactions with hydrocarbons, thermal degradation, sulfonation, halogenation of the alkyl groups, and reduction of the sulfate groups. Aromatic hydrocarbons, eg, benzene and naphthalene, react with alkyl sulfates when catalyzed by aluminum chloride to give Friedel-Crafts-type alkylation product mixtures (59). Isobutane is readily alkylated by a dipropyl sulfate mixture from the reaction of propylene in propane with sulfuric acid (60). 

In carrying out the alkylation of benzene the propylene tetramer is reacted with an excess of benzene in the presence of a Friedel-Crafts catalyst such as aluminum chloride, boron trifluoride, or hydrofluoric acid. With careful control of this reaction, yields of alkylate boiling from 500° to 650° F. are of the order of 80% of theory with the losses due to slight olefin degradation and dialkylation. Inspection of commercial aromatic products, believed to be typical of this process, indicates the composition to be that shown in... 

Alkylation. Friedel-Crafts alkylation (qv) of benzene with ethylene or propylene to produce ethylbenzene [100-41 -4], CgH10, or isopropylbenzene [98-82-8], C9H12 (cumene) is readily accomplished in the liquid or vapor phase with various catalysts such as BF3 (22), aluminum chloride, or supported polyphosphoric acid. The oldest method of alkylation employs the liquid-phase reaction of benzene with anhydrous aluminum chloride and ethylene (23). Ethylbenzene is produced commercially almost entirely for styrene manufacture. Cumene [98-82-8] is catalytically oxidized to cumene hydroperoxide, which is used to manufacture phenol and acetone. Benzene is also alkylated with C1Q—C20 linear alkenes to produce linear alkyl aromatics. Sulfonation of these compounds produces linear alkane sulfonates (LAS) which are used as biodegradable deteigents. 

Boron Bromide. Approximately 30% of BBr3 produced in the United States is consumed in the manufacture of proprietory pharmaceuticals (qv) (7). BBr3 is used in the manufacture of isotopically enriched crystalline boron, as a Friedel-Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in semiconductor doping and etching. Examples of use of BBr3 as a catalyst include copolymerization of butadiene with olefins (112) polymerization of ethylene and propylene (113), and IV-vinylcarbazole (114) in hydroboration reactions and in tritium labeling of steroids and aryl... 

Friedel-Crafts alkylation of benzo[6]thiophene has received little attention. The published results, which deserve reexamination, indicate that exclusive 3-substitution occurs in some cases, whereas in others, 2-substitution predominates. Benzo[6]thiophene is alkylated with isopropyl chloride, isopropanol, or propene in the presence of various acid catalysts under a variety of reaction conditions to give a mixture of 2- and 3-isopropylbenzo[6]thiophene in which the 2-isomer predominates (78-92%).358 410 In contrast, alkylation with isobutene in the presence of either 80% sulfuric acid415 or 100% phosphoric acid416 is said to afford exclusively 3-/er<-butylbenzo[6]thiophene in yields of 100 and 75%, respectively. In neither case was the structure of the product rigorously confirmed. Likewise, 3-Jeri-amylbenzo [63-thiophene is the exclusive product of alkylation with tert-amyl alcohol in the presence of stannic chloride414 alkylation with pent-l-ene, hex-l-ene, and a Ci8 propylene polymer is also claimed to give... 

The synthetic detergents industry originated in the 1940s, when it was found that a new anionic surfactant type—alkylbenzene sulfonate—had detergent characteristics superior to those of natural soaps. The first surfactant of this kind was sodium dodecylbenzene sulfonate (SDBS). This material was produced by the Friedel-Crafts alkylation reaction of benzene with propylene tetramer (a mixture of Co olefin isomers), followed by sulfonation with oleum or sulfur trioxide and then neutralization, usually with sodium hydroxide. The alkylation was typically performed using homogenous acid catalysts, such as HF or sulfuric acid. 

An interesting but rarely observed reaction is the mro-Friedel-Crafts acylation it has been known for years and studied with fcp as substrates [160]. The a-oxo-propylene bridge of 174 rearranges in the presence of Lewis acids to give 175 and 176 the missing of 177 and 178 in the reaction mixture makes it evident that the Cp-ring-acyl-bond was cleaved exclusively (Fig. 45) [160],... 

The branched alkylbenzenes, produced predominantly between 1950 and 1970, were obtained from propylene tetramer and benzene at temperatures from 20 to 50 °C, with a reaction time of a few minutes, using Friedel-Crafts catalysts (HF or AICI3). To avoid polyalkylation as far as possible, the operation was carried out with a 5 to 10-fold excess of benzene. The yield of dodecylbenzene was 70 to 80%. 

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