Cumene, bromination

Purification of industrial oils, kerosene/jet fuel, lubricating oils Mono- dicumyldiphenylamine Mono- dioctyldiphenylamine Dimer fatty acids Purification of xylenes Improvement of bromine number of recycle cumene in phenol plants Improvement of bromine number of recycle ethylbenzene in styrene plants based on liquid pha.se oxidation Alkylation of xylenes with diisobutylenes to mono-/ rr-butyI derivatives Phenyl xylyl ethane... 

Copper(II) sulfate Cumene hydroperoxide Cyanides Cyclohexanol Cyclohexanone Decaborane-14 Diazomethane 1,1-Dichloroethylene Dimethylformamide Hydroxylamine, magnesium Acids (inorganic or organic) Acids, water or steam, fluorine, magnesium, nitric acid and nitrates, nitrites Oxidants Hydrogen peroxide, nitric acid Dimethyl sulfoxide, ethers, halocarbons Alkali metals, calcium sulfate Air, chlorotrifluoroethylene, ozone, perchloryl fluoride Halocarbons, inorganic and organic nitrates, bromine, chromium(VI) oxide, aluminum trimethyl, phosphorus trioxide... 

The presence of zeolite catalysts increases the amount of gaseous hydrocarbons produced during pyrolysis but decreases the amount of pyrolysis oil. Further, significant quantities of coke were formed on the surface of the catalysts in the course of pyrolysis. The catalysts reduced the yield of e.g., as styrene and cumene, in favor of naphthalene. The zeolite catalysts, especially Y-Zeolite, were found to be very effective in removing volatile organo bromine compounds. However, they were less effective in removing antimony bromide from the highly volatile products of pyrolysis (133). 

The zeolite catalysts are very effective in removing volatile organic bromine. However, they are not very effective in removing antimony bromide from the volatile pyrolysis products. Actually, the zeolites cause a dramatic increase of the formation of hydrogen by a factor of 10. In addition, zeolite catalysts were found to reduce the formation of some valuable pyrolysis products, such as styrene and cumene, but other products, such as naphthalene were formed instead (53). 

When cumene is to be used as a raw material for the production of nylon, the cumene must be very pure with a bromine number of 0.2 or lower. Although liquid phosphoric acid has been used as a catalyst to make cumene, it has the disadvantage in that it is necessary to acid treat the product to reduce the bromine number of the cumene to the 0.2 level. Some cumene is also lost in the acid treating step. Copper pyrophosphate catalyst has also been used but corrosion of the equipment has been experienced, resulting in longer than average downtime. 

Hydrogen bromide enhances the rate of autoxidation of cumene.262 The effect can be explained by the following scheme, in which a bromine atom replaces an alkylperoxy radical in the usual propagation sequence272 ... 

The systems involving bromine atoms also show the fast drop-off as AH deviates from 0, especially marked in the toluene to cumene series, which implies a small value of the intrinsic barrier. There is a further problem that there is a substantial equilibrium isotope effect of about a factor of 26b accompanied in the aliphatic cases by considerable opportunity for reversibility, thus A H/fcD values in the endothermic attack of Br- on aliphatic RH are unlikely to be less than 2. Correspondingly, isotope effects in the reverse directions can be inverse. This has not been observed, but the trend shown in the last several reactions, in which isotope effects as low as 1.0 are observed suggests this possibility. We attach no meaning to (fcH/ D)max for abstraction from HBr because of the failure of the one-dimensional model. Both chlorine and bromine then fit the scheme of highly variable isotope effects associated with low intrinsic barriers. 

Yields 100,000 metric tons (mt) of cumene are produced from 65,000 mt of benzene and 35,300 mt of propylene giving a product yield of over 99.7%. Cumene product is at least 99.95% pure and has a Bromine Index of less than 2, without clay treatment. 

Bronrnatwn. Bromination of cumene (1) with PNBS in boiling carbon tetrachloride (dibenzoyl peroxide) resulted in the three products shown. The results contrast with those obtained with NBS, which leads to (S) and (6), the latter being the main... 

Ten grams of iodine is dissolved in 80 g. (0.67 mole) of cumene, and 107 g. (0.67 mole) of bromine is added dropwise with agitation and ice-bath cooling of the reaction mixture. (Hood.) The mixture is washed with aqueous potassium hydroxide solution and steam-distilled. The organic layer in the distillate is separated, dried over calcium chloride, and distilled to give 110 g. (83%) of p-bromo-cumene boiling at 216-217.5°/760 mm. 

Surprisingly, the Hunsdiecker reaction using the silver salts of exo- and endo-7-chlorobicyclo[4.1.0]heptanecarboxylic acids and bromine at 0°C did not result in the same ratio of products but instead showed a high retention to inversion ratio of 88 12 for the exo acid and 88 12 for the endo acid". This anomalous result may be a reflection of the bromine radical s ability to trap the cyclopropyl radical but this is unlikely. Altman and Baldwin as well as Ando and coworkers found that the reduction of each of the isomers of 7-bromo-7-chlorobicyclo[4.1.0]heptane, 30 and 31, respectively, by the excellent radical scavenger triphenyltin hydride resulted in an identical mixture (21 79) of exo-(32) and en io-7-chlorobicyclo[4.1.0]heptane (33). This ratio of products is, within experimental error, identical with that found in the thermal decomposition of exo- and endo-t-buiy 7-chlorobicyclo[4.1.0]heptane-7-percarboxylate in cumene. 

Determination of phenol by C NMR spectroscopy has the advantage that each determination affords three independent results that can be averaged, allowing rejection of results with too large RSD. The method was applied to the determination of phenol in tars of the cumene process, and were correlated with those of H NMR, UVV spectroscopy and titration with bromine. RSD for single results was 0.8% . ... 

Because new high-acfivify befa zeolife cafalysfs such as QZ-2000 catalyst are such strong acids, they can be used at lower reaction temperatures than SPA catalyst or other relatively lower-activity zeolites such as MCM-22 catalyst. The lower reaction temperature in turn reduces the olefin oligomerization reaction rate, which is relatively high for SPA catalyst. The result is that beta zeolite catalysts tend to have higher selectivity to cumene and lower selectivity to both nonaromatics that distill with cumene (such as olefins, which are analyzed as Bromine Index, and saturates) and heavy by-products. For example, although butyl-benzene is typically produced from traces of butylene... 

COBALT (7440-48-4) An extreme fire hazard. Pyrophoric particles or dust can self-ignite in air. Violent reaction with acetylene, ammonium nitrate, bromine pentafluoride, bromine trifluoride, cumene hydroperoxide, hydrogen peroxide (90%), nitryl fluoride, organic peroxides forms explosive mixture with potassium chlorate. Incompatible with sodium borohydride. Capable of promoting the decomposition of many organic materials. 

Radical bromination of cumene 46 produced the tribromide 47 (85%) 47 is not obtained in the solution phase reaction with NBS.2J2... 

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