Benzene-chlorine

The cumene oxidation route is the lea ding commercial process of synthetic phenol production, accounting for more than 95% of phenol produced in the world. The remainder of synthetic phenol is produced by the toluene oxidation route via benzoic acid. Other processes including benzene via cyclohexane, benzene sulfonation, benzene chlorination, and benzene oxychl orin ation have also been used in the manufacture of phenol. A Hst of U.S. phenol production plants and their estimated capacities in 1994 are shown in Table 2, and worldwide plants and capacities are shown in Table 3. 

Benzene Chlorination. In this process, benzene is chlorinated at 38—60°C in the presence of ferric chloride catalyst. The chlorobenzene is hydrolyzed with caustic soda at 400°C and 2.56 kPa (260 atm) to form sodium phenate. The impure sodium phenate reacts with hydrochloric acid to release the phenol from the sodium salt. The yield of phenol is about 82 mol % to that of the theoretical value based on benzene. Plants employing this technology have been shut down for environmental and economic reasons. 

Hquid and gaseous reactants, Hquid products benzene chlorination, oxidation 0.01-0.2 1-30 100-500 100-500... 

Benzene chlorination reactors are subject to design and operating hazards. Stagnant areas must be avoided in reactor design as they allow chlorination to the tetra- and pentachlorobenzenes. These compounds have low solubiUty in the Hquid and can cause plugging. Another hazard is the... 

Chlorination of benzene is an electrophilic substitution reaction in which CL serves as the electrophile. The reaction occurs in the presence of a Lewis acid catalyst such as FeCls. The products are a mixture of mono- and dichlorobenzenes. The ortho- and the para-dichlorobenzenes are more common than meta-dichlorobenzene. The ratio of the mono-chloro to dichloro products essentially depends on the benzene/chlorine ratio and the residence time. The ratio of the dichloro-isomers (0- to p- to m-dichlorobenzenes) mainly depends on the reaction temperature and residence time ... 

Aromatics, chlorinated hydrocarbons, lower alcohols, ketones, esters Alcohol, benzene, chlorinated hydrocarbons, esters, ether Alcohol, esters, ketones, dioxane... 

A mixture in the vapour phase exploded when exposed to light [1], Benzene-chlorine mixtures, though combustible, represent a low explosion hazard [2],... 

U.S. consumption pattern 1999, 3 619t U.S. producers, 3 610t vapor-phase nitration of, 17 257 vinyl chloride reactions with, 25 632 world production by country, 3 611-612t Benzene-based catalyst technology, 15 500 Benzene-based fixed-bed process technology, 15 505-506 Benzene chlorination process, of phenol manufacture, 18 751 m-Benzenedisulfonic acid, 3 602 p-Benzenedisulfonic acid, 3 602 Benzene feedstock, 23 329 Benzene hexachloride, 3 602 Benzene manufacture, toluene in, 25 180-181... 

Richter. J.E., Peterson. S.F., and Kleiner. C.F. Acute and chronic toxicity of some chlorinated benzenes, chlorinated ethanes, and tetrachloroethylene to Daphnia magna. Arch. Environ. Contam. Toxicol, 12(6) 679-684,1983. 

Reactor-Separator-Recycle System—Benzene Chlorination. Here the elementary reactions are... 

Let us make some general comments on this type of LFER. First, reasonable correlations are found for sets of compounds that undergo primarily London dispersive interactions (Fig. 9.11 alkylated and chlorinated benzenes, chlorinated biphenyls). Good correlations are also found for sets of compounds in which polar interactions change proportionally with size (PAHs) or remain approximately... 

Perhaps the best-known photoaddition reaction of benzene is that with chlorine to produce hexachlorocyclohexane (3.37). of which one steroisomer is widely used as an active component in insecticides. However, this reaction does not involve the excited state of benzene chlorine absorbs light and cleaves homolytically to give chlorine atoms, which then attack the ground state of benzene, leading to overall addition. 

Pibouleau et al. (1988) provided a more flexible representation for the synthesis problem by replacing the single reactor unit by a cascade of CSTRs. They also introduced parameters for defining the recovery rates of intermediate components into the distillate, the split fractions of top and bottom components that are recycled toward the reactor sequence, as well as parameters for the split fractions of the reactor outlet streams. A benzene chlorination process was studied as an example problem for this synthesis approach. In this example, the number of CSTRs in the cascade was treated as a parameter that ranged from one up to a maximum of four reactors. By repeatedly solving the synthesis problem, an optimum number of CSTRs was determined. 

The 3Pi/2 i/2(m) Crystal Structure of the Addition Compound Benzene-Chlorine... 

Free cyanides Aromatic halogenated solvents (monochlorinated benzene chlorinated phenols)... 

Chlorination of Benzene Chlorination of benzene works much like bromination, except that aluminum chloride (A1C13) is most often used as the Lewis acid catalyst. 

Basic data and assumptions for reactor-design example dealing with optimization of yields for benzene chlorinator... 

Benzyl chloride C4H3CH2CI, chlorodiphenyls and derivatives C,2H,o-XC1X, chlorinated benzenes, chlorinated naphthalenes CioHj-xCl... 

According to Tsao et al. [62], three possible structures of benzene-chlorine complex were obtained (Figure 13.1). The first one is high symmetric C(,v) hexahapto-complex with chlorine atom over the centre of the benzene ring (Figure 13.1a), which was firstly proposed by Russel [63]. The second and third structures had Cs symmetry the chlorine atom was located over the carbon-hydrogen bond... 

FIGURE 13.1 Structures of benzene-chlorine complexes, (A) C v symmetric complex, (B) p-complex, (C) s-complex. 

FIGURE 13.2 Potential energy surface scan at (A) BPE0/6-3H-G and (B) MP2/6-3H-G levels of theory of benzene-chlorine system in plane perpendicular to the benzene ring passing through opposite carbons atoms of benzene. 

TABLE 13.1 Relative energy, enthalpy and free energy (kcal/mol), and equilibrium constants (cmVnnolecule) of benzene-chlorine complexes, transition state and products of benzene-chlorine reaction... 

Among the numerous polyhalogeno derivatives, we chose 1,2,4- and 1,2,3-trichlorobenzenes. Indeed several nucleophilic substitutions had already been studied with the first compound and results published44 did not give a good explanation of its reactivity. In fact, basic systems used by the authors chiefly lead to trisubstitutions and hardly give a good idea of the successive products formed. Moreover both trichlorobenzenes are side products of industrial benzene chlorination and are easily obtained in mixture. 

An alternate synthesis was developed by E. Smissman and G. Hite2, using a modified Favorski rearrangement. Iso-nicotinic acid was methylated, reduced to 1-methyl-U-piperi-dinecarboxylic acid hydrochloride, and converted to the acid chloride hydrochloride. This was then condensed with benzene, chlorinated, treated with alkali, esterfied, and converted to the hydrochloride (See Figure 8). 

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