177. The kinetics of the sulphonation of some aromatic compounds by sulphur trioxide

Dresel, E. M.; Hinshelwood, Cyril Norman

doi:10.1039/jr9440000649

Cited by 17 publications

(6 citation statements)

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“…A series of aromatic compounds reacted with S03 in nitrobenzene solution (152,521,524), yielding the kinetic data summarized in Table XVII for the initial stage of the reaction. Some degree of correlation is noted for the three functions given for each compound, except for the dipole moment function in the case of nitroanisole.…”

Section: Kinetics and Mechanismmentioning

confidence: 99%

“…As the S03 content of the oleum is increased, the order with respect to S03 steadily increases, approaching 2 for pure S03 as shown above. This has led to the suggestion (152,329,521,524) that dimeric S03 (S2O6) may be the effective species. However, the kinetic data can also correspond to successive reaction with two moles of monomeric S03-one attacking the ring, the other then protonating the incipient sulfonate group and also functioning as a base for removal of the proton, forming a pyrosulfonate step I: C6H6 + S03…”

Section: Kinetics and Mechanismmentioning

confidence: 99%

See 1 more Smart Citation

The Reactions of Sulfur Trioxide, and Its Adducts, with Organic Compounds.

Gilbert¹

1962

Chem. Rev.

173

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Section: Kinetics and Mechanismmentioning

confidence: 99%

Section: Kinetics and Mechanismmentioning

confidence: 99%

The Reactions of Sulfur Trioxide, and Its Adducts, with Organic Compounds.

Gilbert¹

1962

Chem. Rev.

173

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“…200 g) for a good liquid-gas reaction interface. Solvents typically used in laboratory-scale sulfonation reactions, such as nitrobenzene (7,8) or nitromethane (9), act as Lewis bases that form complexes with SO 3 . The use of these solvents was undesirable because the sulfonating species would no longer be representative of those encountered in plant-scale sulfonation.…”

Section: Resultsmentioning

confidence: 99%

“…However, if the differences in reactivities among the alkylbenzenes are not large, the distribution of sulfonic acids will not vary much over the course of the reaction, and, as a simplifying approximation, this factor can be treated as constant. With this approximation made, the above rate equations can be combined and integrated to give the normal relative rate expressions: [8] However, each k rel value is the ratio of two composite rate constants, each made up of a number of terms equal to the number of alkylbenzenes competing in the sulfonation reaction. For four alkylbenzenes A, B, C, and D:…”

Section: Resultsmentioning

confidence: 99%

Relative rates of sulfonation of linear and branched long‐chain alkylbenzenes

Ward

Diaper

Roberts

2001

J Surfact & Detergents

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Relative rates of sulfonation of a series of 1-phenylalkanes and isomeric branched-chain alkylbenzenes by gaseous SO 3 have been determined. It has been shown that the composition of the mixture undergoing sulfonation has an important bearing on the actual relative rate constant (k rel ) values obtained. This is taken as evidence for the involvement of pyrosulfonic acids as the actual sulfonating species involved in the sulfonation reaction. Consistent k rel values have been obtained by using an "active solvent" in 10-fold excess as the sulfonating medium. Whereas the branched-chain isomers show very little variation in their rates of sulfonation, the rates of sulfonation of the 1-phenylalkanes increase as the length of the alkyl chain decreases.The commonly accepted mechanism for aromatic sulfonation involves addition of SO 3 to form a zwitterionic Wheland intermediate 1, as illustrated in Scheme 1 for toluene sulfonation. Recent ab initio calculations carried out in these laboratories for toluene sulfonation (1) estimate the enthalpy of the Wheland intermediate to be ca. 20 kcal mol −1 higher than the combined enthalpies of toluene and SO 3 . It follows that for this mechanism the activation energy must be at least 20 kcal mol −1 . However, this activation energy is inconsistent with the fact that in commercial sulfonation of alkylbenzenes the reaction proceeds to ≥90% conversion in a falling film reactor with a residence time of ca. 30 s and an average temperature well below 100°C (2).An alternative reaction pathway involves formation of a 2:1 SO 3 /substrate π-complex (2), which can then undergo rearrangement to a "pyrosulfonic acid Wheland intermediate" 2, stabilized by intramolecular hydrogen bonding (Scheme 2). The activation energy in this case should be much lower than for the pathway via 1 since it avoids the high-energy Wheland intermediate 1. However, the pathway via the 2:1 π-complex is kinetically third-order and, by analogy with other known third-order reactions (3), it is expected to have a very low preexponential factor. Consequently, although this reaction pathway is plausible as an initiation or "priming" process, it is not consistent with the high reaction rate observed in commercial sulfonation.A third possibility (2) is that, following "priming" by a pathway such as that shown in Scheme 2, the reaction proceeds via the pyrosulfonic acid as a continually regenerated sulfonating agent (Scheme 3). The computed enthalpy changes (1) for the steps in this pathway are consistent with a rapid reaction, with k 2 being the most likely rate-determining step.These different reaction pathways have different implications regarding the relative reactivities of alkylbenzenes in sulfonation.In an earlier paper, we reported an investigation of the relative rates of sulfonation of a series of linear alkylbenzenes, involving competition reactions carried out on a multicomponent commercial mixture (4). In the commercial

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“…To solve these problems it is necessary to know more about the rate of reaction and its mechanisms. However, there has been found to date no report dealing with these topics on those industrially used starting materials with 14 to 19 carbon atoms, except the work by Hinshelwood et al 6) on aromatic compounds in homogeneous liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Rate of Sulfonation of Alpha-Olef1n by Gaseous So3 Using Pulse Method

Miyauchi

Kikuchi

Ogoshi

et al. 1971

J. Chem. Eng. Japan

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The rate coefficient of reaction between liquid Ci8 alpha-olefin and gaseous SO3 dissolved in it is measured by using a pulse method, developed first to measure the film coefficient of mass-transfer in packed beds. To interpret the rate data obtained from the pulse reactor, a criterion is developed based on the penetration theory to approximate the behavior of a rapid second-order irreversible reaction by that of a pseudo first-order reaction. Experimental procedures and the underlying concept of getting rate coefficient by the pulse method are given to apply it to gaseous SO3 absorption by liquid alpha-olefins. The second-order rate coefficient k2 of the reaction for liquid Ci8 alpha-olefin and SO3dissolvedin itisfoundtobe: k2 = 7.7X109exp(-6.2X103/KT)

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177. The kinetics of the sulphonation of some aromatic compounds by sulphur trioxide

Cited by 17 publications

References 0 publications

The Reactions of Sulfur Trioxide, and Its Adducts, with Organic Compounds.

The Reactions of Sulfur Trioxide, and Its Adducts, with Organic Compounds.

Relative rates of sulfonation of linear and branched long‐chain alkylbenzenes

Rate of Sulfonation of Alpha-Olef1n by Gaseous So3 Using Pulse Method

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