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US 5,294,741 AGranted
Continuous process for the preparation of sulfonylisocyanates
AssigneeHoechst Aktiengesellschaft
InventorsGunter Schlegel, Stephen Lachhein, Harald Berger
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Abstract
The invention relates to an improved process for the preparation of a compound of the formula R.sup.1 -X-SO.sub.2 -NCO in which X is O or NR.sup.2, R.sup.1 is alkylsulfonyl or phenyl which is optionally substituted by Hal, alkyl and/or alkoxy, and R.sup.2 is alkyl, by reacting R.sup.1 XH with ClSO.sub.2 NCO to give the compound R.sup.1 XCONHSO.sub.2 Cl followed by a rearrangement reaction, which comprises carrying out the process continuously in the presence or absence of an inert solvent.
Claims20
A process for the preparation of a compound of the formula I
- R.sup.1 --X--SO.sub.2 --N=C=O (I)
- in which
- X is O or NR.sup.2,
- R.sup.1 is (C.sub.1 -C.sub.4) alkylsulfonyl or phenyl which is unsubstituted or monosubstituted or polysubstituted by radicals selected from the group consisting of halogen, (C.sub.1 -C.sub.4) alkyl and (C.sub.1 -C.sub.4)-alkoxy, and
- R.sup.2 is (C.sub.1 -C.sub.4) alkyl,
- by reacting a compound of the formula II
- R.sup.1 --X--H (II)
- in which X and R.sup.1 have the meanings given in formula I, with the chlorosulfonyl isocyanate of the formula III
- Cl--SO.sub.2 --N=C=O (III)
- to give a compound of the formula IV
- R.sup.1 --X--CO--NH--SO.sub.2 --Cl (IV)
- in which R.sup.1 and X have the meaning given in formula I, and the subsequent rearrangement of the compound of the formula IV to give the compound of the formula I, which comprises carrying out the process continuously, wherein the temperature during said rearrangement is from 90.degree. C. to 165.degree. C. and the reactor residence time during said rearrangement is from 30 to 90 minutes, without a solvent or in the presence of an inert organic solvent.
9 more elements
Dependencies are inferred from the claim text.