Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1996-10-25
1998-11-03
Shippen, Michael L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568715, 568834, 568852, 568904, 968905, C07C 3508
Patent
active
058311343
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention concerns a new process for the production of tertiary alcohols by radical addition of secondary alcohols to carbon-carbon double bond systems.
The addition of secondary alcohols to alkenes with formation of tertiary alcohols is in principle known in the art.
U.S. Pat. No. 3,352,929 describes the production of condensation products from isopropanol and acetylene compounds. This process can be carried out in two steps, the first step comprising reaction of an acetylene compound with isopropanol to form an alkenol and the second step comprising the addition of a further isopropanol with formation of a saturated tertiary (multivalent) alcohol. This reaction can be carried out in the presence of organic peroxides as a catalyst. According to U.S. Pat No. 3,352,929 (column 5, lines 43-51) only a short reaction period of e.g. 5 minutes is necessary for the first step of the reaction i.e. the addition of a secondary alcohol to a carbon-carbon triple bond whereas a considerably longer reaction period of about two to five hours is required for the second step i.e. the addition of a further molecule of isopropanol to the addition product of the first reaction step having a carbon-carbon double bond.
In addition it is known from "Methoden der organischen Chemie" (Houben-Weyl), Vol. VI/1b, Georg Thieme Verlag Stuttgart, N.Y., 1984, page 654 ff) that tertiary alcohols can be obtained by addition of alcohols (e.g. secondary alcohols such as isopropanol, isobutanol) to alkenes. The reaction is carried out by heating the olefin in excess alcohol (in a molar ratio of olefin to alcohol of 1:10-50) with addition of a dialkyl peroxide as an initiator (10 to 20 mole percent with respect to the olefin) to 110.degree. to 135.degree. C. for a time period of 35 to 40 hours. In this literature reference it is described that higher alcohols are mainly obtained by telomerization while the monomeric addition product is formed only in a relatively low yield.
Thus a serious disadvantage of the reactions described above is that considerable amounts of telomeric or polymeric by-products are formed in the reaction mixture due to the long contact period of the reactants of several hours. A further disadvantage of the processes of the state of the art is the low/space time yield of monomeric addition products due to the long reaction period.
Therefore the object of the present invention was to provide a process for the production of tertiary alcohols by addition of secondary alcohols to alkenes in which the above-mentioned disadvantages can be completely or at least substantially avoided.
The object according to the invention is achieved by a process for the production of tertiary alcohols by radical addition of secondary alcohols to alkenes which is characterized in that the reaction is carried out as a continuous process in the presence of an organic peroxide as a radical initiator and with an average contact time of the reaction mixture of up to a maximum of 1 hour.
It was surprisingly found that by carrying out the reaction continuously according to the present invention a monomeric addition product is obtained in a high space/time yield and with a low amount of polymeric or/and telomeric by-products even with a contact time of the reaction mixture of up to a maximum of 1 hour, preferably up to a maximum of 30 minutes, particularly preferably up to a maximum of 20 minutes.
The production of tertiary alcohols by a radical addition reaction of secondary alcohols to carbon-carbon double bond systems takes place according to the following reaction scheme: ##STR1## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 denote hydrogen or alkyl or aryl residues which are substituted if desired and R.sub.5 and R.sub.6 denote alkyl or aryl residues which are substituted if desired.
The process according to the invention has a broad range of applications since it can be carried out advantageously with a large number of different alkenes and secondary alcohols. Compounds with 2 to 20 C atoms, particularly preferably 4 to 1
REFERENCES:
Webster's II New Riverside University Dictionary, 1994.
Eckert Maria
Gnann Michael
Rieth, deceased Robert
Rieth, heir Emma Marianne Christine
Rieth, heir Werner Eberhard Wilhelm
Peroxid-Chemie GmbH
Shippen Michael L.
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