Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1983-11-07
1985-05-07
Lone, Werren B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568807, C07C 3334
Patent
active
045159904
DESCRIPTION:
BRIEF SUMMARY
It is well known to react an aromatic compound with a Friedel Craft reactant in the presence of a Friedel Craft catalyst. The reaction mixture is often heterogeneous, for instance as a result of using aluminium chloride as the complexing agent. The reaction is often exothermic. This is acceptable in many instances but in some instances the reaction is so exothermic and so fast that serious problems can arise. These are accentuated by having a heterogeneous reaction mixture since the solids in the mixture inhibit rapid heat transfer out of the mixture. It is sometimes necessary not only to keep the bulk temperature of the reaction mixture (i.e. the temperature recorded by inserting a thermometer at random locations in the reaction mixture) within controlled limits but it is also necessary to prevent local over heating, on a microscale.
These problems are particularly serious when an indane or tetralin of formula I ##STR1## is reacted with an alkylene oxide to form an aryl alcohol of formula II ##STR2##
In these formulae R.sup.1 to R.sup.6 may be the same or different and are selected from hydrogen and alkyl groups having 1 to 4 carbon atoms, n is 1 or 2 and R.sup.7 is hydrogen or methyl when the alkylene oxide is ethylene oxide or propylene oxide respectively.
The compounds of formula II are useful perfumery ingredients and they are also useful as intermediates for the production of isochromans, which also are useful perfumery ingredients. For instance a compound of formula II can be reacted with formaldehyde to form an isochroman of formula III ##STR3##
FIGS. 1, 2 and 3 shows formulae for compounds employed in the process of the invention.
The synthesis of a compound of formula II from a compound of formula I is exemplified in U.S. Pat. No. 3,360,530. The reaction is conducted in the presence of excess indane and in the presence of aluminium chloride and using propylene oxide. The reaction is highly sensitive to temperature and it is necessary to ensure that the reaction mixture does not rise above about 20.degree. C. and that local over heating does not occur. Otherwise significant quantities of by-products may occur. However the reaction mixture tends to be viscous and the reaction is very fast and highly exothermic. Accordingly there is a great tendency for the reaction mixture to become too hot and for local over heating to occur.
In U.S. Pat. No. 3,532,719 it is proposed to conduct the reaction in the presence of a halogenated aromatic hydrocarbon solvent, monochlorobenzene, bromobenzene and o-dichlorobenzene being specifically proposed. The alkylene oxide is added slowly to the reaction mixture at a rate that permits adequate cooling, with addition times of 2 to 16 hours being proposed.
In European Patent Publication No. 4914 it is proposed to conduct the reaction in the presence of an alkane having from 5 to 10 carbon atoms, the preferred alkanes being isooctane, n-hexane and n-octane. The alkylene oxide is added with indane to a cold stirred slurry of aluminium chloride in the solvent over a period that, in the examples, is always 2.5 hours or longer.
In laboratory scale operation it is possible, by careful selection of reaction conditions, to operate such processes to give satisfactory yields of the compounds of formula II and low by-product formation. It is necessary to provide good cooling and stirring, but this is possible with small scale apparatus. It is also necessary to perform the reaction at a predetermined rate, such that the cooling that is provided can dissipate the exotherm. In practice the reaction is generally conducted by continuously adding alkylene oxide to the reaction mixture with the result that the amount of heat depends upon the rate of introduction of the alkylene oxide. Accordingly its rate of introduction has to be controlled very accurately having regard to the degree of cooling that is available.
Although satisfactory operation is possible on a laboratory scale it is not possible using simple apparatus on an industrial scale. This is because the size of an industrial re
REFERENCES:
patent: 3856875 (1974-12-01), Wood
patent: 4250200 (1981-02-01), Wieger et al.
Ferber John G.
Goddard Peter J.
Holden Robert S.
Bush Boake Allen Limited
Lone Werren B.
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