Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Utility Patent
1999-05-06
2001-01-02
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S375000, C422S129000, C201S029000, C203S088000, C203S091000
Utility Patent
active
06169211
ABSTRACT:
This invention relates to a novel process and apparatus for the production of a 5-cyclohexadecen-1-one, and, particularly to a process and apparatus for producing a 5-cyclohexadecen-1-one from 1,2-divinylcyclododecanol by an oxy-cope reaction.
BACKGROUND OF THE INVENTION
5-Cyclohexadecen-1-one has a relatively strong musk fragrance and is well-known as a compound useful for a starting material of perfumes. This 5-cyclohexadecen-1-one is generally produced according to the following chemical reaction:
wherein X represents a halogen atom.
First, cyclododecanone (1) is halogenated to synthesize 2-halogenocyclododecanone (2). The resulting 2-halogenocyclododecanone (2) is reacted with vinyl magnesium Grignard to produce 1,2-divinylcyclododecanol (3), which is then converted into 5-cyclohexadecen-1-one (4) by an oxy-cope reaction, followed by refining to obtain the objective 5-cyclohexadecen-1-one.
1,2-divinylcyclododecanol (3) embracesacis-isomerand a trans-isomer. The trans-isomer is quantitatively converted into 5-cyclohexadecen-1-one whereas the cis-isomer is accompanied by a side reaction and hence is not quantitatively converted into 5-cyclohexadecen-1-one. The reaction rate of the trans-isomer is larger than that of the cis-isomer. Accordingly, the theoretical yield in the early stage of the reaction of the trans-isomer is almost 100%. However, the theoretical yield decreases with the progress of the reaction.
In the reaction of 2-halogenocyclododecanone (2) with vinyl magnesium Grignard, 2-vinylcyclododecanone (5) is produced together with 1,2-divinylcyclododecanol (3). Since 1,2-divinylcyclododecanol (3) is produced through 2-vinylcyclododecanone (5), the by-production can be restrained with difficulty. If the 2-vinylcyclododecanone (5) is reacted again with the vinyl magnesium Grignard's reagent, it is easily converted into the objective 1,2-divinylcyclododecanol (3). The 2-vinylcyclododecanone (5) is however highly reactive so that it is easily resinified or isomerized into unacceptable ethylidene ketone.
Conventionally, the oxy-cope reaction such as described is usually carried out by heating the reaction raw material as it is or after it is dissolved in a solvent (for instance, Tetrahedron Letters No. 7, pp. 509-512, 1970). Accordingly, when 5-cyclohexadecen-1-one (4) is produced from 1,2-divinylcyclododecanol (3), a similar oxy-cope method is conventionally used. For instance, Japanese Patent Publication (JP-B) No. S52-42787 discloses a method in which 1,2-divinylcyclododecanol is heated either using no solvent or in an appropriate solvent at a temperature of 180-250° C. in a flowing inert gas for about 3 hours to produce 5-cyclohexadecen-1-one. JP-B No. S55-34781 reveals a method in which refined or unrefined 1,2-divinylcyclododecanol in a liquid state is heated either as it is or after it is dissolved in a solvent to produce 5-cyclohexadecen-1-one. JP-B No. S52-39025 reports a method in which 1,2-divinylcyclododecanol is heated in the presence of N,N-disubstituted carboxylic acid amides, N-substituted lactams or sulfoxides to produce 5-cyclohexadecen-1-one. JP-B No. S58-13528 suggests a method in which 1,2-divinylcyclododecanol is heated in the presence of a specific phosphorus compound to produce 5-cyclohexadecen-1-one.
These known manufacturing methods give the objective 5-cyclohexadecen-1-one in high yields. However, heat treatment at 150-350° C. for several hours is required to sufficiently complete the reaction. This reaction time is ratherlong. Also, since the reaction is a batch-type reaction, the production efficiency is poor. When a solvent is used, the cost increases. In addition, the solvent must be removed after the reaction is completed and it is necessary to recover the objective product by distillation under reduced pressure. In conventionally known methods, negative side reactions are also caused. For instance, when the oxy-cope reaction is made using unrefined 1,2-divinylcyclododecanol as a starting material, 2-vinylcyclododecanone which was contained in the starting material as an impurity is isomerized into ethylidene ketone by heat treatment.
SUMMARY OF THE INVENTION
Objects of the present invention are to provide a process for producing a 5-cyclohexadecen-1-one and an apparatus used for the process. The process is characterized in that it has no problems such as those involved in the conventional processes for the production of 5-cyclohexadecen-1-one, can produce 5-cyclohexadecen-1-one in a short reaction time in a high yield, can improve the production efficiency by simplifying the production process and making the process steps continuous and gives rise to no reactions other than the oxy-cope reaction when 1,2-divinylcyclododecanol is converted into 5-cyclohexadecen-1-one.
The inventors of the present invention have made earnest studies to attain the above objects and, as a result, found that the prior art problems can be solved by heating 1,2-divinylcyclododecanol in the vapor phase at high temperatures under reduced pressure to complete the invention.
According to a first embodiment of the present invention, there is provided a process for producing a 5-cyclohexadecen-1-one comprising heating 1,2-divinylcyclododecanol in the vapor phase at 400 to 650° C. under reduced pressure.
According to a second embodiment of the present invention, there is provided a process for producing a 5-cyclohexadecen-1-one comprising heating a liquid raw material containing 1,2-divinylcyclododecanol at a temperature less than 400 ° C. under reduced pressure to gasify at least 1,2-divinylcyclododecanol in advance, introducing the gas into a reaction zone kept at 400 to 650° C. under reduced pressure and cooling the reacted gas flowing out of the reaction zone once the reaction is completed.
According to a third embodiment of the present invention, in comparison with the above first and second embodiments, the pressure is set to be lower than the saturated vapor pressure of 1,2-divinylcyclododecanol, for instance, equal to or lower than 5 mm Hg.
According to a fourth embodiment of the present invention, in contrast with the above second and third embodiments, the gas exiting from the reaction zone is first rectified, then cooled to recover 5-cyclohexadecen-1-one.
According to a fifth embodiment of the present invention, in comparison with the above second to fourth embodiments, 2-vinylcyclododecanone is recovered from the gas exiting from the reaction zone or from crude 5-cyclohexadecen-1-one obtained by cooling the reaction gas, and the recovered 2-vinylcyclododecanone is recycled as the starting material for synthesizing 1,2-divinylcyclododecanol.
According to a sixth embodiment of the present invention, in comparison with the above first to fifth embodiments, a hydrogen halide trapping means is provided between pumping means for reducing the pressure at least in the reaction zone, and the reaction zone, the hydrogen halide trapping means being cooled and containing an alkali metal alcoholate or an alkali metal hydroxide, and the pressure in the reaction zone is reduced through the hydrogen halide trapping means.
According to a seventh embodiment of the present invention, there is provided an apparatus used for producing 5-cyclohexadecen-1-one comprising flashing means for vaporizing a raw material containing at least 1,2-divinylcyclododecanol, reaction means for converting 1,2-divinylcyclododecanol, which is in the vapor phase heated to 400 to 650° C., into 5-cyclohexadecen-1-one, recovery means for recovering the produced 5-cyclohexadecen-1-one and pumping means for reducing the pressures in the flashing means, in the reaction means and in the recovery means.
According to an eighth embodiment of the present invention, in comparison with the above seventh embodiment, the reaction means is filled with a filler.
According to a ninth embodiment of the present invention, differing from the above seventh and eighth embodiments, the apparatus further comprises hydrogen halide trapping means containing an alkali metal alcoholate or an alkali metal hydroxide.
R
Amano Akira
Itakura Keisuke
Yagi Misao
Yamamoto Ken-ichi
Kubovcik & Kubovcik
Padmanabhan Sreeni
Takasago International Corporation
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