JPH0365399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the aromatic properties of macrocyclic compounds obtained by thermal depolymerization.

Macrocyclic compounds that have an odor similar to natural turmeric and methods for producing them are known. The most commonly used method, and currently considered the only industrial process, is the depolymerization of linear polyesters with formation of macrocycles by ring closure.

U.S. Pat. No. 2,092,031 discloses a process for making cyclic esters with more than 7 atoms in the ring by depolymerizing the corresponding polyester by heating the linear polyester under vacuum in the presence of a metal catalyst. are doing. A similar method is also described in British Patent No.
No. 108,720, U.S. Patent No. 3,431,279, Check Patent No. 108,762, and EW Spanagel et al., J. Am. Chem. Soc., 57, 929-934 (1935).

Although this method of thermal depolymerization is extremely convenient, there are problems associated with its use. The main problem is the formation of a highly viscous reactant, which makes it difficult to conduct heat into the body. Batch operation with relatively small charge units or even continuous or quasi-continuous operation with effective agitation as described in U.S. Pat. No. 4,165,321 requires some thermal Polymerization occurs. Thermal decomposition products not only cause the discoloration but also impart a characteristic "amber" odor. The properties of this malodorous substance are unknown, but even trace amounts of it in the final product, which cannot be easily detected with sophisticated equipment or analysis, are a nuisance to perfumers. The malodorous components are not completely removed by distillation, and treatment with charcoal, activated carbon, or viscosity improves the color of the product considerably, but does not completely remove the odors.

It would be highly desirable to have a method for removing this malodorous component that mars or overshadows the pleasant odor of macrocyclic aromatic compounds. This method can be applied to industrial operations and improves the odor as well as the color of the final product.
It would be even more convenient if other benefits were available, such as improved thermal stability.

It has now been unexpectedly discovered that malodorous components, such as those resulting from the thermal depolymerization of polyesters, can be easily, effectively and economically removed by treating macrocyclic aromatic products with ozonation and hydrogen peroxide. be. Ozone treatment can be conveniently carried out during any step in the production of macrocyclic compounds after depolymerization and cyclization. This process brings the macrocyclic product containing the malodorous substance into intimate contact with ozone in the liquid or fluid state, most conveniently at temperatures between 40 and 90°C. Although as little as 0.001 mole ozone per pound of product being treated can be used, at least 0.01 mole ozone per pound is commonly used.

In the present invention, ozone treatment is performed in conjunction with hydrogen peroxide treatment. These treatments can be carried out simultaneously or are usually carried out separately from the macrocyclic aromatic compound treatment. If the separate operation includes peroxide treatment, it may be treated before or after contact with ozone. In the peroxide treatment, an aqueous solution generally containing 15 to 50% hydrogen peroxide is brought into intimate contact with the macrocycle at a temperature of about 25 to about 105°C. Generally, about 0.001 to 1 mole of hydrogen peroxide is used per pound of product processed.

In a preferred embodiment of the invention, the coarse cyclic product is contacted with ozone and distilled under reduced pressure, and the distillate is treated with aqueous hydrogen peroxide to remove volatile components.

The method of the invention is the ozone/peroxide treatment of macrocycles such as those obtained by depolymerization of polyesters. This depolymerization and cyclization process is known in the art and is not part of this invention, and is generally carried out at reduced pressure and elevated temperature in the presence of a metal catalyst. Representative methods of this type are described, for example, in US Pat. No. 2,092,031 and US Pat. No. 4,165,321. This depolymerization with cyclization is 50mmHg
200 to 400℃ at a pressure below, preferably
It is commonly carried out at temperatures ranging from 250 to 350°C. Magnesium, titanium, manganese, iron, aluminum, cobalt, tin and lead oxides, hydroxides,
Metal catalysts such as halides and carboxylates are commonly used. The particular depolymerization method used to obtain the macrocycles is not critical, as the nature of the reaction results in even the most effective processes producing somewhat objectionable, malodorous pyrolysis products, and the resulting products are suitable for use in the present invention. can benefit from ozone treatment.
However, some products require and benefit from the process of the present invention more than others due to their thermal history and other operating conditions during depolymerization and macrocycle formation.

A variety of macrocyclic compounds, including cyclic esters, cyclic ether-esters, lactones and ether-lactones, can be obtained by thermal depolymerization of the corresponding linear polyesters and can be conveniently prepared by the method of the present invention. It is processed. This macrocycle can have 8 to 20 atoms in the ring, but
Compounds with an 11- to 18-membered ring structure have a very pleasant odor, and are useful as aromatic essential chemicals in perfumes, perfume oils, perfume fixers, colognes, after-shave lotions, etc. It has a ring structure. The presence of malodorous components along with macrocyclic aromatic compounds in these and other related applications such as health care product manufacturing, including bath oils, shampoos, hair conditioners, deodorants, shaving creams, bar soaps and specialty beauty soaps, etc. I don't like what I do and I can't stand it.

More specifically, the macrocycles treated according to the present invention have the general formula: (In the formula, R' is a divalent hydrocarbon group having 1 to 15 carbon atoms, which may be linear or branched, and may be saturated or unsaturated, and R ₁ is a divalent hydrocarbon group having 1 to 15 carbon atoms.
17, _R2 is a saturated divalent hydrocarbon group having 1 to 8 carbon atoms, and x is an integer from 0 to 4) and (wherein R'' is a branched or straight chain, saturated or unsaturated divalent hydrocarbon group having 1 to 18 carbon atoms, and R ₁ and x are as defined above)
corresponds to Macrocyclic compounds corresponding to the above formula, which have particularly favorable aromas, and for which ozone/peroxide treatment is particularly advantageous, have R′ and R″ of the formula (—CR ₃ R ₄ )— _y (y
is an integer from 4 to 15, and R ₃ and R ₄ are hydrogen or C _1-4 alkyl groups), and R ₁ and R ₂ are saturated hydrocarbons having 2 to 6 carbon atoms. group, especially the group -CH ₂ CH ₂ -.

Examples of macrocyclic compounds of the above type obtained by thermal depolymerization include tetradecamethylene carbonate,
Dodecamethylene oxalate, 7-oxa-tridecamethylene oxalate, 3,6,9-tridecamethylene malonate, dodecamethylene malonate, decamethylene malonate, ethylene suberate, ethylene azelate, 3-oxy -Pentamethylene azelate, 3-methylpentamethylene sebacate, ethylene undecanedioate, ethylene dodecanedioate, methylene decanedioate, methylene brasilate, ethyridine brasileate, ethylene brasileate, ethylene-α-
Methylbrasillate, ethylene-α,α-dimethylbrasileate, ethylene-α,α-ethylbrasileate, pentadecanolide, 2-oxa-pentadecanolide, hexadecanolide, 3-oxa-hexadecano 10-oxa-hexadecanolide, 11-oxa-hexadecanolide, and 12-oxa-hexadecanolide.

The method of the present invention for the removal of malodor components that offend macrocyclic aroma compounds involves treating macrocycles of the type described above with ozone itself or with hydrogen peroxide. Close contact with ozone is necessary to achieve the desired result, so that the material to be treated is kept in liquid form and the ozone is dispersed in this liquid medium in such a way as to allow effective contact between the liquid and gas phases. I am made to do so.

The amount of ozone used for malodorant removal will vary depending on the conditions, the nature of the product being treated and whether the product is also treated with peroxide.
However, generally at least 0.001 mole of ozone is used per pound of product processed. Usually the amount of ozone is 0.01 moles per pound or more. Although up to 10 moles per pound or more of ozone may be used, practical economic considerations dictate that the lowest amount of ozone necessary for effective removal of malodor components be used. The amount of ozone in the practice of this invention generally does not exceed 5 moles per pound, most commonly in the range of 0.05 to 1 mole ozone per pound of product being treated.

Any conventional ozone generation method can be applied to this method, and ozone can be obtained from pure oxygen, air or other oxygen-rich gases. The ozone concentration in the gas stream is approximately 0.1
may vary from up to about 10% by weight. Oxygen, carbon dioxide, and inert gases such as helium and argon can be conveniently utilized with ozone in this manner.
The carrier gas must be of such type and quality that it does not impart any odor to the resulting processed macrocyclic product. It is generally considered convenient to generate ozone from pure oxygen, such as from a liquid oxygen source.

As previously mentioned, in order to bring ozone into intimate and effective contact with the macrocyclic product being treated, the product is kept in a liquid or fluid state. If the substance is solid or semi-solid, whether in its crude state or after one or more purification operations, it should be heated to a temperature above its solidification point before contacting with the ozone-containing gas. do. Even if heating is required, the temperature is generally around 120℃
not exceed. Even if the product to be treated is liquid at room temperature, the ozone treatment is preferably carried out at a temperature of 40 to 90°C. Although not required, a diluent (primarily a hydrocarbon) may be included in the process contact with ozone. Suitable diluents are those which are not attacked by ozone or which do not interfere with the operation or impart an odor to the resulting treatment product.

As will be apparent to those skilled in the art, considerable variation is possible in the operation and amount of ozone necessary to remove malodorous components and obtain other improvements in the final macrocyclic product. For example, the crude product obtained directly from depolymerization can be used according to the invention and treated with ozone. This crude product may be solid or semi-solid and generally contains large amounts of unwanted by-products that impart undesirable colors and odors and therefore require substantial ozonation to yield a desirable product.
However, if the crude material is subjected to distillation, separation or treatment with suitable solvents or extractants to remove most of the impurities present, or if the crude product is first treated with peroxide or charcoal, activated carbon or clay before ozonation, The amount of ozone and treatment time required to remove the unpleasant "amber" odor and yield a suitable product would be significantly reduced if treated with other materials such as However, it is important to note that without ozonation, none of the above treatments of the crude product, alone or in combination, can completely remove malodorous components and produce a product with a good odor that can be used in the aroma industry. That's true. This was completely unexpected since it is possible to obtain a product with a suitable color without ozonation. However, the present invention, which utilizes ozone itself or combines ozone and hydrogen peroxide, results in macrocyclic products having both suitable color and good aroma.

The method of contacting the ozone with the macrocycles varies widely depending on the particular equipment used and the ozone concentration. The equipment used to contact the macrocyclic product, including malodorous byproducts, with ozone is not critical. Any equipment capable of making suitably effective gas-liquid contact can be used, and many commercial systems are available for this purpose. The apparatus may consist of a sophisticated countercurrent device for contacting gas and liquid, such as a bubble plate system, or it may be a simple stirrer in which the ozone-containing gas is introduced through a suitable dispersion tube or ring. The only limitation is that the ozone gas mixture is sufficiently dispersed to effectively contact and react with the malodorous byproducts and destroy them.
It is also possible to blow ozone into the system adsorbed on an inert support such as silica gel or alumina.

It is possible to improve the aromatic quality of the macrocyclic products obtained by thermal depolymerization by treatment with ozone alone according to the method of the invention. However, further benefits are realized if ozone treatment is used in conjunction with peroxide treatment. Contacting with peroxide and ozone can be done in the same operation, or they can be done in separate operations. Most of the contact with ozone is done before the peroxide treatment, but it is also possible to contact the peroxide first and then contact the ozone. In the latter case, the ozone may be passed in the presence of water with hydrogen peroxide or after removal of all or part of this water.

Hydrogen peroxide is commonly used in the process of the present invention because of its ready availability, ease of handling, and favorable economics. Other peroxides and hydrogen peroxides compatible with this system can however be used. Hydrogen peroxide is commonly used as a 15% to 50% aqueous solution. However, solutions with lower peroxide concentrations can also be used;
The amount of water required to achieve the desired peroxide concentration is generally considered to be in excess. Liquids with a peroxide concentration of 50% or more can be used, but there are problems in handling them. Therefore
It is most common to use readily available technical grade hydrogen peroxide containing 25 to 50% H ₂ O ₂ . A liquid amount of hydrogen peroxide is used so as to provide about 0.001 to 1 mole, preferably 0.01 to 0.3 mole, of hydrogen peroxide per pound of product treated.

The close contact between peroxide and macrocyclic product is approximately 25 to
This is carried out at a temperature of 105°C, usually between about 40 and 98°C, with vigorous stirring of the mixture. Any suitable agitator capable of effective agitation of viscous materials may be used herein. Contact time depends on stirring efficiency, peroxide concentration and amount of impurities present in the product. Excessive contact times are not necessary or preferred. In most cases the contact time is 0.5 to 2 hours. The water added with hydrogen peroxide in a later step of the operation is necessarily removed from the macrocyclic product by distillation or vacuum stripping in order to obtain the final active aromatic material.

It is particularly preferred if the macrocyclic product is distilled under reduced pressure after ozonation, in order to obtain a product with an aromatic quality which is also particularly favorable for the process of the invention. It is even better if the coarse cyclic aromatic compound is first treated with ozone, vacuum distilled, and then treated with a hydrogen peroxide solution. In the case of distillation after peroxide treatment, the product is subjected to a degassing/stripping operation to remove water and other volatile substances present therein. This can be conveniently done by simply using vacuum suction for an extended period of time while keeping the material at an elevated temperature, preferably below its decomposition temperature. Stripping and degassing operations can be carried out by passing an inert gas through the product. The inert gas may be dispersed by blowing below the liquid surface or by dispersing tubes, stirring or similar means.

The following examples and references are illustrative of the invention and its related art. In the examples, all parts and percentages are by weight unless otherwise specified. Color was measured photometrically by AOCS method Td2a-64 at 440 mμ and 550 mμ.
Reported as 100x absorbance.

Reference Example Production of Poly(Ethylene Brasillate) 109 parts of dimethyl brassylate containing about 2.3 mol % of methyl ester of a monocarboxylic acid and 30.5 parts of polymer grade ethylene glycol were charged into an upper stirred resin kettle equipped with a distillation head and a condenser. U.S. Patent No. 4,
A supported titanium catalyst (0.08 parts) prepared by reacting tetraisopropyl titanate with natural acidic montmorillonite clay according to No. 032,550 was added to the reaction mixture under positive pressure of nitrogen and heated. Methanol began to distill from the reaction mixture when the reaction mixture temperature reached about 180°C. After collecting the methanol and removing most of the methanol, the temperature was reduced to about 195
Raise the temperature to -205℃ and apply a 2 inch Hg vacuum.
Raised to 30 inches Hg. Samples were periodically taken from the reaction mixture for analysis and after about 11 hours the acid value of the reaction mixture was 0.1 and the hydroxyl value was 15.3. At this point the reaction was terminated and the titanium supported catalyst was removed by passing through a high molecular weight poly(ethylene brasileate) having a viscosity of 177 centistokes at 210°C.

Depolymerization of Poly(Ethylene Brasillate) Lead stearate (1.35% by weight) was dissolved into poly(ethylene brasillate) and placed in a heated 2 gallon stainless steel vertical inverted cone reactor.
The reactor has two conical spiral blades aligned with its axis, which interlock in opposite directions as they rotate (~20 rpm) to mix the entire volume of the reaction mixture up and down. The blades were placed in the reactor so that there was a maximum blade-to-wall spacing of approximately 0.25". The vacuum was maintained at approximately 1-2 mm Hg, and for the first 2 hours, poly(ethylene brasileate) was applied at a rate of approximately 4 lb/hr. 1.5 lbs/hour was then added continuously for 4.5 hours. Crude ethylene brasileate was continuously distilled and collected from the reactor. After about 1-1.5 hours, the percentage of ethylene brasileate recovered was essentially It remained constant for about 12 hours and then gradually decreased as the amount of poly(ethylene brasileate) in the reactor was depleted.When the ethylene brasileate recovery rate fell below 0.25 lb/hr, heating was stopped and the reaction stopped. Finished it.

Ozone treatment of ethylene brasilate Obtained crude ethylene brasilate (color 54/94)
The mixture was placed in a mixing vessel equipped with a high-speed electric stirrer, and an oxygen-ozone mixture (0 ₃ 5.9%) was blown into the liquid through a sparge ring while stirring vigorously and heating the mixture to 65-76°C.
The O ₂ /O ₃ gas mixture was introduced in 3SCFM and essentially all of the ozone was utilized. After 6 hours the color of the product was significantly improved (93/100) and ozonation was discontinued. total ozone per pound in processing
0.084 mol was used, and in addition to improving the color of the product, the aroma of the substance was significantly increased.

The product is 171- at reduced pressure (2-3 mmHg).
Further improvements were made by distilling at a temperature range (pot) of 218°C. Pre-distillate part (5% of total product
After removing the distillate (distillation), the main distillate fraction (78%) was collected at a temperature (steam) of 160-170°C. The main distillate of ethylene brasilate (color 99/100) had a very strong yellow odor and no trace of the unpleasant "amber" component.

Reference Example The following experiment was conducted to demonstrate the flexibility of ozone treatment and the variability of treatment time. . Crude ethylene brasilate (480 parts) with a color of 48/85 obtained by thermal depolymerization was treated with ozone at 65-75°C for 8 hours.
The O ₂ /O ₃ mixture and its proportions were the same as used in the example treatments. The aroma of the ozonated ethylene brasilate product obtained was significantly improved and the color was also improved. (88/100). Highly purified ethylene brasilate (color 99/
100) was obtained by vacuum distillation of the ozonated product.
The process was repeated using 496 parts of crude ethylene brasilate, but the contact time was reduced to 4 hours at 70-80°C. The color of the final product after processing and distillation is 98/100
However, no foul odor was detected.

Reference Example Crude ethylene brasileate obtained from the depolymerization of poly(ethylene brasileate) was ozonated as follows. 200 pounds of the crude product was placed in a distiller and heated at 100°C while oxygen-ozone (ozone
4.3%) mixture was blown below the liquid surface at a rate of 0.5 CFM through a gas dispersion ring. The treatment continued for 3 hours and at least 90% of the ozone introduced during the first hour was consumed, but as the treatment continued the ozone consumption decreased considerably so that at the end of the treatment time about 20% of the ozone was consumed.
Only % was consumed. Vacuum distillation of the ozonated material yielded a very useful main fraction (73%) of ethylene brasilate (color 97/100) with a very nice succulent odor. The test panel contains an unpleasant "amber" that impairs the natural odor of synthetic macrocycles.
No odor or other malodorous components could be detected.

Reference Example A polyester was obtained from dimethyl ester of a mixed _C7 - _C10 aliphatic dicarboxylic acid by the method of Reference Example. The polyester was then depolymerized in the same manner as described above to yield a coarse cyclic product (mixture of ethylene esters of _C7 - _C10 acids). After vacuum stripping, the product (color 59/98) was brought into vigorously stirred contact with ozone (0.27 moles per pound) at 65°C.

After 5 hours of treatment, product odor and color (86/99)
Both have been significantly improved. Distillation of the ozonated product yielded a very useful fragrance composition with further improved color (98/100) and no malodorous components detected.

Reference Example To demonstrate the flexibility of the ozonation process and the possibility of use with other ozonation agents, 500 parts of crude ethylene brasilate (color 61/92) was ozonated in the presence of 0.01% sodium borohydride. brought into contact with.
The temperature was kept at 100°C during the treatment time of 1.5 hours. The color of the crude product was significantly improved to 95/100 by this treatment and further improved to 100/100 by distillation. The odor of both products was also improved by the removal of unpleasant odor substances.

For comparison and to demonstrate the need for ozonation, 500 parts of crude ethylene brasilate (color 45/92) was mixed with 0.2% sodium borohydride and heated to 90-100°C.
The mixture was heated and stirred for 1.5 hours. Although the color of the treated product was significantly improved (47/94), the aroma was not significantly improved and unpleasant odor components still remained. Further distillation improved the color, but did not remove the unpleasant odor.

When the crude material used in the above experiments was treated with ozone alone by the method described in the previous example, both the color and odor of the non-distilled and distilled products appeared to be the same as those obtained by the ozone-sodium borohydride treatment. It was in good condition.

Reference Example A sample of crude ethylene brasilate (color 42/96) was contacted with ozone by the method of the present invention using the treatment method as described in the reference example. The obtained ozonated product is vacuum distilled and has a good color (99/100).
We obtained a very high quality ethylene brasilate that has a woody aroma and no bad odor.

A sample of crude ethylene brasilate without prior ozonation was vacuum distilled in the same manner. The color of the ethylene brasilate obtained was only 85/96 and the product had a very unpleasant odor. When the product containing unpleasant and malodorous components was treated with a small amount of ozonation at 70-80℃ and degassed, the color and odor of the product were significantly improved. It was comparable to something.

Reference Example Air-oxidized pentadecanolide having a color of 75/94 and an unpleasant odor was treated by ozone treatment to improve the color and odor of the product. 99 parts of pentadecanolide were treated with ozone (0.68 moles per pound of pentadecanolide) at 50-60°C. The material was then distilled to 1.6mm at 141-146°C using a shot-pass distiller.
Vacuum distilled in Hg. After removing 12-15% of the pre-distillate from this distillation, the main distillate had a color of 98/100 and a pleasant odor. All malodorous components present in the original air-oxidized pentadecanolide sample were effectively removed by this treatment.

When the original air-oxidized pentadecanolide sample was similarly shot pass distilled, the product obtained after removing 12-15% of the fore-distillate (color 97/100) had an unpleasant odor. The unpleasant odor components present in the first sample were still evident and obliterated the pleasant aroma of pentadecanolide.

REFERENCE EXAMPLE The unexpected properties of the ozonation process become even more apparent from experiments in which it was treated with distilled ethylene brachylate bleaching charcoal, which had a color of 85/97 and a pronounced "amber" odor. This treatment is commonly used with ester products (such as ester plasticizer and lubricant compositions) to improve the color and odor of these products.
Ethylene brasilate distilled in this example
Mix 250 parts with 25 parts of bleaching charcoal (Darco G-60).
The mixture was stirred at 80°C for 1 hour. The product was then cooled and filtered. Final color of ethylene brushlate (98/
100) was significantly improved, but no significant improvement was observed in the aromatic properties of the charcoal-treated material.

EXAMPLE To demonstrate the possibility of using peroxide treatment in conjunction with ozone treatment, three
Poly(ethylene brasilate) in a glass reaction vessel
2055 g of crude ethylene brasilate obtained from the thermal depolymerization of 30% hydrogen peroxide solution 24.7
g was added and the mixture was heated gently with stirring to 105° C. over 1 hour and held at this temperature for an additional 30 minutes.
Water was removed from the reactor during heating. When water production decreased, vacuum (1.2 mmHg) was applied for 30 minutes to completely remove water.

A portion of 987 g of the product thus obtained was then brought into contact with ozone at 80 DEG C. for 7 hours. Ozone is 7 psigO ₂
It was generated using a Welsvatzha ozone generator operating at an oxygen flow rate of 0.04 SCFM at 80 volts.
Ozone was blown into the liquid through a gas dispersion ring with vigorous stirring. The product after ozonation treatment is completed.
Distillation was carried out at a pressure of 0.5 to 1.2 mmHg to remove 5.1% of the pre-distillate and then 77.9% of the main distillate was collected. The final ethylene brasilate product had a color of 96/99 and a very good yakuza aroma with no unpleasant "amber" odor.

Comparable results were obtained when ozone treatment was started without completely removing the water introduced during peroxide treatment.

EXAMPLES Crude ethylene brassylate (obtained from thermal depolymerization of poly(ethylene brassylate)) using the same method as described in the Examples was contacted with ozone and peroxide to yield a highly useful fragrance material. However, in this example the treatment order was reversed, ie the product was first treated with ozonation and then contacted with peroxide. To further illustrate the versatility of the process and the possibility of producing useful aromatic products by various methods, experiments were carried out.
In (A), the product obtained after ozonation was directly contacted with hydrogen peroxide and then distilled, and in the second experiment (B), the product obtained after ozonation and before peroxide treatment was distilled. A
In both experiments, crude ethylene brasilate (color
46/94) with ozone (generator operated at 7 psigO ₂ pressure, 75 volts and O ₂ flow rate of 0.04 SCFM) at approximately 75°C.
Contact was made for 12 hours. The color of the product at the end of the contact is
Improved in 87/98.

Part of the ozonated material in Experiment A886
g was mixed with 10.91 g of 30% hydrogen peroxide solution and stirred vigorously for 1-1.5 hours at a maximum temperature of 105°C. The product (color 86/98) was vacuum distilled at 0.7-1.05 mmHg using vacuum (1 mmHg) for 30 minutes to completely remove water.
Main distillate obtained from distillation (676.9g, boiling point 155-
166°C) had a good color and a very good gypsum aroma.

In the second method (experiment B), ozonated substances
346.5g was first vacuum distilled (0.78-1.2mmHg) and the main distillate part (boiling point 154-180℃, 269.7g, color 95/99)
was contacted with 1% by weight peroxide (35% aqueous solution) in the usual manner. Approximately 100− after peroxide treatment
A vacuum was applied to the material kept at 105°C to remove final traces of water and other volatile materials. The obtained ethylene brasilate had no unpleasant "amber" odor and exhibited good aromatic properties.

It is clear from the above examples that the aroma and other properties of macrocycles are significantly improved by the ozone or ozone-peroxide treatment of the present invention. This example clearly shows that this treatment not only yields a product with good color, but also removes the malodorous components that detract from the odor of the aromatic compound and are objectionable to perfumers. It has also been shown that color improvement and unpleasant odor removal can only be achieved by treating macrocyclic products with ozone itself or with peroxide. Other methods, such as effective vacuum distillation or treatment with sodium borohydride or other agents, can be used to obtain products with suitable colors, but such treatments are not associated with macrocycles. Does not eliminate unpleasant odors.

Only by use of the method of the present invention can highly desirable improvements in both color and odor be achieved. This is unexpected in view of the extremely strong oxidizing properties of ozone and hydrogen peroxide and the fact that a large number of oxidizing by-products are expected to be produced which spoil the odor of the process product. Further, unless the product is ozonated at some stage of the recovery operation, considering the fact that contact with hydrogen peroxide alone will not effectively remove unpleasant malodorous substances nor will it produce a fragrance product acceptable to perfumers. That's unexpected. For example, a crude sample of ethylene brasilate exposed to 0.5% hydrogen peroxide at 90°C for 1 hour under nitrogen improves in color from 45/93 to 65/95;
Even if the color after distillation is further improved to 95/100, the smell is not completely improved.

Further advantages are obtained with the method of the invention. For example, the oxidative stability of macrocycles treated in this manner is improved. ozonated and distilled
When air is blown onto the surface of ethylene brasilate kept at 205°C for 3 hours, the color decreases by only about 5 units, but distilled ethylene brasilate (without ozone treatment before distillation) loses color under the same oxidation conditions.
Showing a decrease of 36 units. The ethylene brasilate obtained according to the example, ie distilled after treatment with peroxide and ozone, also lost only 5 units after 3 hours. The same test of the product treated with hydrogen peroxide alone and then distilled resulted in a 26 unit reduction in color. All of these oxidation stability comparison tests were conducted at a wavelength of 440 mμ.

Claims (1)

[Scope of Claims] 1. A liquid macrocyclic compound selected from the group consisting of cyclic esters, cyclic ether-esters, lactones, and ether-lactones having 8 to 20 carbon atoms in the ring, at least per pound thereof. A method for improving the odor of macrocyclic compounds, characterized by bringing them into intimate contact with 0.001 mol of ozone and 0.001 to 1 mol of hydrogen peroxide. 2. The method according to claim 1, wherein the ozone treatment and the hydrogen peroxide treatment are performed as separate operations during the operation. 3 In ozonation, macrocyclic compounds are treated with 0.01 to 10 moles of ozone per pound at 40 to 90°C.
3. The method according to claim 2, wherein the macrocyclic compound is contacted with a 15-50% aqueous hydrogen peroxide solution at a temperature of 25-105° C. in the peroxide treatment. 4. The method according to claim 3, wherein a 25-50% aqueous hydrogen peroxide solution is used in the peroxide treatment at a temperature of 40-98°C. 5 Ozone 0.1 to 10% by weight in ozone treatment
4. A method according to claim 3, using an ozone-oxygen mixture comprising: 6 Claim 3 in which the macrocyclic compound is first brought into contact with ozone and then brought into contact with an aqueous hydrogen peroxide solution.
The method described in section. 7. The method according to claim 6, in which the macrocyclic compound is first distilled under reduced pressure between the ozone treatment and the peroxide treatment. 8. The method according to claim 7, wherein the macrocyclic compound is separated by heating under reduced pressure at a high temperature to remove substantially all of the water and volatile components present in the macrocyclic compound after the peroxide treatment. 9. The method according to claim 8, wherein an inert gas is passed through the macrocyclic compound during the separation operation. 10 The macrocyclic compound has the general formula: (In each formula, R' represents a divalent hydrocarbon group having 1 to 15 carbon atoms, R ₁ represents a saturated divalent hydrocarbon group having 1 to 17 carbon atoms, and R ₂ represents a saturated divalent hydrocarbon group having 1 to 8 carbon atoms. represents a saturated divalent hydrocarbon group with x representing an integer from 0 to 4) or 11. The method according to claim 1, wherein R'' represents a divalent hydrocarbon group having 1 to 18 carbon atoms and R ₁ and x are as defined above. Saturated 2 with R ₁ and R ₂ having 2 to 6 carbon atoms
It is a valent hydrocarbon group, and R′ and R″ have the formula: (-CR ₃ CR ₄ )-
11. The method according to claim 10, which is a divalent hydrocarbon group having _y (where y is an integer from 4 to 15 and R ₃ and R ₄ represent hydrogen or a C _1-4 alkyl group). 12. The method according to claim 11 _, wherein _R1 and _R2 are _-CH2CH2- groups. 13. The method according to claim 12, wherein the macrocyclic compound is ethylene brasilate. 14. The method according to claim 12, wherein the macrocyclic compound is pentadecanolide.