SU759502A1 - Method of purifying syntetic camphor - Google Patents

Description

The invention relates to the technology of production of synthetic camphor, used as a plasticizer and in medicine as an aphrodisiac for the decline of cardiac and respiratory activity, as well as an antiseptic.

There are various methods of purification of synthetic camphor: distillation, sublimation and recrystallization [ΐ].

The most common in the industry is a method of recrystallization by dissolving synthetic camphor in a solvent, turning the solution into supersaturated, from which purified camphor crystals are isolated.

The yield of recrystallized camphor at each recrystallization is about 65%. The mother liquors obtained after isolation of 20 camphor crystals are evaporated and camphor is isolated from them with a reduced degree of purity, which is sent to secondary recrystallization. The process of processing mother liquors is usually continued until no non-crystallisable oil remains in the residue, which is a waste product. Total yield recapitalized camphor

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is about 80%, the crystallization temperature of the product at this level increases from about 163 to 169 ° C and the content of the basic substance increases from 86 to 92%. During recrystallization from alcohol, the content of isofenchen and izokamphanone decreases, and the content of isocamphanum impurity practically does not decrease.

However, the known method of purification of synthetic camphor is a multistage process, and cleaning the product from impurities, especially izrkamfana, is not effective enough.

The literature indicates the possibility of purification of synthetic camphor by the method of rectification [2]. However, in practice this process was not carried out. The main obstacle in the implementation of the process of rectification of camphor is its high volatility. Thus, at a melting point of 178 ° C, the vapor pressure of camphor is 368 mm Hg. In addition, the narrow interval between the melting point and boiling point (209 ° C) of camphor does not allow the process to be carried out in industry, since its fast sublimation is not sufficient

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but heated surfaces lead to blockage of the apparatus.

The purpose of the invention is to simplify the process and improve the quality of the product.

The goal is achieved by rectification synthetic cam- headlamp 5 in the presence of an aromatic hydrocarbon having a boiling point below the boiling point of camphor, and a melting temperature lower than 20 ^e C, with a ratio solvent and 'θ camphor 0,07-0,65: 1.

The process of the proposed method is carried out in the presence of toluene or. xylene, '._

The use of a low-boiling solvent allows the process to be carried out in industry on batch or continuous columns.

When carrying out the process, the solvent performs two functions: firstly, having a higher volatility as compared with camphor, it comes into contact with the unheated surfaces of the system, warms it, and secondly, condenses on cold surfaces.

For example, it washes away camphor from them, for example, after the previous rectification in a periodic process. In addition, the use of a solvent allows the headlight to be supplied to the column in the form of a concentrated solution by pumps along heated lines or by gravity of the pressure tank at lower concentrations of camphor in the solvent. $$

For example, at 20 ° C, 155 g of camphor dissolves in 100 g of xylene. It follows that in the case of feeding the distillation column and the pressure tank along unheated lines, a 50-60% solution can be used. 40

camphor, i.e. in the ratio of xylene and camphor, equal to 0.65: 1. When applied In heated lines, a solvent to camphor ratio of 0.07: .1 can be used. At such a ratio of 45 bp. the mixture (in the case of xylene or toluene) is 175-185 ⁱⁿ C.

With this ratio, the productivity of the distillation column increases, but more stringent health is required.

control of the temperature on the line of supply of raw materials.

The periodic process of camphor rectification can be combined with the liquid phase dehydrogenation process of isoborneol, while the liquid phase dehydrator serves at the same time as the cube of the distillation column.

The temperature at the reflux condenser, as the toluene is distilled off with periodic rectification, is set at 180–200 ° C. Camphor condensation is carried out on a drum condenser with cleansing knives.

As the starting product, either camphor 65 can be used.

obtained by the liquid-phase dehydrogenation of isoborneol in toluene, or vapor-phase camphor, previously dissolved in toluene or xylene.

Rectification of the camphor solution is carried out on the column as a periodic, as well as continuous action. At periodic rectification of the camphor solution, the solvent is first distilled off, then fractions enriched with impurities are removed, after which the target fraction of the purified camphor is selected, and after the process is completed, the residue enriched with iocamphanone is removed from the bottom of the column.

With the continuous rectification of the camphor solution, the latter is fed into the middle part of the column, from the top of which solvent is taken, selection of purified camphor is carried out from the exhaustive part of the column, and from the cube of the column, the residue enriched with dryestryot and eocamphanone is taken.

Example 1. Purification of synthetic camphor on a laboratory batch column with an efficiency of 49 theoretical plates.

1000 parts of a solution of vapor-phase synthetic camphor in xylene containing, parts of o-xylene 107.2, camphene 0.6, isocamphanum 23.4, fenchon 1.6, isofenhon 13.3, camphor 832.9, isocamphanone are loaded into the cube of the distillation column. 21.1, and this mixture is subjected to rectification. With a reflux of 8-10 and a vapor temperature of 145 ° C, the xylene fraction is distilled off in an amount of 94.3 parts, containing,%: o-xylene, 99.3, camphene 0.1 and isocamphene 0.6.

Further, at a temperature interval of vapors of 145–150 ° C and a reflux number of 75, an intermediate fraction in the amount of 13.1 ′ parts is taken, containing ^: o-xylene 71, camphene 3 and iocamphan 26.

The following fraction is taken at a temperature interval of vapors of 150170 ^r C and a reflux number of 75 and an amount of 26.7 parts, containing: o-, -Xylene 2.4, camphene 0.7, isocamphone 83.3, fenchon 1.4, isofenhon 3, 6, camphor 8.6. Next, at a temperature interval of vapor 170–206 ° C and a reflux number 75, a fraction is taken in an amount of 19.8 parts, containing: isocamphanum 2, fenchone 5.5, isofenhone

28.4 and camphor 64.1.

The next fraction of purified camphor is selected at a vapor temperature of 206–207 ° C and a reflux number of 10 in the amount of 739.5 parts, containing,%: camphor 99.2, isofenhon 0.8 with a crystallization temperature of 175, g ^ C. This fraction is combined from two parts:

1 part containing,%: camphor 98.7 and isofenhon 1.3 (with a crystallization temperature of 174.4 ° C) is selected in the initial period in amount 5

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We selected 44.4 parts / C part (containing ^: camphor 99.2 and isophene> xon 0.8, with a crystallization temperature of 176 ° C) in the final period in the amount of 695.1 parts.

At the end of the rectification, 106.6 parts of the residue remain in the cube, containing,?;: Isocamphanone 34 and camphor 66.

As a result of rectification, the yield of purified camphor is 82.8%, and when only part II is taken into account, 77.8% of the initial 100% taken, or 88 and 82.8%, respectively, of camphor contained in the original product.

Example 2. Purification of synthetic camphor on a laboratory batch column with an efficiency of 5 theoretical plates.

1000 parts of a solution of vapor-phase synthetic camphor in toluene containing parts: toluene .378.6, tricycylene 0.36, camphene 1.61, isocamphanum 9.69, isofenhon 15.22, camphor 588.75, and isocamphanone 5,77, and this mixture is subjected to rectification. With a reflux ratio of 8-10 and a vapor temperature of 110 ° C, the solvent is distilled off - toluene in the amount of 365.1 parts. Further, with a reflux number of 2530, at a vapor temperature range of 111–205 ° C, a wide fraction is taken in an amount of 66.9 parts, containing,%: toluene 10.2, tricyclein 0.5, camphene 2.4, isocamphanum 14.5, isofenhon 4.9 and camphor 67.5. The target camphor fraction is distilled off with a reflux number of 10-12 and a vapor temperature of 205-207 ⁱⁿ C in an amount of 453.6 parts, containing,%: camphor 98, isocamphenone 1.7 and isocamphanone 0.3 with a crystallization temperature of 173.2 C. rectification in cuba remains

88.5 parts of a residue containing 5.2% isocamphanone and 94.8 camphor.

As a result of rectification, the yield of purified camphor was 73% of the original, taken as 100%.

Example Purification of synthetic camphor on a laboratory column of continuous action with the effectiveness of strengthening part 5 theoretical plates and an exhaustive part of 16 theoretical plates with side selections of the isocamphanic fraction from 8 from the bottom and purified camphor from 3 from the bottom of the theory—

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chesky plates.

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After loading the raw mix into the cube and setting the unit to continuous operation when feeding 100 g / h of the raw mix containing,%: toluene 30.83, tricycylene 0.06, camphene 0.21, isocamphone 1.21, isofenhon 1.80 , camphor 64.89 and isocamphanone 1.00, top is used to select toluene, and side selection of the isocamphanic fraction, which has the following composition,% · ® *

camphene 1.5, isocamphanum 12, isofenhon 3.5, camphor 82.5 and isrkampanone 0.5, are produced at a rate of 10.1 g / H. The camphor fraction containing 2.5% isophenchone, 97% camphor and 0.5% isocamphanone is selected at a rate of

58.3 g / h. The crystallization temperature of the product is 171 ^ 0. Cubic. isocamphanone-enriched fluid is continuously withdrawn from the cube.

The yield of purified camphor is 84.3% of the original, taken as 100%.

Example 4. Cleaning low-quality synthetic camphor on a laboratory batch column with an efficiency of 5 theoretical plates.

1864 g of camphor with a crystallization temperature of 162.5 ° С, containing,%: Tricycline 0.1, camphene 0.5, isocamphanum 4.1, isofenhon 2.5, isocamphanone 3.0 and camphor 89.8 dissolved in 136 g toluene, subjected to rectification. With a reflux number of 6-8 and a vapor temperature of 110 ° C, the solvent is distilled off - toluene in the amount of 107.4 g. Then, with a reflux number of 16-40 and a temperature interval of vapor 111—

180 C select an intermediate fraction in the amount of 98.4 g, containing ’,%: toluene 15.5, tricycylene 2, camphene 9.8; isocamphanum 26.8, isofenhon 10.3, and camphor 35.6.

Further, with a reflux number of 45-60 at a temperature interval of vapors of 150-180 ° C, the fraction in the amount of 132.8 g is distilled off, containing,%: isocamphone 36.6, isofenhon 13.2, camphor 50.2. The target product is collected in two fractions, of which the first, 825.02 g, is taken at a reflux ratio of 20-25, at a vapor temperature of 205-207 ° C, and the second is 700.9 g, at a reflux ratio of 25-10, at temperature of 207-210 ° C. The first fraction has a temperature, crystallization of 174.6 ° C and contains,%: isofenhon 1.4, isocamphanone 0.6 ', camphor 98. The second fraction has a crystallization temperature of 173 ° C and contains,%: isofenhon 0.8, isocamphanone 3, 4 and camphor 95.8. VAT residue, column capture and loss amount to 120, b7 g composition,%: isofenhon 1,2, isocamphanone 20.8, camphor 79.0.

The proposed method of purification of synthetic camphor allows to obtain a high quality product with the content of the main substance of 97-99.2% with a crystallization temperature of 171-175.2 ° C.

The use of the proposed method in the technology of camphor synthesis will lead to a significant simplification of the technological process, reduction of production areas with

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at the same time improving product quality.

Claims (2)

Claim 1. The method of purification of synthetic camphor, from those who, in order to simplify the process and improve the quality of the target product, purification is carried out by rectification in the presence of an aromatic hydrocarbon, the boiling point of which is lower than the temperature of the camphor ν-groove, and the melting point below 20 ° C, with a ratio of solvent and camphor 0.07-0.065: 1. 2. The method according to claim 1, of which is toluene or toluene or x5 lol.