DE1157595B - Process for the preparation of 2-amylanthraquinones - Google Patents

Description

Process for the preparation of 2-amylanthraquinones 2-amylanthraquinones, produced by the process of the invention are new compounds.

They have a defined chemical composition and are a member the alkyl anthraquinones.

Some alkyl anthraquinones have been reported before, however the total number was limited.

The following table lists the names, properties, method of preparation and references for such previously known compounds, all of which have been shown to be crystalline substances and to have characteristic melting points Representational Mole melting method and Alkyl anthraquinones) kular point literature weight ° C note 2-methylanthra- chinone. ... 222 r 176 / cyclization with oleum a> 2-ethylanthraquinone 236 109 cyclization 2-n-propylanthra- with oleum b) chinone. . 250 99 cyclization 2-iso-propylanthra- with Qleum c) chinone. 250 45 cyclization 2-n-butylanthra- with oleum C) chinone. .. 264 90 Cyclization 2-t-butylanthra- with oleum d) quinone. 264 104 cyclization 2-n-heptylanthra- with oleum d) chinone. .. 306 88 of Naphtho- 2-n-decylanthraquinone e) chinone. .. 348 103; from Naphtho- chinone e) a) Org.Synth. Coll., Vol. I, 345, John Wiley & Sons, NYC, 1932. b) PB Report 44, 961, August, 1946, Library of Congress. c) Beilstein. d) J Chem. Soc., 1945, 1811182. e) JACS, 55, 2815 (1933).

The first six listed compounds, which the methyl bis Butyl derivatives are of economic importance, while the the last two has been found to be of purely scientific interest are what is due to the absurd and costly manufacture. the simpler of the known connections which are the number of carbon atoms in The alkyI group did not exceed four, were caused by the action of smokers Sulfuric acid to the corresponding 2- (4'-alkylbenzoyl) -benzoic acids in different Yields shown. The parent substance, the anthraquinone itself, was 100% iger Yield, the simplest methylanthraquinone derivative in 85% yield and the next simple Ethyl anthraquinone in 75010 yield, the isopropyl derivative in 60% yield etc., the difficulty of illustration being generally to the same extent increases as the number of carbon atoms in the linked alkyl group. Peters and Rowe (J. Chem. Soc., 1945, p. 181) had in the preparation of certain Butyl derivatives success, their attempts to produce amyl, heptyl, octyl, dodecyl derivatives, but remained unsuccessful. These all have more than 4 carbon atoms in the alkyl group. The physical existence of the last four derivatives listed has never been proven, only the heptylanthraquinone was some Listed as a scientific curiosity for decades.

Hypothetical formulas and names for other alkyl anthraquinones were used earlier adopted with a more complex structure or higher molecular weight, but theirs real existence remained in doubt, as there was no evidence for this, such as a Report on the synthetic method of representation or a description of the physical one and chemical properties of these hypothetical substances.

The process of the invention aims to prepare 2-amylanthraquinones with certain chemical and physical properties. 2-amylanthraquinones are liquids that contain most common organic solvents are easy to mix.

2-Amylanthraquinone has the molecular formula C19H18O2 and the molecular weight of approximately 278. It may consist of one or more of eight isomers, what on the spatial arrangement of the 5 carbon atoms in the amyl radical associated with the Antrhachinonkern is linked, depends.

2-Amylanthraquinone is a valuable intermediate for manufacturing of hydrogen peroxide.

In accordance with this invention, 2-amylanthraquinones can be prepared by the action of fuming sulfuric acid on 2- (4'-amylbenzoyl) benzoic acid, but only with a number of special precautions. Finding these particular conditions when carrying out the cyclization and the steps necessary to obtain the product after the cyclization are part of this invention and are described as follows: The formation of 2-amylanthraquinone can be characterized by the general equation: 24'-amylbenzoylbenzoic acid molecular weight: 296 2-Amylanthraquinone, molecular weight: 278 The basic substances are 2- (4'-amylbenzoyl) -benzoic acid and fuming sulfuric acid, water is a by-product of the reaction and is absorbed by the sulfuric acid medium.

It is a monomolecular type of reaction which the starting and end products are dissolved. The temperature coefficient for a Temperature increase of 10 "C is about 3. Among the various factors, on which the speed and the yield depend, the temperature is far most importantly. At room temperature the reaction is slow, if at all, at 50 "C it becomes noticeable and takes place very quickly at 95C, with sulfonation of the product can occur noticeably at the latter temperature.

The reaction time for 950/0 conversion is approximately 14 hours at 650 ° C, 5 hours at 75 ° C, 1/2 hour at 85 "C and 1/2 hour at 95" C. Of the best Temperature range is between 75 and 90 "C.

They also have an impact on the rate of reaction and the yield the purity of the starting materials, the concentration of oleum, catalysts and stirring the reaction mixture has an effect.

The amylbenzoylbenzoic acid represented in the above equation by the formula characterized by molecular weight 296 can be selected from one or more of eight theoretically possible isomers exist, which is evident from the spatial arrangement of the 5th Carbon atoms in the amyl residue attached to the benzoyl group. (YES. C. S., 60, 1476, 1938). For best results, this material should be dry and at least 95 to 990/0 purity, although lower degrees of purity can be used, but with a correspondingly lower yield. This Raw material can be crystalline or amorphous, depending on the content of isomers and the existing impurities depends. If the acid is crystalline, the melting point may be between 100 and 1500C.

Technical or pure oleum is used, which is between Contains 5 and 10% sulfur trioxide.

With 1000/0 but sulfuric acid, which contains no free sulfur trioxide, Although the cyclization gets underway, what is released during the reaction is diluted Water the mixture below the original concentration of 1000 / o such that the reaction rate drops sharply. Oleum with a sulfur trioxide content of more than 100 / o the amylbenzoylbenzoic acid cyclizes somewhat faster, but up Unwanted sulfonation of the product results in a higher SO3 concentration generally a lower overall yield of the desired product.

The initial SO8 concentration in oleum in the process of the invention is 5 to 10%, of which about 40% by combination with that in the cyclization released water are consumed (see above equation). The presence of one a small excess of SO3 during the entire course of the reaction is desirable, since he was within a reasonable time for completion of the response cares.

Organic impurities in the raw materials consume SO3 and slow down the course of the main reaction or bring it to a standstill; also, in sulfonation, which is a side reaction, the small one becomes Excess SO3 consumed. These side reactions can be avoided by exact temperature control and constant stirring of the reaction mixture during the cyclization process be kept to a minimum.

The reaction can be carried out in a closed, jacketed vessel that with a low-clay stirring mechanism, a drain tap, is sufficient Connections to the top for thermometer, ventilation opening, stirrer shaft and a filling opening is provided.

The ratio of the substances used can be between 5 and 10 parts by weight Oleum will vary on every part of amylbenzoylbenzoic acid added. At the the best is a ratio of about 8 parts oleum to one part of the acid mentioned, which when dissolved gives a solution with a specific gravity of about 1.75. More than 10 parts of oleum can be used without fundamentally affecting the results to influence.

The oleum can first be added to the reaction vessel and brought up to 10 "C be heated below the selected reaction temperature. The amylbenzoylbenzoic acid can then be added in the form of granules to the heated oleum while stirring, after which the temperature of the reaction mixture can be brought to the desired level can then hold them there for a certain period of time. The desired reaction time is practically equal to the time in which about 01o of the amylbenzoylbenzoic acid is consumed will. Varies in the range between 80 and 90 ° C with an SO3 content of 50/0 in the oleum the reaction time between about 4 hours at the lower temperature and about 70 minutes at the higher temperature. At 85 "C the duration is about 2 hours. For a particular temperature and specified working conditions, the appropriate Duration can be determined experimentally beforehand. When the cyclization is almost complete the mixture can be cooled and transferred from the reaction vessel to another container or pour a sedimentation vessel that also has a stirring mechanism and a quantity of water (cold), which is about three times the amount of the original reaction mixture, contains. The temperature of the diluted mixture, which is now four times the amount of The reaction mixture is then kept in the settling vessel at about 60 ° C. 1 Part by volume carbon tetrachloride or another suitable extractant can then added. The entire contents are stirred and then the mixture is left sit in two shifts. The organic layer that contains the product will separated from the aqueous phase and retained. This extraction with divided Quantities are repeated twice more with additional solvent, after which the consumed Sulfuric acid mixture is discarded. The organic extracts are combined, Washed with water and treated with 20/0 but sodium hydroxide solution to about unused To remove amylbenzoylbenzoic acid and later to recover it. The solvent is distilled off and recovered from the combined extracts, the crude, orange oily product remains. The latter then consists of amylanthraquinone of more than 950/0 of purity, and the yield can be between 70 and 80 ° / o at optimal conditions fluctuate.

The above-described separation of the product from the dilute sulfuric acid Mixture, which has a specific gravity of around 1.2, can also be used in large vessels can be achieved without the use of solvents, e.g. B. by settling or by allowing settling and solvent extraction in one process combined.

The crude product of amylanthraquinone can be used for various purposes can be used directly, it can also be used by washing with various absorbent Agents can be further purified with suitable organic solvents.

The invention is illustrated by the following examples: Example 1 A crude 2- (4'-amylbenzoyl) benzoic acid of about 900/0 but purity in the form of yellow-brown grains with a melting point between 107 and 112 "C, which consist of a Mixture of primary, secondary and tertiary isomers was made into one implementation used in the manner described above. 20 parts by weight of the granules were added with stirring to 156 parts by weight of oleum with 100 / o sulfur trioxide, in a reaction vessel with a stirrer, thermometer, ventilation opening 85 "C. The resulting dark red mixture was protected from moisture protected, stirred slowly for 11/2 hours at 85 "C and then to room temperature cooled down. The reaction mixture, which now amounted to about 100 parts by volume, was slowly passed into a sedimentation vessel with stirring and cooling, which was 300 parts by volume Contained water. While 100 parts by volume of carbon tetrachloride were poured in, the diluted mixture in the settling vessel was stirred and maintained at about 600.degree. The contents were mixed at the same temperature. After weaning, the Carbon tetrachloride layer that the product bowie slightly unreacted Amylic acid, poured into a separate jar.

The diluted reaction mixture was extracted twice in succession, 50 parts by volume of solvent were added each time. After weaning and draining the sulfuric acid layer was discarded. The three carbon tetrachloride extracts were returned together to the original sedimentation vessel and washed with water, until they were neutral. The extracts were then aqueous 20/0 but with 50 parts by volume Washed sodium hydroxide solution to remove the unused amylic acid.

Then she was allowed to sit down. This caustic soda washing solution was used retained to later remove the amylic acid from the carbon tetrachloride solution to get from it again. The carbon tetrachloride solution was made with solid sodium carbonate dried and filtered through a fixed layer of activated magnesia clarified. Thereafter the solvent was evaporated, leaving the crude product from amylanthraquinone stayed behind. This, in an amount of 12.3 parts, was an orange colored low volatility viscous oil with a specific gravity of 1.07 at 25 "C. The amount of not cyclized amylic acid obtained from the alkali washing solution was 0.9 Parts by weight from the original 20 parts used at the beginning of the synthesis became. There were thus 19.1 parts of amylbenzoylbenzoic acid consumed, while the The yield of the crude product was 690 / o. After 1 1/2 hours of reaction time was the Cyclization carried out to 96%.

The next example illustrates, among other things, the effect of purity of the starting material on the yield of the end product.

Example 2 A crude amylic acid benzoylbenzoic mixture consisting primarily of consisted of secondary isomers, was recrystallized from benzene and petroleum ether cleaned. The recrystallized material was almost colorless, had a melting range from 120 to 125 "C and was of over 950/0 but purity. This purified secondary Amylbenzoylbenzoic acid was reacted under the same conditions as in Example 2 brought, with the exception that the reaction time was 3 hours. With the cleaned Starting material and the longer reaction time, 0.6 part of amylbenzoylbenzoic acid was obtained return. The yield of amylanthraquinone was or 13.6 parts 750 / o, and the cyclization had occurred at 97 ° IQ. The specific gravity of the yellow oily Product was 1.13 at 25 ° C, Example 3 A crude 2- (4'-tert-amylbenzoyl) benzoic acid in the form of a light, free-flowing powder with a melting point of 138 to 1400 C, which consisted mainly of the tertiary isomers became a reaction among the same conditions used as in Example 3, the oleum contained 10 0 / o SO ', the cyclization temperature was 850 ° C. and the reaction lasted 3 hours. from 20 parts of starting material reacted 19.1 parts, 0.9 parts were recovered unchanged, and 13.4 parts of amylanthraquinone were obtained in 750/0 yield. The cyclization was done to 9501a. This product was a viscous yellow oil with the specific Weight 1.14 at 25 ° C.

From the physical point of view, that is made in accordance with the present invention Product containing a heat-resistant, non-volatile pale yellow substance the consistency, which, if liquid, is similar to that of castor oil, and with a specific gravity between 1.07 and 1.14. It solidifies into one when it cools down vitreous solid and is insoluble in water, but in most common Easily soluble in organic solvents. The yellow product is not in all Miscible proportions with methanol or ethylene glycol, but is in ethanol or Propanol is much more soluble. With hydrocarbons such as mineral oil, petroleum, Gasoline and petroleum ether, it mixes easily, also with organic acids, esters, Ethers, ketones, amines and most plasticizing agents. The product is Completely soluble in concentrated sulfuric acid and can be obtained from this by dilution can be obtained again with water. This was due to the previous knowledge of the properties of other alkyl anthraquinones, which are solid substances and relatively heavy are soluble, hardly to be expected.

Perhaps the most salient physical characteristic of 2-amylanthraquinone is that certain forms persist as liquids at normal temperature. The previously known alkyl anthraquinones are crystalline solid substances with a considerably higher specific weight than that produced according to the invention Product shows.

Chemically speaking, 2-amylanthraquinone is opposite to oxidizing agents stable, but can be reduced to anthrahydroquinone by reducing agents. By hydrogenation with active catalysts at elevated temperature, amylanthraquinone be reduced to tetrahydroamylanthrahydroquinone.

Separation and purification of the product from organic niche solutions can by treating with an excess of sodium dithionate, then filtering the red aqueous solution to remove foreign objects and blow through Reach air. If amylanthraquinone is treated with oleum at excessive temperatures, so sulfonation occurs.

Of course, when manufacturing the product after commercial Mixtures of the amylanthraquinones are generally more economical are produced as the pure individual isomers.

It can be either the purified or the raw product for most Purposes in the production of other chemicals, both organic and inorganic, can be used directly. It is also evident that the invention is in the form organic mixtures with other solvents can be used, especially, if the main or active ingredient of such a solution is 2-amylanthraquinone is.

Claims (4)

PATENT CLAIMS-. 1. Process for the preparation of 2-amylanthraquinones, characterized in that that a mixture of oleum containing 5 to 10% SOa and 2- (4'-amylbenzoyl) benzoic acid in a ratio of at least 5 parts oleum to 1 part of this benzoic acid heated to a temperature of about 65 to 95 "C for between about 0.5 and 14 hours, the reaction mixture is diluted with water and then the reaction product is recovered will. 2. The method according to claim 1, characterized in that the 2-amylanthraquinone is obtained by extraction with an organic solvent. 3. The method according to claim 2, characterized in that as organic Solvent carbon tetrachloride is used and the carbon tetrachloride extract washed with water and then treated with sodium hydroxide solution in order not to to remove converted 2- (4'-amylbenzoyl) benzoic acid. 4. The method according to claim 1, characterized in that the reaction mixture after diluting with water it is left to stand until it is in two layers separated, and the 2-amylanthraquinone-containing layer is separated. Papers considered: Journal of the Chemical Society, 1945, p. 181; Journal of Applied Chemistry (Russian), 33, 1960, pp. 1893 to 1896, reported in the Chemisches Zentralblatt, 1967, 5.1265.