UA44026A - METHOD OF ISOLATION OF WIDE FRACTION OF MONOTOMIC PHENOLS - Google Patents

Abstract

The proposed method of extraction of wide fraction of monoatomic phenols is based on continuous distillation of a raw product at atmospheric pressure by reducing heating temperature to 230 - 240 °С and adding steam. Separation of the water-steam mix into the vapor and liquid phases is accomplished in the presence of water in an amount of 8-20 % of the raw product mass. The mix screening is performed by extraction of steam and concentrated neutral impurities at the upper part of the rectification column. The wide phenol fraction is extracted at the side part of the rectification tower, and the bottom sediments are added to the raw product.

Description

Description of the invention

The invention relates to the field of chemical technology, namely to methods of obtaining a wide fraction of phenols, preferably of the first echelon 180 - 230"С, from the initial raw materials in the form of phenol solvates of various compositions, which are obtained mainly from sub-tar waters containing a large percentage of monoatomic A similar broad fraction of low-boiling monoatomic phenols, largely purified in advance from impurities, can serve as the initial raw material for obtaining crystalline phenol, orthocresol, and narrow fractions of monoatomic phenols, which are an important type of target products for chemical synthesis.

Industrial methods of obtaining phenols of various composition from coal tar formed in coke chemical production, synthetically from benzene, etc. are known and widely used.

In the post-war period, especially in the former USSR, interest in mining and processing such a type of solid organic fuel as oil shale, of which there are significant reserves in many countries of the world, has grown significantly. 12 The organic matter of oil shale (kerogen) is on average 10 - 3095 mass, in the process of burning the latter there is an increased yield of resins, up to 20 - 3095, from which monoatomic phenols are obtained at various stages of their processing: cresols, naphthols, diatomic phenols: hydroquinone , resorcinol and other polyatomic phenols.

The term "Shale phenols" refers to a large group of substances characterized by the presence of hydrogen, which unites 10 - 15 homologous series of phenols, consisting of 400 - 500 compounds with the number of carbon atoms from 7 to 23.

Basic information about shale phenols (along with an extensive list of bibliographic references) is presented in the book: Yu. V. Pokonova, V. A. Proskuryakov, V. MY. Levanovsky "Chemistry and technology of shale phenols", Leningrad, ed. Leningrad University, 1979 |1). Handbook of shale processing. Reference edition, Leningrad, Chemistry, 1988 |2). Shale phenols have attracted the special attention of chemists and technologists also because their chemical composition differs significantly from phenols obtained from other types of solid fuels.

In the USSR, at the first stage of the development of shale processing, phenols were not specially extracted from the resin, but only diatomic phenols in aggregate form were used for the production of synthetic leather tanners and some types of adhesive resins. what

In the 1970s, when a scheme for deep processing of water-soluble phenols emerged, it was shown that it is more effective to use this type of raw material after separating it into fractions by rectification under vacuum. The scheme for obtaining and processing shale phenols covers the following main links: o 1) extraction of phenols (washing of resins or individual fractions); "And 2) detarmination of phenolic waters; 3o C) dephenolation of water to obtain crude water-soluble phenols; C 4) rectification of phenols and further use of the fraction.

The general scheme of processing shale phenols is given in |2), on p. 103, fig. 3.5. The technology for extracting water-soluble phenols from shale tar waters was developed by B. I. Ivanov (VNIIPS) in 1946-1947. and has been preserved until now without significant changes ((2), on p. 108). Z 50 The patent information search conducted by the applicant showed that most of the published inventions of the USSR with etc. countries of the world on methods of isolation of monoatomic phenols and diatomic phenols pursue the goal of increasing

From" the quality of diatomic phenols by reducing the content of monoatomic phenols in them as an undesirable admixture (see, for example): as. USSR Mo 386901, MKl SO7S 37/28, bld. May 27, 1973, Applicant: Shale Research Institute, Method for isolating diatomic phenols from shale resins; t- as. USSR Mo493457, MKl So7S 37/22, 24, 44, bull Mo44, 1975, applicant: Slate processing plant "Kokhtla Jarve", Method for isolation of monoatomic and diatomic phenols; AS USSR Mo518487, MKl СО7С 37/24, 36 bull Mo 23, 1976, Applicant: "Kyviyli" Shale Chemical Plant; th Method of isolating a mixture of diatomic phenols from shale; ka 20 as. USSR Mo798084, MKl СО7С 37/08; СО7С 39/04, bull. Mo Z, 1981, The method of isolating phenols from reaction mixtures by decomposition of hydroperoxides of benzene or toluene; shi as USSR Mo 1127882, MKl СО7С37/68, 80; СО7С39/04,06, Applicant: Research Institute of Petrochemical Production, Method for separation of a mixture of phenol and cresol; US patent Mo 4605790, MKl СО7С 37/68, phenol from coal and biomass, by separating a mixture of phenols into 29 o-, m- and p-cresols by isomerization in the presence of (Mi) catalyst; in. Application of Japan Mo 3-33142 (ISM, 1992) Method of extraction of phenols from aqueous solutions;

VINITI, Chemistry, ref. 7P106P (Japanese) Method of cleaning acidic compounds (phenol) from resins by vacuum distillation).

Previously, it was assumed that the development of methods for separating the mixture of phenols into narrow fractions, which differ in the homogeneity of the composition, will allow to significantly improve the quality of many 60 products synthesized on their basis, since phenols themselves can become the main product of the primary processing of shale. At the same time, the methods of extracting phenols may also change significantly (11, p. 19-20)...

The problem of clear separation of monoatomic and diatomic shale phenols in large-scale industrial production continues to be relevant. There is also an urgent need for the development of a technically and economically advantageous method of isolating a wide fraction of low-boiling monoatomic phenols and, accordingly, its subsequent separation into narrow fractions of monoatomic phenols.

In section 3.2.4. "Rectification of phenols" ((2 | p. 110-113) provides a technological scheme for the rectification of water-soluble phenols from shale resin and the main technological indicators: 1) the main fraction of phenols is 180 - 270"С, which can be obtained in the form of two epaulettes: 180 - 230 " and 230 - 270"С; the output of the specified fraction is 1290; 2) fraction 270 - 2807С, output 1090

C) fraction 280 - 2957, output 3390 4) fraction 295 - 340"С, output ЗО90 5) residue above 340"С and losses 15905. 70 Low-boiling fractions (in the temperature range 180 - 260"С) diatomic alkyl resorcinols, high-boiling shale phenols from fractions 300 - 340"С, oxy and dioxy derivatives of naphthalene are represented.

In addition to components with a phenolic function, so-called "neutral oxygen compounds" are always present in the mixture of shale phenols, which are thermally unstable compounds that are easily oxidized, which are undesirable impurities that significantly impair the consumer properties of the product.

A characteristic feature of shale water-soluble phenols is their instability in the processes of separation and fractionation, as they are thermolabile. Even during the distillation of monoatomic phenols at atmospheric pressure, the thermal effect causes a significant change in the chemical structure of diatomic phenols. In practical terms, an important consequence of the thermal instability of phenols is the formation during distillation of a significant amount of pitch, water, gas, and light fractions, including neutral oils.

A well-known raw material is the so-called shale total phenols (TU 38.10935-75), which are extracted from sub-tar phenol waters and consist of 10-1595 monoatomic phenols and 85-9095 diatomic phenols. Basically, depending on the brand, they include neutral oils no more than 2.795, water no more than 1 - 596, their ash is 0.06 - 0.395 and narrow distillate fractions extracted from them serve as raw materials for obtaining various target products, (see |2) p. 147).

In order to withstand the maximum allowable norm of the content of neutral oils in commercial algae-soluble phenols, namely no more than 2.795, phenolic waters undergo additional treatment. "

In addition, at this time, the industry is experiencing known complications in obtaining large-tonnage batches of such a raw product as total shale phenols, and there is a problem of processing a raw product of lower quality. Similar raw products can be characterized by the general term "phenolsolvanes". Gas Such mixtures are obtained during the dephenolization of wastewater from coke, gas, chemical plants, semi-coking and coal hydrogenation plants, oil shale processing, etc., as well as during the dephenolization of shale resins, coal semi-coking resins, etc. (see 1) H. D. Kharlampovych, Yu. V. Churkin, Phenols, Ed. at

Chemistry, 1974, p. 343 - 352. 2) N. 1. Zelenii et al., "On the possibility of separating phenols from shale resin" in the collection: "

Chemistry and technology of oil shale and their processing products, issue 5, Gostoptehvydat, 1956, p. 271 - 280. "E

C) A. Dirichs and R. Kubichka, Phenols and bases from coal, Moscow, 1958, p. 45 - 156, p. 105 - 136.

Phenol-solvent extraction by the Dirichs method.

Intensification of shale phenol extraction processes leads to an increase in the content of emulsified resins in wash and pitch waters, as impurities, which are also called "neutral impurities". "

As an example of such a phenol solvent, we can cite the product of thermal processing of oil shale, which is available on the European market: - a dark-colored liquid with a characteristic phenolic smell, which corresponds to the following quality indicators: 15 g to m)

Ф According to the data of chromatographic analysis, the composition of acidic oils, taken as 10095, contains: - 5095- phenol; 7 - 895 - orthocresol; 11.5 - 13.896 - paracresol; 12 - 1495 - metacresol; 0.3 - 0.590 - 2.6 xylenol; 7 - 890 - other xylenols; 4 - 5905 - ethyl and trimethyl phenols; 7 - 895 - diatomic phenols.

Table 1 shows some physicochemical properties of a number of the specified monoatomic components.

Table 1 » Physicochemical properties of components 2 b5 6) 2,5-xylenol SvnoOn 122.16 211.5 750 1.069

Holy 00obnyunelerooroavo vovyazhyuyutnia 000ovnyun but 00ove000b5l101 wolves 000ovnyun but 00058800 lo razyuteyut 00seyuno 00012701

The following methods of obtaining monoatomic phenols from raw materials in the form of total shale phenols are known, tested in the former USSR at pilot plants under the conditions of Slantsehim. (11, pp. 31 - 32 Batch distillation; pp. 32 - 34 Continuous distillation; pp. 34 - 35 Film rectification; above in (11 70 data reproduced in |2), pp. 110 - 113, section 3.2.4. Rectification of phenols, with additional information on pages 111 - 113 and Fig. 3.7 on the technology of vacuum rectification of diatomic phenols using a falling film evaporator and a film-type column). 1. Periodic distillation on a cube unit under vacuum. A pair of total shale phenols from the distillation cube enters through the rectification column or outside it into the condenser refrigerator, from where 75 condensate flows into the vacuum collectors and further into the capacity. Previously, when heating the cubes with flue gases, it was established the fact of unwanted overheating of phenols, and as a result, deterioration of the quality of the final product.

Therefore, distillation cubes are heated by vapors of a high-temperature organic coolant (ditolylmethane), which has a boiling point of 300" at Tatm. and 350" C at 2.25 atm. For this purpose, a special boiler room is required, where the condensed ditolylmethane in the cube heaters evaporates again. Distillation of loading from 40 m of total shale phenols continues for 16 - 20 hours. The residual pressure in the cube (vacuum) is 140 - 170 mm Hg. Art. The maximum temperature of the liquid, even under vacuum conditions, should not exceed 250 - 26070. Otherwise, with prolonged heating, along with the intensification of sealing, the rate of decomposition reactions of phenols increases with the formation of a significant amount of water, gas and light fractions, including neutral oils.

From the consideration of the indicated method of periodic distillation on a cube plant under vacuum, its significant technical and economic shortcomings are clearly visible. « 2. Film rectification of total shale phenols.

This method is characterized in the above sources of information as the most promising process of rectification of water-soluble and tar shale phenols. However, its implementation requires equipment in the form of a film evaporator of a special design, which is expensive, in the pipes of which the evaporating liquid (Se) moves from bottom to top along its inner surface of the pipe in the form of a thin film. Due to the high kinetic energy of the vapor phase and a special column of the Kloss system operating under vacuum conditions, the method allows, in contrast to the periodic distillation method, to isolate 4 fractions: 180 - 2707; 270 - 28072280 - (av) 29572; 295 - 330"С and provide the possibility of more qualified use of phenols, mainly diatomic.

The method of continuous distillation at atmospheric pressure can serve as a prototype that matches the claimed invention in terms of purpose and a number of common essential features, which allows reducing the duration of heating phenols. The technological scheme of the installation, intended for the separation of diatomic phenols, is shown in fig. 7th century

G1) (p. 33), (Yu. V. Pokonova et al. Chemistry and technology of shale phenols. L-d, ed. LGU, 1979) "

A part of the installation for obtaining a wide fraction of monoatomic phenols is used as a prototype. Raw phenols are supplied from the consumption capacity to an electric tubular furnace, where water vapor is also supplied. From the furnace, the vapor and liquid mixture enters the evaporator, from above which the vapor phase enters the packing and rectification column, and the liquid phase flows into the residue receiver through the film evaporator. Column heating is electric. Dehydration of the vapor phase takes place in a packed rectification column. The column has a dephlegmator. The indicated features of the prototype are common with the claimed invention. The first fraction of phenols together with water vapor is obtained from the top of the column, and the second fraction from the bottom of the column. This scheme, although it shortens the heating time, has a significant drawback: excessive pressure leads to an increase in the heating temperature in the tubular furnace. Therefore, it is not possible to solve the problem of removing impurities, mainly neutral oils, at elevated temperatures due to the additional formation of neutral components. (ав) The invention is based on the task of improving the process of isolating a wide fraction of monoatomic 7 50 phenols by the method of continuous distillation at atmospheric pressure, mainly from raw materials in the form of shale phenol solvate, in which due to the peculiarities of the selection of the temperature regime and the azeotrope in the form of 4) water vapor - a significant reduction in the amount of neutral oils and other impurities in the initial raw material mixture is ensured. Due to this, it is possible to obtain a broad fraction of monoatomic phenols, suitable for further dividing it into narrow fractions of monoatomic phenols that meet the requirements of quality standards. c" The problem is solved by the fact that in the method of isolating a wide fraction of monoatomic phenols, mainly from raw materials in the form of shale phenol solvate, based on continuous distillation at atmospheric pressure, successively by heating the raw materials in a tube furnace with the addition of steam, supplying a mixture of steam and liquid in an evaporator for separating it into a vapor phase and a liquid residue, dewatering the distillate on a rectification packing column, according to the invention, distillation is carried out at a temperature of 230 - 240 C, depending on the content of neutral oils in the raw material, an additional amount of water is supplied, the separation of the vapor and liquid phases is carried out in the presence of water vapor with a mass ratio of distillate - water equal to 1:0.08 - 1:0.3, dehydration is carried out by the selection of water vapor and a concentrate of neutral components from the top of the rectification column at a temperature of 96 - 1007"C at reflux numbers of 5 - 15, lateral selection from 65 rectification columns take a wide fraction of monatomic Fe zeros, and the bottom residue is sent to the initial raw material.

The listed features make up the essence of the invention, as they are necessary in any variant of its implementation and sufficient to achieve the set task.

The specific difference of the method is that the total water content in the mixture is regulated within 8 - 2095 wt.

Another specific difference is that the water is injected directly into the container with the raw phenol solvate, after which the mixture is stirred for 2 hours.

Another difference is that for complete removal of monoatomic phenols from the residue, steam is introduced into the liquid phase as part of the total content. 70 The specified features of the implementation of the invention are not mandatory, but the most preferred from the point of view of the applicant and do not exclude the possibility of other implementation within the scope of the stated essence.

The causal-investigative relationship between the distinguishing features of the invention and the technical result achieved is as follows.

The short duration of the heating of the initial raw phenol solution is ensured by the continuity of heating, /5 heating in a tubular furnace to a temperature of 230 - 2407C significantly reduces the intensity of reactions of compaction and decomposition of phenols and impurities, which lead to the unwanted formation of pitch and neutral oils and ensures an increase in quality, as a low-boiling wide fraction of monoatomic phenols, as well as the following high-temperature fractions of diatomic phenols.

The supply of water in the range of 8 - 2095 from the total mass of the raw phenol solvate allows, without overheating, to ensure the complete extraction of monoatomic phenols into the vapor phase, and then clearly separate neutral oils at a temperature of 967C in the form of an azeotropic mixture with water in the dehydration process at reflux numbers of 5 - 15.

Regulation of water supply is carried out depending on the measured amount of neutral oils in the initial raw material.

The possibility of dividing the supply of the total amount of water either into the initial mixture with subsequent mixing, or into the evaporator, or partially in the form of steam into the liquid phase ensures the flexibility of conducting the technological process.

For a better understanding of the essence of the invention, below are examples of implementation of the claimed method in different operating modes of the pilot plant. The installation contains the main devices connected by pipelines: a gas gas tube furnace, an evaporator, a rectification column with 80 plates of the cap type.

The technological scheme of the installation includes the following operations. with

The initial raw material mixture in the form of shale phenolsolvane is continuously fed with the addition of water vapor into a gas tube furnace, in which the liquid is heated to a given temperature at atmospheric pressure.

The vapor-liquid mixture from the tubular furnace enters the evaporator, where, also in the presence of water vapor in the required amount, it is separated into a vapor phase and a liquid phase. The liquid phase flows into the residue receiver, and the vapor phase enters the rectification column under the 7th plate. At a certain value of the phlegm number, an aqueous concentrate of neutral oils is taken from the top of the rectification column at a temperature of 96 - 1007"C, a purified broad fraction of monoatomic phenols is taken from the 58th plate by side sampling, and the bottom residue is sent back to the initial raw material mixture from the bottom of the rectification column.

Below, as an example, the yield of products at various stages of technological operations from 100Okg of initial shale phenolsolvane is given at the optimal mode: temperature 235"С; mass ratio of distillate-water 1:0.2; phlegm number 10. The yield per 1000Okg of initial raw material is : ;» - the residue after the evaporator 156 kg; - the concentrate of neutral oils 76 kg (after water separation); - the broad purified fraction of monoatomic phenols 74 kg; they - the bottom residue after the rectification column 18 K kg.

The residue after the evaporator contains 51,396 diatomic phenols, 44,995 other high-boiling components and tarry substances and it is used for the purpose of preparing, for example, binders, o tamponage compounds or as a raw material for the isolation of diatomic phenols.

The concentrate of neutral oils contains 61.895 neutral components (including butyl acetate), 38.2905 o of monoatomic phenols (phenol 26.395, cresols 11.995) and it is dephenolized by a known method (alkaline

F washing) and used, for example, for the preparation of fuel mixtures, the separation of butyl acetate.

The broad purified fraction contains, by weight (sum of main substances 99.296): phenol 52.3905, cresols 40295, xylenols-6.796, neutral oils 0.495. it is used to obtain phenolic products by a known method of rectification: phenol, pro-cresol, dicresol, xylenols.

The bottom residue after the rectification column contains 38.995 xylenols, 55.695 high-boiling and diatomic

P phenols and it is sent to the initial phenol mixture.

Table 2 shows the results of experiments on the justification of the optimal temperature interval in a tubular furnace depending on the content of neutral oils in the purified broad fraction of monoatomic phenols. 60 5 240 74.8 04

Table C shows the rationale for choosing the range of phlegm numbers depending on the content of neutral impurities, for a temperature of 235 "С, the distillate-water ratio is 1:0.2

Cleaning efficiency decreases 7

Table 4 shows the rationale for choosing the distillate-water ratio interval depending on the 12 content of neutral oils:

The temperature in the tubular oven is 2357C; phlegm number 10. "

The proposed method allows to simplify the process of isolation of a wide fraction of monoatomic phenols at atmospheric pressure with the selection of optimal limits of temperature values, distillate - water ratio. The quality of the broad fraction of monoatomic phenols that is released, primarily due to the content of neutral oils, allows to obtain phenol and narrow fractions of monoatomic phenols when using it as a raw material in the future, which re) satisfies the requirements of the standards for the quality of the target products. with (av)

Claims (1)

The formula of the invention "I 1. The method of isolation of a wide fraction of monoatomic phenols, mainly from raw materials in the form of shale "phenol solvate", which consists in continuous distillation at atmospheric pressure, successively by heating the raw materials in a tube furnace with the addition of water vapor, feeding the vapor-liquid mixture into the evaporator to separate it into the vapor phase and the liquid residue, dewatering the distillate in a packed rectification column, which differs in that the distillation is carried out at a temperature of 230-240 °C, depending on the content of neutral impurities in the raw material, an additional amount of water is added, the separation of the vapor and liquid phases is carried out in the presence of water c steam with a mass ratio of distillate - water, equal to y ; pe -41; 0, » dehydration of the distillate. ," is carried out by the selection of water vapor and the concentrate of neutral impurities from the top of the rectification column at a temperature of 96-1002C at reflux numbers of 5-15, a wide fraction of monoatomic phenols is taken from the rectification column by lateral selection, and this residue is sent to the initial raw material. - 2. The method according to claim 1, which differs in that the total water content in the mixture is regulated within 8-20965. iz C. The method according to claim 1, which differs in that part of the water is introduced directly into the container with the raw phenol solvate with stirring for at least 2 hours. ("in 4. The method according to claim 1, which differs in that part of the water is introduced in the form of a sharp vapor into the liquid phase. with 50 ШЙ | | | What Official Bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integral I) microcircuits", 2002, Mo1, 15.01.2002. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. R" because b5