Method of oxidising saturated cyclic hydrocarbons with oxygen
SUBSTANCE: present invention relates to a method of continuous oxidation of saturated cyclic hydrocarbons using oxygen, into a mixture of hydroperoxide, alcohol and ketones. The method involves feeding into the lower part of a column and in parallel flow, a stream of oxidisable liquid hydrocarbon and a gas stream containing oxygen, and degassing the liquid phase in the upper part of the column by forming a gas dome and extraction of the degassed liquid phase. The gas containing oxygen is let into different compartments of the column, and into the dome and/or liquid phase at the level of the degassing zone, or directly above. A stream of non-oxidising gas with output sufficient for maintaining concentration of oxygen in the gas layer at the level of volume concentration, less than or equal to the upper limiting concentration of oxygen is supplied.
EFFECT: possibility of implementing a method with high selectivity on an explosion safe level.
9 cl, 1 dwg, 1 ex
The present invention relates to a continuous method for the oxidation of saturated cyclic hydrocarbons to obtain a mixture of hydroperoxides, alcohols and ketones.
More specifically, it relates to a method of oxidation of cyclohexane is carried out in the column, forming a bubble reactor, with the aim of obtaining cumene cyclohexyl, cyclohexanol and cyclohexanone.
Mentioned oxidation step is the first stage of the method of producing adipic acid, for example.
Among the methods for producing adipic acid is one of the most widely used is the oxidation by molecular oxygen of cyclohexane hydroperoxide of cyclohexyl, followed by the catalytic decomposition of the above-mentioned manner with the formation of a mixture of cyclohexanone and cyclohexanol. The resulting mixture was then oxidizes in adipic acid nitric acid oxidation.
Mentioned first phase oxidation of cyclohexane is usually carried out in a two phase medium liquid/gas, while the oxidizing gas is injected in the form of bubbles in a liquid environment, in tubular reactors, called bubble reactors.
Already suggested many ways in which streams of oxidizing gas and the liquid flow in the reactor can be co-current or counter-current.
The method according to the invention concerns the methods Khujand the exercise in a tubular reactor with liquid and gas flows, in the co-current.
In the method of this type the liquid phase Tegaserod in the upper part of the column to form a gaseous code and to extract the liquid phase, free from gas, or substantially free from gas. Mentioned gaseous arch composed of unreacted gas supplied, in particular, nepotreblenie oxygen and vapors from hydrocarbon and other organic products. The concentration of hydrocarbons and other organic products is determined by the vapor pressure of the above-mentioned compounds used in the conditions of temperature and pressure.
To prevent explosion mentioned mixture of gas and steam it is necessary that the volume concentration of oxygen relative to the amount of gas in the shell, with the exception of hydrocarbons, would be below the limit. So, in the case of a mixture of oxygen, nitrogen, cyclohexane, this upper limit is 8.5% oxygen relative to the amount of oxygen and nitrogen. Thus, in this region the concentration of oxygen, the gaseous mixture is always in explosion-proof areas, whatever the concentration of the vapor of a hydrocarbon, such as cyclohexane, and other organic compounds. Mentioned within the oxygen concentration or published and well-known specialist for some existing systems, as the system is sour the od/nitrogen/cyclohexane, either can be easily determined by the expert by means of known and open methods for the determination of the limits of explosive gaseous mixtures. Thus, for each private system, before you can carry out the oxidation of the hydrocarbon, the specialist will determine the mentioned upper limit of oxygen concentration using conventional techniques. For clarity, in this text referred to the limit concentration will be called the upper limit of oxygen concentration”.
Currently, the security rule is observed, for example, controlling the amount of oxygen fed to the reactor.
In this regard, it is not currently possible to feed the reactor, a large amount of oxygen and, on the other hand, the oxygen concentration decreases during the movement of the gas phase in a tubular reactor.
This drill the amount of oxygen fed to the reactor, in particular its concentration in the gas phase, it is not possible to obtain rapid kinetics of the oxidation reaction. Mentioned low oxygen concentration also affects the selectivity of the oxidation reaction in the hydroperoxide.
In addition, in order to exercise effective control of the volume concentration of oxygen in the body of the reactor, it is known that it is necessary to submit all the oxygen in the lower part of the column. Therefore, the concentration or party is the emotional pressure of oxygen decreases along the length of the reactor, not allowing you to have fast reaction kinetics in the entire reactor.
One of the objectives of the invention is to eliminate the above mentioned inconveniences by using method, giving the opportunity to enlist the fact that the volume concentration of oxygen in the body of the reactor is lower than the concentration of 8.5%, whatever the concentration or the partial pressure of oxygen in the liquid phase contained in the reactor.
To this end, the invention provides a continuous method for the oxidation of a saturated cyclic hydrocarbon in a mixture of cumene hydroperoxide, alcohol and ketone in the tubular bubble reactor, which consists in applying to the above reactor, in the lower part of the column of liquid flow oxidize hydrocarbons and a gas stream containing oxygen, and the gas flow is injected in the form of gas bubbles circulating in the aforementioned column liquid stream containing the gas bubbles in the upper part of the column, the degassing of the liquid phase with the formation of a gas layer in the upper part of the column and removing the liquid phase containing the reaction products at the level of the degassing zone.
The method according to the invention differs in that it consists in applying to the reactor non-oxidizing gas in the liquid phase at the level of the degassing zone or directly above the,and/or in the gas layer of the reactor performance, the residual for in order to maintain the volumetric concentration of oxygen in the arch reactor size is less than or equal to the upper limit of oxygen concentration. When the hydrocarbon is a cyclohexane and oxidizing gas is a mixture of nitrogen with oxygen, the above mentioned limit is 8.5%. Favorably, the consumption neoislamic gas is defined in such a way as to receive the body of the reactor, the oxygen concentration is approximately 30% smaller than the upper limit of oxygen concentration. So, when the hydrocarbon is a cyclohexane, the flow of oxidizing gas is defined in such a way as to obtain the value of the oxygen concentration in the volume of the reactor is less than or equal to 5%.
Non-oxidizing gas is chosen preferably among nitrogen, inert gases, air, oxygen-depleted.
According to another characteristic of the invention, saturated cyclic hydrocarbons choose among cyclohexane, decaline and cyclododecane.
According to the invention the supply of certain quantity of non-oxidizing gas in the gas layer of the reactor allows some control that the volumetric oxygen concentration in the arch will always be below a certain value, namely, 8.5%, which when oxidized hydrocarbon is a cyclohexane, and the gases are oxygen and nitrogen.p> Mentioned a number neoislamic gas fed to the code, determined depending on the amount of oxygen supplied to the tubular reactor.
Thus, it is possible to determine the maximum number of non-oxidizing gas, which is necessary to inject in order to obtain a concentration of oxygen less than 8,5%, when all the oxygen injected into the column is in the arch reactor, that is, when the oxidation reaction will not occur. Of course, this number represents the maximum amount of inert gas that can be entered. Smaller amounts can be introduced, taking into account the consumption of oxygen in the column.
The method according to the invention also allows you to apply a greater amount of oxygen in the column, in particular, the feeding gas with a high oxygen content, such as, for example, oxygen-enriched air or even pure oxygen. As the oxygen partial pressure in the gas bubbles dispersed in the liquid is higher, the reaction rate of oxidation will increase. Referred faster kinetics accompanied by higher selectivity of oxidation to hydroperoxide of cyclohexyl.
The method according to the invention also allows you to submit an oxygen or a gas containing oxygen, at different points along the length of the column, and the support is tested as a higher partial pressure of oxygen in the gas bubbles almost throughout the reaction zone of the column. In fact, it is not necessary that the concentration of oxygen in the bubbles coming into the arch reactor, would be very low, because the oxygen supplied to the gas layer is diluted in a non-oxidizing gas supplied according to the invention.
Therefore, the method according to the invention can be obtained fast kinetics of the oxidation reaction throughout the reaction zone of the column.
According to the special method of carrying out the invention the tubular reactor comprises a plate which divides the reactor into several tiers. The said plates are perforated to allow circulation of liquid and gas bubbles without accumulation or formation of a gas layer at the level of each of the plates. Such reactors are already known, and a method of manufacturing a reactor containing perforated plates, described in the international patent application WO 03/031051.
The gas containing oxygen may be fully enjoyed in the lower part of the column or served in several points of the column, preferably at the level of each tier is defined by the plates.
In the implementation method, which consists in feeding a gas containing oxygen, in several points of the column, the concentration of oxygen in the feed gas may be the same or different for each supply point. Also the amount of gas and oxygen, similarly, may be the same Il is different at each point of supply. Preferably, the oxygen content of the oxidizing gas supplied to the lower part of the column is high and varies, decreasing, starting from the bottom of the column to the upper part of the column, to other points in the supply oxidizing gas.
According to one method of carrying out the invention the non-oxidizing gas is fed, preferably,in the liquid phase,directly above the degassing device. In fact, the supply mentioned gas contributes to the mixing of gas bubbles containing oxygen, and an inert gas. Thus, the homogeneity of the oxygen content is provided to the gas inlet into the gas layer.
Other details, advantages of the invention will become more clear when considering the following examples are for reference only and the description which is made with reference to the accompanying figure schematically represents how the implementation of the principle of the bubble reactor by the method according to the invention.
The method according to the invention is carried out in a tubular bubble reactor (1)containing a device for feeding oxidized hydrocarbon (2)located in the bottom of the column.
The reactor also includes a device for supplying oxidizing gas (3), also located in the lower part of the column. This device for supplying oxidizing gas contains the device, n is depicted, allows you to apply the gas in the form of bubbles that are dispersed in the liquid phase.
In the depicted implementation method the reactor (1), or a column that contains perforated plates or horizontal partitions (4)separating the column into several layers.
The above reactor (1) contains also other devices for supplying oxidizing gas (5)located at the level of several tiers defined by the plates 4. These adaptations for feeding (5), preferably, identical to the device for feeding (3).
In the head of the column, the reactor (1) contains an outlet for gases (6), allowing you to divert gas from the layer,formed in the upper part of the column (7).
According to the illustrated method implementation reactor equipped with a degassing device (8)formed by the tank immersed in the liquid phase just below the upper level of the liquid phase.
The liquid phase penetrates into the said tank through the overflow. The tank contains a device (9) for discharge of liquid from the column to the outside. The liquid collected in this way through the exhaust pipe (9), contains oxidized compounds without dispersed gas bubbles.
According to the invention the reactor is equipped with a device for feeding (10), facing, in the illustrated implementation method, at the level of the last tier above degassing lighting the deposits.
Through this input device serves non-oxidizing gas, so as to maintain and regulate the concentration of oxygen in the body (7) of the reactor.
Other details, advantages of the invention will appear more clearly when we consider the examples only to illustrate and not having restrictive, and with reference to the sole accompanying figure which is a block diagram of embodiments of a reactor used for implementing the method according to the invention.
Study of the oxidation of cyclohexane to a mixture of cumene cyclohexyl (GPIG) (HPOCH), cyclohexanone and cyclohexanol was carried out in the reactor (1), shown in the drawing.
This reactor has a diameter of 0.1 m, height 8 m and contains 5 perforated plates (4).
The temperature in the reactor is 184°C and absolute pressure of 22.6 bar.
Column or reactor (1) contains a device for supplying oxidizing gas (3)located in the lower part of the column, and a second inert-gas supply (10), located about 10 cm below the upper boundary of the gas/liquid, or liquid level in the column.
Through the fixture (2) serves a stream of cyclohexane containing 0.2 wt.% cumene cyclohexyl.
The degree of transformation cyclo is Aksana in the reactor is 4.5%. To obtain this degree of transformation, adjust the feed rate of the cyclohexane in the reactor. The flow of inert or non-oxidizing gas fed through the device (10), defined in such a way as to obtain in the gas layer (7) of the reactor volume ratio of About2in relation to the total amount of N2+O2equal to or less than 2%.
Conditions and the results obtained for the different experiments are presented in table 1.
|Experience||Consumption of cyclohexane (kg/h)||The nature and flow of oxidizing gas (kg/h)||The nature and flow of non-oxidizing gas (kg/h)||Productivity, kg/m3/h||The selectivity (GPIG, cyclohexanone, cyclohexanol), %|
|293||The air containing 21% O219 kg/h||no||136||86,5|
|1||430||The air containing 21% O225 kg/h||Nitrogen 26||br93.1|
|2||389||The air containing 21% O235 kg/h||Nitrogen 150||187||for 95.2|
|3||554||The air containing 40% O219 kg/h||Nitrogen 61||305||93,8|
Productivity is the amount of oxidized products extracted per unit time, is given to the volume of the reactor 1 m3.
These experiments show that the method according to the invention allows to increase the selectivity of transformation to more expensive products, that is, which, for example, can be converted into adipic acid. The term "selectivity" refers to the more expensive products, divided by the degree of transformation of a more expensive product.
They also show a significant increase in the performance of this reactor. The above results have been obtained in strict compliance with safety rules.
In fact, the method according to the invention allows to make a more significant amount of cyclohexane in a reactor of the same size. Reality is about, feeding performance of cyclohexane in experiments 1-3 significantly more feeding performance in a comparative experience. Thus, the performance of the reaction increased with improved selectivity.
1. Continuous oxidation of a saturated cyclic hydrocarbon in a mixture of cumene hydroperoxide, alcohol, ketone, which consists in the introduction into the lower part of the column and in a co-current flow oxidized liquid hydrocarbons and a gas stream containing oxygen, degassing of the liquid phase in the upper part of the column by means of the formation of the gas code and removing degassed liquid phase, characterized in that it consists in the supply of gas containing oxygen, at different tiers of the column and fed through the arch and/or in the liquid phase at the level of the degassing zone, or directly above, the flow of non-oxidizing gas with performance sufficient to maintain the concentration of oxygen in the gas layer at the level of the volume concentration less than or equal to the upper limit of oxygen concentration.
2. The method according to claim 1, wherein the non-oxidizing gas is nitrogen, inert gas or air depleted in oxygen.
3. The method according to claim 1 or 2, characterized in that the saturated hydrocarbon selected from the group containing cyclohexane, decalin, cyclododecane.
4. The method according to claim 3, characterized in, th is the upper limit of oxygen concentration is equal to 8.5% when the hydrocarbon is a cyclohexane.
5. The method according to claim 1, characterized in that the column contains perforated plates.
6. The method according to claim 1, characterized in that the amount of oxygen supplied to each tier of columns are equal.
7. The method according to claim 1, characterized in that the liquid phase is circulated in the column and the amount of oxygen supplied to each tier of the column, reduced in relation to the direction of circulation of the liquid phase in the column.
8. The method according to claim 1, characterized in that the oxidizing gas supplied to the various tiers of the column contains a variable concentration of oxygen.
9. The method according to claim 1, characterized in that the gas containing oxygen is selected from the group containing oxygen, air enriched or depleted in oxygen.
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for synthesis of 3-bromoadamantyl-1-alkyl(aryl)-ketones of the general formula: , wherein that can be used as intermediate substances for synthesis of some biologically active compounds. Method involves interaction of 1,3-dehydroadamantane with α-bromoketones of the following order: α-bromoacetone, α-bromoacetophenone, α-bromocyclohexanone in the mole ratio of reagents = 1:(2-3), respectively, in absolute diethyl ether medium, at temperature 34-40°C for 3-4 h. Method provides preparing the claimed compounds with high yield.
EFFECT: improved method of synthesis.
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to an improved method for synthesis of 2,6-di-(3,3',5,5'-di-tert.-butyl-4,4'-oxybenzyl)-cyclohexane-1-one used as a stabilizing agent of polyolefins and low-unsaturated carbon=chain rubbers. Method involves interaction of cyclohexanone with N,N-dimethyl-(3,5-di-tert.-butyl-4-oxybenzyl)amine in the ratio = (1-1.2):2, respectively, and process is carried out at temperature 125-145°C up to ceasing isolation of dimethylamine. Method provides simplifying technology and preparing the end product with the yield 61-85.4%.
EFFECT: improved method of synthesis.
12 tbl, 23 ex
FIELD: organic chemistry, chemical technology, catalysts.
SUBSTANCE: invention relates to catalytic decomposition of organic hydroperoxides representing important compounds on organic synthesis. Decomposition of cycloalkyl hydroperoxides comprising from 6 to 12 carbon atoms results to formation a mixture of corresponding alcohols and ketones. Process is carried out in the presence of a solvent (alkane, halogen-containing hydrocarbon) at temperature from 20°C to 200°C. Catalyst comprises ruthenium as a catalytically active metal added to a solid carrier chosen from the following group: carbon prepared by pyrolysis of acetylene and metal oxides chosen from the group comprising zirconium, aluminum, lanthanum and manganese. The amount of catalyst expressed as the mole percents of ruthenium to the amount of moles of hydroperoxide to be decomposed is from 0.0001% to 20%. Preferably, the catalyst comprises one additional rare-earth element as a component of alloy. The carrier represents, as a rule, metal oxide with high specific surface above 10 m2/g but preferably, above 100 m2/g that is resistant against oxidation. The hydroperoxide concentration is in the range from 1 to 80 wt.-% with respect to the solution mass. Preferably, hydroperoxide represents cyclohexyl, cyclododecyl, tetraline, ethyl benzene or pinane hydroperoxide and hydrocarbon used in preparing the parent hydroperoxide is used as a solvent. Invention provides the development of the modified catalyst enhancing conversion and selectivity in decomposition of hydroperoxides.
EFFECT: improved method for decomposition.
8 cl, 24 ex
FIELD: organic chemistry, in particular production of carbonyl compounds such as aldehydes and ketones.
SUBSTANCE: claimed method includes reaction of nitrous oxide with alkenes in presence of inert gas as diluent. Reaction is carried out in gas phase at 401-700°C and under pressure of 2-300 atm. Target compounds represent value intermediates for precise and base organic synthesis.
EFFECT: method of high selectivity in relation to target products and improved explosion proofing.
5 cl, 1 tbl, 14 ex
SUBSTANCE: invention relates to improved method of obtaining (meth)acrylic acid or (meth)acrolein, which includes process of catalytic gas-phase oxidation for obtaining (met)acrylic acid or (meth)acrolein by supplying propylene, propane or isobutylene and gas, containing molecular oxygen, into reactor, filled with catalyst, which contains composition of metal oxides, including Mo, where gas, containing molecular oxygen, is continuously supplied from outside on catalyst both during installation operation, and during stoppage of catalytic gas-phase oxidation process.
EFFECT: obtaining gaseous reaction product, which includes (meth)acrylic acid or (meth)acrolein, in which reduction of catalyst activity and selectivity of target product formation do not occur when installation operation is restarted after stoppage of catalytic gas-phase oxidation process.
2 cl, 2 tbl, 2 ex
SUBSTANCE: invention concerns improved method of catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product. Method of catalytic oxidation is disclosed in the vapour phase (a) of propylene, propane or isobutene by the instrumentality of molecular oxygen for receiving (meth)acrolein, and/or oxidation (b) of (meth)acrolein by molecular oxygen for receiving (meth)acryl acid, by the instrumentality of multiple-tubular reactor, contained: cylindrical reactor vessel, outfitted by initial material supply inlet hole and discharge hole for product, variety of reactor coolant pipes, located around the cylindrical reactor vessel and used for insertion the heat carrier into cylindrical reactor vessel or for removing the heat carrier from it, circulator for connection of variety loop pipeline to each other, variety of reaction tube, mounted by the instrumentality of tube reactor lattices, with catalyst. Also multiple-tubular reactor contains: variety of partitions, located lengthways of reaction tubes and used for changing heat carrier direction, inserted into reactor vessel. According to this heat carrier coolant flow is analysed and there are defined zones in reactor which have heat-transfer coefficient of heat carrier less than 1000 W/(m2·K); also reaction of catalytic oxidation is averted in the vapour phase in mentioned zones of reactor and reaction of catalytic oxidation is implemented in the vapour phase in reactor.
EFFECT: receiving of improved method catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product.
3 cl, 6 dwg, 2 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to an improved method for synthesis of acrolein or acrylic acid or their mixture. Method involves at step (A) propane is subjected for partial heterogenous catalyzed dehydrogenation in gaseous phase to form a gaseous mixture A of product comprising molecular hydrogen, propylene, unconverted propane and components distinct from propane and propene, and then from a gaseous mixture of product from step (A) distinct from propane and propylene at least partial amount of molecular hydrogen is isolated and a mixture obtained after this isolation is used as a gaseous mixture A' at the second step (B) for loading at least into one oxidation reactor and in at least one oxidation reaction propylene is subjected for selective heterogenous catalyzed gas-phase partial oxidation with molecular oxygen to yield as the end product of gaseous mixture B containing acrolein or acrylic acid, or their mixture, and the third (C) wherein in limits of partial oxidation of propylene at step (B) of gaseous mixture B acrolein or acrylic acid or their mixtures as the end product are separated and at least unconverted propane containing in gaseous mixture at step (B) is recovered to the dehydrogenation step (A) wherein in limits of partial oxidation of propylene at step (B) molecular nitrogen is used as additional diluting gas. Method provides significant decreasing of by-side products.
EFFECT: improved method of synthesis.
39 cl, 11 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for synthesis of acrolein and/or acrylic acid from propane and/or propene. Method involves the following steps: (a) isolating propane and/or propene from gaseous mixture A containing propane and/or propene by their absorption with adsorbent; (b) isolating propane and/or propene from adsorbent to form gas B containing propane and/or propene, and (c) using gas B obtained in stage (b) for oxidation of propane and/or propene to acrolein and/or acrylic acid wherein the heterogeneous catalytic dehydrogenation of propane without feeding oxygen is not carried out. Method shows economy and maximal exploitation period of used catalyst without its regeneration.
EFFECT: improved method of synthesis.
12 cl, 7 dwg, 1 ex
FIELD: oxidation catalysts.
SUBSTANCE: invention relates to catalytic oxidation of saturated hydrocarbons with oxygen-containing gas. Process according to invention comprises contacting alkane with oxygen source in presence of catalyst including compound of general formula: , where R1 and R2 independently represent hydrogen atom, halogen atom, alkyl, aryl, cycloalkyl, hydroxy, alkoxy, carboxyl, alkoxycarbonyl, or acyl, or R1 and R2 can together form double bond or aromatic or non-aromatic ring; Y represents oxygen atom; X oxygen atom to hydroxyl group; m is integer 1 or 2; and n = 1. Process is conducted at 20 to 100°C. Advantageously, catalyst includes cocatalyst.
EFFECT: increased efficiency of catalytic system.
14 cl, 5 tbl, 6 ex
SUBSTANCE: invention concerns method of cyclic alkane oxidation by oxidation agent for obtaining a product, where oxidation is performed in cracking fractionator including vat zone at bottom end, head zone at top end, and reaction zone between vat and head zones. Reaction mix is kept boiling in reaction zone, and oxidation agent is added into reaction zone in at least two split flows. Non-reacted raw material leaving reaction zone is recycled into reaction zone. Gas containing molecular oxygen is used as oxidation agent, and reaction mix containing target product is collected below reaction zone.
EFFECT: simple and cost-effective method of obtaining the product, enhanced conversion of source material and selectivity of target product generation.
6 cl, 1 dwg, 3 ex