Method and apparatus for producing monocarboxylic acids from carbohydrates, derivatives of carbohydrates or primary alcohols
(57) Abstract:The described method of obtaining monocarboxylic acids by oxidation of the corresponding carbohydrates, derivatives of carbohydrates or primary alcohols with selection of the target product by electroanalysis consists in the fact that carbohydrates, derivatives of carbohydrates or primary alcohols continuously oxidized in an aqueous solution with a mass concentration of 0.1-60% oxygen or oxygen-containing gas on the catalysts based on noble metals or mixed metal catalysts based on noble metals and promoters, followed by a continuous flow of the formed products by stage of electroanalysis, after which the monocarboxylic acid as the target products, and produce. Also describes a device for implementing the method, characterized in that it comprises a series-connected stage passing the gas (10), the stage of oxidation (30) and the stage of electroanalysis. The technical result consists in the oxidation of carbohydrates and their derivatives, and primary alcohols with the best selectivity for minoocycline products. 2 S. and 19 C.p. f-crystals, 4 Il. The invention relates to a method and apparatus for obtaining monocarbonic what means can selectively oxidize carbohydrates. These methods of preparation, however, have significant drawbacks. First, the reproduction of microorganisms or getting biocatalysts fraught with considerable difficulties. The ways of getting mainly include fermentation (for example, in the process of getting gluconic acid), so that the use of nutrient salts in the fermentation solution leads to a significant downloads salts. Another disadvantage is the requirement of sterility work, often required for these processes, so it is associated with significant cost of the equipment.Of particular importance is heterogeneous catalytic oxidation on noble metals of the 8th subgroup of the Periodic table of elements deposited on appropriate substrates. This scheme can be performed in the oxidation of glucose to gluconic acid, such as Pt/C catalysts. However, the disadvantage of this method of obtaining a sharp decrease in the selectivity of the reaction and rapid deactivation of the catalyst (see "Ullmanns Enzyklopadie der Technischen Chemie", 4 th newly revised edition, vol. 24, page 785, Verlag Chemie (1983).Similar problems are observed in the oxidation of sucrose. Harry and Paulsen already investigated this reaction on platinum catalysts (K. Soedinenii, which due to the existing difficulties there are no data on their chemical structure and composition.From the patent EP N 0040709 B1 is known a method of obtaining diacetonitrile acid, in particular, decatanzaro oxidize and produce by electrodialysis. In this case, carry out periodic way and, thanks to the introduction of protective groups, the source is derived contains only one oxidizable group.From patents DE 3803465 A1, DE 3916206 A1 and US - PS 4985553 known various periodic methods, which are quantitatively unacceptable degree of conversion or the mixture of products containing unacceptable amounts of pollution. In some cases, it was proposed to carry out the selection of product expensive purification methods.In the patent EP 2181501 on the method of catalytic oxidation of sucrose, clearly note that with periodic way multiple oxidation products are obtained in large scale.Attempts selective oxidation of sucrose traditional ways only one primary OH group had no success.In addition to 3-m possible monocarboxylic acids obtained by oxidation of primary OH-groups in the mixture with the specified without specific details, that leads to a significant loss of the final product and a significant decrease in the selectivity of the reaction towards formation of monocarboxylic acids (Les A. Edye, George V. Meehan, Geoffrey N. Kichards, Platinum catalyst oxidation of sucrose. J. Carbohydrate Chemistry, 10 (1), 11-23 (1991)).The same is observed in the case of recovery of sugars, for example, that shown by tests on palatinose (Dissertation H. Puke, T. U Braunschweig).The aim of the invention is the oxidation of carbohydrates, derivatives of carbohydrates and primary alcohols with the best selectivity for minoocycline products.This goal is achieved by the fact that carbohydrates, derivatives of carbohydrates or primary alcohols continuously oxidized in an aqueous solution with a concentration of from 0.1 to 60% oxygen or oxygen-containing gases on the catalyst based on a noble metal or mixed metal catalysts, flow thus obtained products are sent to stage electrodialysis and allocate target monocarboxylic acid.This method is especially suitable for obtaining minoocycline oxidation products of carbohydrates, derivatives of carbohydrates and primary alcohols. Tech continuous and simultaneous selection of products on the changes of carbohydrates and their derivatives or primary alcohols. At the same time is possible high output volume-time.Special funktsionalizirovannyi saccharides and derivatives of saccharides, which prevail among the source materials is of considerable industrial interest from the point of view of synthesis of hydrophilic constituent units for the polymer and surfactants carbohydrate origin.Thanks to its environmentally preferable properties, these source materials have advantages over synthetic products.Especially effective if the substance remaining after stage electrodialysis and removal of monocarboxylic acids, again are passed once through a stage of oxidation. In this way we get a continuous loop and is especially effective educts.Advantageously, if the flow of the original substances prior to introduction into the catalytic layer is enriched free from air bubbles, so that there is enough oxygen for oxidation reactions.This invention relates to a continuous method, in which carbohydrates or their derivatives can be selectively converted into monocarboxylate in the about precious metal or mixed metal catalysts. The latter are also suitable, but from the point of view of recyclization catalysts based on noble metals with a catalytically active element are preferred.Formed in the oxidation process monocarboxylic acid is then continuously removed from the reaction mixture using the second stage of the process - stage electrodialysis. Specified, is still nowhere to be described, the combination of stages, ongoing oxidation with almost continuous removal of the formed oxidation products is suitable, in particular, to obtain monocarboxylic acids from carbohydrates and their derivatives. In this way implements a higher rate of conversion than described on ways today, and selectivity, from the point of view of education monocarboxylic acids, unexpectedly higher than 95%.Continuous oxidation by the present method is as follows:
a) the Reaction system consists of a node passing the gas (the vessel with stirrer) with a tubular reactor, in which is placed a fixed catalyst bed. Stage passing the gas can in particular be carried out in a mixing vessel (reactor with a stirrer). In the reactor with mesalc is Kim partial pressure of oxygen or pure oxygen in the form of melkodispersionnyh bubbles or free from bubbles through special hoses) for introducing gas under pressure or without pressure. The specified reactor with a stirrer connected to a tubular reactor, installed in parallel (above or below potential flow), which is the actual oxidation in contact with the catalyst.b) Oxidation can also be performed with suspended catalysts (suspension method) in a mixing vessel, coupled with electrodialysis installation using a single node. In the simplest case, this can be used desantiruemye centrifuge or modules with cross-over.Technological solution to this problem is also feasible with the use of appropriate systems holding, such as filter backwashing, separators, etc.Suitable is the use of catalysts based on noble metal or mixed metal catalysts that can be used, for example, in the form of extrudates (C), oxides), fibers, pellets or powder. If you are using catalysts based on noble metals, the proportion of the metal should be 0.1 - 10%. Especially good results were achieved with Pt-catalysts, which had a Pt content of only 1% and were in the form of a powder, from which, however, milked the m electrodialysis installation on the side of dilution, so oxidized products migrate to concentrate when a voltage is applied and then removed from the reaction system. In order to maintain the equilibrium state of the continuously operating the reaction system, the amount that is removed from concentrate is dosed into the reactor with a stirrer in a controlled way with the compensation quantity of the extracted solution.Mixed metal catalysts are, for example, such as supplied by the company Degussa AG and described in the article by K. Deller and B. Despeyroux in: "Catalysis of organic reaction" (1992).Especially acceptable device for implementing the method according to the invention characterized in that it comprises, connected in series, the node passing the gas, the site of oxidation and site electrodialysis.In order to provide accurate control of the quantity of substances handled in some cases, particularly preferably, if there is a branch line parallel to the stage electrodialysis.With this additional parallel line is kind of bypass (bypass) line parallel to the stage electrodialysis. Together with the appropriate devices to control the flow or pumps can number on stage electrodialysis only to such extent, in which they can be processed and unprocessed number immediately returned to the step of passing the gas again through the bypass line. At each stage so processed strictly optimal amount of substance.Name three possible sucrose-monocarboxylic acids in this description are used only in abbreviated form. Full names, together with the names of two other products, also listed below, are the following:
C6-sucrose-monocarboxylic acid: 1-0-(-D - fructofuranosyl) --D - glucopyranoside;
C1-sucrose-monocarboxylic acid: 2-keto-2-0-( -D- -glyukopiranozil) --D - glucofuranose acid;
C6-sucrose-monocarboxylic acid: 1-0-( -D - fructofuranosyl) --D - glucopyranoside;
C1-oxidized GMF: 5-(-D - glyukopiranozil-oxymethyl)-furan-2-carboxylic acid;
C6-oxidized GMF: 5-(-D - glucopyranosyl-oxymethyl)-furfural.The device for implementing the method explained below in detail using the drawings, and particularly preferred settings.Fig. 1 shows a preferred variant of the technological scheme according to the invention;
Fig. 2 is Gras is t an alternative variant of the invention in relation to Fig. 1.The scheme shown in Fig. 1 shows a vessel with a stirrer or tank 10 with a stirrer 11 and El. the engine 12 to the mixer 11. Shown schematically introduction into the vessel 10 selected substances through 15, figure 17 indicated pH meter, 18 - data that goes to thermostat, and 19 - data incoming from the last. In addition, the air (N2/O2) is fed into the tank 10 through 21.After stirring in a vessel with stirrer output material with controlled pH, such as a carbohydrate, which is enriched and mixed with oxygen, served one of the pumps, denoted by P, to the stage of oxidation of 30. Specified by the acidification stage 30 contains a catalyst based on a noble metal or mixed metal catalyst, in this case Pt-catalyst C-substrate. At the stage of oxidation 30 is continuous oxidation of the source material; the latter is then passed through several pumps, denoted by P, on stage electrodialysis 40. Last, ED-block or electrodialyzer, also shown only schematically. Here monocarboxylic acid is derived continuously from the partially oxidized mixture, namely, along the line indicated as 41, which also set the measuring cell electrade on line 43 again into the vessel 10 for further processing in addition to the displayed product 15, which in any case they correspond chemically.Monocarboxylic acid after passing through the measuring cell conductivity 42 serves in the capacity of 50 here and concentrate. In the vessel 50 is continuously measure pH, indicated by the numeral 51. The product shown here through the output 52, then through the output 53 unloaded product is returned again to the stage electrodialysis pump P.Fig. 4 shows a process flowchart corresponding to almost all parts of the circuit of Fig. 1. In additional line 60 provides a by-pass line between the output stage of oxidation 30 and the return line 43 from the stage electrodialysis in the tank 10.This line 60 is here purely schematic; it may contain additional capacity, measuring devices, pumps and controls flow.The pump P, which are available in the variant according to Fig. 1, alone or with the above elements is capable of feeding from the stage 30 on stage electrodialysis 40 only such quantities of substances that can be optimally processed here. Excess can be returned through the bypass line, line 60, again on stage ol CLASS="ptx2">As an example here would be considered unrestored disaccharide sucrose, which can turn selectively into the corresponding monocarboxylic acid is shown in the device described manner.Although the molecule contains three reactive primary hydroxy-group, in each case, the oxidation of only one of these groups, so that one obtains exclusively minoocycline derivatives of sucrose. Selectivity for these products comes at least 95%, and when using this continuous method is not observed the formation of di - or tricarboxylic acid.In addition to high selectivity for this continuous method, in comparison with a periodic way, you may experience a significant increase in the reaction rate. The advantage of the method according to the invention in respect of reactivity to glucose and sucrose confirmed, compared with the periodic method of Fig. 2 and Fig. 3.In Fig. 2 and 3, in each case the horizontal axis is marked time in minutes; the vertical axis is the rate of conversion in percent. Graphically in each case marks the data of the periodic process of Fig. 2 for the year 3 for sucrose. In Fig. 3 in addition presents a continuous process with pure oxygen (O2).Further increase in the reaction rate, from the point of view of education monocarboxylic acids, can be reached by increasing the partial pressure of oxygen in solution, for example, with the introduction of pure oxygen (instead of air or oxygen-nitrogen mixtures).An additional advantage of this method of the invention is that it is not observed desactivate catalyst, which usually occurs when periodic work (compare K. Heyns, H. Paulsen; H. Puke, Dissertation TU Braunschweig). Even with the introduction of pure oxygen decontamination unexpectedly has no place. This advantage is not described in the literature, and is a great advantage from the point of view of technology, with the selective conversion of carbohydrates.The method can be easily applied for the recovery of sugars, such as, for example, palatinose and glucose.The selectivity towards specific products minoocycline can be adjusted by selection of appropriate catalysts, or using specific substrates or catalysts based on mixed Mazomanie one particular catalysts based on noble metal (for example, Pt/Al2O3(1% Pt), the firm Aldrich, in which Al2O3is used as the substrate to oxidize the primary OH-group in the 6'-position to the maximum extent.In this case established that, despite the possibility of formation of dicarboxylic acid, obtained exclusively monocarboxylic acid. In addition, you can observe that this method selectivity can be influenced by the choice of the catalyst so that the oxidation unexpectedly leads mainly to only one oxidation product.Experiments with other catalysts also showed that not only the selectivity in respect of monocyclic, but also the selectivity for the desired product may be regulated in this way. The method is not only suitable for the oxidation of sugars, but it is also possible to turn polyalcohols, xylytol (for example, isomalt) in the appropriate monocellate.You can also oxidize derivatives of carbohydrates, such as, for example, glucoronosyltransferase, so that on the one hand, 6'-position, and on the other hand, the aldehyde functional group into relevant groups monocarboxylic acid.While the purpose ground receiving stations group, similarly receive the products, which contain a carboxyl group exclusively in C6'-position. The aldehyde function is stored in these compounds.This method can be oxidized similar Alkylglucoside or mixture, such as, for example, alkylpolyglycoside.The examples show that the described method is suitable for the oxidation of the aldehyde and a primary hydroxyl functional groups in order to get minoocycline products. The substance used, mainly from the class of carbohydrates should be soluble in water or in mixtures of water and organic solvents (for example, mixtures of water/isopropanol) and not flying in the conditions of the experiments. In the case of substances from neaglewood" method is applicable to obtain minoocycline products (e.g., propanol to propionic acid, provided that they are (even partially) soluble in the described environment.Oxidation takes place at temperatures from 0oup to 80oC, preferably, however, at 20o- 60oC. the Concentration of the substance can vary from 0.1 to 60%, but preferably in the range from 3 to 20%. The pH value can be adjusted in the range from 1 the clients".To highlight monocarboxylic acid by electrodialysis can be used ion-exchange membranes. In this case, however, the free acid can be obtained only at low pH values. Despite the neutral conditions, however, in this case is allocated a large part of the Na-salts of monocarboxylic acids.If the electrodialysis is performed with bipolar membranes, the neutralizing agent can be regenerated again and additionally get monocarboxylic acid from the corresponding starting materials. Although the use of bipolar membranes is associated with higher investment, the economic factor, however, must be validated each time, including processing, including subsequent operations.Comparative experiments with periodic way clearly show the advantages of the method according to the invention. In the case of periodic testing of the reaction rate are significantly lower. In the case of comparative experiments selectivity towards monocarboxylate sharply reduced, and largely are by-products that are not accurately identified.In the case of a continuous method of operation, desactivate deactivation of the catalyst takes place already after a short time, as already described in the literature.To effect the oxidation device is used with the circulation shown in Fig. 1. The transmission of gas takes place in the mix cylindrical double-walled reactor (500 ml) with stirring over frittoli base. A glass plate is used as a relaxation zone, from which part of the flow is supplied by the centrifugal pump through the catalytic layer, which is placed in a glass column, closed two Frits. After passing through the fixed layer, this portion of the stream enters electrodialyzer and after separation of the oxidation products are then returned to the reactor with stirrer. The product is discharged through a concentrated series of electrodialyzer and the equivalent quantity of a solution of the original substance is dosed into the reactor with stirrer adjustable manner by means of a sleeve of the pump. Loss solution in the course concentrated cycle covered by water.Example 1.Continuous oxidation of palatinose 35oC
When using the described device 20 g of the catalyst platinum/activated carbon (5% Pt/C; particle size 40 - 100 µm; Degussa) and 1000 ml of 0.1 molar solution palatinose is loaded into the device the I water and 1 M Na2SO4is used as the electrode rinsing.The temperature is maintained at 35oC using a circulating thermostat, gas (N2:O2= 4:1) is controlled by bleeding valves and needle valves and the volumetric rate of gas flow measured by the flowmeter, so that the rate of gas supply 100 cm3/min for oxygen and 400 cm3/min for nitrogen are consistent with each other. The pH is kept constant at 6,5 titration pachanoi acid using 1 M NaHCO3. Electrodialyzer (Bel III, Berghot Labortechnik GmbH) equipped with 6 pairs of membranes AMV/CMX (the effective area of the membrane = 360 cm2) and is operated at a voltage of 5 - 6 B. When reaching the equilibrium state of the reaction course is monitored by measurement method GHUR (liquid chromatography high resolution). The obtained product has the following composition:
6-0-(- glucopyranosyl)-D-fructofuranose (C6'-acid) - 50%,
2-keto-6-0-(-D - glyukopiranozil)-D-arabino-EcoNova acid (C1-acid - 42,5%,
5-0-(-D - glyukopiranozil)-D-Urbanova acid (HPA-acid) - 3,5%.Selectivity for monocarboxylic acids: 96%.Substances can be identified by ven is palatinose when 42,5oC
Analogously to example 1 palatinose oxidized at the reaction temperature of 42.5oC. the resulting mixture contained in concentrate in the following composition:
C6'-acid - 50,0%
C1-acid - 42,5%
HPA-acid - 4,0%
Selectivity for monocerata: 96,5 %.Periodic comparative experiment 1.Oxidation palatinose
Periodic oxidation similarly carried out in a circulation reactor system, but without electrodialysis and dispensing the selected substances.36 g palatinose dissolved in 1000 ml of distilled water and is oxidized at the 35oC. as the catalyst used, the catalyst type platinum/activated carbon (5% Pt, Degussa, 40 - 100 µm).The oxidation is conducted with a reaction rate of palatinose 80%, as determined after 4 days, and oxygenated products stand out in the chromatography.The product is obtained of the following composition:
C6'-acid - 50,6%
C1-acid - 23,5%
DI-acid - 8,1%
plus a significant number of unidentifiable products.The selectivity for the formation of monocarboxylic acids is in this case only 74,1%.Example 3.About the t NaHCO3and the temperature of the 35oC.A continuous process is obtained a solution of the product of the following composition:
Na-salt of gluconic acid - 92%
Na-salt of glucuronic acid - 7%
The selectivity in respect of monocolor: 99%.Periodic comparative example 2.The transformation of glucose is carried out at 35oC, pH 6.5 and the use of the catalyst platinum/activated carbon (5% Pt, Degussa, 40 - 100 µm). After 3 days is determined by the rate of conversion, which is equal to approximately 80%.The main oxidized products are:
Na-salt of gluconic acid - 60%
Na-salt of glucuronic acid - 15%
Na-salt glucurono acid - 10%
plus 15% unidentified products exactly.The selectivity with respect to monocerata: 75%.On the graph shown in Fig. 2, presents response curves for continuous and periodic oxidation of glucose. Reactivity with the continuous method of operation is much higher, and the deactivation of the catalyst is not observed.Example 4.Oxidation of glucose at pH 3
Oxidation is provided, as described in example 3, but the pH is adjusted accurately by adding NaHCO
Gluconic acid - 60%
- lactone of gluconic acid - 20%
Glucuronic acid - 15%
Example 4A.Mixed metal catalysts are catalysts based on noble metals together with promoters, such as, for example, bismuth. The problem for these catalysts in the periodic experience is that, despite the longer the reaction time, they are not sufficiently selective. Subsequent reaction with monocarboxylic acids in this case are, however, in the course of these reactions are obtained significant amounts of side products. This disadvantage can be eliminated by using the method according to the invention. The resulting products are removed by electrodialysis directly after their formation and so long are in contact with the catalyst.This is illustrated by practical comparative experience with mixed metal catalyst Pt/Pd/Bi (Degussa) by the oxidation of glucose to gluconic acid or glucuronic acid.The oxidation is carried out, as The composition of the product.Na-salt of gluconic acid - 94%
Na-salt of glucuronic acid - 4%
The selectivity in respect of monocolor: 98%.Example 5.Oxidation of sucrose
Sucrose is converted to the corresponding monocarboxylic acid in accordance with the procedure described in example 1.The oxidation is carried out at pH values of 6.5 and a temperature of 35oC, and the product obtained is a mixture of three monocarboxylic acids:
C6'-sucrose-monocarboxylic acid - 46,5%
C6-sucrose-monocarboxylic acid - 43,7%
C1-sucrose-monocarboxylic acid of 4.9%
Selectivity: more than 95%.Periodic comparative experience 3.Oxidation of sucrose
When performing periodic oxidation process at 35oC and pH 6.5 in 6 days is reached, the reaction rate is 90% and the product is obtained of the following composition:
C6'-sucrose-carboxylic acid - 40,0%
C6-sucrose-carboxylic acid - 31,0%
(of which approximately 10% dikelola)
C1-sucrose-carboxylic acid was 8.8%
The selectivity in respect of monocarboxylic acids: approximately 70%.The graph presented is measures 6.Oxidation glyukopiranozil-methyl-furfural (HMF)
Continuous oxidation GMF is carried out in accordance with the procedure described in example 1.When the temperature of the 35oC and pH 7 is obtained:
C6'-oxidized GMF - 33%
C1-oxidized GMF - 66%
Selectivity for minoocycline products: 99%.Example 7.Oxidation of sucrose
Oxidation of sucrose is held in the device described in example 1 at pH values of 6.5 and at a temperature of 35oC. Instead of the oxygen-nitrogen mixture is injected pure oxygen, so the formation of oxidized products accordingly accelerated (Fig. 3).The main oxidation products are:
C6'-sucrose-carboxylic acid - 43,0%
C6-sucrose-carboxylic acid - 43,0%
C1-sucrose-carboxylic acid - 9,5%
Selectivity: above 95%.Thus, the invention relates to a method and apparatus for obtaining minoocycline products from carbohydrates, their derivatives and primary alcohols. Source materials arrive at ongoing stage of oxidation, where contact with a catalyst based on a noble metal or mixed metal catalyst. Flux the monocarboxylic acid is continuously emit and receive as target products. 1. The method of obtaining monocarboxylic acids by oxidation of the corresponding carbohydrates, derivatives of carbohydrates or primary alcohols with selection of the target product by electrodialysis, wherein the carbohydrates, derivatives of carbohydrates or primary alcohols continuously oxidized in an aqueous solution with a mass concentration of 0.1 - 60% oxygen or oxygen-containing gas on the catalysts based on noble metals or mixed metal catalysts based on noble metals and promoters, followed by a continuous flow of the formed products on stage electrodialysis, after which the monocarboxylic acid as the target products, and produce.2. The method according to p. 1, characterized in that the extracted after separation of monocarboxylic acids substances return to the stage of oxidation.3. The method according to p. 1 or 2, characterized in that the flow of the original substances prior to introduction into the catalytic layer enrich free from bubbles of oxygen.4. The method according to p. 3, characterized in that at the stage of oxidation conduct a preliminary enrichment of oxygen in the oxidation reactor by introducing air or gas mixtures with a high partial pressure, CI is the gas is injected under pressure or not under pressure to and from the oxidation reactor part of the flow pumped by the pump connected therewith and mounted parallel to the tubular reactor, where is the catalytic Converter.5. The method according to p. 3, characterized in that at the stage of oxidation in the vessel with stirrer carry out suspension method with suspended catalysts.6. The method according to p. 5, characterized in that the stage of oxidation and phase electrolysis divided by the separation unit.7. The method according to PP. 1 - 6, characterized in that the catalyst used noble metals of group VIII of the Periodic system of elements.8. The method according to p. 7, characterized in that use, in particular Pt-catalysts on substrates with platinum concentration of 0.1 - 10%, in particular powder Pt/C-catalyst with a platinum content of 0.1 to 10%, of which removed the fine fraction.9. The method according to PP.1 to 8, characterized in that the source and minoocycline substance use reducing sugars, such as for example, palatinose, glucose, fructose, sorbose, and/or non sugars, such as sucrose, trehalose, and/or sugar alcohols, such as, for example, palatinit, sorbitol, and/or Alkylglucoside and alkylpolyglycoside, such as for example, methylglucoside, octylglucoside or a mixture of such, and/or specially modified derivatives at>/P>10. The method according to PP.1 to 9, characterized in that as solvents for the original substances using water or a mixture of water and secondary alcohols, preferably isopropyl alcohol.11. The method according to PP.1 to 10, characterized in that the oxidation and the electrodialysis is carried out in the range of pH 1 - 13.12. The method according to PP.1 - 11, characterized in that the temperature of oxidation is maintained within the range of 0 - 80oC, preferably 20 - 60oC.13. The method according to PP.1 - 12, characterized in that the extracted after separation of monocarboxylic acids substances are used in a weight concentration of 3 to 20%.14. The method according to PP.1 - 13, characterized in that for adjustment of pH using Na2CO3, NaHCO3or NaOH or other alkalizing agents.15. The method according to PP.1 to 14, characterized in that when using a Pt-catalyst on Al2O3substrate non glucopyranosyl unit selectively oxidize only in the 6-position.16. The method according to PP.1 - 15, characterized in that use additional line (60) and the flow going from the stage of oxidation, is separated from the stream coming from the stage electrodialysis.17. The device for implementing the method of paluckiene in aqueous solution with oxygen or oxygen-containing gases on the catalyst with subsequent flow educated so products on stage electrodialysis and allocation of monocarboxylic acids with obtaining the target product, characterized in that it comprises a series-connected stage passing the gas (10), the stage of oxidation (30) and the stage electrodialysis (40).18. The device under item 17, characterized in that it further comprises a supply line of monocarboxylic acids (41) to the collection tank acids (50) and the return line nemonoxacin carbohydrates (43) to the stage of passing the gas (10).19. The device under item 17 or 18, characterized in that the stage of passing the gas (10) is in the vessel with stirrer.20. The device according to PP.17 to 19, characterized in that on the stage electrodialysis (40) use or bipolar ion-exchange membrane.21. The device according to PP.17 to 20, characterized in that it contains an additional line-of-way (60) stage of oxidation, parallel with the stage electrodialysis (40).
FIELD: organic chemistry, chemical technology, catalysts.
SUBSTANCE: invention relates to a method for preparing acetic acid by gas-phase oxidation of ethane and/or ethylene with oxygen using catalyst comprising molybdenum and palladium. For realization of method gaseous feeding comprising ethane, ethylene or their mixture and oxygen also are contacted at enhanced temperature with catalyst that comprises elements Mo, Pd, X and Y in combination with oxygen of the formula (I): MoaPdbXcYd wherein X and Y have the following values: X means V and one or some elements optionally taken among the following group: Ta, Te and W; Y means Nb, Ca and Sb and one or some elements optionally taken among the following group: Bi, Cu, Ag, Au, Li, K, Rb, Cs, Mg, Sr, Ba, Zr and Hf; indices a, b, c and d mean gram-atom ratios of corresponding elements wherein a = 1; b = 0.0001-0.01; c = 0.4-1, and d = 0.005-1. Niobium is added to the catalyst structure using niobium ammonium salt. Preferably, niobium ammonium salt is used as the niobium source. The continuance of contact time and composite values of the parent gaseous mixture are so that taken to provide output value by acetic acid to be above 470 kg/(m3 x h). The selectivity of oxidation reaction of ethane and/or ethylene to acetic acid is above 70 mole %. Invention provides enhancing stability and output of catalyst.
EFFECT: improved preparing method.
14 cl, 1 tbl, 6 ex
FIELD: production acetic acid by ethane oxidation.
SUBSTANCE: claimed method includes ethane oxidation with molecular oxygen in reactor with at least one fluidized bed of catalyst particles wherein at least 70 % of used particles have diameter 80 mum or less and density of catalyst particles is 500-6000 kg/m3. Gas stream is fed in such a manner that bulb diameter of reaction gas mixture in reactor will be less than 12 cm. Process is carried out at preferable temperature of 100-5000C and pressure of 1-50 bar. Inert gas, carbon dioxide and/ore water steam may be added in addition to ethane and molecular oxygen in reaction mixture.
EFFECT: improved high exothermic oxidation process; high yield of finished product.
13 cl, 2 ex, 3 tbl, 9 dwg
FIELD: industrial organic synthesis.
SUBSTANCE: invention relates to improved method for production of carboxylic acids and polyacids via liquid-phase oxidation of cyclohexane with molecular oxygen in presence of catalyst: lipophilic acidic organic compound with solubility in water below 10 wt % at 10-30°C, which forms with cyclohexane at least one homogenous liquid phase. Molar ratio of lipophilic acid to catalyst-forming metal lies within a range of 7.0 to 1300. Lipophilic acid is selected from group consisting of 2-ethylhexanoic, decanoic, undecanoic, stearic acids and permethylated derivatives thereof, alkyl(preferably tert-butyl-type)substituted 2-octadecylsuccinic, 2,5-di-tert-butylbenzoic. 4-tert-butylbenzoic, 4-octylbenzoic, tert-butylhydro-o-phthalic, naphthenic, and anthracenic acids, fatty acids, and substituted phthalic acid derivatives.
EFFECT: simplified separation and recycling of oxidation intermediates and catalyst as compared to methods wherein acetic acid is used as solvent.
8 cl, 11 tbl, 26 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to the improved method for oxidation of cycloaliphatic hydrocarbons and/or alcohols and ketones in liquid medium with a molecular oxygen-containing oxidizer to acids or polybasic acids. The reaction is carried out in the presence of manganese-base catalyst and organic acid compound of the general formula (I): HOOC-Ar-[R]n wherein Ar means aromatic radical comprising aromatic cycle or some aromatic cycles in condensed form; n means a whole number 1, 2 or 3; R means radical of the general formula (II): wherein R1, R2 and R3 are similar or different and mean alkyl chain comprising from 1 to 4 carbon atoms, or fluorine, chlorine or bromine atom. In more detail, the invention relates to oxidation of cyclohexane and/or cyclohexanol/cyclohexanone to adipic acid with an oxidizer in the presence of aromatic organic acid and manganese-base catalyst. The yield and selectivity by adipic acid are at higher level with respect to yield and selectivity as compared with result obtaining with other solvents and catalysts.
EFFECT: improved oxidation method.
20 cl, 13 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to the improved method for oxidation of (C2-C4)-alkane and preparing the corresponding alkene and carboxylic acid. Method involves addition of this alkane to contact with molecular oxygen-containing gas in oxidative reaction zone and optionally at least one corresponding alkene and water in the presence of at least two catalysts with different selectivity. Each catalyst is effective in oxidation of alkane to corresponding alkene and carboxylic acid resulting to formation of product comprising alkene, carboxylic acid and water wherein the molar ratio between alkene and carboxylic acid synthesized in the reaction zone is regulated or maintained at the required level by regulation the relative amounts of at least two catalyst in the oxidative reaction zone. Also, invention relates to the combined method for preparing alkyl carboxylate comprising abovementioned stage in preparing alkene and carboxylic acid in the first reaction zone. Then method involves the stage for addition of at least part of each alkene and carboxylic acid prepared in the first reaction zone to the inter-contacting in the second reaction zone the presence of at least one catalyst that is effective in preparing alkyl carboxylate to yield this alkyl carboxylate. Also, invention relates to a method for preparing alkenyl carboxylate comprising the abovementioned stage for preparing alkene and carboxylic acid in the first reaction zone and stage for inter-contacting in the second reaction zone of at least part of each alkene and carboxylic acid synthesized in the first reaction zone and molecular oxygen-containing gas in the presence of at least one catalyst that is effective in preparing alkenyl carboxylate and resulting to preparing this alkenyl carboxylate.
EFFECT: improved method for oxidation.
30 cl, 1 dwg, 5 tbl, 14 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: industrial organic synthesis.
SUBSTANCE: invention relates to improved process to produce acrylic acid via heterogeneously catalyzed gas-phase partial oxidation of propane wherein starting reactive gas mixture containing propane, molecular oxygen, and at least one gas diluent is passed at elevated temperature over a multimetal oxide bulk depicted by total stoichiometry as Mo1VbM1 сM2 вOn (I), in which M1 = Te and/or Sb and M2 is at least one element from group comprising Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Ga, Fe, Ru, Co, Rh, Ni, Pd, Pt, La, Bi, B, Ce, Zn, Si, and In; b = 0.01 to 1, c = >0 to 1, d = >0 to 1, and n = number, which is determined by valence and number of non-oxygen elements in (I). Propane is partially oxidized to produce acrylic acid in a process wherein composition of starting reaction mixture is at least two times varied in the course of process such that molar percentage of gas diluent (water steam) in starting reaction gas mixture decreases relative to molar percentage of propane contained in starting gas mixture.
EFFECT: reduced amount of water steam in gas mixture without loss in selectivity and activity of catalyst regarding target product.
5 cl, 1 dwg, 10 ex
FIELD: chemistry of halogenated hydrocarbon, chemical technology.
SUBSTANCE: invention relates to an improved method for synthesis of higher saturated chlorinated acids of the general formula: R(CHCl)nCOOH wherein R means aliphatic hydrocarbon radical comprising 9-22 carbon atoms; n = 1-4. Method involves oxidation of chloroparaffins in the presence of catalyst that is mixed with chloroparaffins in the presence of air oxygen at temperature 120-1250C, and oxidation is carried out with air oxygen at temperature 105-1100C under atmosphere pressure for 30-32 h, and wherein cobalt stearate is used as catalyst taken in the amount 1.5-1.7 wt.-% of the reaction mass. Invention provides increasing rate in carrying out the reaction and simplifying the method.
EFFECT: improved method of synthesis.
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: industrial organic synthesis.
SUBSTANCE: invention relates to a process for production of C2-C4-alkane into alkene and carboxylic acid and immediately using them in ester synthesis stage. According to invention, to produce alkyl carboxylate, in particular ethyl acetate, or alkenyl carboxylate, in particular vinyl acetate, stage wherein alkane is oxidized to corresponding alkene and carboxylic acid is combined with alkenyl carboxylate or alkyl carboxylate production stage. Process comprises contacting of alkane- and alkene-containing gas raw material with molecular oxygen and catalyst in the first oxidation reaction zone, catalyst being efficient in oxidation of alkane into corresponding alkene and carboxylic acid. In the second reaction zone, part of streams isolated in separation stage and enriched with alkene and carboxylic acid is brought into contact with at least one catalyst efficient to produce either alkyl carboxylate or alkenyl carboxylate in presence of oxygen-containing gas. For example, first product stream consists of ethylene and acetic acid with water admixture. In the second reaction zone, stream enriched with alkene and carboxylic acid comes into contact with oxygen, optionally in presence of additional amount of ethylene and/or acetic acid from the first product stream. As a result, second product stream comprising vinyl acetate, water, acetic acid, and optionally small amounts of carbon oxides is obtained. Second product stream is separated into fractions containing vinyl acetate and acetic acid, which are subjected to further purification. In a cycle wherein acetic acid from main fraction is regenerated, the latter is recycled to vinyl acetate stage in the second reaction zone.
EFFECT: improved economical efficiency of process.
36 cl, 1 dwg