TW200424155A - Ammoxidation of carboxylic acids to mixture of nitriles - Google Patents

Abstract

A process for increasing the yield of acetonitrile produced during the manufacture of acrylonitrile comprising introducing a hydrocarbon selected from the group consisting of propylene and propane, a carboxylic acid, ammonia, and air into a reaction zone containing an ammoxidation catalyst, reacting the hydrocarbon, carboxylic acid, ammonia and oxygen over said catalyst at an elevated temperature to produce acrylonitrile, hydrogen cyanide, and acetonitrile, and recovering the acrylonitrile, hydrogen cyanide, and acetonitrile from the reactor.

Description

200424155 发明 Description of the Invention: This application requests US Provisional Patent Application Serial No. 60 / 381,066 (filed on May 16, 2002). [Chi ^ ^ ^ ^ ^ super page ^] 5 The present invention relates to a method for the amidation and oxidation of carboxylic acids (especially carboxylic acid mixtures) to nitriles or nitrile mixtures. Background of the invention

Acrylonitrile is an important chemical. It is mainly used as a monomer for the manufacture of a wide range of different polymer materials (such as polymers for propylene-based fibers used in fabrics) and trees (such as ABS and SAN resins). Worldwide, acrylonitrile is manufactured in quantities of more than four million tons per year. The most commonly used method for making acrylonitrile is to react an appropriate hydrocarbon such as propylene or propane using an air or other molecular oxygen source as an oxidant in an ammoxidation reactor in the presence of ammonia. These 15 oxidation reactions (also known as amination oxidation reactions) typically use fluidized catalysts.

The solid particle heterogeneous catalyst of the chemical agent bed catalyzes the amidation oxidation reaction and provides the desired acrylonitrile with acceptable conversion and yield. In addition to the manufacture of acrylonitrile, these amidation reactions generally also produce acetonitrile, hydrogen cyanide (HCN), and other valuable co-products. For example, acetonitrile is used as the solvent. A method for catalyzing the oxidation of a hydrocarbon feedstock 20 to acrylonitrile is disclosed, for example, in U.S. Patent Nos. 5,093,299; 4,863,891; 4,767,878; 4,503,001, all of which are incorporated herein by reference. Methods that are widely used commercially to recover the products of such hydrocarbon amination reactions (e.g., amination reactions of propylene) generally include steps: a) 5 200424155

Contacting the effluent of the amination hydrolysis reactor with an aqueous quench liquid in a quench tower to cool the gaseous effluent; b) contacting the quenched effluent with water in an absorber to form an amination hydrolysis product Aqueous solution; c) subjecting the aqueous solution to water extractive distillation; and d) removing the first overhead vapor stream containing acrylonitrile and some water from the top of the column, and collecting water and contaminants from the bottom of the column Liquid waste stream. Further purification of acrylonitrile can be accomplished by passing the overhead vapor stream to a second distillation tube column to remove at least some impurities from the crude acrylonitrile and further distilling the partially purified acrylonitrile. The effluent from the ammoxidation reactor typically contains some ammonia. Therefore, the quench fluid used in the quench tower 10 may also contain a strong mineral acid (such as sulfuric acid) to react and thereby form a water-soluble salt of ammonia, such as ammonium sulfate. Used or spent quench fluids containing ammonium sulfate and other components are typically disposed of or disposed of in an environmentally safe manner. The crude acetonitrile can be obtained by using the bottom 15 fluid of the above-mentioned extractive distillation column, and then subjected to further purification procedures, such as those disclosed in U.S. Patent No. 6,204,407.

It is desired to be able to adjust the relative content of acrylonitrile and acetonitrile produced by the amidation oxidation reaction of a hydrocarbon feed (such as propylene or propane), because sometimes it is desired to have additional acetonitrile to meet changing or increasing market demand . In addition, it is intended to produce used quenched liquids that can be recycled (rather than disposed of) in the process for making acrylonitrile. The present invention provides such methods. It is desired to be able to adjust the relative content of acrylonitrile and acetonitrile produced by the amidation oxidation reaction of a hydrocarbon feed (such as propylene or propane), because sometimes it is desired to have additional acetonitrile to meet changing or increasing market demand . In addition, it is intended to produce used quenched liquids that can be recycled (rather than disposed of) in the process for making acrylonitrile. The present invention provides such methods. The present invention relates to a method for the amidation and oxidation of carboxylic acids (especially carboxylic acid mixtures) to nitriles or nitrile mixtures. This fortune is related to the ratio of acetonitrile to acrylonitrile produced during the ammoxidation (such as the conversion of propylene or propane to acrylonitrile) of hydrocarbons in Chejiajia. The present invention also relates to a method for increasing the yield of co-product acetonitrile during the production of acrylonitrile by the ammoxidation reaction of a hydrocarbon feed (such as propylene or propane) and the same% savings in raw material costs related to the increase in co-product yield. Method. The relative amount of acetonitrile can be controlled by the present invention by adjusting the acid content added to the amidation oxidation reaction. It has been unexpectedly found that the use of carboxylic acids (especially crude carboxylic acid mixtures) can achieve the desired increase in acetonitrile production during the production of acrylonitrile. The present invention also relates to a method for recycling the quenched liquid from a used quench tower to an amination hydrolysis reactor. Contents of the Invention Summary of the Invention The present invention includes a method for substantially increasing the amount of acetonitrile produced during the production of propylene nitrile from propylene or propane or a mixture thereof. Accordingly, the present invention includes a method for increasing the yield of acetonitrile, a co-product produced during the manufacture of acrylonitrile, including the inclusion of at least one hydrocarbon selected from the group consisting of propylene and propane, a few acids, ammonia, and a molecular oxygen-containing gas The reactants are introduced into a reaction zone (for example, a fluid bed reactor) containing an amidation oxidation reaction catalyst, and the hydrocarbons, carboxylic acids, gases, and oxygen are reacted on the catalyst at an elevated temperature to produce acrylonitrile, hydrogen cyanide, and acetonitrile. And a product containing acrylonitrile, hydrogen cyanide, and acetonitrile from the reaction zone. The present invention includes a method for converting a carboxylic acid (especially a crude Wei acid, and more particularly a crude Wei acid mixture) into acetonitrile during acrylonitrile production. A process that does not significantly affect the yield of acrylonitrile. Therefore, the present invention includes allowing a reactant 51 including at least one hydrocarbon selected from the group consisting of propylene and propane, at least one ferulic acid, ammonia, and molecular oxygen-containing gas into a reaction zone containing an amination oxidation reaction catalyst (for example, a 'fluid Bed reactor), and reacting hydrocarbons, pelic acid, ammonia, and molecular oxygen on catalysts at elevated temperatures to produce acrylonitrile, hydrogen cyanide, and acetonitrile. The present invention includes introducing at least one hydrocarbon selected from the group consisting of propylene and propane, at least one carboxylic acid, ammonia, and molecular oxygen-containing gas into a reaction zone (such as a 'fluid bed reaction group) for the amidation oxidation reaction. A catalyst (for example, a fluid bed amination reaction catalyst) reacts in the presence of a reactor effluent containing acrylonitrile, hydrogen cyanide, and acetonitrile, and the reactor effluent containing acrylic, hydrogen nitride, and acetonitrile is sent to Quenching the column to cool the reactor effluent 'and recovering the desired product containing at least one of acrylonitrile, acetonitrile, and hydrogen cyanide from the reaction as effluent. In one embodiment of the invention, one or more carboxylic acids may be added to the quench liquid to react with excess ammonia present in the effluent of the amination oxidation reactor. Preferably, at least part of the quench liquid system comprising an ammonium salt formed by the reaction of ammonia with one or more carboxylic acids is recycled to the amolysis oxidation reactor or reaction zone. Products formed by the method of the present invention (such as acrylonitrile, acetonitrile, and cyanide 200424155 hydrogen hydride) can be recovered, and by methods known to those skilled in the art (for example, U.S. Patent Nos. 4,234,501; 3,885,928; 3,352,764; 3,198,750 And the method disclosed in Case No. 3,044,966, which is hereby incorporated by reference) for purification. 5 In a preferred embodiment of the present invention, the crude carboxylic acid is used as the carboxylic acid source. As used herein, the crude carboxylic acid includes pelic acid or a mixture thereof that has not been purified to a generally commercially available grade of pure grade carboxylic acid, and preferably it means that one or more Carboxylic acids prepared by methods of making carboxylic acids but which have not been purified to a generally commercially acceptable grade of pure grade carboxylic acids or 10 mixtures thereof. The crude carboxylic acid or mixture may contain water, other impurities, or both. For example, the water content of the crude carboxylic acid may be from about 2, about 5, or about 10% by weight to about 98% by weight of Nanda. . Crude acetic acid is the preferred carboxylic acid used in the examples of the present invention. 15

Any amidation oxidation catalyst can be used in the embodiments of the present invention. A typical amination hydrolysis catalyst is summarized by the following two chemical formulas:

AaBbCcDcM〇i2〇x, where

• Na K Ca, T1 and mixtures thereof, especially & and κ Ni Co Mn, Mg, Ca and mixtures thereof, preferably ⑽, co and Mg 20 P and mixtures thereof, and more preferably Fe, Cr and Ce EKBi and / or Te, preferably Bi a = 0.1-4.0, preferably 〇 丨 to 〇5 b = 0.110. 0, more preferably 5 to 9, 9 200424155 c, d = 0.1-10.0, It is preferably 0.5 to 4, particularly preferably 0.5 to 3; and AaBbSbi20x 'where A = Fe, Cr, Ce, V, U, Sn, Ti, Nb, and mixtures thereof, and more preferably Fe, V, Sn, and Ti 5 B = Mo, W, Co, Cu, Te, Bi, Zn, B, Ni, Ca, Ta

And mixtures thereof, preferably Mo and Cu a = 0.1-16, preferably 2 to 12, particularly preferably 4 to 10 b = 0.0-12, preferably 1 to 10, particularly preferably 2 to 6, and The value of X depends on the oxidation state of the element used. 10 The appropriate amination oxidation catalyst used in the present invention may be used unsupported, or it may be supported by silica, alumina, titanium oxide, zirconia, etc .; however, a silica-based support is preferred. Examples of catalysts suitable for use in the practice of the present invention are disclosed in U.S. Pat. Nos. 3,642,930; 4,485,079; 3,911,089; 4,873,215; 5,134,105, and 5,093,299, which are incorporated herein by reference. 15 [Embodiment] Detailed description of the present invention

The present invention is an amidation oxidation reaction method comprising a mixture of one or more propylene and propylene, ammonia, a source of molecular oxygen, and a carboxylic acid. The carboxylic acid is preferably a crude carboxylic acid or a mixture of crude carboxylic acids. The present invention is a feedstock that uses a carboxylic acid (especially a crude carboxylic acid) as a useful nitrile co-product such as acetonitrile produced during the manufacture of acrylonitrile. In addition, a carboxylic acid or a mixture thereof containing a large amount of a diluent (e.g., water) can be used in the practice of the present invention, thereby further reducing the cost of a carboxylic acid or a carboxylic acid-containing raw material suitable for producing a co-product. The present invention is also a 10% increase in the yield of acetonitrile during the manufacture of acrylonitrile, so that it contains at least one hydrocarbon selected from the group consisting of propylene and propane, and at least one asset is attractive, ammonia, and The reaction of a molecular oxygen gas (such as air) to the reaction zone of 3 shame-dissolving oxidation catalysts, and the reaction of hydrocarbons, carboxylic acids or acid mixtures, and idiot knife oxygen on this catalyst at elevated temperature produces ^ cyanide The product of rat and acetonitrile, and the product containing one or more of acrylonitrile, hydrogen cyanide, and acetonitrile is recovered from the reactor one or more nights. The preferred carboxylic acid used in the present invention is a carboxylic acid having a relatively low carbon number, which has 8 or less carbon atoms (preferably 6 or less carbon atoms, and most preferably 3 or less). Carbon atoms). The carboxylic acid may be saturated or unsaturated, branched or linear, and may be aromatic or have an aromatic component. The meta-acid used in the present invention may be a monovalent, or it may be a multivessel, ~, having several acid groups, and thus may be, for example, a ditrit-, tetra-carboxylic acid. Suitable carboxylic acids include, for example, one or more of acetic acid, acetic acid, propionic acid, butyric acid, oxalic acid, acrylic acid, butenoic acid, maleic acid, succinic acid, adipic acid, benzoic acid, toluic acid, and the like. As used herein, crude acetic acid (such as crude acetic acid) may be no more than about 98% by weight purity (preferably no more than about 95% by weight purity, and more preferably no more than about 90% by weight purity). Single carboxylic acid. Preferably, the carboxylic acid-based acetic acid 'used in the present invention is more preferably crude acetic acid. Another preferred acid used in the present invention comprises a mixture of formic acid, acetic acid and propionic acid; for example, a mixture obtained as a by-product or waste fluid produced from acetic acid. Contains about 5 and up to about 98 (or up to about 95 or up to about 90 or 55) weight percent acetic acid, about 0 (or about work, or about 10) to up to about 25% by weight of formic acid and about 0 or about 1 and up to about 20 (or up to about 10, or up to about 5) reset acid branching acid mixtures of propionic acid can be used in the method of the invention. These crude carboxylic acid mixtures can be obtained from the waste stream or side stream of pure 200424155 acetic acid. In the method of the present invention, some or all of the carboxylic acid may be added as a salt, preferably a salt formed by mixing a carboxylic acid with an amine or ammonia. The preferred salt is Syria salt. If the acid is added and some or all of it is a salt (such as an ammonium salt), then this salt is preferably added to the amination hydrolysis reactor as an aqueous solution. For example, aqueous solutions up to about 33% by weight of salt (preferably from about 5 to about 33% by weight ammonium salt). When an aqueous solution is used, the aqueous solution is preferably sprayed into an amination hydrolysis reaction zone (for example, a fluidized bed of an amination hydrolysis catalyst). The preferred concentration of this ammonium salt is about the same concentration as the circulating fluid available from the quenching operation used in the process for recovering propylene from the effluent of the ammoxidation reactor. In the quenching operation as described above, the hot gaseous effluent of the ammoxidation oxidation reactor is contacted with a quenching mash (preferably a water-cooled liquid) to cool the ammoxidation reactor effluent. During the quenching process, excess ammonia in the amine oxidant reactor effluent may react with the acid or a mixture of acid that is added to the aqueous quench liquid to form ammonia salts (i.e., money salts). The used or spent quenching liquid obtained from this quenching operation (containing the ammonium salt of 1 or 1) is a preferred source of the present invention for addition to the amidation oxidation reaction. The acid that is added to the quench liquid to react with excess ammonia and remove this ammonia may be one or more of the retarded acids described herein or a mixture thereof. Therefore, in the embodiment of the present invention, Wei or a mixture thereof (preferably the acid or more as described above) is added to the step for quenching the effluent of the ammoxidation reactor for producing propylene. Cold liquid (preferably aqueous quench liquid). After the ammonia reaction used to quench the amidation oxidation reactor effluent and the ammonium amination reaction reactor effluent, the liquid system containing 12 200424155 ammonium salt or at least part of it is recycled to the amination hydrolysis reactor. The amount of carboxylic acid-ammonium salt in the circulating quench liquid may be from about 5 to up to about 33 (more preferably up to about 15)% by weight of the carboxylic acid ammonium salt. The preferred carboxylic acid to be added to the quenched liquid is acetic acid, more preferably crude acetic acid. Another preferred carboxylic acid is a mixture containing acetic acid, acetic acid, and propionic acid as described above. Preferred is a mixture in which the content of propionic acid is low (e.g., not more than 5% by weight of the mixture, more preferably not more than 1% by weight). The quench liquid (preferably an aqueous quench liquid) is preferably added to the ammoxidation by spraying the quench liquid into the reactor (preferably the fluidized bed of the fluidized bed reactor). reactor. The amount of g 10 added to the reaction zone in the method of the present invention or a mixture thereof (added in the form of a minus or salt (such as an ammonium salt)) can be used as the ammonia feed rate to the reaction zone based on the mole. It is up to about 50%, or up to about 25 or 40%, for example, between about 15% and about 15%. In a preferred embodiment of the present invention, the conditions of the ammoxidation oxidation reactor can be adjusted to obtain an increased yield of acetonitrile obtained by using a ship or a mixture thereof. In the practice of the present invention, the conditions of the amidation oxidation reaction are preferably within the following parameters: a few acids or #f added in the form of acid or salt (such as money salt). The feed rate of this mouthpiece is in moles As a reference, it can be up to · or up to about 25 or 40% of the ammonia feed rate, for example, between about 15% and about 15%, and the temperature of the 20 amidation oxidation reaction can be about 42G. To about vague. Between c, it is preferably about 430. To about 440 ° C, the pressure is suitably maintained between about i to about 2 atmospheres, preferably about 1 to about 1.2 or 1.1 lambda. In a preferred embodiment of the present invention, this method is carried out in a fluid bed reactor using a particulate amination oxidation catalyst. 13 200424155

The following examples are for illustrative purposes and are not to be considered as limiting the implementation of the invention. The acrylamide deoxidation reaction using air and ammonia is performed with or without the addition of 5 catalysts. The catalyst used in the examples is a promoted BiFeM which is known to be suitable for the hydrolysis of acrylonitrile to acrylonitrile. x. The crude acetic acid in an amount of 2.5, 5 and 0% of the ammonia supply based on Mohr was added to the amination and oxidation reactor together with propylene and air, and the results shown in Table 1 below were produced. The crude acetic acid mixture was changed to pH 5 by adding ammonium hydroxide solution, and the acid that formed 10 was diluted to 67% of water before being supplied to the reaction. In each of the following examples, the 'reactor temperature is 440 ° C, the pressure is 10.0 psig, and the molar / ammonia / acid molar feed ratio is 1 / 1.17 / 10.0 / X (X = 0.029, 0.059 , 0.12). wwh is 0.08 (grams of hydrocarbons / grams of catalyst, hours). Table 1 Example No. Acetic acid, ammonia feed acrylonitrile yield, acetonitrile yield% Morse% HCN production 1 (comparative example) 0 79.6 1.5 6.1 2 2.5 80.1 2.2 5.9 3 5 78.7 2.8 5.8 4 10 77.3 3.9 6.0 15 The data in Table 1 demonstrates an increase in the yield of acetonitrile from the addition of acetic acid to the amidation oxidation reaction. In general, all carboxylic acids can be oxidized to a nitrile mixture. In particular, acetic acid, and preferably crude acetic acid, can be amine-oxidized to acetonitrile. Preferred acids include carboxylic acids from 20 to 20 Å. The present invention is also a method comprising introducing a reactant comprising at least one carboxylic acid, ammonia, and a molecular oxygen-containing gas to an amidation oxidation catalyst 14 200424155 ( Such as, one of the catalysts described here) in a reaction zone (eg, a fluid bed reaction), and the use of temperatures and pressures such as those described herein to raise the temperature of reactants containing carboxylic acids, ammonia, and molecular oxygen at elevated temperatures The catalyst is reacted to produce a product comprising a nitrile, preferably in which the carboxylic acid comprises acetic acid, more preferably in which the carboxylic acid comprises crude acetic acid, and when the carboxylic acid comprises acetic acid or crude acetic acid, the nitrile preferably comprises acetonitrile.

Only certain embodiments and examples of the present invention are exemplified, and other embodiments and various modifications will become apparent to those skilled in the art from the above description. These and other alternative embodiments may be considered equivalents and within the spirit and scope of the present invention. US Provisional Patent Application Serial No. 60 / 381,066 (filed on May 16, 2002) is hereby incorporated by reference in its entirety. I: Brief description of the drawing 3 (none) 15 [List of symbols for the main components of the drawing] (none)

15

Claims (1)

200424155 Scope of patent application: 1. A method comprising introducing a reactant containing at least one hydrocarbon selected from the group consisting of propylene and propane, at least one carboxylic acid, ammonia, and molecular oxygen-containing gas to an amidation oxidation catalyst In the reaction zone, and reacting the reactant containing the hydrocarbon, the carboxylic acid, the ammonia, and the molecular oxygen at the elevated temperature on the catalyst, a product containing acrylonitrile, hydrogen cyanide, and acetonitrile is produced. 2. The method as described in item 1 of the patent application scope, wherein the carboxylic acid comprises a crude carboxylic acid. 3. The method as described in claim 1 wherein the carboxylic acid comprises a carboxylic acid 10 mixture. 4. The method according to item 1 of the scope of patent application, wherein the carboxylic acid is at least partially in the form of an ammonium salt. 5. The method according to item 1 of the scope of the patent application, wherein the carboxylic acid is at least partially in the form of a salt of an amine. 15 6. The method according to item 4 of the patent application, wherein the ammonium salt comprises an aqueous solution. 7. The method as described in item 1 of the patent application scope, wherein the carboxylic acid comprises acetic acid. 8. The method as described in claim 1 wherein the carboxylic acid comprises crude 20 acetic acid. 9. The method according to item 1 of the scope of patent application, wherein the carboxylic acid comprises a mixture of formic acid, acetic acid and propionic acid. 10. The method as described in claim 6 of the scope of the patent application, wherein the carboxylic acid comprises crude acetic acid. 16 200424155 ιι · A method comprising introducing a reactant containing ammonia, a molecular oxygen-containing gas, and at least one hydrocarbon selected from the group consisting of propylene and propane into a reaction region containing an amination oxidation catalyst, and including the hydrocarbon, The reactant of the ammonia and the molecular oxygen reacts with the catalyst at an elevated temperature to produce a reaction zone effluent containing acrylonitrile, cyanohydrin 5 and acetonitrile, so that the reaction zone effluent and Cold liquid contact, and at least a portion of the quench liquid is added to the reaction zone after the quench liquid contacts the effluent from the reaction zone. 12. The method according to item 11 of the scope of patent application, wherein the carboxylic acid comprises a crude carboxylic acid. 13. The method of claim 11 in which the carboxylic acid comprises a carboxylic acid mixture. 14. The method according to item u of the patent application, wherein the carboxylic acid comprises a mixture of acetic acid, acetic acid and propionic acid. 15 15. The method according to item 11 of the scope of patent application, wherein the quench liquid added to the reaction zone comprises an ammonium salt of the carboxylic acid. 16. · A method for increasing the yield of acetonitrile, a co-product during the manufacture of acrylonitrile, comprising the step of including at least one hydrocarbon selected from the group consisting of propylene and acrylic acid, acid, ammonia, and molecular oxygen-containing gas The reactant is introduced into a reaction zone containing an amination oxyhydrogenation catalyst, and the reactant containing the hydrocarbon, the carboxylic acid, the ammonia, and the oxygen is reacted on the catalyst at an elevated temperature to produce acrylonitrile, cyanide The product of hafnium and acetonitrile. 17. The method according to item 1 in the scope of patent application, wherein the carboxylic acid comprises acetic acid. 0 17 200424155 18. The method according to item 16 in the scope of patent application to produce acetic acid. 19. A method as described in item 16 of the scope of the patent application. A mixture of acid, acetic acid and propionic acid. 5 20. The method described in item 16 of the scope of patent application is partially in the form of an ammonium salt. 21. Method as described in item 11 of the scope of patent application. 22. Production of acetic acid as described in item 11 of the scope of patent application. Wherein the carboxylic acid contains crude, where the carboxylic acid contains methyl, where the carboxylic acid is at least, where the carboxylic acid contains ethyl, and where the carboxylic acid contains crude 18 200424155 柒, designated representative map: (a) The designated representative map in this case is: () Illustration. (2) Brief description of the representative symbols of the components in this representative diagram: (none) 捌 If there is a chemical formula in this case, please disclose the chemical formula that can best show the characteristics of the invention: