CA1067061A - Recovery of catalysts in a fluidized bed - Google Patents
Recovery of catalysts in a fluidized bedInfo
- Publication number
- CA1067061A CA1067061A CA239,905A CA239905A CA1067061A CA 1067061 A CA1067061 A CA 1067061A CA 239905 A CA239905 A CA 239905A CA 1067061 A CA1067061 A CA 1067061A
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- Prior art keywords
- catalyst
- compound
- fluidized
- water soluble
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/32—Separation; Purification
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G31/00—Compounds of vanadium
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G33/00—Compounds of niobium
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G41/00—Compounds of tungsten
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- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Epoxy Compounds (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a process for the separation of a catalyst employed in the epoxidation or hydroxyl-ation of an olefinic compound with a peroxy compound in a reactor, distilling off the epoxidized or hydroxylated product and separ-ation of the catalyst from the distillation residue containing said catalyst and said high boiling organic compounds, said catalyst being a compound of a transition metal, the improvement comprising introducing the distillation residue into a bed of fluidized inert solid particles, burning the organic compounds of said distillation residue with an oxygen containing gas while in contact with said fluidized particles and separating fluidized particles containing a compound of the metal employed in the catalyst from the waste gas of said burning.
The present invention provides a process for the separation of a catalyst employed in the epoxidation or hydroxyl-ation of an olefinic compound with a peroxy compound in a reactor, distilling off the epoxidized or hydroxylated product and separ-ation of the catalyst from the distillation residue containing said catalyst and said high boiling organic compounds, said catalyst being a compound of a transition metal, the improvement comprising introducing the distillation residue into a bed of fluidized inert solid particles, burning the organic compounds of said distillation residue with an oxygen containing gas while in contact with said fluidized particles and separating fluidized particles containing a compound of the metal employed in the catalyst from the waste gas of said burning.
Description
.~ ~067061 The present invention relates to a process for separating epoxidation and hydroxylation catalysts from residues from distillation. In a particular aspect thereof the present invention relates to a process for recovering catalysts in the epoxidation and hydroxylation of olefinic compounds with hydrogen peroxide.
It is known that compounds of particular transition elements are very effective catalysts in the epoxidation and hydroxylation of olefinic compounds. Epoxidation and hydroxyla-tion catalysts are primarily compounds of transition metals suchas zirconium, vanadium, columbium, tantalum, chromium, molybdenum, tungsten, rhenium, uranium. These catalysts are used frequently in the form of their salts but also in the form of organo-metallic compounds. When the catalysts are used as organic compounds, then they are used in the presence of basic components such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium (see, for example, US Patent 3,351,635).
Heteropoly acids of elements of group VI of the periodic system are also used (see US Patent 2,754,325). Organic peroxides and hydrogen peroxides may be used as oxidizing agents.
In the processes for the catalytic epoxidation and hydroxylation of olefinic compounds residues from distillation are obtained which contain high-boiling, primarily polymeric organic compounds as well as the catalyst compounds. These high-boiling organic compounds cannot be used industrially and must therefore be destroyed. Since the above catalysts are compounds which contain valuable metals, the recovery of these metals is very important. The combustion of the organic components of the residues from distillation in the presence of catalysts in a standard combustion furnace causes considerable difficulties, which render such combustion virtually impossible (see laid-open German Specification 2,252,938). Therefore, according to the process of this la~d-open German specification the catalyst--1- ~
containing residue from distillation is evaporated to dryness in an evaporator with an oscillating blade, first, to obtain the major portion of the organic components in a combustible form and, second, to be able to separate most of the catalyst.
An evaporator constructed in this manner is subjected to relatively great wear so that foreign metals get into the dischar-ged solids and may thus be extracted with the separated catalyst.
These foreign metals are so concentrated in the end that the catalyst can no longer be recycled. Moreover the discharged solids also contain carbonized material, some of which is soluble, for example, with water or organic solvents, in the extraction of the catalyst and can cause problems in the subsequent reuse of the catalyst.
The present invention provides for the complete recovery of the metals from the catalyst compounds and the destruction of the high-boiling and primarily polymeric compounds contained in the residues from distillation in the catalytic epoxidation and hydroxylation of olefinic compounds in a manner which has a favourable effect on the environment.
According to the present invention the residue which is obtained upon distilling off the epoxidation or hydroxylation product and contains the high-boiling organic compounds and the catalyst is passed into an inert material, which is in a fluidized motion. The organic components contained in the resi-due from distillation are burned with oxygen or oxygen-containing gases and the metallic compounds of the catalyst are deposited on the fluidized material or in the solids separators connected to the outlet side of the reactor According to the present invention therefore there is provided a process for the separation of a catalyst employed in the epoxidation or hydroxylation of an olefinic compound with a peroxy compound in a reactor,distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue containing said catalyst and said high boiling organic compounds, said catalyst being a compound of a transition metal, the improvement comprising introducing the distillation residue into a bed of fluidized inert solid particles, burning the organic compounds of said distillation residue with an oxygen containing gas while in contact with said fluidized particles and separating fluidized particles containing a compound of the metal employed in the catalyst from the waste gas of said burning.
It is known that compounds of specific transition metals are particularly effective catalysts in the epoxidation and hydro-xylation of water-soluble olefinic compounds, for example, of allyl alcohol, with hydrogen peroxide. Compounds of vanadium, molybdenum and tungsten have been found to be suitable. Tungsten compounds are particularly preferred for the epoxidation. Since due to its high price the catalyst is a principal economic factor in the process, there exist, particularly for tungsten, a number of processes for recovering the tungsten - containing catalyst. Thus, in the epoxidation or hydroxylation of allyl alcohol to glycide or glycerin aqueous reaction solutions are obtained from which the catalyst must be recovered.
According to the process of the US Patent No. 2 869 986 tungstic acid can be absorbed from acid solutions (pH<3) on aluminium oxide. The absorbed tungstic acid can be recovered with a solution of caustic soda and the aluminium oxide is regenerated at the same time. However, the tungstic acid must in turn be isolated from the regenative solution by precipitating with strong acids (HNO3, HCl, H2SO4). In total this means a relatively large expanditure for the recovery of the catalyst.
Ion exchangers can also be used instead of aluminium oxide (see German Patent No 1 114 468). The tungstic acid is precipitated from the eluates with strong acids.
After the hydroxylation of the allyl alcohol the remov-al of tungstic acid from the glycerin solution can be carried out by adding calcium chloride to the glycerin solution the tungstic acid dissolved in said solution is precipitated and separated while the insoluble calcium tungstate is formed. For reuse as tungstic acid reprecipitation with acids must also be carried out (see German Patent No 1 230 000). However, by precipitating the tungstic acid with strong acids waste waters containing substan-tial amounts of salts are obtained.
All the above processes mentioned hereinbefore have theadditional disadvantage that the catalyst cannot be recovered quantitatively.
Accordingly the present invention relates to a process in which the catalyst, i.e., the usual alkali metal vanadates, alkali metal molybdates and alkali metal tungstates (see Wiberg, Anorganische Chemie, 24th and 25th edition, page 476 and 477), can be reused without prior precipitation.
According to a particularly preferred aspect of the invention the residue which is obtained upon distilling off the epoxidation or hydroxylation product and which contains the cata-lyst is passed into an inert material, which is in a fluidized motion. The organic components contained in the residue from distillation are burned with oxygen or with oxygen-containing gases, whereupon the catalyst compound deposited on the fluidized inert material, together with the proportion of catalyst compound obtained in the solids separator connected the outlet side of the reactor, is dlssolved out with water and the solution obtained is used again for the epoxidation or hydroxylation. The catalyst thus obtained from the residue from distillation can be reused directly for the epoxidation or hydroxylation, as mentioned above According to said preferred aspect of the present 106706~
invention therefore there is provided a process for the recovery of a catalyst employed in the epoxidation or hydroxylation of a water soluble olefinic compound with hydrogen peroxide in a reactor, distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue, containing said catalyst, and high boiling organic compounds, said catalyst being a water soluble compound of vanadium, molyb-denum or tungsten,the improvement comprising introducing the distillation residue into a bed of fluidized inert, water insolu-ble solid particles, burning the organic components of said distillation residue with an oxygen containing gas at a temper-ature below the melting point of said catalyst while in contact with said fluidized particles, removing a portion of said inert solid particles containing said water soluble compound from the burning zone, dissolving said water soluble catalyst compoundin water and separating the aqueous solution from said inert solid particles.
The alkali metal salts mentioned hereinbefore are the sodium, potassium and lithium salts, primarily the sodium salts.
Any hard, chemically inert material can be used as flu-idized material, such as, quartz sand, silicon carbide, highly burned alumina for example, corundum and highly burned clay for example, chamotte. The particle size is suitably from 0.1 to 5 mm, preferably from 0.5 to 1.5 mm.
A reactor of any conventional construction can be used as the fluidization reactor. It may be constructed such that continuous or discontinuous exchange of the fluidized material in the reactor, i.e., the fluidized material coated with the catalyst, with fresh fluidized material may be carried out by means of two fundamentally different methods. According to the first method, a specific amount of the fluidized material coated with the catalyst is continuously or discontinuously discharged ~067061 from the lower portionof the reactor. Approximately at the same time the same amount of fresh fluidized material is continuously or discontinuously fed to the fluidization reactor. According to the second method, the fluidization reactor is provided with an overflow and after the continuous and discontinuous addition of fresh fluidized material the same amount of fluidized material, the major portion of which is coated with the catalyst, flows off continuously or discontinuously by way of the overflow, for example, into a cyclone connected at the outlet end.
Apart from oxygen, oxygen-containing gases, primarily air, are used. The amount of gas used must be so adjusted that the fluidization of the entire particle spectrum of fluidized material is assured.
If the combustion of the organic components of the residue from distillation in the fluidization reactor is to be complete, i.e., so that the waste gas is almost free from carbon monoxide, whic~ is necessary for protecting the environment, then the maximum amount of product which can be put through is determined by the amount of gas applied. The gas can be preheated by hot gases if required.
The usual kind of apparatus, such as gravity separa-tors or cyclone air separators or dust separators are used as solids separators.
The reactor temperatures are suitably between 500 and approximately 1000C or between 500C and the melting points of the corresponding catalyst-containing compounds when these melting points are belo~ 1000C.
The reactor temperatures are controlled and kept constant with conventional coolers and coolants. The excess h~at of combustion which is removed by the coolant can be used for producing energy, for example, for generating steam or for operating a turbine. The excess heat of combustion is the 1067~61 residual heat upon drawing off the amount of heat required for heating the reactants to reaction temperature and upon removal of the amount of heat radiated by the reactor. For example, the reactor wall and cooling pipes or cooling plates installed in the fluidization reactor can be used as coolers. For example, the known nitrite/nitrate melts can be used as coolants.
Upon leaving the reactor the waste gas containing the solid particles is passed to a solids separator, preferably a cyclone, where the major portion of the entrained solid particles is separated. If required, the waste gas can subsequently be subjected to a further purification by separating the fine dust which was not separated in the solids separator, particle sizes lower than approximately 10 to 30 ~ for example, by means of filters or by washing with water.
The residue from distillation which is to be used is recovered in a known manner, for example, with the aid of circulation evaporators or falling film evaporators.
The metal compounds of the catalysts are obtained almost entirely on the fluidized mateiral and in the solids separator. The manner in which the recovered metal compounds are converted into a fresh catalyst depends on the kind of catalysts to be reused. The examples providea number of possi-bilities.
In the particularly preferred aspect of the present invention the discharged fluidized material and the material separated in the solids separator are combined and treated with water or with the aqueous solution from the gas washer. The amount is preferably adjusted to the desired concentration of the solution to be reused. The recovered catalyst solution can be reused immediately.
The residue from distillation can be recovered in the usual manner, for example, with the aid of circulation evaporators ~06706~
or falling-film evaporators. The process is applicable to the epoxidation and hydroxylation of water-soluble olefinic compounds, such allyl alcohol, crotyl alcohol, methallyl alcohol or cyclopentenol-3.
The present invention will be further illustrated by way of the accompanying drawings in which Fig. 1 is a flow sheet of the process according to one embodiment of the present invention; and Fig. la is a flow sheet according to the particularly preferred aspect of the present invention.
When the catalyst-containing residue from the distil-lation is not pumpable, then it can be converted into a pumpable state either by heating or by diluting with water. During the dilution heating can also be applied.
Referring to Fig. 1 the reactor 6 is heated to the desired temperature, suitably, to least 500C. which can be achieved with the aid of a starting heater, the fluidization reactor 6 being heated to the temperature required for initiating the combustion reaction either directly by the hot exhaust gases or by the air heated by heat exchange in the starting heater.
After the start of the combustion reaction in the fluidization reactor 6 excess heat of reaction is removed by a cooling system.
The residue from distillation is then pumped by way of pipe 1 into the lower portion of the reactor 6. At the same time air is blown through by way of pipe 2 in order to avoid possible clogging. The principal amount of the air required for both the combustion and the fluidization is supplied by way of pipe 3 and preheated if required by way of the heat exchanger 12.
A salt bath 5, which, for example, contains conventional nitrite-nitrate melts, is preferalby used for heating the fluidiz-ation reactor 6. Upon putting the reactor into operation the salt bath serves for transmitting the heat. The excess heat of 106706i cOmbustion can be used for producing energy, as for example, for generating steam, by means of a heat exchanger 19 mounted in the salt bath. The fluidized material is added through pipe 7 and removed together with the metallic compounds of the catalysts through pipe 4.
The fluidized material which contains the metallic compounds is passed to a tank 14, where it is washed with water, liquors, acids or organic solvents such as aliphatic alcohols, if a recovery is intended. The fluidized material is then sep-arated from the solution, dried and returned to the fluidization reactor through pipe 17.
The exhaust air, from the reactor 6 which contains only small amounts of carbon monoxide for environmental reasons, is passed through pipe 8 into the cyclone 9, where entrained solids are separated. These solids are also passed through line 10 to the washing tank 14. The outgoing air, which is still hot, serves for heating the fresh air 12 and is subjected to purifi-cation in order to separate the fine dust by means of a filter or by ~ashing (13).
Referring to Fig. la the residue is then pumped through pipe 1' into the lower portion of the reactor 6'. At the same time air is blown through pipe 2' in order to avoid possible clogging. The mixture is dosed into the reactor through pipe 3'. The principal amount of the air required for both the combustion and the fluidization is supplied through pipe 4' and preheated when required.
The reactor 6' is heated to the desired temperature suitably at least 500C.which can be achieved with the aid of a starting heater the fluidization reactor 6' being heated to the temperature required for initiating the combustion reaction either directly by the hot exhaust gases or by the air heated by heat exchange in the starting heater. After the start of the ~067061 combustion reaction in the fluidization reactor 6' excess heat of reaction is removed by a cooling system. A salt bath, which, for example, contains the conventional nitrite-nitrate melts, is preferably used for heating the fluidization reactor 6'.
When the salt bath is used for cooling on putting the reactor 6' into operation it removes the heat set free and thus keeps the temperature on a constant level. Fluidized material is added through the pipe 7' and removed together with the catalyst, through pipe 5'. The catalyst-containing fluidized material passes from pipe 5 into a tank 13', where it is leached with water supplied through pipe 14'. The aqueous catalyst solution is separated from the fluidized material and may be fed directly to the epoxidation reaction through pipe 15'. The dried fluid-ized material is returned to the fluidization reactor through pipe 16'.
The exhaust air, from the reactor 6' which contains only small amounts of carbon monoxide for environmental reasons, is passed through pipe 8' into the cyclone 9', where entrained solids are separated. These separated solids are also passed through line lO' to the washing tank 13' and freed from the catalyst. The exhaust air is then subjected to a further purification, for example, by means of a filter device 12' by washing.
An advance in the art of the broad process according to the invention lies in that the entire carbon-containing proportion of the residue from distillation in the presence of metal-containing catalysts is burned in a single stage. The metallic compounds of the catalysts which are thus obtained are not contaminated either by organic by-products or by foreign ions.
A significant advance in the art of the preferred aspect of the process according to the invention is that the ~06706~
catalyst is recovered quantitatively. Moreover it is recovered in such a form that it can be reused. The yields obtained with the recovered catalyst are practically the same as those obtained with a fresh catalyst. Moreover, the process has a favourable effect on the environment due to the absence of salt-containing waste waters and since there are no problems with outgoing air.
The present invention will be further illustrated by way of the ~ollowing Examples.
Example 1 The process was carried out continuously over a period of five days in the epoxidation or hydroxylation of allyl alcohol with aqueous hydrogen peroxide to glycide or glycerin in the presence of sodium hydrogen tungstate a residue from distillation is obtained which consists of 20% by weight of the catalyst, the remainder being glycerin or polyglycerin. This residue from distillation is mixed with water in the ratio of 4 to 8 : 1 (residue from distillation to water) and heated to a temperature of 70 to 80C. The mixture, which now is pumpable, is fed to the bottom of the reactor (approximately 2 kg per hour) while at the same time approximately 8 cu m of air are blown into the reactor per hour. By way of a flow tray further 16 cu m of air, preheated to approximately 350C, are supplied per hour.
The fluidization reactor (height 2400 mm, diameter 150 mm, Cr-Ni steel~ is surrounded by a salt bath (nitrite-nitrate melt) which serves first for heating and later, when the reactor is an operation, as a heat acceptor. The excess heat of combustion is utilized for generating steam, by means of a heat exchanger installed in the salt bath. Quartz sand having a particle size of 0.5 to 1.5 mm is used as fluidized material.
The reactor is heated to 540C with the aid of the salt bath. After the start of the combustion the temperatures ~067061 in the reactor are from 580 to 650C. The combustion is complete so that the waste gas contains only small amounts of carbon monoxide (approximately 0.1% by ~olume).
Every hour approximately 2 to 3 litres of sand are replaced. The discharged sand, which contains the tungstate, is leached with the corresponding amount of water so that an approximately 4 to 8% by weight tungstate solution is obtained.
The sand washed out is separated, dried and returned to the reactor.
The sand and tungstate particles entrained by the waste gas are separated in a cyclone and also washed out. The exhaust air, which is still hot, is used in a heat exchanger in order to heat the fresh air required for the combustion. For further purification, the cooled waste gases are then passed over a washer. The wash water obtained which contains small amounts of tungstate is used for diluting the residue from distillation.
The aqueous tungstate solution can be used directly for the epoxidation of allyl alcohol with hydrogen peroxide.
158 g (273 moles) of allyl alcohol, 200 g of water 33 g of the aqueous sodium-tungstate solution recovered (with 4.9% of tungstic acid) is put into a round-bottomed flask and heated to 45C. 97g (1 mole) of a 35.6~ hydrogen peroxide are added dropwise within 10 minutes with stirring. After three hours the hydrogen-peroxide reaction rate is quantitative. The yield of the glycide reaction is 85% of the theoretical yield, relative to hydrogen peroxide.
Example 2 tComparison Example using fresh tungstate solution) 158 g of allyl alcohol and 200 g of water are put into a l-litre three-necked bottle fitted with stirrer, dropping funnel, thermometer and reflux condenser. 1.5 g of NaHWO3 are dissolved in 33 ml of water and added. The solution is heated to 45C. While stirring, 97 g of a 35.6% hydrogen peroxide are added dropwise within 10 minutes. After three hours the hydrogen peroxide reaction rate is quantitative. The yield of the glycide reaction is 86% of the theoretical yield, relative to hydrogen peroxide.
Example 3 Crotyl alcohol or methallyl alcohol may also be used instead of the allyl alcohol usedinthe Examplesland 2. The corresponding data are listed in Table 1. The conditions of the reaction are the same as those in example l and 2.
~able 1 epoxide yield (%) ~_ fresh catalyst recovered catalyst epoxide obtained crotyl alcohol 83.2 82.5 2,3-epoxy butanol-l methallyl alcohol 55.2 54.7 1,2-epoxy-2-methyl pro-panol-3 _ _ NaHMoO4 is used instead of NaHWOin amanner analogousto that of Example l and2. 58 g (l mole) of allyl alcohol and 3 g of NaHMoO4, dissolved in 74 ml of H20, are put into a three-necked bottle fitted with stirrer, inside thermometer, cooler and dropping funnel and heated to 60C. 102 g (1.1 moles) of a 36.7% H2O2 are added dropwise over one hour. After four hours the H2O2 reaction rate is quantitative. The yield of glycerine is 70%. When using the recovered Mo catalyst analogously to Example 1 the yield of glycerine was 67%.
Example 5 Vanadium (Na2HVO4+NaH2VO4) was used instead of the tungsten used in Examples l and 2. The amounts were the same.
The reaction temperature was 60C and the reaction time 24 hours.
10670~;1 The yield of glycerine relative to H2O2 applied was 20% with the fresh catalyst and 22% with the recovered catalyst.
The concentration of the hydrogen peroxide for the epoxidation or hydroxylation is not critical. Commercial concentrations (in % by weight) are preferably used.
Example 6 In the epoxidation of cyclohexene with cumene hydrogen peroxide in the presence of vandyl acetyl acetonate to 1,2-epoxy cyclohexene a residue from distillation which contains the vanadium compound is obtained. This residue from distillation is burned in a manner analogous to that of Example 1.
The vanadium pentoxide thus formed is deposited on the fluidized material or in the cyclone. The vandium pentoxide is separated from the fluidized material by means of liquors.
From these aqueous vanadate solutions the vanadium or its compounds can be recovered by means of conventional methods. By heating the vanadium-pentoxide-containing fluidized material with an alcohol, for example, propanol, the vanadium pentoxide can be converted into the corresponding vanadic ester.
Example 7 In the epoxidation of propylene with tertiary butyl peroxide in the presence of columbium phthalate to propylene oxide a residue from distillation which contains the columbium compound is obtained. This residue from distillation is burned in amanner analogous to that of Example 1.
The columbium pentoxide thus formed is deposited on the fluidized material or in the cyclone. The columbium pentoxide is separated from the fluidized material by means of liquors.
These wash solutions are processed by means of conventional methods.
Example 8 In the epoxidation or hydroxylation of allyl alcohol with aqueous hydrogen peroxide to glycide or glycerin, calcium 106~
tungstate, which also is obtained in the residue from distillation, can be used instead of sodium hydrogen tungstate (Example 1).
This residue from distillation is burned in a manner similar to that of Example 1. The calcium tungstate is deposited on the fluidized material or in the cyclone and can be recovered there-from.
It is known that compounds of particular transition elements are very effective catalysts in the epoxidation and hydroxylation of olefinic compounds. Epoxidation and hydroxyla-tion catalysts are primarily compounds of transition metals suchas zirconium, vanadium, columbium, tantalum, chromium, molybdenum, tungsten, rhenium, uranium. These catalysts are used frequently in the form of their salts but also in the form of organo-metallic compounds. When the catalysts are used as organic compounds, then they are used in the presence of basic components such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium (see, for example, US Patent 3,351,635).
Heteropoly acids of elements of group VI of the periodic system are also used (see US Patent 2,754,325). Organic peroxides and hydrogen peroxides may be used as oxidizing agents.
In the processes for the catalytic epoxidation and hydroxylation of olefinic compounds residues from distillation are obtained which contain high-boiling, primarily polymeric organic compounds as well as the catalyst compounds. These high-boiling organic compounds cannot be used industrially and must therefore be destroyed. Since the above catalysts are compounds which contain valuable metals, the recovery of these metals is very important. The combustion of the organic components of the residues from distillation in the presence of catalysts in a standard combustion furnace causes considerable difficulties, which render such combustion virtually impossible (see laid-open German Specification 2,252,938). Therefore, according to the process of this la~d-open German specification the catalyst--1- ~
containing residue from distillation is evaporated to dryness in an evaporator with an oscillating blade, first, to obtain the major portion of the organic components in a combustible form and, second, to be able to separate most of the catalyst.
An evaporator constructed in this manner is subjected to relatively great wear so that foreign metals get into the dischar-ged solids and may thus be extracted with the separated catalyst.
These foreign metals are so concentrated in the end that the catalyst can no longer be recycled. Moreover the discharged solids also contain carbonized material, some of which is soluble, for example, with water or organic solvents, in the extraction of the catalyst and can cause problems in the subsequent reuse of the catalyst.
The present invention provides for the complete recovery of the metals from the catalyst compounds and the destruction of the high-boiling and primarily polymeric compounds contained in the residues from distillation in the catalytic epoxidation and hydroxylation of olefinic compounds in a manner which has a favourable effect on the environment.
According to the present invention the residue which is obtained upon distilling off the epoxidation or hydroxylation product and contains the high-boiling organic compounds and the catalyst is passed into an inert material, which is in a fluidized motion. The organic components contained in the resi-due from distillation are burned with oxygen or oxygen-containing gases and the metallic compounds of the catalyst are deposited on the fluidized material or in the solids separators connected to the outlet side of the reactor According to the present invention therefore there is provided a process for the separation of a catalyst employed in the epoxidation or hydroxylation of an olefinic compound with a peroxy compound in a reactor,distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue containing said catalyst and said high boiling organic compounds, said catalyst being a compound of a transition metal, the improvement comprising introducing the distillation residue into a bed of fluidized inert solid particles, burning the organic compounds of said distillation residue with an oxygen containing gas while in contact with said fluidized particles and separating fluidized particles containing a compound of the metal employed in the catalyst from the waste gas of said burning.
It is known that compounds of specific transition metals are particularly effective catalysts in the epoxidation and hydro-xylation of water-soluble olefinic compounds, for example, of allyl alcohol, with hydrogen peroxide. Compounds of vanadium, molybdenum and tungsten have been found to be suitable. Tungsten compounds are particularly preferred for the epoxidation. Since due to its high price the catalyst is a principal economic factor in the process, there exist, particularly for tungsten, a number of processes for recovering the tungsten - containing catalyst. Thus, in the epoxidation or hydroxylation of allyl alcohol to glycide or glycerin aqueous reaction solutions are obtained from which the catalyst must be recovered.
According to the process of the US Patent No. 2 869 986 tungstic acid can be absorbed from acid solutions (pH<3) on aluminium oxide. The absorbed tungstic acid can be recovered with a solution of caustic soda and the aluminium oxide is regenerated at the same time. However, the tungstic acid must in turn be isolated from the regenative solution by precipitating with strong acids (HNO3, HCl, H2SO4). In total this means a relatively large expanditure for the recovery of the catalyst.
Ion exchangers can also be used instead of aluminium oxide (see German Patent No 1 114 468). The tungstic acid is precipitated from the eluates with strong acids.
After the hydroxylation of the allyl alcohol the remov-al of tungstic acid from the glycerin solution can be carried out by adding calcium chloride to the glycerin solution the tungstic acid dissolved in said solution is precipitated and separated while the insoluble calcium tungstate is formed. For reuse as tungstic acid reprecipitation with acids must also be carried out (see German Patent No 1 230 000). However, by precipitating the tungstic acid with strong acids waste waters containing substan-tial amounts of salts are obtained.
All the above processes mentioned hereinbefore have theadditional disadvantage that the catalyst cannot be recovered quantitatively.
Accordingly the present invention relates to a process in which the catalyst, i.e., the usual alkali metal vanadates, alkali metal molybdates and alkali metal tungstates (see Wiberg, Anorganische Chemie, 24th and 25th edition, page 476 and 477), can be reused without prior precipitation.
According to a particularly preferred aspect of the invention the residue which is obtained upon distilling off the epoxidation or hydroxylation product and which contains the cata-lyst is passed into an inert material, which is in a fluidized motion. The organic components contained in the residue from distillation are burned with oxygen or with oxygen-containing gases, whereupon the catalyst compound deposited on the fluidized inert material, together with the proportion of catalyst compound obtained in the solids separator connected the outlet side of the reactor, is dlssolved out with water and the solution obtained is used again for the epoxidation or hydroxylation. The catalyst thus obtained from the residue from distillation can be reused directly for the epoxidation or hydroxylation, as mentioned above According to said preferred aspect of the present 106706~
invention therefore there is provided a process for the recovery of a catalyst employed in the epoxidation or hydroxylation of a water soluble olefinic compound with hydrogen peroxide in a reactor, distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue, containing said catalyst, and high boiling organic compounds, said catalyst being a water soluble compound of vanadium, molyb-denum or tungsten,the improvement comprising introducing the distillation residue into a bed of fluidized inert, water insolu-ble solid particles, burning the organic components of said distillation residue with an oxygen containing gas at a temper-ature below the melting point of said catalyst while in contact with said fluidized particles, removing a portion of said inert solid particles containing said water soluble compound from the burning zone, dissolving said water soluble catalyst compoundin water and separating the aqueous solution from said inert solid particles.
The alkali metal salts mentioned hereinbefore are the sodium, potassium and lithium salts, primarily the sodium salts.
Any hard, chemically inert material can be used as flu-idized material, such as, quartz sand, silicon carbide, highly burned alumina for example, corundum and highly burned clay for example, chamotte. The particle size is suitably from 0.1 to 5 mm, preferably from 0.5 to 1.5 mm.
A reactor of any conventional construction can be used as the fluidization reactor. It may be constructed such that continuous or discontinuous exchange of the fluidized material in the reactor, i.e., the fluidized material coated with the catalyst, with fresh fluidized material may be carried out by means of two fundamentally different methods. According to the first method, a specific amount of the fluidized material coated with the catalyst is continuously or discontinuously discharged ~067061 from the lower portionof the reactor. Approximately at the same time the same amount of fresh fluidized material is continuously or discontinuously fed to the fluidization reactor. According to the second method, the fluidization reactor is provided with an overflow and after the continuous and discontinuous addition of fresh fluidized material the same amount of fluidized material, the major portion of which is coated with the catalyst, flows off continuously or discontinuously by way of the overflow, for example, into a cyclone connected at the outlet end.
Apart from oxygen, oxygen-containing gases, primarily air, are used. The amount of gas used must be so adjusted that the fluidization of the entire particle spectrum of fluidized material is assured.
If the combustion of the organic components of the residue from distillation in the fluidization reactor is to be complete, i.e., so that the waste gas is almost free from carbon monoxide, whic~ is necessary for protecting the environment, then the maximum amount of product which can be put through is determined by the amount of gas applied. The gas can be preheated by hot gases if required.
The usual kind of apparatus, such as gravity separa-tors or cyclone air separators or dust separators are used as solids separators.
The reactor temperatures are suitably between 500 and approximately 1000C or between 500C and the melting points of the corresponding catalyst-containing compounds when these melting points are belo~ 1000C.
The reactor temperatures are controlled and kept constant with conventional coolers and coolants. The excess h~at of combustion which is removed by the coolant can be used for producing energy, for example, for generating steam or for operating a turbine. The excess heat of combustion is the 1067~61 residual heat upon drawing off the amount of heat required for heating the reactants to reaction temperature and upon removal of the amount of heat radiated by the reactor. For example, the reactor wall and cooling pipes or cooling plates installed in the fluidization reactor can be used as coolers. For example, the known nitrite/nitrate melts can be used as coolants.
Upon leaving the reactor the waste gas containing the solid particles is passed to a solids separator, preferably a cyclone, where the major portion of the entrained solid particles is separated. If required, the waste gas can subsequently be subjected to a further purification by separating the fine dust which was not separated in the solids separator, particle sizes lower than approximately 10 to 30 ~ for example, by means of filters or by washing with water.
The residue from distillation which is to be used is recovered in a known manner, for example, with the aid of circulation evaporators or falling film evaporators.
The metal compounds of the catalysts are obtained almost entirely on the fluidized mateiral and in the solids separator. The manner in which the recovered metal compounds are converted into a fresh catalyst depends on the kind of catalysts to be reused. The examples providea number of possi-bilities.
In the particularly preferred aspect of the present invention the discharged fluidized material and the material separated in the solids separator are combined and treated with water or with the aqueous solution from the gas washer. The amount is preferably adjusted to the desired concentration of the solution to be reused. The recovered catalyst solution can be reused immediately.
The residue from distillation can be recovered in the usual manner, for example, with the aid of circulation evaporators ~06706~
or falling-film evaporators. The process is applicable to the epoxidation and hydroxylation of water-soluble olefinic compounds, such allyl alcohol, crotyl alcohol, methallyl alcohol or cyclopentenol-3.
The present invention will be further illustrated by way of the accompanying drawings in which Fig. 1 is a flow sheet of the process according to one embodiment of the present invention; and Fig. la is a flow sheet according to the particularly preferred aspect of the present invention.
When the catalyst-containing residue from the distil-lation is not pumpable, then it can be converted into a pumpable state either by heating or by diluting with water. During the dilution heating can also be applied.
Referring to Fig. 1 the reactor 6 is heated to the desired temperature, suitably, to least 500C. which can be achieved with the aid of a starting heater, the fluidization reactor 6 being heated to the temperature required for initiating the combustion reaction either directly by the hot exhaust gases or by the air heated by heat exchange in the starting heater.
After the start of the combustion reaction in the fluidization reactor 6 excess heat of reaction is removed by a cooling system.
The residue from distillation is then pumped by way of pipe 1 into the lower portion of the reactor 6. At the same time air is blown through by way of pipe 2 in order to avoid possible clogging. The principal amount of the air required for both the combustion and the fluidization is supplied by way of pipe 3 and preheated if required by way of the heat exchanger 12.
A salt bath 5, which, for example, contains conventional nitrite-nitrate melts, is preferalby used for heating the fluidiz-ation reactor 6. Upon putting the reactor into operation the salt bath serves for transmitting the heat. The excess heat of 106706i cOmbustion can be used for producing energy, as for example, for generating steam, by means of a heat exchanger 19 mounted in the salt bath. The fluidized material is added through pipe 7 and removed together with the metallic compounds of the catalysts through pipe 4.
The fluidized material which contains the metallic compounds is passed to a tank 14, where it is washed with water, liquors, acids or organic solvents such as aliphatic alcohols, if a recovery is intended. The fluidized material is then sep-arated from the solution, dried and returned to the fluidization reactor through pipe 17.
The exhaust air, from the reactor 6 which contains only small amounts of carbon monoxide for environmental reasons, is passed through pipe 8 into the cyclone 9, where entrained solids are separated. These solids are also passed through line 10 to the washing tank 14. The outgoing air, which is still hot, serves for heating the fresh air 12 and is subjected to purifi-cation in order to separate the fine dust by means of a filter or by ~ashing (13).
Referring to Fig. la the residue is then pumped through pipe 1' into the lower portion of the reactor 6'. At the same time air is blown through pipe 2' in order to avoid possible clogging. The mixture is dosed into the reactor through pipe 3'. The principal amount of the air required for both the combustion and the fluidization is supplied through pipe 4' and preheated when required.
The reactor 6' is heated to the desired temperature suitably at least 500C.which can be achieved with the aid of a starting heater the fluidization reactor 6' being heated to the temperature required for initiating the combustion reaction either directly by the hot exhaust gases or by the air heated by heat exchange in the starting heater. After the start of the ~067061 combustion reaction in the fluidization reactor 6' excess heat of reaction is removed by a cooling system. A salt bath, which, for example, contains the conventional nitrite-nitrate melts, is preferably used for heating the fluidization reactor 6'.
When the salt bath is used for cooling on putting the reactor 6' into operation it removes the heat set free and thus keeps the temperature on a constant level. Fluidized material is added through the pipe 7' and removed together with the catalyst, through pipe 5'. The catalyst-containing fluidized material passes from pipe 5 into a tank 13', where it is leached with water supplied through pipe 14'. The aqueous catalyst solution is separated from the fluidized material and may be fed directly to the epoxidation reaction through pipe 15'. The dried fluid-ized material is returned to the fluidization reactor through pipe 16'.
The exhaust air, from the reactor 6' which contains only small amounts of carbon monoxide for environmental reasons, is passed through pipe 8' into the cyclone 9', where entrained solids are separated. These separated solids are also passed through line lO' to the washing tank 13' and freed from the catalyst. The exhaust air is then subjected to a further purification, for example, by means of a filter device 12' by washing.
An advance in the art of the broad process according to the invention lies in that the entire carbon-containing proportion of the residue from distillation in the presence of metal-containing catalysts is burned in a single stage. The metallic compounds of the catalysts which are thus obtained are not contaminated either by organic by-products or by foreign ions.
A significant advance in the art of the preferred aspect of the process according to the invention is that the ~06706~
catalyst is recovered quantitatively. Moreover it is recovered in such a form that it can be reused. The yields obtained with the recovered catalyst are practically the same as those obtained with a fresh catalyst. Moreover, the process has a favourable effect on the environment due to the absence of salt-containing waste waters and since there are no problems with outgoing air.
The present invention will be further illustrated by way of the ~ollowing Examples.
Example 1 The process was carried out continuously over a period of five days in the epoxidation or hydroxylation of allyl alcohol with aqueous hydrogen peroxide to glycide or glycerin in the presence of sodium hydrogen tungstate a residue from distillation is obtained which consists of 20% by weight of the catalyst, the remainder being glycerin or polyglycerin. This residue from distillation is mixed with water in the ratio of 4 to 8 : 1 (residue from distillation to water) and heated to a temperature of 70 to 80C. The mixture, which now is pumpable, is fed to the bottom of the reactor (approximately 2 kg per hour) while at the same time approximately 8 cu m of air are blown into the reactor per hour. By way of a flow tray further 16 cu m of air, preheated to approximately 350C, are supplied per hour.
The fluidization reactor (height 2400 mm, diameter 150 mm, Cr-Ni steel~ is surrounded by a salt bath (nitrite-nitrate melt) which serves first for heating and later, when the reactor is an operation, as a heat acceptor. The excess heat of combustion is utilized for generating steam, by means of a heat exchanger installed in the salt bath. Quartz sand having a particle size of 0.5 to 1.5 mm is used as fluidized material.
The reactor is heated to 540C with the aid of the salt bath. After the start of the combustion the temperatures ~067061 in the reactor are from 580 to 650C. The combustion is complete so that the waste gas contains only small amounts of carbon monoxide (approximately 0.1% by ~olume).
Every hour approximately 2 to 3 litres of sand are replaced. The discharged sand, which contains the tungstate, is leached with the corresponding amount of water so that an approximately 4 to 8% by weight tungstate solution is obtained.
The sand washed out is separated, dried and returned to the reactor.
The sand and tungstate particles entrained by the waste gas are separated in a cyclone and also washed out. The exhaust air, which is still hot, is used in a heat exchanger in order to heat the fresh air required for the combustion. For further purification, the cooled waste gases are then passed over a washer. The wash water obtained which contains small amounts of tungstate is used for diluting the residue from distillation.
The aqueous tungstate solution can be used directly for the epoxidation of allyl alcohol with hydrogen peroxide.
158 g (273 moles) of allyl alcohol, 200 g of water 33 g of the aqueous sodium-tungstate solution recovered (with 4.9% of tungstic acid) is put into a round-bottomed flask and heated to 45C. 97g (1 mole) of a 35.6~ hydrogen peroxide are added dropwise within 10 minutes with stirring. After three hours the hydrogen-peroxide reaction rate is quantitative. The yield of the glycide reaction is 85% of the theoretical yield, relative to hydrogen peroxide.
Example 2 tComparison Example using fresh tungstate solution) 158 g of allyl alcohol and 200 g of water are put into a l-litre three-necked bottle fitted with stirrer, dropping funnel, thermometer and reflux condenser. 1.5 g of NaHWO3 are dissolved in 33 ml of water and added. The solution is heated to 45C. While stirring, 97 g of a 35.6% hydrogen peroxide are added dropwise within 10 minutes. After three hours the hydrogen peroxide reaction rate is quantitative. The yield of the glycide reaction is 86% of the theoretical yield, relative to hydrogen peroxide.
Example 3 Crotyl alcohol or methallyl alcohol may also be used instead of the allyl alcohol usedinthe Examplesland 2. The corresponding data are listed in Table 1. The conditions of the reaction are the same as those in example l and 2.
~able 1 epoxide yield (%) ~_ fresh catalyst recovered catalyst epoxide obtained crotyl alcohol 83.2 82.5 2,3-epoxy butanol-l methallyl alcohol 55.2 54.7 1,2-epoxy-2-methyl pro-panol-3 _ _ NaHMoO4 is used instead of NaHWOin amanner analogousto that of Example l and2. 58 g (l mole) of allyl alcohol and 3 g of NaHMoO4, dissolved in 74 ml of H20, are put into a three-necked bottle fitted with stirrer, inside thermometer, cooler and dropping funnel and heated to 60C. 102 g (1.1 moles) of a 36.7% H2O2 are added dropwise over one hour. After four hours the H2O2 reaction rate is quantitative. The yield of glycerine is 70%. When using the recovered Mo catalyst analogously to Example 1 the yield of glycerine was 67%.
Example 5 Vanadium (Na2HVO4+NaH2VO4) was used instead of the tungsten used in Examples l and 2. The amounts were the same.
The reaction temperature was 60C and the reaction time 24 hours.
10670~;1 The yield of glycerine relative to H2O2 applied was 20% with the fresh catalyst and 22% with the recovered catalyst.
The concentration of the hydrogen peroxide for the epoxidation or hydroxylation is not critical. Commercial concentrations (in % by weight) are preferably used.
Example 6 In the epoxidation of cyclohexene with cumene hydrogen peroxide in the presence of vandyl acetyl acetonate to 1,2-epoxy cyclohexene a residue from distillation which contains the vanadium compound is obtained. This residue from distillation is burned in a manner analogous to that of Example 1.
The vanadium pentoxide thus formed is deposited on the fluidized material or in the cyclone. The vandium pentoxide is separated from the fluidized material by means of liquors.
From these aqueous vanadate solutions the vanadium or its compounds can be recovered by means of conventional methods. By heating the vanadium-pentoxide-containing fluidized material with an alcohol, for example, propanol, the vanadium pentoxide can be converted into the corresponding vanadic ester.
Example 7 In the epoxidation of propylene with tertiary butyl peroxide in the presence of columbium phthalate to propylene oxide a residue from distillation which contains the columbium compound is obtained. This residue from distillation is burned in amanner analogous to that of Example 1.
The columbium pentoxide thus formed is deposited on the fluidized material or in the cyclone. The columbium pentoxide is separated from the fluidized material by means of liquors.
These wash solutions are processed by means of conventional methods.
Example 8 In the epoxidation or hydroxylation of allyl alcohol with aqueous hydrogen peroxide to glycide or glycerin, calcium 106~
tungstate, which also is obtained in the residue from distillation, can be used instead of sodium hydrogen tungstate (Example 1).
This residue from distillation is burned in a manner similar to that of Example 1. The calcium tungstate is deposited on the fluidized material or in the cyclone and can be recovered there-from.
Claims (29)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for the recovery of a catalyst employed in the epoxidation or hydroxylation of a water soluble olefinic compound with hydrogen peroxide in a reactor, distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue, containing said catalyst, and high boiling organic compounds, said catalyst being a water soluble compound of vanadium, molybdenum or tungsten, the improvement comprising introducing the distillation residue into a bed of fluidized inert, water insoluble solid particles, burning the organic components of said distillation residue with an oxygen containing gas at a temperature below the melting point of said catalyst while in contact with said fluidized particles, removing a portion of said inert solid particles containing said water soluble compound from the burning zone, dissolving said water soluble catalyst compound in water and separating the aqueous solution from said inert solid particles.
2. The process of claim 1 including the step of returning the aqueous solution of water soluble catalyst to the reactor for use in the epoxidation or hydroxylation of a water soluble olefinic compound.
3. The process of claim 1 wherein the oxygen contain-ing gas is air.
4. The process of claim 1 wherein the oxygen contain-ing gas is pure oxygen.
5. The process of claim 1 wherein the catalyst is an alkali or alkaline earth metal vanadate, molybdate or tungstate.
6. The process of claim 5 wherein the catalyst is a sodium tungstate.
7. The process of claim 5, wherein the catalyst is a calcium tungstate.
8. The process of claim 1 wherein the water soluble olefinic compound is allyl alcohol, crotyl alcohol, methallyl alcohol or cyclopentanol-3.
9. The process of claim 1 wherein the water soluble olefinic compound is allyl alcohol.
10. The process of claim 1 wherein the inert solid particles are quartz sand, silicon carbide, highly fired alumina or highly fired clay.
11. The process of claim 1 wherein the fluidized particles have a particle size of 0.1 to 5 mm.
12. The process of claim 11 wherein the fluidized particles have a particle size of 0.5 to 1.5 mm.
13. The process of claim 1 wherein the burning temper-ature is between 500 and 1000°C.
14. The process of claim 1 wherein the waste gas produced in the burning and containing entrained solid particles comprising said inert solid particles and water soluble catalyst is passed to a solids separator to separate the waste gas from the solids and the water soluble catalyst portion of the entrained solids is dissolved in water and the aqueous solution thus produced separated from the inert solid particles.
15. The process of claim 14 comprising returning to the reactor both the aqueous solution of catalyst obtained from the solids separator and from the portion of inert solids particles removed from the fluidized bed for use in the epoxida-tion or hydroxylation of a water soluble olefinic compound.
16. The process of claim 14 wherein the solids separator is a cyclone and the process comprises passing the waste gas containing fine dust not separated in the cyclone to a water containing washer and thereby dissolving the catalyst portion of the fine dust in water.
17. The process of claim 14 wherein the solids separator is a cyclone and the process comprises filtering the waste gas containing fine dust after the cyclone to separate the fine dust from the waste gas.
18. The process of claim 1 wherein the catalyst is a sodium tungstate and there is employed sufficient water in dissolving the catalyst from the inert water insoluble particles that there is obtained a 4 to 8 weight % catalyst solution and then returning this solution to the reactor for use in the epoxidation or hydroxylation of a water soluble olefinic compound.
19. In a process for the separation of a catalyst employed in the epoxidation of hydroxylation of an olefinic compound with a peroxy compound in a reactor distilling off the epoxidized or hydroxylated product and separation of the catalyst from the distillation residue containing said catalyst and said high boiling organic compounds, said catalyst being a compound of a transition metal selected from zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and rhenium, the improve-ment comprising introducing the distallation residue into a bed of fluidized inert solid particles, burning the organic compounds of said distillation residue with an oxygen containing gas while in contact with said fluidized particles and separating fluidized particles containing a compound of the metal employed in the catalyst from the waste gas of said burning.
20. The process of claim 19 wherein the catalyst is a compound of vanadium, tungsten or niobium.
21. The process of claim 19 wherein the catalyst is a compound of tungsten molybdenum or vanadium.
22. The process of claim 19 in which the catalyst is an alkali metal vanadate, molybdate and tungstate.
23. The process of claim 22 wherein the olefinic compound is allyl alcohol, cyclohexene or propylene.
24. The process of claim 22 wherein the peroxy compound is an organic peroxide, organic hydro-peroxide or hydrogen peroxide.
25. The process of claim 22 wherein the inert solid particles are quartz sand, silicon carbide, highly fired alumina or highly fired clay.
26. The process of claim 22 wherein the fluidized particles have a particle size of 0.1 to 5mm.
27. The process of claim 26 wherein the fluidized particles have a particle size of 0.5 to 1.5mm.
28. The process of claim 22 wherein the oxygen containing gas is air.
29. The process of claim 22 wherein the burning temper-ature is between 500 and 1000°C. and also is not over the melting point of the inorganic compound of the metal of the catalyst formed in the burning.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742454572 DE2454572C3 (en) | 1974-11-18 | 1974-11-18 | Process for the separation of epoxidation and hydroxylation catalysts from distillation residues |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1067061A true CA1067061A (en) | 1979-11-27 |
Family
ID=5931109
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,905A Expired CA1067061A (en) | 1974-11-18 | 1975-11-18 | Recovery of catalysts in a fluidized bed |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5843136B2 (en) |
| AT (1) | AT347412B (en) |
| CA (1) | CA1067061A (en) |
| DE (1) | DE2454572C3 (en) |
| FR (1) | FR2290955A1 (en) |
| NL (1) | NL182125C (en) |
| PL (1) | PL99331B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022064037A1 (en) * | 2020-09-28 | 2022-03-31 | Avantium Knowledge Centre B.V. | Process for producing glycols from carbohydrates and burning waste |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6126515A (en) * | 1984-07-18 | 1986-02-05 | Daicel Chem Ind Ltd | Recovery of tungsten compound |
| ES2267376B1 (en) * | 2005-03-16 | 2008-01-01 | Gonzalo Yebenes De Madrid | FORCED FLAGING SYSTEM OF FLAGS FOR ADVERTISING AND SIMILAR DEVICES AND THE CORRESPONDING OPERATING METHODS OF SUCH SYSTEM. |
-
1974
- 1974-11-18 DE DE19742454572 patent/DE2454572C3/en not_active Expired
-
1975
- 1975-09-25 NL NL7511300A patent/NL182125C/en not_active IP Right Cessation
- 1975-10-31 JP JP13055575A patent/JPS5843136B2/en not_active Expired
- 1975-11-17 AT AT872675A patent/AT347412B/en not_active IP Right Cessation
- 1975-11-17 PL PL18478575A patent/PL99331B1/en unknown
- 1975-11-18 CA CA239,905A patent/CA1067061A/en not_active Expired
- 1975-11-18 FR FR7535226A patent/FR2290955A1/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022064037A1 (en) * | 2020-09-28 | 2022-03-31 | Avantium Knowledge Centre B.V. | Process for producing glycols from carbohydrates and burning waste |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2290955A1 (en) | 1976-06-11 |
| JPS5843136B2 (en) | 1983-09-24 |
| ATA872675A (en) | 1978-05-15 |
| DE2454572A1 (en) | 1976-05-26 |
| NL7511300A (en) | 1976-05-20 |
| JPS51101800A (en) | 1976-09-08 |
| PL99331B1 (en) | 1978-07-31 |
| FR2290955B1 (en) | 1977-12-16 |
| DE2454572C3 (en) | 1983-05-19 |
| DE2454572B2 (en) | 1977-04-28 |
| AT347412B (en) | 1978-12-27 |
| NL182125B (en) | 1987-08-17 |
| NL182125C (en) | 1988-01-18 |
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