CA1077066A - Process for the direct separation of isobutylene from mixtures of hydrocarbons - Google Patents
Process for the direct separation of isobutylene from mixtures of hydrocarbonsInfo
- Publication number
- CA1077066A CA1077066A CA264,132A CA264132A CA1077066A CA 1077066 A CA1077066 A CA 1077066A CA 264132 A CA264132 A CA 264132A CA 1077066 A CA1077066 A CA 1077066A
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- Canada
- Prior art keywords
- reaction mixture
- isobutylene
- methanol
- weight
- amount
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/05—Preparation of ethers by addition of compounds to unsaturated compounds
- C07C41/06—Preparation of ethers by addition of compounds to unsaturated compounds by addition of organic compounds only
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
- C07C7/14875—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound with organic compounds
- C07C7/14891—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound with organic compounds alcohols
Abstract
PROCESS FOR THE DIRECT SEPARATION OF ISOBUTYLENE
FROM MIXTURES OF HYDROCARBONS
ABSTRACT OF THE DISCLOSURE
Isobutylene-containing hydrocarbon mixtures are reacted with an excess of methanol in the presence of sulphuric acid to form for separation methyl t-butyl ether selectively from the isobutylene.
FROM MIXTURES OF HYDROCARBONS
ABSTRACT OF THE DISCLOSURE
Isobutylene-containing hydrocarbon mixtures are reacted with an excess of methanol in the presence of sulphuric acid to form for separation methyl t-butyl ether selectively from the isobutylene.
Description
" 10~'7066 The invention relates to a process for the direct obtaining of isobutylene. The process is equally suitable for the removal of isobutylene from gas mixtures having a high butadiene content or from gas mixtures containing only butenes and butane, by means of selective reaction with methanol. The formed methyl tert.butyl ether (NTBE) can be easily separated from the C4 hydrocarbons. Most parts of the isobutylene used in the art originate from the C4 fraction obtained via pyrolysis or out of butane-de-hydrogenation processes. However, these processes do not yield pure isobutylene and the product contains also other olefins and diolefins in addition to saturated hydrocarbons.
A more purified compound can be obtained only by using expensive equipments and complicated operations.
The C4 fraction arising from the pyrolysis of hydrocarbons and gas mixtures prepared by dehydrogenation processes could not serve hitherto as direct sources of iso-butylene, due to their high butadiene contents. In the known processes at first butadiene is extracted and after iso-butylene is separated generally by means of absorption with sulphuric acid (G. D. Hobson: Modern Petroleum Techn. p.
460). Tert. butanol is formed in the course of the absorption which after purification is dehydrated and yields pure isobutylene.
Isobutylene can be reacted also with methanol in the presence of acidic catalysts when MTBE is formed.
According to the British Patent Specification No. 1.165.479 e.g. MTBE can be easily decomposed over an A1203 catalyst to methanol and pure isobutylene. A further advantage is that the formed MTBE may be used preferably as a component having 1 ~07706~;
high octane number in motor gasolines.
A requirement of environmental protection is to re-duce the lead content of gasolines. This requires in turn a posslbly cheap method for the production of gasoline components having high octane number. In this field the production of MTBE from isobutene-containing gas mixtures represents a significant technical progress.
The freaction of isobutene with methanol in the presence of acidic catalysts has been described by T. E. Evans (Ind. Eng. Chem. 28 /N 10/ 1186). Sulphuric acid is the most efficient catalyst of this reaction. In the process according to the U.S. Patent Specification No.
A more purified compound can be obtained only by using expensive equipments and complicated operations.
The C4 fraction arising from the pyrolysis of hydrocarbons and gas mixtures prepared by dehydrogenation processes could not serve hitherto as direct sources of iso-butylene, due to their high butadiene contents. In the known processes at first butadiene is extracted and after iso-butylene is separated generally by means of absorption with sulphuric acid (G. D. Hobson: Modern Petroleum Techn. p.
460). Tert. butanol is formed in the course of the absorption which after purification is dehydrated and yields pure isobutylene.
Isobutylene can be reacted also with methanol in the presence of acidic catalysts when MTBE is formed.
According to the British Patent Specification No. 1.165.479 e.g. MTBE can be easily decomposed over an A1203 catalyst to methanol and pure isobutylene. A further advantage is that the formed MTBE may be used preferably as a component having 1 ~07706~;
high octane number in motor gasolines.
A requirement of environmental protection is to re-duce the lead content of gasolines. This requires in turn a posslbly cheap method for the production of gasoline components having high octane number. In this field the production of MTBE from isobutene-containing gas mixtures represents a significant technical progress.
The freaction of isobutene with methanol in the presence of acidic catalysts has been described by T. E. Evans (Ind. Eng. Chem. 28 /N 10/ 1186). Sulphuric acid is the most efficient catalyst of this reaction. In the process according to the U.S. Patent Specification No.
2.721.222 (Esso Res. Eng. Co.) similarly sulphuric acid is used as catalyst. The reaction is carried out in a heterogeneous phase, then the reaction mixture is diluted with a great amount of methanol in order to decrease the de-composition during distillation. Accord$ng to the U.S. Patent Specification No~ 2.720.547 (Standard Oil Co.) the reaction is carried out similarly in a heterogeneous phase and 80 %
sulphuric acid or alkane-sulphonic acid is applied as catalyst ln order to decrease decomposition during distlllation as a consequence of using a catalyst of lower activity. However, up to the present it was not possible to solve by means of a simple method the problem of the separation and recirculation of the catalyst. Thus, the recently applied processes are using in general solid heterogeneous catalysts. In the majority of processes one operates with an ion exchanger catalyst of a sulphonated type of styrene-divinylbenzene base. Processes of this type are e.g. those described in the Belgian Patent Specification 107'~06!~
No. 612.33B (Bayer), in the U.S. Patent Specification No.
sulphuric acid or alkane-sulphonic acid is applied as catalyst ln order to decrease decomposition during distlllation as a consequence of using a catalyst of lower activity. However, up to the present it was not possible to solve by means of a simple method the problem of the separation and recirculation of the catalyst. Thus, the recently applied processes are using in general solid heterogeneous catalysts. In the majority of processes one operates with an ion exchanger catalyst of a sulphonated type of styrene-divinylbenzene base. Processes of this type are e.g. those described in the Belgian Patent Specification 107'~06!~
No. 612.33B (Bayer), in the U.S. Patent Specification No.
3.170.000 (Sinclair Res. Inc.) or in the British Patent Specification No. 1.176.620 (Shell). However, these catalysts have essentially lower activities and are extremely sensitive to even small contaminations of the raw materials.
In general, these processes lend themselves only to the conversion of pure isobutylene because in this case the low conversion can be increased by recirculating the butane and the amount of detrimental contaminants such as butadiene is small. The processing of mixtures of isobutylene and n-butylene is limited because of the low cqnversion.
According to the latest processes, German Patent Specification No. 2.246.004 (Sun Oil Co.) only a part of isobutylene is allowed to react and the gas mixture with the residual isobutylene content is then used for other purposes.
The prerequisite of the economic production of MTBE
out of isobutylene and methanol is the possibility of producing MTBE by the direct extraction of the isobutylene content of gases of various origin. For this purpose the best suitable raw material is the C4 fraction of the gasoline pyrolysis. However, the isobutylene content of the mixture of C4 hydrocarbons which contains about 40 % of butadiene could not be obtained economically by known processes.
Namely, butadiene polymerizes readily under the action of strong acids and reacts also with methanol. This is shown in the U.S. Patent Specification No. 2.922.822 (Esso Res.
Eng. Co.) according to which unsaturated ethers are proced from butadiene-containing gases and from methanol under conditions similar to those of the reaction of isobutylene.
In the course of our experimental work we examined
In general, these processes lend themselves only to the conversion of pure isobutylene because in this case the low conversion can be increased by recirculating the butane and the amount of detrimental contaminants such as butadiene is small. The processing of mixtures of isobutylene and n-butylene is limited because of the low cqnversion.
According to the latest processes, German Patent Specification No. 2.246.004 (Sun Oil Co.) only a part of isobutylene is allowed to react and the gas mixture with the residual isobutylene content is then used for other purposes.
The prerequisite of the economic production of MTBE
out of isobutylene and methanol is the possibility of producing MTBE by the direct extraction of the isobutylene content of gases of various origin. For this purpose the best suitable raw material is the C4 fraction of the gasoline pyrolysis. However, the isobutylene content of the mixture of C4 hydrocarbons which contains about 40 % of butadiene could not be obtained economically by known processes.
Namely, butadiene polymerizes readily under the action of strong acids and reacts also with methanol. This is shown in the U.S. Patent Specification No. 2.922.822 (Esso Res.
Eng. Co.) according to which unsaturated ethers are proced from butadiene-containing gases and from methanol under conditions similar to those of the reaction of isobutylene.
In the course of our experimental work we examined
- 4 -: - . , .
~0'77066 thoroughly the behaviour of butadiene under the conditions under which MTBE is being produced. It was found in these experiments that isobutylene can be selectively reacted in the presence of butadiene provided the amount of sulphuric acid applied as catalyst is below 20 Z by weight calculated on the reaction mixture and the reaction is carried out at a temperature between 50 and 120 C in a homogeneous liquid phase with an excess of methanol. Under such conditions the polymerization of butadiene can be reduced to a neglibible extent.
The methanol addition of isobutylene takes place under these conditions in a thousand times higher rate than the reaction rate of butadiene and methanol. According to the process of invention isobutylene reacts completely selectively with methanol even in the case if the raw material contains 40 to 60 Z of butadiene.
The environmental protection necessitates the de-crease of the amount of sulphuric acid involved in the process. This can be accomplished in the present invention by a recirculation of the catalyst. Investigations were carried out to establish the dissolving capacity of the re-action mixture having a different composition relating to sulphuric acid. It has been recognized that under particular conditions after a reaction carried out at a temperature between 50 and 120 C in a homogenous liquid phase, the reaction mixture when cooled to room temperature, a major part of the catalyst forms a separate phase with a part of the excess methanol. The separated lower phase contains 10 to 50 % of sulphuric acid and can be directly employed as a catalyst of the synthesis. The separation of this 10'7'~066 catalyst phase after the reaction is influenced by the proportion of methanol to isobutylene and by the sulphuric acid content. In Fig. l the values of the maximum concentration of sulphuric acid in per cent by weight are plotted against the contents of methanol at 90 C and 30 C. These data relate to a raw material having 95 % of isobutylene content. In the case of an identical methanol content the amount of dissolved sulphuric acid decreases parallely to the decrease of the isobutene content whereas the amount of dissolved sulphuric acid increases with the increase of the molar ratio of methanol, as shown by Fig. 1. The deviation between the two curves shows the separating efficiency of the catalyst which takes place on the effect of cooling. The initial molar ratio of methanol to isobutylene is apparently re-duced by the amount of methanol entering the sulphuric acid phase, increasing in this way the amount of separated sulphuric acid.
It has been found that the separation of the catalyst can be promoted by recirculating after the reaction mixture free of methanol or the C4 fraction set free from isobutylene which fraction leaves the process. The surprising efficiency of recirculating is illustrated by Fig. 2 which shows the amount of the separated phases plotted against the amount of hydro-carbons recirculated. The amount of hydrocarbons which have been recirculated are given in per cent referred to the initial hydrocarbon content of the reaction mixture. The curve on Fig. 2 relates to the product of the reaction of a hydro-~07'~'0~6 carbon mixture having 27 % of isobutylene content, carried out at a 3.5 molar ratio of methanol to isobutylene and in the presence of 3.2 % by weight of sulphuric acid as catalyst up to a 90 % conversion of isobutylene. As shown by the curve on Fig. 2, the amount of the separated phase is remarkably influenced by already small amounts of re-circulated material whereas the recirculation of greater amounts of material did not influence significantly the amount of separated phase.
The two effects referred to namely the decrease of temperature and the decrease of methanol content make possible either alone or combined a separation of the sulphuric acid in a rather simple way. The separated phase having high sulphuric acid content can be preferably employed directly as catalyst. It is of advantage that the costs of recovering excess methanol is reduced because the recovery of methanol content of the catalyst phase can be easily carried out.
The flow scheme of the claimed process is shown on Fig. 3.
The isobutylene-containing mixture of hydrocarbons is fed through pipeline 1 and methanol through pipeline 2 into reactor 4. Fresh sulphuric acid catalyst is introduced into reactor 4 through pipeline 3 whereas the catalyst solution separated from the reaction mixture through pipeline 9. The reaction takes place in a homogeneous liquid phase. The reaction mixture leaving reactor 4 through pipeline 5 is cooled in condenser 6.
Simultaneously with the cooling of the batch a part of the hydrocarbon fraction from which isobutylene has been ~077()66 removed and is recirculated through pipeline 7 and/or a part of the reaction mixture free from methanol is re~
circulated as well through pipelines 7 and 14. Under the effect of cooling and recirculating the homogeneous reaction mixture is decomposed in two phases which are subsequently separated in separator 8. The lower phase having a high sulphuric acid content and serving as catalyst is trans-ferred from separator 8 through pipeline 9 into reactor 4.
The upper phase with a decreased sulphuric acid content is conducted in turn through pipeline 10 into washing tank 11 whereto water containing if necessary alkali is fed through pipeline 12 in order to remove traces of catalyst. me washing water leaving the tank 11 through pipeline 13 contains the excess of methanol used in the reaction. This excess of methanol can be separated in a known way by distillation and ~hen recirculated in the reaction system.
The reaction mixture after having removed the methanol, leaving the system through pipeline 15 is partly re-circulated through pipelines 14 and 7 to the separation of the catalyst. The residual part is transferred through pipeline 15 into distilling column 16 where the unreacted hydrocarbons are separated from MTBE. The hydrocarbon mixture after removing the isobutylene leaves the column at the top through pipeline 18. However, a part of the leaving mixture is recirculated to the separation step of the catalyse through pipeline 7. The MTBE formed from the isobutylene present originally in the raw material leaves the column at the bottom through pipeline 17.
The MTBE obtained here can be used directly or eventually after an adequate purification as a component of motor fuels ~77()~6 or can be decomposed to isobutylene and methanol.
It can be seen from the abovementioned process that it is suitable in a wider concentration range for the conversion of the isobutylene content of gaseous mixtures of hydrocarbons in to MTBE even in case of raw materials having a high butadiene content. A further advantage is that sulphuric acid can be applied in the process as a catalyst having high activity and low price and that a considerable part of the sulphuric acid can be separated after the reaction and recirculated.
The process is illustrated by the Examples given below:
Example 1 Into a 0.5 liter autocalve lined with polypropylene 259.8 ml. of liquid isobutylene of 95 % purity, 140.2 ml.
of methanol and 9.5 g. of sulphuric acid are fed at -20 C.
The reaction is carried out at 90 C, the reaction mixture is homogeneous and 87 % of isobutylene is converted into MTBE in 20 minutes. On cooling the reaction mixture, a phase of higher specific gravity is separating from the product. This phase contains beside methanol more than 80 % of the sulphuric acid catalyst introduced. On re-circulating the catalyst phase and calculaeing the amount thereof in a concentration corresponding to its content of sulphuric acid and methanol, no difference was observed carrying out the reaction and the separability of the catalyst phase from the reaction product remained as good as in the previous step.
Example 2 Into a reactor kept under a pressure of 20 atm _ g _ ~077()66 and at a temperature of 90 C continuously 5 literslhour of a liquid C4 fraction (containing 25 % of isobutane and 41 %
of butadiene) originating from gasoline pyrolisis, 1.22 liter of methanol, 15 ml. of sulphuric acid and 0.75 liter of catalyst solution containing sulphuric acid are intro-duced. The isobutylene content of the raw material in the homogeneous reaction mixture leaving the reactor is converted in a rate of 93.8 % into MTBE. The reaction mixture is colled and at the same time 1 liter/hour of C4 fraction free from isobutylene added. The catalyst solution containing 26.9 % of sulphuric acid which is separating from the reaction mixture owing to its higher specific gravity is recirculated to the entry of the reactor whereas the upper phase is introduced into an aqueous washing vessel kept under pressure of 5 atm in order to remove excess methanol. The washing water contained 2 % of sodium hydroxide which serves for the removal of traces of the catalyst. The reaction mixture after re-moval of methanol is decomposed in an apparatus for continuous distillation to NTBE and to fractions con-taining C4 hydrocarbons under a pressure of about 4 atm.
A part of these C4 hydrocarbons is recirculated to the separation step of the catalyst. me capacity of the apparatus of the amount to 3.~3 liter/hour of liquid C4 hydrocarbons having 2 % of isobutylene and 52 % of butadiene content.
Example 3 Into the reactor described in Example 2, continuously 5.0 liters/hour of a liquid C4 fraction containing 20 % of isobutene which fraction originates ~077066 from catalytic cracking, 1.0 liter of methanol, 10 ml. of 98 % sulphuric acid and 0.65 liter of catalyst solution are introduced. To the reaction mixture leaving the reactor 1.2 literlhour of reaction mixture already free from methanol is recirculated and at the same time the reaction mixture is cooled to room temperature. The separated catalyst phase contains 25.4 % of sulphuric acid. Then methanol is removed from the reaction mixture by washing it with water and a part o the reaction mixture containing MTBE and C4 hydrocarbons is recirculated for the separation of the catalyst. The residual part is fed into a ~ !
distilling apparatus where the residual C4 hydrocarbons are separated from MTBE. 94.6 % of the introduced isobutylene was converted. The C4 gas leaving the system contained more than 98 % of the introduced n-butylenes.
~0'77066 thoroughly the behaviour of butadiene under the conditions under which MTBE is being produced. It was found in these experiments that isobutylene can be selectively reacted in the presence of butadiene provided the amount of sulphuric acid applied as catalyst is below 20 Z by weight calculated on the reaction mixture and the reaction is carried out at a temperature between 50 and 120 C in a homogeneous liquid phase with an excess of methanol. Under such conditions the polymerization of butadiene can be reduced to a neglibible extent.
The methanol addition of isobutylene takes place under these conditions in a thousand times higher rate than the reaction rate of butadiene and methanol. According to the process of invention isobutylene reacts completely selectively with methanol even in the case if the raw material contains 40 to 60 Z of butadiene.
The environmental protection necessitates the de-crease of the amount of sulphuric acid involved in the process. This can be accomplished in the present invention by a recirculation of the catalyst. Investigations were carried out to establish the dissolving capacity of the re-action mixture having a different composition relating to sulphuric acid. It has been recognized that under particular conditions after a reaction carried out at a temperature between 50 and 120 C in a homogenous liquid phase, the reaction mixture when cooled to room temperature, a major part of the catalyst forms a separate phase with a part of the excess methanol. The separated lower phase contains 10 to 50 % of sulphuric acid and can be directly employed as a catalyst of the synthesis. The separation of this 10'7'~066 catalyst phase after the reaction is influenced by the proportion of methanol to isobutylene and by the sulphuric acid content. In Fig. l the values of the maximum concentration of sulphuric acid in per cent by weight are plotted against the contents of methanol at 90 C and 30 C. These data relate to a raw material having 95 % of isobutylene content. In the case of an identical methanol content the amount of dissolved sulphuric acid decreases parallely to the decrease of the isobutene content whereas the amount of dissolved sulphuric acid increases with the increase of the molar ratio of methanol, as shown by Fig. 1. The deviation between the two curves shows the separating efficiency of the catalyst which takes place on the effect of cooling. The initial molar ratio of methanol to isobutylene is apparently re-duced by the amount of methanol entering the sulphuric acid phase, increasing in this way the amount of separated sulphuric acid.
It has been found that the separation of the catalyst can be promoted by recirculating after the reaction mixture free of methanol or the C4 fraction set free from isobutylene which fraction leaves the process. The surprising efficiency of recirculating is illustrated by Fig. 2 which shows the amount of the separated phases plotted against the amount of hydro-carbons recirculated. The amount of hydrocarbons which have been recirculated are given in per cent referred to the initial hydrocarbon content of the reaction mixture. The curve on Fig. 2 relates to the product of the reaction of a hydro-~07'~'0~6 carbon mixture having 27 % of isobutylene content, carried out at a 3.5 molar ratio of methanol to isobutylene and in the presence of 3.2 % by weight of sulphuric acid as catalyst up to a 90 % conversion of isobutylene. As shown by the curve on Fig. 2, the amount of the separated phase is remarkably influenced by already small amounts of re-circulated material whereas the recirculation of greater amounts of material did not influence significantly the amount of separated phase.
The two effects referred to namely the decrease of temperature and the decrease of methanol content make possible either alone or combined a separation of the sulphuric acid in a rather simple way. The separated phase having high sulphuric acid content can be preferably employed directly as catalyst. It is of advantage that the costs of recovering excess methanol is reduced because the recovery of methanol content of the catalyst phase can be easily carried out.
The flow scheme of the claimed process is shown on Fig. 3.
The isobutylene-containing mixture of hydrocarbons is fed through pipeline 1 and methanol through pipeline 2 into reactor 4. Fresh sulphuric acid catalyst is introduced into reactor 4 through pipeline 3 whereas the catalyst solution separated from the reaction mixture through pipeline 9. The reaction takes place in a homogeneous liquid phase. The reaction mixture leaving reactor 4 through pipeline 5 is cooled in condenser 6.
Simultaneously with the cooling of the batch a part of the hydrocarbon fraction from which isobutylene has been ~077()66 removed and is recirculated through pipeline 7 and/or a part of the reaction mixture free from methanol is re~
circulated as well through pipelines 7 and 14. Under the effect of cooling and recirculating the homogeneous reaction mixture is decomposed in two phases which are subsequently separated in separator 8. The lower phase having a high sulphuric acid content and serving as catalyst is trans-ferred from separator 8 through pipeline 9 into reactor 4.
The upper phase with a decreased sulphuric acid content is conducted in turn through pipeline 10 into washing tank 11 whereto water containing if necessary alkali is fed through pipeline 12 in order to remove traces of catalyst. me washing water leaving the tank 11 through pipeline 13 contains the excess of methanol used in the reaction. This excess of methanol can be separated in a known way by distillation and ~hen recirculated in the reaction system.
The reaction mixture after having removed the methanol, leaving the system through pipeline 15 is partly re-circulated through pipelines 14 and 7 to the separation of the catalyst. The residual part is transferred through pipeline 15 into distilling column 16 where the unreacted hydrocarbons are separated from MTBE. The hydrocarbon mixture after removing the isobutylene leaves the column at the top through pipeline 18. However, a part of the leaving mixture is recirculated to the separation step of the catalyse through pipeline 7. The MTBE formed from the isobutylene present originally in the raw material leaves the column at the bottom through pipeline 17.
The MTBE obtained here can be used directly or eventually after an adequate purification as a component of motor fuels ~77()~6 or can be decomposed to isobutylene and methanol.
It can be seen from the abovementioned process that it is suitable in a wider concentration range for the conversion of the isobutylene content of gaseous mixtures of hydrocarbons in to MTBE even in case of raw materials having a high butadiene content. A further advantage is that sulphuric acid can be applied in the process as a catalyst having high activity and low price and that a considerable part of the sulphuric acid can be separated after the reaction and recirculated.
The process is illustrated by the Examples given below:
Example 1 Into a 0.5 liter autocalve lined with polypropylene 259.8 ml. of liquid isobutylene of 95 % purity, 140.2 ml.
of methanol and 9.5 g. of sulphuric acid are fed at -20 C.
The reaction is carried out at 90 C, the reaction mixture is homogeneous and 87 % of isobutylene is converted into MTBE in 20 minutes. On cooling the reaction mixture, a phase of higher specific gravity is separating from the product. This phase contains beside methanol more than 80 % of the sulphuric acid catalyst introduced. On re-circulating the catalyst phase and calculaeing the amount thereof in a concentration corresponding to its content of sulphuric acid and methanol, no difference was observed carrying out the reaction and the separability of the catalyst phase from the reaction product remained as good as in the previous step.
Example 2 Into a reactor kept under a pressure of 20 atm _ g _ ~077()66 and at a temperature of 90 C continuously 5 literslhour of a liquid C4 fraction (containing 25 % of isobutane and 41 %
of butadiene) originating from gasoline pyrolisis, 1.22 liter of methanol, 15 ml. of sulphuric acid and 0.75 liter of catalyst solution containing sulphuric acid are intro-duced. The isobutylene content of the raw material in the homogeneous reaction mixture leaving the reactor is converted in a rate of 93.8 % into MTBE. The reaction mixture is colled and at the same time 1 liter/hour of C4 fraction free from isobutylene added. The catalyst solution containing 26.9 % of sulphuric acid which is separating from the reaction mixture owing to its higher specific gravity is recirculated to the entry of the reactor whereas the upper phase is introduced into an aqueous washing vessel kept under pressure of 5 atm in order to remove excess methanol. The washing water contained 2 % of sodium hydroxide which serves for the removal of traces of the catalyst. The reaction mixture after re-moval of methanol is decomposed in an apparatus for continuous distillation to NTBE and to fractions con-taining C4 hydrocarbons under a pressure of about 4 atm.
A part of these C4 hydrocarbons is recirculated to the separation step of the catalyst. me capacity of the apparatus of the amount to 3.~3 liter/hour of liquid C4 hydrocarbons having 2 % of isobutylene and 52 % of butadiene content.
Example 3 Into the reactor described in Example 2, continuously 5.0 liters/hour of a liquid C4 fraction containing 20 % of isobutene which fraction originates ~077066 from catalytic cracking, 1.0 liter of methanol, 10 ml. of 98 % sulphuric acid and 0.65 liter of catalyst solution are introduced. To the reaction mixture leaving the reactor 1.2 literlhour of reaction mixture already free from methanol is recirculated and at the same time the reaction mixture is cooled to room temperature. The separated catalyst phase contains 25.4 % of sulphuric acid. Then methanol is removed from the reaction mixture by washing it with water and a part o the reaction mixture containing MTBE and C4 hydrocarbons is recirculated for the separation of the catalyst. The residual part is fed into a ~ !
distilling apparatus where the residual C4 hydrocarbons are separated from MTBE. 94.6 % of the introduced isobutylene was converted. The C4 gas leaving the system contained more than 98 % of the introduced n-butylenes.
Claims (7)
1. A process for producing methyl tertiary butyl ether from a mixture of C4 hydrocarbons containing isobutylene and butadiene, comprising the steps of selectively reacting the isobutylene with a greater than stoichiometric amount of methanol, at a temperature of 50°C to 120°C, in a homogeneous liquid phase and in the presence of a catalytic amount of sulfuric acid, said sulfuric acid being present in an amount less than 20% by weight based on the weight of the reaction mixture, said homogeneous liquid phase being maintained throughout the reaction, whereby a reaction mixture containing methyl tertiary butyl ether is produced and undesired polymer-ization of the butadiene is avoided; cooling the reaction mixture then adding to it reaction mixture which has been washed free of methanol or separated unreacted C4 fraction which is isobutylene-free whereby an upper phase containing hydrocarbons and methyl tertiary butyl ether and a part of the methanol and a lower phase containing methanol and 10 to 50% sulfuric acid is formed; and recirculating the lower phase as a catalyst to said step of selectively reacting the isobutylene with methanol.
2. A process according to claim 1 for working up a C4 fraction derived from a catalytic cracking process or from pyrolysis of gasoline containing 10 to 40% of isobutylene characterized by reacting in a homogeneous phase, calculated on the whole amount of reaction mixture, 15 to 35% by weight of methanol, 0.2 to 5.0% by weight of sulfuric acid catalyst;
and after the reaction takes place, cooling the reaction mixture to a temperature between -25°C to +40°C in order to separate the catalyst, and adding thereto, calculated on the amount of the whole reaction mixture, 0.01 to 2.0% by weight a part of the reaction mixture, free of methanol and/or a C4 hydrocarbon fraction free of isobutylene obtained in the course of the reaction.
and after the reaction takes place, cooling the reaction mixture to a temperature between -25°C to +40°C in order to separate the catalyst, and adding thereto, calculated on the amount of the whole reaction mixture, 0.01 to 2.0% by weight a part of the reaction mixture, free of methanol and/or a C4 hydrocarbon fraction free of isobutylene obtained in the course of the reaction.
3. A process according to claim 1 to work up raw materials containing isobutylene in an amount more than 80% by weight characterized by reacting in a homogeneous phase, calculated on the amount of the whole reaction mixture, 35 to 50% by weight of methanol and 0.5 to 8.0%
by weight of sulfuric acid catalyst and after the reaction is complete cooling the reaction mixture to a temperature of -20°C to +40°C to separate the catalyst phase.
by weight of sulfuric acid catalyst and after the reaction is complete cooling the reaction mixture to a temperature of -20°C to +40°C to separate the catalyst phase.
4. A process according to claim 1 for working up a C4 fraction derived from a catalytic cracking process or from pyrolysis of gasoline containing 10 to 40% of isobutylene characterized by reacting in a homogeneous phase, calculated on the whole amount of reaction mixture, 25 to 30% by weight of methanol, 1.0 to 2.5% by weight of sulfuric acid catalyst;
and after the reaction takes place, cooling the reaction mixture to a temperature between -25°C to +40°C in order to separate the catalyst, and adding thereto, calculated on the amount of the whole reaction mixture, 0.1 to 1.0% by weight a part of the reaction mixture, free of methanol and/or a C4 hydrocarbon fraction free of isobutylene obtained in the course of the reaction.
and after the reaction takes place, cooling the reaction mixture to a temperature between -25°C to +40°C in order to separate the catalyst, and adding thereto, calculated on the amount of the whole reaction mixture, 0.1 to 1.0% by weight a part of the reaction mixture, free of methanol and/or a C4 hydrocarbon fraction free of isobutylene obtained in the course of the reaction.
5. A process according to claim 1 to work up raw materials containing isobutylene in an amount more than 80%
by weight characterized by reacting in a homogeneous phase, calculated on the amount of the whole reaction mixture, 40 to 45% by weight of methanol and 2.0 to 5.0% by weight of sulfuric acid catalyst and after the reaction is complete cooling the reaction mixture to a temperature of -20°C to +40°C to separate the catalyst phase.
by weight characterized by reacting in a homogeneous phase, calculated on the amount of the whole reaction mixture, 40 to 45% by weight of methanol and 2.0 to 5.0% by weight of sulfuric acid catalyst and after the reaction is complete cooling the reaction mixture to a temperature of -20°C to +40°C to separate the catalyst phase.
6. A process according to claim 1 wherein in said step of selectively reacting the isobutylene with the methanol is carried out at a temperature of 80°C to 100°C.
7. A process according to claim 1 wherein in said cooling step the reaction mixture is cooled to a temperature of -25°C to +40°C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HUMA002724 HU175954B (en) | 1975-10-29 | 1975-10-29 | Process for direct separation of isobutylene form mixtures of hydrocarbones |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1077066A true CA1077066A (en) | 1980-05-06 |
Family
ID=10998814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,132A Expired CA1077066A (en) | 1975-10-29 | 1976-10-25 | Process for the direct separation of isobutylene from mixtures of hydrocarbons |
Country Status (16)
| Country | Link |
|---|---|
| JP (1) | JPS5257103A (en) |
| AT (1) | AT346297B (en) |
| BE (1) | BE847862A (en) |
| CA (1) | CA1077066A (en) |
| CS (1) | CS205045B2 (en) |
| DD (1) | DD126591A1 (en) |
| DE (1) | DE2649623A1 (en) |
| FR (1) | FR2329622A1 (en) |
| GB (1) | GB1532477A (en) |
| HU (1) | HU175954B (en) |
| IT (1) | IT1079198B (en) |
| NL (1) | NL7611965A (en) |
| PL (1) | PL110592B1 (en) |
| RO (1) | RO71263A (en) |
| SU (1) | SU915797A3 (en) |
| YU (1) | YU39977B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2928509A1 (en) * | 1979-07-14 | 1981-01-29 | Basf Ag | METHOD FOR THE SIMULTANEOUS PRODUCTION OF METHYL-TERT.-BUTYL ETHER AND PRODUCTION OF ISOBUTEN |
| DE2928510A1 (en) * | 1979-07-14 | 1981-01-29 | Basf Ag | METHOD FOR PRODUCING ISOBUTEN FROM ISOBUTEN CONTAINING C TIEF 4-HYDROCARBON MIXTURES |
| US4392003A (en) * | 1980-06-12 | 1983-07-05 | The British Petroleum Company Limited | Isobutene by dehydroisomerization of normal butane |
| CN113582801B (en) * | 2020-04-30 | 2023-09-05 | 中国石油化工股份有限公司 | Process for preparing isooctenes by mixing carbon four selective overlapping |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3121124A (en) * | 1959-05-04 | 1964-02-11 | Sinclair Research Inc | Tertiary olefin separation via etherification |
| US3170000A (en) * | 1962-10-24 | 1965-02-16 | Sinclair Research Inc | Tertiary olefin separation via etherification with small surface area catalysts |
| JPS5126401B1 (en) * | 1969-03-12 | 1976-08-06 |
-
1975
- 1975-10-29 HU HUMA002724 patent/HU175954B/en unknown
-
1976
- 1976-09-27 AT AT712976A patent/AT346297B/en not_active IP Right Cessation
- 1976-09-30 FR FR7629363A patent/FR2329622A1/en active Granted
- 1976-10-07 GB GB4168876A patent/GB1532477A/en not_active Expired
- 1976-10-14 YU YU253076A patent/YU39977B/en unknown
- 1976-10-21 SU SU762414047A patent/SU915797A3/en active
- 1976-10-25 CA CA264,132A patent/CA1077066A/en not_active Expired
- 1976-10-26 DD DD19545576A patent/DD126591A1/xx unknown
- 1976-10-26 CS CS688076A patent/CS205045B2/en unknown
- 1976-10-27 RO RO7688240A patent/RO71263A/en unknown
- 1976-10-27 JP JP12929876A patent/JPS5257103A/en active Granted
- 1976-10-28 IT IT2882476A patent/IT1079198B/en active
- 1976-10-28 PL PL19333076A patent/PL110592B1/en unknown
- 1976-10-28 NL NL7611965A patent/NL7611965A/en not_active Application Discontinuation
- 1976-10-29 BE BE171988A patent/BE847862A/en not_active IP Right Cessation
- 1976-10-29 DE DE19762649623 patent/DE2649623A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB1532477A (en) | 1978-11-15 |
| DE2649623A1 (en) | 1977-05-12 |
| HU175954B (en) | 1980-11-28 |
| CS205045B2 (en) | 1981-04-30 |
| FR2329622A1 (en) | 1977-05-27 |
| YU39977B (en) | 1985-06-30 |
| JPS5614089B2 (en) | 1981-04-02 |
| ATA712976A (en) | 1978-03-15 |
| NL7611965A (en) | 1977-05-03 |
| AT346297B (en) | 1978-11-10 |
| JPS5257103A (en) | 1977-05-11 |
| BE847862A (en) | 1977-02-14 |
| FR2329622B1 (en) | 1980-07-25 |
| YU253076A (en) | 1982-05-31 |
| IT1079198B (en) | 1985-05-08 |
| RO71263A (en) | 1981-06-26 |
| SU915797A3 (en) | 1982-03-23 |
| PL110592B1 (en) | 1980-07-31 |
| DD126591A1 (en) | 1977-07-27 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |