WO2013128654A1 - Method for improving oxo reaction catalyst longevity - Google Patents

Description

Oxo reaction catalyst life improvement method

Rhodium is a valuable and expensive noble metal that produces only a dozen tons per year worldwide. Therefore, in the industry using rhodium, it is important to use it while preventing loss for as long as possible.
The present invention relates to a method for improving the catalyst life of a reaction system in which an olefin is hydroformylated with carbon monoxide and hydrogen in the presence of a rhodium-phosphorus compound complex.

More specifically, the present invention uses two reaction systems in an economical and effective manner, while maintaining the economical production efficiency of the product aldehyde and bleed the catalyst solution from the reaction system. The catalyst life of the gas circulating rhodium-phosphorus compound complex catalyzed hydroformylation method can be doubled compared to the conventional method.
By adopting this method, it is possible to avoid handling the catalyst such that the catalyst is withdrawn from the operating reactor which is complicated and troubles frequently occur and then returned to the reactor. As a result, long-term high-load and high-efficiency continuous operation can be achieved, and the magnitude of the economic effect is immeasurable.

A process for producing aldehydes by hydroformylating olefins with carbon monoxide and hydrogen in the presence of a rhodium-phosphorus compound complex catalyst and a free phosphorus ligand at a reaction pressure of 3 MPa or less is well known as a low pressure oxohydroformylation process. ing. In addition, various continuous processes have been developed to prevent significant loss of rhodium catalyst life, reaction rate and efficiency, including gas circulation rhodium-phosphorus compound complex hydroformylation process (hereinafter abbreviated as gas circulation method) and liquid circulation rhodium. -Phosphorus compound complex-catalyzed hydroformylation process (hereinafter abbreviated as liquid circulation method), two-phase reaction / extraction method, etc. have been introduced (Non-Patent Document 1 and Non-Patent Document 2).

(Gas circulation method)
The gas circulation method is a process (Patent Document 1 and Patent Document 2) developed in cooperation with Debbie (UK) and Dow (USA).
Gas circulation methods are limited in the combination of reaction and separation conditions. Stripping requires a combination of high temperature (low selectivity, low linearity, paraffin formation), low pressure (low activity) and high gas velocity. Moreover, this gas circulation method is essentially limited by the volatility of high-boiling compounds (aldehyde trimers, tetramers, etc.) produced by the reaction. The rate at which high-boiling compounds are removed through the gas phase must be at least as fast as the formation of high-boiling compounds. If the production rate of the high boiling point compound is larger than the removal rate through the gas phase, the following trouble occurs.

1) High boiling point compounds accumulate and the reactor liquid level rises. As a result, it is necessary to stop the production operation and extract a high boiling point compound containing an active catalyst out of the system.
2) Even if the operation is performed under a low pressure or high temperature condition, the catalyst performance becomes unacceptable, and it is necessary to stop the production operation and extract the high boiling point compound including the catalyst.
For example, in a gas circulation method using propylene as an olefin raw material, it is possible to maintain an efficient production efficiency (N / I ratio = 10 or more, propylene yield = 94% or more) and to operate continuously for 1 to 3 months. It is.

(Liquid circulation method)
Examples of the liquid circulation method include a joint development process (Patent Document 3) between Debbie (UK) and Dow (USA), and a Mitsubishi Chemical process (Patent Document 4).
In the liquid circulation method, the product is removed from the reactor in a liquid phase and carefully evaporated from the catalyst in a special evaporator installed separately from the reactor. By not carrying out the reaction and product / catalyst separation simultaneously, the reactor reaction conditions may be optimized. Since a high conversion rate of olefin in one pass is required, it is required to use many continuous reactors. The reaction conditions are almost the same as in the gas circulation method, but the reaction temperature and catalyst concentration can be slightly reduced.
The liquid product is depressurized and transferred to the evaporator at a high temperature. Thus, the product aldehyde is distilled in a short time to protect the rhodium catalyst. The rhodium catalyst dissolved in the high boiling point compound is separated from the product and recycled to the reactor. Distillation at atmospheric pressure results in a relatively high temperature and generates high-boiling compounds due to rhodium coating, clustering, and aldehyde oligomerization. Although distillation under reduced pressure leads to a low temperature, phosphorus compound ligands and aldehydes are oxidized by the intrusion of oxygen, which causes a decrease in catalytic activity.
In the liquid circulation method, as described above, rhodium coating and clustering, high boiling point compound generation, or phosphorus compound ligand oxidation in the evaporator causes a decrease in catalytic activity. As a result, accumulation of high boiling point compounds is unavoidable, and it is necessary to extract high boiling point compounds and remove the inert catalyst.

Including the above, it has also been found through substantial repetitive use that continuous recycling of rhodium catalysts dissolved in high boiling compounds has disadvantages. These are summarized as follows.
1) The steady movement of the catalyst causes catalyst loss.
2) Some of the catalyst is external to the reactor and requires significant catalyst volume.
3) The production rate of the high boiling point compound is maintained at a significant level, and it is necessary to remove it, which affects the stability of the catalyst and makes it difficult to adjust the pressure of carbon monoxide.
4) Since the hot liquid is constantly moved through the system, heat loss is caused as a recirculation property, and a small amount of oxygen leakage (which is harmful) tends to occur.

(Two-phase reaction / extraction method)
The two-phase reaction / extraction method is a process (Patent Document 5) developed by both Luhrhemy (Germany) and Rhone-Poulenc (France).
The basic principle is that two liquid phases are used for both the reactor and the separator. The first phase is a crude product phase, and the second phase is a phase containing a rhodium catalyst and an excess of ligand, whereby the catalyst and product can be separated effectively. The second phase is generally composed of an aqueous (polar) and water-soluble ligand. The best ligand is triphenylphosphine metasulfonate (hereinafter abbreviated as TPPTS). Nonpolar propylene is diffused into the aqueous phase in a two-phase hydroformylation reactor and again high boiling compounds such as nonpolar aldehydes are separated from the aqueous phase. In effect, the extraction takes place in the reactor.
The by-product of high-boiling compounds was one of the main factors causing problems in the gas and liquid circulation methods described above. On the other hand, rhodium may be lost by extraction into the organic phase.

Inside the reactor, there is a limit to the phase transfer between both the gas / liquid (aqueous phase) and the liquid / liquid (water phase), and because of this limitation, the reactor is agitated. Nevertheless, mass transfer is limited and the reaction is considered to be limited to the liquid / liquid (aqueous phase) interface. As a result, in order to solve the low solubility of propylene as the reaction conditions, it is necessary to increase the reaction temperature and to make the rhodium concentration higher than that of the above gas circulation method or liquid circulation method.
The reaction temperature is 125 ° C. or higher, and the reaction pressure is about 6 MPa. The rhodium concentration is about 300 ppm, but the ratio of the aqueous phase / organic phase in the reactor is as high as about 6, and it is necessary to give a high rhodium concentration to the entire reactor.

The two-phase reaction liquid is transferred from the reactor to the decanter without cooling, in which excess unreacted synthesis gas is separated. The remaining two liquids are separated by simple sedimentation. The aqueous phase containing the catalyst is recycled to the reactor. As described above, since the reaction temperature is as high as 125 ° C. or higher, there is a high probability that catalyst loss due to catalyst deactivation occurs.
Further, the synthesis of the free phosphorus compound ligand TPPTS to be used is not easy and expensive.
Furthermore, since the reaction pressure is as high as 6 MPa or more, the capital investment amount increases.
While this process has provided a clue that can solve the problem of high-boiling compounds being by-produced, in other respects it has not led to high-efficiency use of rhodium.

US Pat. No. 3,527,809 JP 52-125103 A U.S. Pat. No. 4,247,486 Japanese Patent Laid-Open No. 50-58008 French Patent Specification No. 2314910

“Rhodium catalyzed hydroformylation”, (Kluwer Academic Publishers, 2000) “Kirk-Othmer Encyclopedia of Chemical Technology”, 4th Edition, Vol, pp 902-919 (1996)

An object of the present invention is to improve the catalyst life of a reaction system in which olefin is hydroformylated with carbon monoxide and hydrogen in the presence of a rhodium-phosphorus compound complex. Also in the liquid circulation method, complicated operations such as extraction of high-boiling compounds and deactivated catalysts generated by the reaction are required. The period for stopping the apparatus for the work and the time required for the work for reactivating the catalyst are long. In the two-phase reaction / extraction method, the high-boiling compounds by-produced in the reactor have been successfully treated, but the loss of the catalyst is also increased.

On the other hand, in the continuous operation by the gas circulation method, the ratio (N / I ratio) of the linear aldehyde having a high economic value to the branched aldehyde having a slightly inferior economic value among the generated aldehydes is maintained at 10 or more, and the high In order to continue the load operation, it is necessary to take measures to compensate for the decrease in the catalyst activity. The following items are listed as effective countermeasures.
(1) Increase in reaction temperature (2) Increase in partial pressure of propylene in the gas phase of the reactor (3) Decrease in partial pressure of carbon monoxide in the gas phase of the reactor (4) Addition of rhodium catalyst (5) Phosphorus compound arrangement Adding a scale

Even after combining these countermeasures in 6 months after the start of continuous operation, it is difficult to maintain a high load. Moreover, increasing the propylene partial pressure in the gas phase of the reactor causes loss of propylene into the exhaust gas, leading to deterioration in propylene efficiency. After 6 months, the reaction temperature will increase, and the high boiling point in the reactor will increase. If the reactor is stopped after 12 months and the catalyst / high boiling point is not extracted, The fact is that it cannot be implemented.

The object of the present invention is to carry out a product without extracting a rhodium catalyst for a continuous period of 2 years or more without carrying out a complicated operation of extracting a high-boiling compound or catalyst generated in the reaction during commercial operation of a gas circulation method plant. Operation that allows the N / I ratio of aldehyde to be 10 or more, the feed amount of raw olefin to be 95% or more of the design value of the reaction system, and the efficiency of raw olefin to aldehyde to be 94% or more (hereinafter referred to as long-term high load and high efficiency) Defined as continuous operation). By adopting this method, it is possible to avoid handling the catalyst such that the catalyst is withdrawn from the operating reactor which is complicated and troubles frequently occur and then returned to the reactor. As a result, long-term high-efficiency high-load continuous operation can be achieved, and the magnitude of the economic effect is immeasurable.

If the following items are carried out in order to solve the above-mentioned problems, loss of rhodium can be prevented, and long-term high-load high-efficiency continuous operation for two years or more can be achieved.
The present invention includes the following items (1) to (18).

(1) Olefin, carbon monoxide and hydrogen are reacted in the presence of a soluble rhodium-phosphorus compound complex catalyst, a free phosphorus ligand, an aldehyde and its condensation by-products to produce an aldehyde product, and unreacted olefin And a gas-circulating rhodium complex-catalyzed hydroformylation method in which a gaseous effluent composed of the aldehyde product, hydrogen, carbon monoxide and alkane by-products is discharged from the first reaction system. A method for achieving continuous operation by supplying and reacting with a gas composed of carbon monoxide and hydrogen. According to this method, the loss of rhodium can be minimized, the supplied olefin can be used more effectively than before, and long-term high-efficiency high-load continuous operation can be achieved.

(2) The method according to (1), wherein the first reaction system is composed of 1 to 5 reactors, and the second reaction system is composed of 1 to 2 reactors.

(3) The free phosphorus ligand and the phosphorus ligand of the rhodium-1-phosphorus compound complex catalyst are triorganophosphine compounds, more preferably triphenyl which is industrially mass-produced and is available at a relatively low cost. The method according to any one of (1) to (2), which is phosphine.

(4) The ratio of the catalyst volume of the second reaction system to the catalyst volume of the first reaction system is in the range of 0.05: 1 to 1.0: 1.0, more preferably the second reaction system The method according to any one of (1) to (3), wherein the ratio of the catalyst volume to the catalyst volume of the first reaction system is in the range of 0.1: 1 to 1.0: 1.0. If it is within this ratio range, the capital investment can be optimized.

(5) The hydroformylation reaction of the first and second reaction systems is carried out at a reaction temperature of 50 ° C. to 145 ° C., more preferably the hydroformylation reaction of the first and second reaction systems is 80 ° C. to 110 ° C. The method according to any one of (1) to (4), which is carried out at a reaction temperature of Within this temperature range, the reaction rate is high and there are few side reactions.

(6) The rhodium concentration in the first and second reaction systems is in the range of 10 to 900 ppm calculated as rhodium, more preferably the rhodium concentration in the first and second reaction systems is calculated as rhodium metal, 6. The method according to any one of (1) to (5), which is in the range of 50 to 500 ppm. Within this concentration range, the reaction rate is fast and clustering can be minimized.

(7) The method according to any one of (1) to (6), wherein 1 to 200 mol of a free ligand is present per 1 mol of rhodium. In particular, in the range of 100 to 200 mol, the N / I ratio can be maintained at 10 or more, which is industrially useful.

(8) The total pressure of each olefin, carbon monoxide and hydrogen in the first and second reaction systems is 3 MPa or less, and the molar ratio of hydrogen to carbon monoxide is from 1: 100 to 100: 1. More preferably, the total pressure of each olefin, carbon monoxide and hydrogen of the first and second reaction systems is 2.3 MPa or less, and the molar ratio of hydrogen to carbon monoxide is hydroformyl. 8. The method according to any one of (1) to (7), which is in a range of 1: 1 to 3: 1 that can increase the crystallization reaction rate.

(9) Any one of (1) to (8), wherein the ratio of the aldehyde product to the high boiling point compound in the hydroformylation reaction of the first and second reaction systems is in the range of 5: 1 to 100: 1. The method described in 1.

(10) The propylene partial pressure is adjusted to maintain the target reaction efficiency because the reaction efficiency changes according to the formula (I) due to the change in the propylene partial pressure in the gas phase part of the reactor of the first reaction system. The method according to any one of (1) to (9).
<Relationship between propylene partial pressure and reaction efficiency>
Reaction efficiency (%) = [Propylene partial pressure (kPa)] × [A] + [B] Formula (I)
[A]: (−0.0070) to (−0.0100), more preferably (−0.0080) to (−0.0090) [B]: 80 to 100, more preferably Is in the range of 90 to 100

(11) The propylene partial pressure prediction in the gas phase part of the reactor of the first reaction system when the reaction temperature is changed is carried out using the formula (II) in any one of (1) to (10) The method described.
<Prediction formula for decrease in propylene partial pressure by reaction temperature increase of 1 ° C>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [C] + [D] Formula (II)
[C]: in the range of 0.02 to 0.06, more preferably in the range of 0.03 to 0.05 [D]: in the range of 0.05 to 0.09, more preferably in the range of 0.06 to 0.08 Range

(12) When the rhodium catalyst is added, the propylene partial pressure in the reactor gas phase part of the first reaction system is predicted using the formula (III). Any one of (1) to (11) The method described.
<Prediction formula for drop in propylene partial pressure when 1 gram of rhodium is added>
Decrease in partial pressure (kPa) = [rhodium concentration (ppm)] ² × [E] − [F] × [rhodium concentration (ppm)] + [G] Formula (III)
[Rhodium concentration (ppm)] indicates the rhodium concentration of the reaction solution in the first reaction system before addition of rhodium.
[E]: a range of 0.00005 to 0.0004, more preferably a range of 0.0001 to 0.0003 [F]: a range of 0.05 to 0.30, more preferably 0.10 to 0.20 [G]: a range of 10 to 50, more preferably a range of 20 to 40

(13) The propylene partial pressure in the gas phase part of the reactor of the first reaction system when the operation days are changed is implemented using the formula (IV). Any one of (1) to (12) The method described.
<Prediction formula for increasing propylene partial pressure per 10 operating days>
Increase in partial pressure (kPa) = [number of operating days] × “H” + [I] (formula (IV))
[H]: in the range of 0.001 to 0.03, more preferably in the range of 0.005 to 0.02. [I]: in the range of 1 to 30, more preferably in the range of 5 to 15.

(14) The propylene partial pressure prediction of the reactor gas phase portion of the first reaction system when the operation load is changed is carried out using the formula (V), any one of (1) to (13) The method described in 1.
<Partial pressure change prediction formula by changing the operating load by 1%>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [J] + [K] Expression (V)
[J]: in the range of 0.005 to 0.010, more preferably in the range of 0.008 to 0.0095 [K]: in the range of 0.001 to 0.009, more preferably in the range of 0.005 to 0.007 Range

(15) Using the relational expressions of the formulas (I) to (V), the optimum operating condition calculation for the long-term high-load and high-efficiency continuous operation is performed, and the reaction of the present invention is performed as follows based on the calculation result. The method according to any one of (1) to (14), wherein the system is operated.
1) The rhodium catalyst is dividedly charged into the first and second reaction systems at the start of operation in the range of 10% to 70% by weight of the total weight used during the planned operation period.
2) In the first half of the continuous operation, when the catalyst activity decreases, the reaction temperature rises from 1 ° C to 5 ° C in a single operation up to 100 ° C, which has little effect on the catalyst activity due to the composition of the reaction solution. To raise.
3) When the temperature exceeds 100 ° C., the remaining catalyst is divided into 2 to 10 times according to the predicted decrease in catalyst activity, and a predetermined amount of catalyst is replenished.
4) In the latter stage of continuous operation where the catalyst activity further decreases, a single reaction temperature raising operation raises the reaction temperature in the range of 1 ° C to 5 ° C.

(16) For the partial pressure of carbon monoxide, hydrogen, and olefin in both reaction systems, calculate the optimum operating conditions for long-term, high-load, high-efficiency continuous operation using the relational expression (I) to (V). Based on this calculation result, the following range is assumed. That is, the method according to any one of (1) to (15), wherein carbon monoxide is in the range of 17.5 to 55 kPa, hydrogen is in the range of 175 to 265 kPa, and olefin is in the range of 350 to 790 kPa.

(17) Sulfur compounds that pass through the zinc oxide packed tower and chlorine compounds that are filled with copper-impregnated activated carbon are used as catalyst poisons for the rhodium catalyst contained in carbon monoxide, hydrogen, and olefin supplied as raw materials in both reaction systems. The raw material from which the catalyst poison is removed is used by passing through the tower and hydrogenating the triple-bonded hydrocarbon compound and conjugated diene-bonded hydrocarbon in a palladium-filled tower to convert them into saturated hydrocarbons (1) to (16 The method according to any one of (1).

(18) The method according to any one of (1) to (17), wherein the olefin is at least one selected from ethylene, propylene, 1-butene, and isobutene.

A reaction system for producing an aldehyde by hydroformylation of an olefin with carbon monoxide and hydrogen in the presence of a rhodium-phosphorus compound complex. More specifically, in the gas circulation method, the reaction system of the present invention is used, and the long-term high-load and high-efficiency of the present invention. The following effects can be achieved by operating the reaction system according to the continuous operation method.
(1) In the conventional method, the period of continuous operation without removing the catalyst while maintaining the economical olefin reaction efficiency was within 12 months. By adopting the present invention, continuous operation for two years or more can be achieved. As a result, the number of operating days per year can be increased and the production aldehyde can be increased.
(2) When the olefin is propylene, in the conventional method, the reaction efficiency of propylene can be maintained at 94% or more from 1 to 3 months after the start of operation. By adopting the present invention, the reaction efficiency of propylene can be maintained at 94% or more for 2 years or more. As a result, production cost reduction of the product butyraldehyde can be achieved, leading to resource saving.
(3) The deactivated catalyst evaporates a low boiling point substance from the reaction system to obtain a rhodium-containing high boiling point solution, and recovers the catalyst from this solution. There is about 10% catalyst loss in the catalyst recovery process. By reducing the number of times the deactivated catalyst is extracted, the amount of rhodium catalyst loss can be halved.

Hereinafter, the present invention will be described in detail according to embodiments.
In the continuous operation by the gas circulation method, the ratio (N / I ratio) of the straight chain aldehyde having high economic value to the by-product branched aldehyde among the aldehydes to be produced (N / I ratio) is maintained at 10 or more, and the high load operation is continued. In order to compensate for the decrease in the catalyst activity, the olefin partial pressure in the reactor was increased and the carbon monoxide partial pressure was decreased. As a result, even if a high load can be maintained, the loss of olefin in the exhaust gas increases, and the olefin efficiency is greatly deteriorated. Thus, it has been found that this problem can be solved by managing using the reaction system of the present invention in order to maintain the efficiency of the olefin.

(Loss of rhodium catalyst)
There are three main routes for loss of rhodium catalyst:
1) Loss due to rhodium coating or clustering:
Rhodium, one of the noble metals, tends to be coated as a zero-valent metal. It forms a colloidal aggregate or a film on the reactor wall surface. The mechanism by which this coating occurs grows until the rhodium clusters reach a sufficient size by adhesion with other particles or walls. Rhodium coating is suppressed by low rhodium concentration, high ligand / rhodium ratio, and low temperature. Rhodium coating occurs not only inside the reactor but also under distillation conditions outside the reactor (high temperature, reduced carbon monoxide pressure). This is a major concern for stable operation of the liquid circulation method.
2) Loss due to entrainment in the product:
This is due to entrainment of the rhodium catalyst in the gas phase or liquid phase product, or some dissolution in the liquid phase product. Recovery of this rhodium is difficult. This is also a cause of rhodium loss in the liquid circulation method.
3) Extraction from the catalyst recycling loop:
Generally, it depends on the following factors.
(I) Accumulation of high-boiling compounds in the reaction system (when sufficient separation of the catalyst and high-boiling compounds becomes impossible)
(Ii) When it is necessary to remove the catalyst due to catalyst deactivation due to a deteriorated ligand or an external catalyst poison (such as sulfur or diene).
It has long been desired to achieve long-term, high-load, high-efficiency continuous operation by eliminating these catalyst loss factors as much as possible.

(Long-term catalyst management method)
It is well known that rhodium catalyst clusters can be suppressed to some extent by low catalyst concentration, high phosphorus compound complex / rhodium ratio, and low reaction temperature conditions. Considering these known reports, we can analyze the long-term operational results and maintain the catalyst management appropriately using the long-term catalyst management method developed independently, without having to extract the catalyst. We have invented a method for long-term, high-load, high-efficiency continuous operation that allows continuous operation for more than 24 months while maintaining high load and high reaction efficiency.

This long-term catalyst management method is carried out as follows.
Long-term, high-load, high-efficiency continuous operation while maintaining high reaction efficiency (when the olefin raw material is propylene, the product aldehyde linear / branch ratio (N / I ratio) is 10 or more, and propylene efficiency is 94% or more) Is carried out as follows.
Specifically, the propylene partial pressure in the gas phase part of the reactor of the first reaction system is predicted, and when this partial pressure increases, the optimum countermeasure (addition of reaction temperature, catalyst, etc.) is performed.
The higher the propylene partial pressure, the higher the reaction rate. However, since effective propylene components are lost from the reaction system of the present invention, operations such as raising the reaction temperature or adding a catalyst are carried out to lower the propylene partial pressure. Perform the operation.

In order to predict the propylene partial pressure, the following relational expression was derived from long-term operation results and operation data.
(I) Reaction efficiency <Relationship between propylene partial pressure and reaction efficiency>
Reaction efficiency (%) = [Propylene partial pressure (kPa)] × [A] + [B] Formula (I)
[A]: (−0.0070) to (−0.0100), more preferably (−0.0080) to (−0.0090) [B]: 80 to 100, more preferably Is in the range of 90 to 100

(II) Reaction temperature <Prediction formula for decrease in propylene partial pressure due to increase in reaction temperature by 1 ° C>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [C] + [D] Formula (II)
[C]: in the range of 0.02 to 0.06, more preferably in the range of 0.03 to 0.05 [D]: in the range of 0.05 to 0.09, more preferably in the range of 0.06 to 0.08 Range

(III) Rhodium concentration <Prediction formula for decrease in propylene partial pressure when 1 gram of rhodium is added>
Decrease in partial pressure (kPa) = [rhodium concentration (ppm) ² × [E] − [F] × [rhodium concentration (ppm)] + [G] Formula (III)
[Rhodium concentration (ppm)] indicates the rhodium concentration of the reaction solution in the first reaction system before addition of rhodium.
[E]: a range of 0.00005 to 0.0004, more preferably a range of 0.0001 to 0.0003 [F]: a range of 0.05 to 0.30, more preferably 0.10 to 0.20 [G]: a range of 10 to 50, more preferably a range of 20 to 40

(IV) Operating days <Prediction formula for increase in propylene partial pressure per 10 operating days>
Increase in partial pressure (kPa) = [operation days] × “H” + [I] (formula (IV))
[H]: in the range of 0.001 to 0.03, more preferably in the range of 0.005 to 0.02. [I]: in the range of 1 to 30, more preferably in the range of 5 to 15.

(V) Driving load <Partial pressure change prediction formula by changing the driving load by 1%>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [J] + [K] Expression (V)
[J]: in the range of 0.005 to 0.010, more preferably in the range of 0.008 to 0.009 [K]: in the range of 0.001 to 0.009, more preferably in the range of 0.005 to 0.007 Using these relational expressions, the optimum operating condition calculation for long-term, high-load, high-efficiency continuous operation is performed, and the reaction system of the present invention is operated as follows based on the calculation result.

Specific catalyst management is performed by the following method.
1) The catalyst added at the beginning of the reaction is made as low as possible.
2) In order to maintain high efficiency in the first half of the predetermined period, the propylene partial pressure in the reactor gas phase is increased and the carbon monoxide partial pressure is decreased.
3) When the reaction temperature is in the range of 100 ° C. or less, the reaction temperature is raised in the range of 1 ° C. to 5 ° C. in a single reaction temperature raising operation according to the decrease in the catalyst activity. Until the reaction temperature reaches 100 ° C., the clustering of the rhodium catalyst is hardly affected. Increasing the reaction temperature increases the reaction rate, thus reducing the propylene partial pressure.
4) When the reaction temperature reaches 100 ° C., a predetermined amount of an organophosphorus compound and a rhodium catalyst are alternately added in two to ten times according to the decrease in the catalyst activity.
5) In the second half of the predetermined period, in order to maintain high efficiency according to the decrease in the catalyst activity, the reaction temperature is raised within the range of 1 ° C. to 5 ° C. by a single reaction temperature raising operation. .

In accordance with this long-term catalyst management method, the complicated operation of extracting high-boiling compounds and catalysts generated in the reaction during the commercial operation of the gas circulation plant adopting the matrix reaction system that is proposed to manage the catalyst and operating conditions Without this, it is possible to achieve a long-term, high-load, high-efficiency continuous operation method for two years or more.

(Strengthening prevention of catalyst poisoning)
The catalyst poison brought in from the outside is caused by the raw material olefin and synthesis gas (H ₂ / CO = 1/1). The catalyst poison brought in from these raw materials is one of the major factors for reducing the activity of the rhodium catalyst. In order to eliminate these external factors, it is necessary to achieve a reduction in the content of catalyst poisons in these raw materials by securing high-purity raw materials and strengthening the raw material refining system.

As described below, the catalyst poison in the raw material is removed and purified to prevent the catalyst poison from being mixed into the reaction system as much as possible.
Syngas (H ₂ / CO = 1/1) Propylene Sulfur compound Detection limit 0.1 molppm or less Detection limit 0.1 molppm or less Chlorine compound Detection limit 0.1 molppm or less Detection limit 0.1 molppm or less

(Analysis method)
Sulfur compounds: analyzed by gas chromatography. The detection limit is 0.1 molppm.
Chlorine compound: Sampling was performed by gas absorption method, and the obtained solution was analyzed by absorption spectrometry. The detection limit is 0.1 molppm or less.

(Deterioration of phosphorus compound ligand)
The phosphorus compound ligand triphenylphosphine is deteriorated by oxidation reaction or cleavage of the P—C bond.
1) Oxidation reaction:
Phosphorus compound ligands are very oxidizable and thermodynamically oxidize triphenylphosphine to the corresponding oxide even with water or carbon dioxide. Free triphenylphosphine in the reaction solution is oxidized to oxide by the catalytic action of the transition metal catalyst. In order to prevent this, it is absolutely necessary to remove oxygen and peroxide in the raw material alkene.
2) Cleavage of the P—C bond in triphenylphosphine:
The PC bond cleavage reaction is an undesirable side reaction in systems containing transition metals and triphenylphosphine ligands. This leads to a decrease in catalytic activity. The phosphide group produced in the intermediate mechanism of the reaction causes reductive elimination originating from the rhodium propyl group, resulting in diphenylpropylphosphine. Since this phosphine compound is an electron donating compound having a higher coordination power than triphenylphosphine, it leads to a decrease in catalytic activity.
It is desired that long-term high-load and high-efficiency continuous operation can be achieved by eliminating the adverse effects on the reaction due to the deterioration of these organophosphorus compound ligands.

In order to prevent the influence due to the deterioration of the phosphorus compound ligand, as described above, mixing of oxygen from the raw material was prevented so that long-term high-load high-efficiency continuous operation could be achieved. As a result, when triphenylphosphine was used as the phosphorus compound ligand, the concentrations of triphenylphosphine oxide and diphenylpropylphosphine could be controlled as follows immediately before the end of the long-term high-load high-efficiency continuous operation.
Triphenylphosphine oxide 0.35% by weight or less Diphenylpropylphosphine 1.5% by weight or less If this concentration or less, there is little influence on the N / I ratio of the product, and high-efficiency and high-load operation can be maintained.

(Analysis method)
Triphenylphosphinoxide: gas chromatographic method. The detection limit is 0.01% by weight.
Diphenylpropylphosphine: Gas chromatographic method. The detection limit is 0.1% by weight.

(Outline flow sheet)
A preferred flow sheet of the reaction system of the present invention is shown in FIG. The case where propylene was used as an olefin was illustrated.

With reference to FIG.
The raw material propylene and synthesis gas are removed from the catalyst poisons in the purification towers 1 and 2, respectively. The purified propylene is fed to the first reaction system reactor 3. Butyraldehyde as a reaction product is evaporated from the reactor together with the unreacted gas, and a very small amount of rhodium catalyst contained in the evaporated product is separated by the catalyst separator 4 and returned to the first reaction system reactor 3. It is. The mixture of evaporated butyraldehyde, unreacted propylene and synthesis gas is cooled by the condenser 5. Further, the gas-liquid separator 6 separates liquid butyraldehyde, gaseous unreacted propylene, and synthesis gas. Gaseous propylene and synthesis gas are distributed by a predetermined amount to the first reaction system and the second reaction system through the first reaction system circulation blower 7 and circulated. The condensed butyraldehyde is fed to the top of the countercurrent tower 8 and a predetermined amount of purified synthesis gas supplied to the reaction system is supplied from the lower part of the countercurrent tower 8 to remove propylene dissolved in butyraldehyde. To do. Crude butyraldehyde is extracted from the lower part of the countercurrent tower 8.

The above-mentioned predetermined amount is fed from the first reaction system circulation blower 7 to the second reaction system reactor 9. In addition, a predetermined amount of the synthesis gas purified by the purification tower is fed to the second reaction system reactor 9. Butyraldehyde produced in the second reaction system reactor 9 is evaporated together with the gas in the reactor, and a very small amount of rhodium catalyst contained in the evaporated product is separated by the catalyst separator 10 to react with the second reaction system reaction. Returned to vessel 9. The evaporant containing butyraldehyde is condensed in the condenser 11. Further, the gas-liquid separator 12 separates liquid butyraldehyde, gaseous unreacted propylene, and synthesis gas. Gaseous propylene and synthesis gas are circulated to the second reaction system reactor 9 by the second reaction system circulation blower 13.
The exhaust gas of the second reaction system is discharged from the pipeline 14. While analyzing the composition of the release gas, the release amount is adjusted so that the high efficiency of propylene can be maintained.

Hereinafter, a method for carrying out long-term high-load high-efficiency continuous operation according to the present invention will be described in more detail based on examples. However, the present invention is not limited to these examples.

[Example 1]
The first reaction system of the reaction system of the present invention comprises a 200 liter cylindrical reactor as shown in FIG. The second reaction system is composed of a 30 liter cylindrical reactor. As an olefin, the case where propylene is used is shown in the Examples.

1) Optimal operating condition calculation method Based on the long-term catalyst management method devised from past results, calculate the optimal operating conditions for a long-term, high-load, high-efficiency continuous operation for two years for the reactor in the first reaction system. The result of the calculation of the optimum operating condition is as shown in Table 1.

Table 1 Calculation results of optimum operating conditions

The operating load is set to 100% load when the amount of propylene fed to the reaction system of the present invention is 0.21 kmol / h, and the relative load based on 0.21 kmol / h (as 100%). Rate.
Propylene reaction efficiency represents the ratio of fed propylene converted to product butyraldehyde. The propylene partial pressure indicates the propylene pressure in the gas phase portion of the reactor. The carbon monoxide partial pressure indicates the carbon monoxide pressure in the reactor gas phase portion.

2) Continuous operation results Based on the calculation results of optimum operation conditions, the actual operation results for 2 years are as follows. It was possible to operate with almost no difference from the calculation result of the optimum operating conditions.
<First reaction system operation results>
The operation results are summarized in Table 2.

Table 2 Operation results of the first reaction system

(Analysis method)
Propylene partial pressure: Analyzes the propylene concentration in the gas phase of the reactor by gas chromatography, and obtains it from the ratio to the total pressure in the reactor.
Carbon monoxide partial pressure: Analyzes the carbon monoxide concentration in the gas phase of the reactor by infrared analysis, and obtains it from the ratio to the total pressure in the reactor.
Rhodium concentration: An oxidant is added to the sample collected from the reactor and burned. The resulting ash is treated with aqua regia to dissolve rhodium, and then the concentration is analyzed by electron absorption. The measurement limit is 0.1 ppm.

The operating load is set to 100% load when the amount of propylene fed to the reaction system of the present invention is 0.21 kmol / h, and the relative load based on 0.21 kmol / h (as 100%). Rate.
Propylene reaction efficiency represents the ratio of fed propylene converted to product butyraldehyde. The propylene partial pressure indicates the propylene pressure in the gas phase portion of the reactor. The carbon monoxide partial pressure indicates the carbon monoxide pressure in the reactor gas phase portion.

<Second reaction system operation results>
The operation results are summarized in Table 3.

　運転負荷は、本発明の反応系にフィードされるプロピレン量が０．２１ｋｍｏｌ／ｈの時を１００％負荷と設定したものであり、０．２１ｋｍｏｌ／ｈ（ａｓ　１００％）を基準とした相対分率である。
　プロピレン反応効率は、フィードされたプロピレンが製品ブチルアルデヒドに変換された比率を表す。プロピレン分圧は、反応器気相部分のプロピレン圧力を示す。一酸化炭素分圧は、反応器気相部分の一酸化炭素圧力を示す。
　本発明の反応システムによるプロピレンの反応効率を纏めると表４のごとくになる。 Table 3 Operation results of the second reaction system

The operating load is set to 100% load when the amount of propylene fed to the reaction system of the present invention is 0.21 kmol / h, and the relative load based on 0.21 kmol / h (as 100%). Rate.
Propylene reaction efficiency represents the ratio of fed propylene converted to product butyraldehyde. The propylene partial pressure indicates the propylene pressure in the gas phase portion of the reactor. The carbon monoxide partial pressure indicates the carbon monoxide pressure in the reactor gas phase portion.
The reaction efficiency of propylene by the reaction system of the present invention is summarized as shown in Table 4.

Table 4. Reaction efficiency of propylene by the reaction system of the present invention

[Comparative Example 1]
Only the first reaction system of the reaction system of the present invention was operated by the conventional method. The reaction system is composed of a 200 liter cylindrical reactor as shown in FIG.
The results of driving for one year are as shown in Table 5.
The decrease in catalyst activity is covered by addition of catalyst, increase in reaction temperature, etc., but the reaction efficiency decreases as the operating days increase. About one year after the start of operation, the reaction temperature and the catalyst concentration in the reaction system increased, the reaction was stopped, and the catalyst was extracted.
The operating load is a relative fraction based on 0.185 kmol / h (as 100%) when the amount of propylene fed to the reaction system is set to 100% load when the amount is 0.185 kmol / h. .
Propylene reaction efficiency represents the ratio of fed propylene converted to product butyraldehyde. The propylene partial pressure indicates the propylene pressure in the gas phase portion of the reactor. The carbon monoxide partial pressure indicates the carbon monoxide pressure in the reactor gas phase portion.

Table 5 Operation results using the conventional method

　プロピレン反応効率は、フィードされたプロピレンが製品ブチルアルデヒドに変換された比率を表す。上記の比較表より本発明の反応系及び触媒管理法の採用による経済効果が著しいことがわかる。 Table 4 shows a comparison of propylene efficiency between Table 4 of Example 1 and Table 5 of Comparative Example 1.
Table 6 Comparison of propylene reaction efficiency in conventional method before and after improvement by reaction system and catalyst management method of the present invention

Propylene reaction efficiency represents the ratio of fed propylene converted to product butyraldehyde. From the above comparison table, it can be seen that the economic effect by adopting the reaction system and catalyst management method of the present invention is remarkable.

The present invention is industrially used in 90% or more when propylene is used as an olefin raw material. Normal butyraldehyde and isobutyl aldehyde are produced in a 10: 1 ratio from the hydroformylation reaction of propylene. The following derivatives are mass-produced from normal butyraldehyde.
Product name Use Butyl acrylate Polymer raw material 2-ethylhexyl acrylate Polymer raw material Normal butyl acetate Solvent Ethylene glycol monobutyl ether Solvent Normal Butanol Solvent Di (2-ethylhexyl) phthalate Plasticizer

In addition, the following derivatives are mass-produced from isobutyraldehyde.
Product name Use Isobutanol Solvent 2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate Film-forming aid These products are industrially important products. The present invention is used for producing butyraldehyde as a raw material for these products.

Long-term, high-load, high-efficiency continuous operation plant schematic

DESCRIPTION OF SYMBOLS 1 Purification tower 2 Purification tower 3 1st reaction system reactor 4 Catalyst separator 5 Condenser 6 Gas-liquid separator 7 1st reaction system circulation blower 8 Counterflow tower 9 2nd reaction system reactor 10 Catalyst separator 11 Condenser 12 Gas-liquid separator 13 Second reaction system circulation blower 14 Pipe line

Claims (18)

Olefin, carbon monoxide and hydrogen are reacted in the presence of a soluble rhodium-phosphorus compound complex catalyst, a free phosphorus ligand and an aldehyde with its condensation by-products to form an aldehyde product, and unreacted olefin and In a gas-circulating rhodium complex-catalyzed hydroformylation process in which a gaseous effluent containing aldehyde products, hydrogen, carbon monoxide and alkane by-products is discharged from the first reaction system, the gas effluent is monooxidized in the second reaction system. A method for achieving continuous operation by supplying and reacting with a gas composed of carbon and hydrogen. The method according to claim 1, wherein the first reaction system is composed of 1 to 5 reactors, and the second reaction system is composed of 1 to 2 reactors. The method according to claim 1 or 2, wherein the free phosphorus ligand and the phosphorus ligand of the rhodium-1-phosphorus compound complex catalyst are triorganophosphine compounds. The ratio of the catalyst volume of the second reaction system to the catalyst volume of the first reaction system is in the range of 0.05: 1 to 1.0: 1.0. the method of. The method according to any one of claims 1 to 4, wherein the hydroformylation reaction of the first and second reaction systems is performed at a reaction temperature of 50 ° C to 145 ° C. The method according to any one of claims 1 to 5, wherein the rhodium concentration in the soluble rhodium-phosphorus compound complex catalyst in the first and second reaction systems is in the range of 10 to 900 ppm calculated as rhodium. The method according to any one of claims 1 to 6, wherein 1 to 200 mol of a free ligand is present per 1 mol of rhodium. The total pressure of each olefin, carbon monoxide and hydrogen in the first and second reaction systems is 3 MPa or less, and the molar ratio of hydrogen to carbon monoxide is in the range of 1: 100 to 100: 1. 8. A method according to any one of claims 1 to 7. The method according to any one of claims 1 to 8, wherein the ratio of the aldehyde product to the high boiling point compound in the hydroformylation reaction of the first and second reaction systems is in the range of 5: 1 to 100: 1. 2. The propylene partial pressure is adjusted to maintain the target reaction efficiency because the reaction efficiency changes according to the formula (I) due to the change in the propylene partial pressure in the gas phase part of the reactor of the first reaction system. The method according to any one of 1 to 9.
<Relationship between propylene partial pressure and reaction efficiency>
Reaction efficiency (%) = [Propylene partial pressure (kPa)] × [A] + [B] Formula (I)
In this formula (I), [A] is in the range of (−0.0070) to (−0.0100), and [B] is in the range of 80 to 100. The method according to any one of claims 1 to 10, wherein the propylene partial pressure prediction in the gas phase part of the reactor of the first reaction system when the reaction temperature is changed is carried out using the formula (II).
<Prediction formula for decrease in propylene partial pressure by reaction temperature increase of 1 ° C>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [C] + [D] Formula (II)
In this formula (II), [C] is in the range of 0.02 to 0.06, and [D] is in the range of 0.05 to 0.09. The method according to any one of claims 1 to 11, wherein propylene partial pressure prediction in the gas phase part of the reactor of the first reaction system in the case of adding a rhodium catalyst is carried out using the formula (III).
<Prediction formula for drop in propylene partial pressure when 1 gram of rhodium is added>
Decrease in partial pressure (kPa) = [rhodium concentration (ppm)] ² × [E] − [F] × [rhodium concentration (ppm)] + [G] Formula (III)
In this formula (III), [rhodium concentration (ppm)] indicates the rhodium concentration of the reaction solution in the first reaction system before rhodium addition, and [E] is in the range of 0.00005 to 0.0004, [F] is in the range of 0.05 to 0.30, and [G] is in the range of 10 to 50. The method according to any one of claims 1 to 12, wherein propylene partial pressure prediction in the gas phase part of the reactor of the first reaction system when the operation days are changed is performed using the formula (IV).
<Prediction formula for increasing propylene partial pressure per 10 operating days>
Increase in partial pressure (kPa) = [number of operating days] × “H” + [I] (formula (IV))
In this formula (IV), [H] is in the range of 0.001 to 0.03, and [I] is in the range of 1 to 30. The method according to any one of claims 1 to 13, wherein the propylene partial pressure prediction in the gas phase part of the reactor of the first reaction system when the operating load is changed is performed using the formula (V).
<Change in partial pressure by changing operating load by 1%>
Change in partial pressure (kPa) = [partial pressure before change (kPa)] × [J] + [K] Expression (V)
In this formula (V), [J] is in the range of 0.005 to 0.010, and [K] is in the range of 0.001 to 0.009. Formula (I) according to claim 10, Formula (II) according to claim 11, Formula (III) according to claim 12, Formula (IV) according to claim 13, and Formula (V) according to claim 14. The method according to any one of claims 1 to 14, wherein the optimum operating condition calculation is performed using the relational formula: and the reaction system of the present invention is operated based on the following 1) to 4).
1) The rhodium catalyst is dividedly charged into the first and second reaction systems at the start of operation in the range of 10% to 70% by weight with respect to the total weight used during the planned operation period.
2) In the first half of the continuous operation, when the catalyst activity decreases, a single reaction temperature raising operation increases the reaction temperature in the range of 1 ° C to 5 ° C up to 100 ° C.
3) When the temperature exceeds 100 ° C., the remaining catalyst is divided into 2 to 10 times according to the predicted decrease in catalyst activity, and a predetermined amount of catalyst is replenished.
4) In the latter stage of continuous operation where the catalyst activity further decreases, a single reaction temperature raising operation raises the reaction temperature in the range of 1 ° C to 5 ° C. In the first and second reaction systems, the partial pressure of carbon monoxide is in the range of 17.5 kPa to 55 kPa, the partial pressure of hydrogen is in the range of 175 kPa to 265 kPa, and the partial pressure of olefin is 350 kPa to 790 kPa. The method according to any one of claims 1 to 15, which is in the range of Sulfur compounds are passed through a zinc oxide packed tower and chlorine compounds are impregnated with copper, which becomes the catalyst poison of the rhodium catalyst contained in carbon monoxide, hydrogen and olefins supplied as raw materials in the first and second reaction systems. The raw material from which the catalyst poison is removed is used by passing through an activated carbon packed column and hydrogenating in a triple-bonded hydrocarbon compound and conjugated diene-bonded hydrocarbon palladium packed column to convert to a saturated compound. The method according to any one of the above. The method according to any one of claims 1 to 17, wherein the olefin is at least one selected from ethylene, propylene, 1-butene, and isobutene.

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