JPS63264433A - Hydroformylation of olefins - Google Patents

Abstract

PURPOSE:To inhibit the formation of high-boiling by-products by specifying the alcohol content in the recycled catalyst solution in the hydroformylation of an olefin with a specific catalyst through hydroformylation, distillation, oxidation and circulation processes. CONSTITUTION:When an olefin is hydroformylated through i) hydroformylation process where the olefin is allowed to react with hydrogen and carbon monoxide in a catalyst solution containing Rh, an oxide of a trivalent organic phosphorus compound, ii) distillation process where the above-stated phosphorus compound is added to the reaction mixture and the mixture is separated by distillation into the fraction containing aldehyde and the high-boiling fraction containing Rh, and iii) oxidation process where the high-boiling fraction is oxidized to convert the phosphorus compound into its oxide and iv) recycling process where the treated solution is recycled to the process (i), the content of the alcohol in the cycled catalyst solution is kept less than 14wt.% based on the total amount of the feedstock fed to process (i) and the catalyst.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for hydroformylating olein.

Specifically, the present invention relates to a method for suppressing the production of high-boiling byproducts during the hydroformylation reaction of olefins.

[Conventional technology]

The process of producing cetealdehyde by hydroformylating an olefinic compound with carbon monoxide and hydrogen in the presence of a catalyst is well known. In particular, in the hydroformylation of branched olefinic compounds, the hydroformylation reaction is carried out using a rhodium catalyst modified with the oxide of a trivalent organic phosphorous compound, and the resulting reaction product is separated by distillation to produce aldehyde. A method has been proposed in which the rhodium catalyst is obtained by distillation, and the bottoms containing the rhodium catalyst are circulated to the hydroformylation reaction system (Japanese Patent Application Laid-open No. 74-74-3, etc.).

[Problem that the invention seeks to solve]

However, when the hydroformylation reaction is continued for a long time using the above proposed method, the production of high-boiling by-products produced during the hydroformylation reaction, such as trimers of aldehydes, acetals, etc., gradually increases. In addition to reducing the aldehyde yield, the high-boiling by-products accumulate in the circulating catalyst liquid, eventually making it impossible to operate the system at a given capacity.

These problems can be solved by extracting the circulating catalyst liquid from the system in proportion to the amount of high-boiling by-products produced, and then supplying a new catalyst into the system corresponding to the amount of catalyst extracted. If a large amount of high-boiling byproducts are produced during the above hydroformylation reaction, the amount of catalyst liquid extracted will increase, and the cost of recovering the catalyst from the extracted catalyst liquid (catalyst recovery cost) will increase, which cannot be said to be industrially advantageous. .

[Failure to solve the problem]

In order to solve the above-mentioned problems of the prior art, the present inventors have conducted intensive studies on a method for suppressing the production of high-boiling byproducts during hydroformylation reactions, and have found that an olefinic compound and a catalyst liquid are added to the hydroformylation reaction system. By carrying out the hydroformylation reaction by reducing the proportion of alcohol from the circulating catalyst liquid in the charging solution consisting of below a certain proportion,
The present invention was completed by discovering that the production of the above-mentioned high-boiling by-products was significantly reduced.

That is, an object of the present invention is to provide a hydroformylation method in which the production of high-boiling byproducts is suppressed during the hydroformylation reaction of olefins using a rhodium catalyst. A hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing A distillation process that separates a distillate fraction consisting of a distillate fraction containing rhodium and a non-distillate fraction consisting of high-boiling seafood containing rhodium, and the non-distillate fraction obtained from this distillation process is oxidized to convert trivalent organic phosphorus compounds into oxides. An olefin hydroformylation method comprising an oxidation step and a circulation step in which the treated liquid obtained from the oxidation step is circulated as a circulating catalyst liquid to the hydroformylation reaction step. The hydroformylation reaction is carried out under conditions such that the proportion of the alcohol contained in the circulating catalyst liquid and supplied to the total amount of the olefinic compound and catalyst liquid supplied is maintained at a level below 100%. A method for hydroformylating an olefin, and a hydroformylation reaction step of reacting an olefinic compound with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorus compound, and the above steps. A trivalent organic phosphorus compound is added to the reaction solution obtained in step 1, and the resulting solution is distilled in the presence of oxygen to separate the distillate containing aldehyde and the non-distillate fraction consisting of high-boiling seafood containing rhodium. an oxidative distillation step of oxidizing and converting a divalent organic phosphorus compound into an oxide; and a circulation step of circulating the non-distillate fraction obtained from the oxidative distillation step to the hydroformylation reaction step as a circulating catalyst liquid. In the olefin hydroformylation method, the ratio of the alcohol content contained in the circulating catalyst liquid to the total amount of the olefinic compound and catalyst liquid supplied to the hydroformylation reaction step is set to /4. The gist of the present invention is a method for hydroformylating olefins, characterized in that the hydroformylation reaction is carried out under conditions where the hydroformylation reaction is maintained at % by weight or less.

The present invention will be explained in more detail below.

In the first step of the method of the present invention, the hydroformylation reaction itself is carried out according to a conventional method. Usually, a solution containing rhodium and an oxide of a trivalent organic phosphorus compound, which is recycled from a subsequent circulation process, is used as a catalyst liquid, and the reaction is carried out by supplying an olefinic compound, carbon monoxide, and hydrogen to this solution. A catalyst and a solvent can be additionally supplied if desired. Catalyst (well, it can be prepared in the reaction system by adding a rhodium compound and, if desired, an oxide of a trivalent organic phosphorus compound to this hydroformylation reaction step, but the catalyst can be prepared in advance by adding a rhodium compound and an oxide of a trivalent organic phosphorus compound It is preferable to mix the two in a solvent and introduce carbon oxide into the mixture to form an active rhodium catalyst before adding it to the reaction system.

Rhodium compounds used for catalyst preparation include inorganic acid salts such as rhodium nitrate and rhodium sulfate; organic acid salts such as rhodium acetate, rhodium sodium oxalate, and rhodium potassium malate; [RhL,]x3, [RhL, (N20)] x3
, (: Rh, L, (OH) ]X2) (RhL,
(NO2))X2) [Rh(Py)3(N03)2](
In the formula, x represents NO3-1OH-13A (S"+-), L represents NH3, and P7 represents pyridine). Among them, rhodium nitrate and rhodium acetate are preferred. used.

Examples of oxides of trivalent organic phosphorus compounds include arylphosphine oxides such as triphenylphosphine oxide, tritolylphosphine oxide, and dorianisylphosphine oxide; tributylphosphine oxide;
Alkylphosphine oxyto such as trioctylphosphine oxyto; alkylarylphosphine oxyto having both an alkyl group and an aryl group is used. ball,
Aryl phosphite oxides such as triphenylphosphinodoxide (i.e. triphenyl phosphate), tritolylphosphite oxide; alkyl phosphite oxides such as triethylphosphine oxide, tripropyl phosphite oxide, tributyl phosphite oxide: alkyl groups Alkylaryl phosphite oxides having a combination of and an aryl group are also used. Furthermore, bis(diphenylphosphino)methane dioxide, /, -2
- Pis(diphenylphosphino)ethane dioxide, /
, Z-bis(diphenylphosphino)butane dioxide, /,,! -Polydentate phosphine oxides such as bis(diphenylphosphinomethyl)cyclobutane dioxide, 2,3-Q-isopropylidene, 3-dihydroxy-7, and bis(diphenylphosphino)butane dioxide can also be used. .

The oxide of these trivalent organic phosphorus compounds contains phosphorus in the oxide state relative to rhodium/atom in the hydroformylation reaction system, usually at least 1,000 atoms, preferably 70 to 1,000 atoms, more preferably 70 to 1,000 atoms. is 1
It is used in the presence of 0 to SOO atoms.

Incidentally, in order to prepare an active catalyst in advance from a rhodium compound and an oxide of a trivalent organic phosphorus compound, the two may be mixed in the above ratio and then treated with -carbon oxide. The conditions are carbon monoxide partial pressure/~koθOkq/Cm2) preferably 7-10kg/6n2) temperature 70-200
°C1 Preferably 20~/60℃, time 7~700 minutes, preferably 2~! It is appropriately selected from the range of θ minutes. Note that it is preferable to use carbon oxide that does not substantially contain hydrogen.

The catalyst concentration in the reaction zone is typically rhodium/-30
θypy/l, preferably 2% 100 mti/l.

Examples of the olefinic compound to be subjected to the hydroformylation reaction include ethylene, propylene, /-butene, /-
Straight chain α-olefins having 30 or less carbon atoms such as pentene, /-hexene, /-octene, /-decene; straight chain such as λ-butene, two-bentene, 2-hexene, 3-hexene, two-octene, 3-octene, etc. Internal olefins: inbutylene, comethyl-/-butene, two-methyl-/-
Pentene, 3-methyl-7-pentene, comethyl-/
Branched α-olefins such as -hexene, 3-methyl-/-hexene, co-methyl-/-heptene, 3-methyl-/-heptene, Z-methyl-/-heptene: 2.3-dimethyl-/-butene, 2 .3-dimethyl-/-pentene1. :z,y-dimethyl-/-pentene, 2,3-dimethyl-/-hexene, ko, kudimethyl-/-hexene, ! -Dimethyl-/-hexene, hyperbranched α-olefins such as 3,Z-dimethyl-/-hexene; and double bond isomers thereof.

Still, isomer mixtures such as dimers to tetramers of propylene, butene, imbutylene, etc., as well as allyl alcohol,
Olefins having substituents such as acrolein acetal, vinyl acetate, styrene, and alkyl vinyl ether can also be used.

In particular, the method of the present invention is advantageous for the hydroformylation of octenes obtained by trimerizing a fraction with several grams of carbon (hereinafter referred to as BB fraction) obtained in large quantities from the thermal cracking of naphtha or the catalytic cracking of heavy and light oils. Applies to. This is because these are branched internal olefins or mixtures mainly composed of them, but unlike the case where a rhodium catalyst modified with an organic phosphine is used, the method of the present invention using an oxide of a trivalent organic phosphorus compound This is because the reaction proceeds rapidly even when a mixture of these isomers is used as a raw material.

In the method of the present invention, as described above, a solution containing rhodium and trivalent organic phosphorus compound oxides recycled from the circulation step is used as the reaction medium, but additional solvents may also be used. As a solvent, dissolve the catalyst,
Any material can be used as long as it does not adversely affect the reaction. For example, aromatic hydrocarbons such as benzene, toluene, xylene, and dodecylbenzene; alicyclic hydrocarbons such as cyclohexane; dibutyl ether,
Ethers such as ethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and tetrahydrofuran;
Esters such as ethylhexyl) phthalate are used. Moreover, the aldehyde itself produced by the hydroformylation reaction can also be used as a solvent.

A higher reaction temperature is advantageous in terms of reaction rate, but if the temperature is too high, there is a risk that the catalyst will decompose. Therefore usually! It is preferable to carry out the reaction at a temperature of Q to 770°C, especially 700 to 710°C.

As the carbon monoxide and hydrogen gas used in the hydroformylation reaction, the molar ratio of hydrogen and carbon monoxide is 115 to 5/
1, especially a water gas in the range of 1/2 to V1. The partial pressure of water gas is 20~! 00 kg7 cm2
range is used, preferably j O-300k (
j/6n2 range.

The reaction can be carried out either continuously or batchwise.

In the method of the present invention, the hydroformylation reaction is carried out using an olefinic compound (including a newly supplied olefinic compound and a circulating olefinic compound) and a catalyst liquid (a newly supplied catalyst liquid and The amount of alcohol contained in the circulating catalyst liquid (hereinafter referred to as the amount of alcohol supplied from the circulating catalyst liquid) is relative to the total amount of supplied amount (hereinafter referred to as the amount of charged liquid) of the circulating catalyst liquid (including the circulating catalyst liquid). content) is less than /g% by weight, preferably less than 70% by weight, more preferably less than 70% by weight! This is done under conditions that maintain the weight below.

The above-mentioned alcohol to be controlled in the present invention refers to the alcohol (
In other words, it refers to the alcohol (corresponding to the aldehyde produced).

In addition, in the continuous operation of a hydroformylation reaction plant, when the catalyst liquid does not substantially contain alcohol or the alcohol content from the circulating catalyst liquid is It may be less than the amount of liquid to be prepared, but
The method of the present invention does not include these cases. However, even in these cases, if normal industrial hydroformylation reaction conditions are adopted and continuous operation is performed without adjusting the amount of alcohol, the amount of water in the circulating catalyst solution will normally be reduced in about 7 days. Since a larger amount of alcohol accumulates than the weight percentage of /4 above, control by the method of the present invention is performed.

Under conditions in which the ratio of alcohol content from the circulating catalyst liquid to the amount of the charged liquid exceeds 74% by weight, high-boiling by-products during the hydroformylation reaction, such as dimers, which are self-condensation products of the generated aldehyde, The production of aldehyde condensates, acetals, etc. increases significantly,
This is not preferable because the yield of the aldehyde produced decreases.

As a method of adjusting the above alcohol content ratio,
For example, when separating aldehydes by distillation from the reaction product liquid obtained in a hydroformylation reaction, there is a method in which distillation conditions are selected and adjusted so that the alcohol concentration in the bottoms is below a certain concentration, and a part of the circulating catalyst liquid is How to remove and adjust
Examples include a method of adjusting the ratio between the amount of charged (supplied) olefin and the amount of circulating catalyst liquid.

In the first step of the method of the present invention, a trivalent organic phosphorus compound is added to the reaction solution of the hydroformylation reaction, and then distilled to distill out the aldehyde or alcohol produced by the reaction. As the trivalent organic phosphorus compound, it is preferable to use one that corresponds to the oxide in the catalyst solution for the hydroformylation reaction. Usually, triphenylphosphine, tributylphosphine, etc. are preferably used. The trivalent organic phosphorus compound coordinates to the rhodium catalyst in the reaction solution to stabilize it.

The trivalent organic phosphorus compound is added so that the amount of phosphorus in the trivalent state is equal to or more than rhodium/atom. However, even if a large amount is used, the stability of the catalyst does not increase in proportion to the amount used, so usually phosphorus in a trivalent state is /~ioo atom with respect to rhodium/atom, preferably /~, 20
It is added so that it becomes atomic.

The reaction solution of the hydroformylation reaction to which a trivalent organic phosphorus compound is added is a non-distillate fraction consisting of a low-boiling point fraction such as aldehyde and alcohol produced by distillation using a conventional method, and a high-boiling fraction containing a rhodium catalyst. It is separated into distillate and distillate.

Since the rhodium catalyst in the reaction solution is stabilized by a trivalent organic phosphorus compound, any distillation method such as flash distillation, normal pressure distillation, vacuum distillation, or a combination thereof can be used.

Also, the distillation temperature is usually below 200℃, especially 2! ~/-t0
°C is appropriate.

In the third step of the method of the present invention, the rhodium catalyst and oxides of trivalent organic phosphorus compounds discharged as a bottom liquid from the distillation step, as well as high-boiling components containing the above-mentioned trivalent organic phosphorus compounds, are oxidized to produce trivalent organic phosphorus compounds. converts the organophosphorus compound into the corresponding oxide. Usually, this oxidation is carried out by blowing atmospheric pressure air into the high boiling point. The conditions are usually a temperature of 20-200"C1, preferably 20~/!
At 0°C, the time is / minute! Time, preferably! It is appropriately selected from the range of minutes to λ hours. The purpose of this treatment is to convert the trivalent organic phosphorus compounds in the high boiling point fraction into the corresponding oxides, but it is not necessary to convert all of the trivalent organic phosphorus compounds into the corresponding oxides.

The air oxidation of the trivalent organic phosphorus compound can also be carried out in the distillation column in the second step, in which case the λth step becomes an oxidative distillation step. That is, by distilling while introducing a small amount of air into the distillation column, distillation and oxidation of the trivalent organic phosphorus compound can be performed simultaneously. For example, in a vacuum distillation column, there is generally some air leakage, but even with this amount of air, the oxidation of trivalent organic phosphorus compounds proceeds.

In addition, if the oxidation does not proceed sufficiently in the tower, it is better to air-oxidize the high-boiling point component discharged as the tower bottom liquid again as described above. The treatment solution consisting of the above is recycled to the hydroformylation reaction step and used as the catalyst solution or a part thereof. In addition, since high-boiling point by-products and phosphorus compounds produced by the reaction accumulate in this high-boiling point fraction, some of them are continuously or intermittently discharged to the outside of the system to maintain a constant concentration of these in the system. Preferably maintained.

〔Example〕

Next, embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples unless the gist thereof is exceeded. Example 1 and Comparative Example 3 (1) Synthesis of raw material olefin After removing butadiene and isobutyne from the BB fraction obtained from a naphtha cracker, the C1 fraction (isobutyne 3% by weight, butene 4t3% by weight, two butene 2!
Weight%, butanes 2! Composition of weight section, other/weight section)
was dehydrated using Molecular Sheep/3X.

Next, the dehydrated C6 fraction 4 was placed in a SUS induction stirring autoclave with an internal volume of /θt under a nitrogen atmosphere.
tkg, n-hexane solution of nickel octoate L!
(Ni content: 3 wt%) and ethylaluminum dichloride//, 39 were charged, and reacted at 0° C. for 7 sowing periods.

After reaction 1. After deactivating the catalyst by adding fwt%I (3 t of 2So4 aqueous solution and toi), 4 liquids were separated, and then distilled under atmospheric pressure to obtain a C8 olefin mixture (hereinafter referred to as octene).

The above reaction and distillation were carried out three times.

(2) In a 5US-3/6 induction stirring autoclave with an internal volume of 101 for hydroformylation, 7 tons of octene obtained in (1) above and a methanol solution of rhodium acetate (rhodium concentration yoooorrq/l) were added.
> was added in an amount such that the rhodium concentration in the reaction solution was /θ ~ /l, and triphenylphosphine oxyto was added in an amount 20 times the molar amount of rhodium, and the autoclave was sealed.

After purging the inside of the autoclave with nitrogen gas and further pressurizing nitrogen gas to kYOkg/cm2G, the operation of releasing the pressure to normal pressure was repeated three times, and then the temperature was raised to 730°C.

Immediately after reaching 730℃, the total pressure is /70 kg/c
Water gas (H2100=/) was injected under pressure to give m2G, and the reaction was carried out at 730°C for 6 hours. During this time,
The water gas consumed by the reaction is replenished from the pressure accumulator via a constant pressure device, and the inside of the autoclave is heated to 770 to 9/cm.
I kept it at 2G. After the reaction was completed, the reaction solution was analyzed by gas chromatography, and the results showed that the coaldehyde yield was 2,
72%, 09 alcohol yield? 0chi, high boiling point by-product conversion rate 0. It was 0%.

(3) Distillation of the hydroformylation reaction solution To the hydroformylation reaction solution obtained in (2) above, add triphenylphosphine in an amount twice the amount of rhodium in the reaction solution.
Simple distillation was carried out in an air atmosphere at a cuff pressure of 0 Hg and a tower top temperature of 10° C. to distill off the aldehyde, and a distillation residue containing alcohol was obtained as the bottoms. This distillation residue under normal pressure,
Oxidation treatment is carried out by holding at 790°C in an air atmosphere for several hours,
A treated liquid (hereinafter referred to as circulating catalyst liquid A) was obtained.

Further, a part of the circulating catalyst liquid A was heated in a nitrogen atmosphere at a pressure of 30 ml/lrHf and a tower top temperature//! Distillation was carried out under reduced pressure at a temperature of 0.degree. C. to distill off 0.times.ft.

(4) Hydroformylation reaction using circulating catalyst liquid Octene obtained in the above (1) and the circulating catalyst liquid A obtained in the above (3) or B was supplied in the proportion shown in the table, and the autoclave was sealed.

The inside of the autoclave was replaced with nitrogen gas, nitrogen gas was further introduced under pressure to 'rtOkg/car2G, and the operation of releasing the pressure to normal pressure was repeated three times, and then the temperature was raised to 730°C. Immediately after reaching 730 °C, the total pressure is /70 k
water gas (H2/CO=/
) was introduced under pressure, and the reaction was carried out at 730°C until the conversion of octene exceeded 9. During this time, the water gas consumed by the reaction was replenished from the pressure accumulator via the constant pressure device, and the inside of the autoclave was maintained at 77θkg/6n2G.

After the reaction was completed, the reaction solution was analyzed by gas chromatography.

The alcohol concentration in the charged liquid (=ratio of alcohol content from the circulating catalyst liquid to the amount of charged liquid), the aldehyde yield after reaction, the alcohol yield, and the conversion rate of high boiling point byproducts are shown in Table/.

〔Effect of the invention〕

By the method of the present invention, it is possible to effectively suppress the production of high-boiling by-products during the hydroformylation reaction of olefins.

Patent applicant: Mitsubishi Chemical Industries, Ltd. Representative Patent attorney required - Others/names

Claims (7)

[Claims] (1) A hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorus compound; A distillation process in which an organic phosphorus compound is added and distilled to separate a distillate containing aldehyde and a non-distillate fraction consisting of a high boiling point containing rhodium, and the non-distillate fraction obtained from this distillation process is oxidized. A method for hydroformylating olefins, comprising the following steps: an oxidation step in which a trivalent organic phosphorus compound is converted into an oxide, and a circulation step in which a treated liquid obtained from this oxidation step is recycled as a circulating catalyst liquid to the hydroformylation reaction step. Conditions in which the proportion of the alcohol contained in the circulating catalyst liquid and supplied is maintained at 14% by weight or less with respect to the total amount of the olefinic compound and catalyst liquid supplied to the hydroformylation reaction step. A method for hydroformylating an olefin, comprising carrying out a hydroformylation reaction below. (2) In the method for hydroformylating olefins according to claim 1, the non-distillate fraction consisting of high boiling points containing rhodium obtained from the distillation step is air oxidized in the oxidation step. (3) The method for hydroformylating an olefin according to claim 1 or 2, wherein the olefinic compound is a branched internal olefin or a mixture mainly composed of this. (4) The method for hydroformylating an olefin according to claim 1 or 2, wherein the olefinic compound is a butene dimer. (5) A hydroformylation reaction step in which an olefinic compound is reacted with carbon monoxide and hydrogen in a catalyst solution containing rhodium and an oxide of a trivalent organic phosphorous compound; of organic phosphorus compounds are added and distilled in the presence of oxygen, separating the distillate fraction containing aldehydes and the non-distillate fraction consisting of high boiling points containing rhodium, and oxidizing the trivalent organic phosphorus compounds to form oxides. and a circulation step in which the non-distillate fraction obtained from the oxidative distillation step is recycled to the hydroformylation reaction step as a circulating catalyst liquid, the hydroformylation method comprising: The hydroformylation reaction is carried out under conditions in which the proportion of alcohol contained in the circulating catalyst liquid and supplied is maintained at 14% by weight or less with respect to the total amount of the olefinic compound and catalyst liquid supplied to the reaction process. A method for hydroformylating olefins, the method comprising: (6) The method for hydroformylating an olefin according to claim 5, wherein the olefinic compound is a branched internal olefin or a mixture mainly composed of this. (7) The method for hydroformylating olefins according to claim 5, wherein the olefinic compound is a butene dimer.