JPS62242636A - Production of ethanol - Google Patents

Abstract

PURPOSE:The reaction between methanol, carbon monoxide and hydrogen is effected in the presence of a catalyst of high activity and high selectivity which is prepared by treating cobalt carbonyl and a tertiary phosphine in the presence of a hydroxy compound with heat in an inert gas whereby ethanol is obtained in high yield. CONSTITUTION:The reaction between methanol, carbon monoxide and hydrogen is effected in the presence of a catalyst which is prepared by heating cobalt carbonyl and a tertiary phosphine in the presence of a hydroxy compound in an inert gas. In the preparation of the catalyst, the phosphine is used at an atomic ratio of 1-2 P/Co and the amount of the hydroxy compound is 1-10mol per 1g-atom Co. They are heat-treated in an inert gas at 190-210 deg.C. The catalyst prepared can be employed in the reaction as it is, but the complex with 2 P/Co atomic ratio may be used after concentration or isolation.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing ethanol from methanol, carbon monoxide, and hydrogen, and more specifically relates to a method for producing ethanol from methanol, carbon monoxide, and hydrogen. , and a method for producing ethanol using a catalyst with excellent selectivity.

(Prior Art) Conventionally, a method for producing ethanol from methanol, carbon monoxide, and hydrogen using a cobalt compound as a main catalyst is disclosed in British Patent No. 2036.739, which uses iodine or an iodine compound as a co-catalyst. Unexamined Japanese Patent Publication 1986-49
326, JP-A-56-25121. Japanese Patent Publication No. 57-108
No. 027, JP-A-58-26850, and US Pat. No. 4,168.319 are known as using non-iodine catalysts.

(Problems to be Solved by the Invention) However, according to the studies of the present inventors, in the catalyst system mainly composed of cobalt-iodine as described above, in addition to ethanol, dimethyl ether, ethyl methyl ether, diethyl ether, acetaldehyde, etc. dimethoxyethane,
It has been found that there are many liquid products such as methyl formate and methyl acetate, and gaseous products such as methane, and the yield and selectivity to by-product free ethanol are not necessarily sufficient. In addition, the catalyst systems that have been proposed so far using iodine or an iodine compound as a cocatalyst have tended to have multi-component and complex catalyst compositions because the main focus has been on suppressing side reactions.

In addition, non-iodine catalysts are preferable because they are simple catalyst systems that do not contain highly corrosive iodine, but they have the disadvantage that they produce large amounts of methyl acetate, acetic acid, dimethoxyethane, etc. as by-products and have low selectivity to ethanol. there were.

Previously, the present inventor proposed a catalyst system containing cobalt and 6th phosphine as non-iodine-based active ingredients. In addition, when using this catalyst system, it is necessary to perform an activation treatment in advance, for example, by subjecting the cobalt source and the tertiary phosphine to a mixed gas of carbon monoxide and hydrogen under pressure (H2/Co w 1 molar ratio, 200 lc
f/cmz G), and heat treatment at a temperature of 230° C. or higher greatly improves catalyst activity and selectivity. Furthermore, based on these findings, we separated each complex component contained in the catalyst liquid and analyzed in detail its correspondence with catalyst performance. As a result, a specific complex with P/Co = 2 (atomic ratio) had an extremely high It was found to have activity and selectivity to ethanol (Japanese Patent Application No. 61-56140). However, although an effective complex is produced by the above activation treatment method, 230'C
Since the treatment has to be carried out under the above harsh conditions, there is a drawback that a part of the tertiary phosphine is consumed by phosphinic acid, etc., and there is room for improvement.

(Means for Solving the Problems) Against the background of the above facts, the present inventors have conducted extensive research to directly synthesize the complexes that are highly related to catalytically active species from cobalt carbonyl and tertiary phosphine. The present invention was completed based on the discovery that the desired complex can be efficiently obtained under relatively mild conditions by coexisting a hydroxy compound within the compound. That is, in producing ethanol from methanol, carbon monoxide, and hydrogen, the present invention heat-treats a catalyst containing cobalt carbonyl and tertiary phosphine as active ingredients in an inert gas in the presence of a hydroxy compound, and then heat-treats the catalyst as a catalyst. This is a method for producing ethanol characterized by using the following method.

The catalyst preparation solution obtained by the method of the present invention mainly contains complexes with P / Co = 1 and 2 (atomic ratio) and can be used as is, but as an alternative method, for example, by column chromatography etc. It is also possible to separate and use only the complex component of /Co-2 (atomic ratio).

Next, a method for preparing a catalyst of the present invention and a method for producing ethanol from methanol, carbon monoxide, and hydrogen using this catalyst will be specifically explained.

In the present invention, dicobalt octacarbonyl, hydridotetracarbonyl, and the like can be used as a cobalt carbonyl source serving as a catalyst raw material. As the tertiary phosphine, triethylphosphine, tri-n-butylphosphine, tri-n-hexylphosphine, triphenylphosphine, tricyclohexylphosphine, 1,4-bisphenylphosphinobutane, and the like can be suitably used. Hydroxy compounds include water, alcohols, and 11'! of phenols. ! Or a mixture of two or more types can be used. As the alcohol, methanol, ethanol, n-propano-p-cresol, etc. can be used.

The amount of tertiary phosphine used to suitably carry out the present invention is:
P/Co = 0, 5 to 4, preferably 1 in terms of atomic ratio
It is in the range of ~2. The amount of the hydroxy compound used as an accelerator is in the range of 0.1 to 20 mol, preferably 1 to 10 mol, per 1.9N cobal.

The catalyst preparation method of the present invention is carried out by subjecting a cobalt carbonyl, a tertiary phosphine, and a hydroxy compound to a heating reaction in an inert gas in an inert solvent. As the inert gas, ordinary N2, Ar, and He are used, and the pressure may be normal pressure or pressurized. Heating temperature is 180°C to 220°C
, preferably in the range of 190°C to 210°C. If the temperature is lower than this, the desired complex will not be formed, and if the temperature is higher than this, the decomposition of the complex will be accelerated, which is not preferable.

Particularly suitable solvents are hydrocarbons and cyclic ethers. Hydrocarbons include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane and n-octane, and alicyclic hydrocarbons such as cyclohexane. As the cyclic ether, 1,4-dioxane, tetrahydrofuran, etc. can be used. The amount of solvent used is preferably in the range of 2 to 50 mol, preferably 5 to 20 mol, per gram of cobalt atom.

As mentioned above, the catalyst preparation liquid obtained by the method of the present invention can be used as is for the reaction, but P/C.

A complex having an atomic ratio of 2 to 2 (atomic ratio) can be concentrated or separated and then used as a catalyst.

The reaction of methanol, carbon monoxide and hydrogen in the present invention is carried out as follows. The amount of catalyst used is methanol 1
It is in the range of 1 to 300 da atoms, preferably 5 to 1009 da atoms, calculated as cobalt atoms per mole. If it is less than this, the reaction rate will be low, and if it is more than this, it will not have any adverse effect but will not be economical, and the above range will be less than 50% practical.
4/anzQ or more, and there is no particular upper limit, but
Practically speaking, a range of 100 to 500K47cm2G is suitable.

The reaction temperature is 180-280°C, preferably 210-25°C.
It is in the range of 0°C. If the temperature is lower than this, the reaction rate will be low, and if the temperature is higher than this, the amount of by-products will increase, which is not preferable.

Note that the method of the present invention can be suitably carried out either by a batch method or a continuous method.

(Function) The present invention is intended to directly synthesize a complex strongly related to the catalytically active species from cobalt carbonyl and tertiary phosphine and use it in the reaction in a method for producing ethanol from methanol, carbon monoxide, and hydrogen. It is something to do. Usually, from cobalt carbonyl and tertiary phosphine, P/Cow
1 (atomic ratio), i.e. (Co(Co)3(R3
P)]2 and (Co(Co)4(R3F)21 (
Co(Co)4] is known to be easily obtained. According to the catalyst preparation method of the present invention, the P/Co = 1
In addition to the complex of (atomic ratio), P/Co - which is effective for the reaction
A new complex with an atomic ratio of 112 (atomic ratio) is formed, but simply heating cobalt carbonyl and tertiary phosphine hardly forms the desired complex, so the combination of the presence of a hydroxy compound and the heating temperature promotes complex formation. It is inferred that it plays an important role.

(Effects of the Invention) According to the method of the present invention, the catalyst stability and catalytic activity can be increased in the high P/Co (atomic ratio) region, which could not be achieved in the conventional in 5 in situ method due to its low catalyst activity. Moreover, ethanol can be obtained with high selectivity. In addition, from the perspective of catalyst recycling, improved catalyst stability allows catalyst recovery and reuse to be carried out smoothly. Furthermore, this catalyst does not require the use of highly corrosive iodine or dissimilar metal compounds.
Free ethanol can be obtained with high space-time yield and high selectivity.

(Example) Next, the method of the present invention will be explained in more detail with reference to Examples.

In the Examples and Comparative Examples below, the methanol conversion rate, selectivity to each product, substantial methanol conversion rate, and convertible ethanol selectivity are defined as follows.

O methanol reaction rate (chi) O Selectivity to bryozoan parabolites (%) O actual methanol reaction rate (%) O convertible ethanol selectivity (%) Note 1) Converted methanol can be hydrolyzed with dimethoxyethane, methyl ester, etc. means the methanol fraction recovered by

Note 2) Refers to free ethanol and the ethanol content recovered by hydrogenation or hydrolysis, such as acetaldehyde, dimethoxyethane, and ethyl methyl ether.

Example 1 Catalyst preparation: 150 g (1,92 mol) of benzene and dicobalt octacarbonyl Mo9 (0,087
7 mol), tri-n-butylphosphine 71 g (0,
351 mol) and methanol 31 (1.03 mol) were charged and sealed. After replacing the inside of the system with N2 gas several times, heat treatment was performed at a temperature of 200° C. for 3 hours.

Next, the autoclave was cooled, and the taken out contents were charged to a rotary evaporator and heated to [6] under a N2 atmosphere.
Methanol and benzene were distilled off at 0° C. under reduced pressure using 14 g of 60 ml to obtain a black-red viscous liquid.

Approximately 150 g of the catalyst liquid obtained through the above several operations was dissolved in 11 reagents, primary methanol. On the other hand, 656X900L
A glass column was filled with approximately 2.5 ml of a nonpolar porous synthetic resin, High Porous Polymer HP-20 (trade name), with a primary methanol solvent as a reagent. After sufficiently passing methanol through this column, a methanol solution of the catalyst solution was passed therethrough at room temperature. A yellow-orange color was observed on the gel due to selective adsorption of the active complex in the catalyst solution.

Then, when a reagent-grade (methanol:acetone=1=1 volume ratio) mixed solvent was allowed to flow down, the effective complex was immediately eliminated. Approximately 31 g of this eluate was evaporated to dryness using a rotary evaporator to obtain blue crystals. As a result of analyzing this crystal, the cobalt content was 11.3 wt%, P/Co
-2 (atomic ratio) complex.

Reaction: Using the complex obtained above as cobalt, 0°0117I
i atom, methanol 10. lit' (0,512 mol) and benzene 10 g (0,128 mol) content f1
The mixture was placed in a 100 mj stainless steel shaking autoclave and sealed. This is combined with a mixed gas of hydrogen and carbon monoxide (
) (z/Co=1 molar ratio) 200Kf/α2G was press-fitted and reacted at a temperature of 230°C for 15 minutes. After the reaction, the autoclave was cooled and residual gas was purged, and the reaction product liquid was analyzed using an internal standard method using gas chromatography. As a result, the methanol conversion rate was 28.7%.
The ethanol selectivity was 84.5 tlr, and the selectivity of each other component was dimethyl ether 0.14%,
Acetaldehyde 0.67, Methyl formate 1.36
%, ethyl methyl ether 0.54%, vinegar methyl 0
．． 55% %n-proper tool 1.83 yen. At this time, the actual methanol reaction rate was 28.1%, and the convertible ethanol selectivity was 87.0%.

Example 2 Catalyst preparation: 12.9 (0°154 moles) of benzene was placed in a stainless steel shaking autoclave with an internal volume of 100 mJ.
, dicobalt octacarbonyl 2.4! i(0,007
mole), tri-n-butylphosphine 4.27g (0
,0211 mol) and methanol 1.8g (0.05
62 mol) was charged and the container was sealed. After replacing the inside of the system with N2 gas several times, heat treatment was performed at a temperature of 200° C. for 3 hours. As a result of cooling the autoclave and analyzing the catalyst liquid taken out using liquid chromatography, it was found that P/Co=2 (atomic ratio)
The complex contained 30.3% based on the charged cobalt.

Reaction: 17.1p of the catalyst solution obtained above and methanol
10 g (0,312 mol) was charged into a stainless steel break-through autoclave with an internal volume of 100 m/cm and the autoclave was sealed. A mixed gas of hydrogen and carbon monoxide (CH2/CO=1 molar ratio) 200KIF/σ2G was pressurized into this, and the mixture was reacted at 250°C for 1.5 hours. After the reaction, the autoclave was cooled and residual gas was purged, and the reaction product liquid was analyzed using an internal standard method using a gas chromatograph. As a result, the ethanol selectivity was 81.5% at a methanol conversion rate of 27.6%, and the selectivity to other products was 0.49% for acetaldehyde, 2.74% for methyl formate, 1.59% for methyl acetate, The n-proper tool was 1.65 cm. The actual methanol reaction rate at this time was 26.6 inches, and the convertible ethanol selectivity was 85.0 inches.

Example 3 Catalyst Preparation: Water instead of methanol as promoter 1.
Example 2 using og (o, oss 6 moles). ! : A catalyst was prepared in the same manner.

As a result of analyzing the catalyst liquid obtained here using a liquid chromatography, it was found that 30.1 units of zero isomers with T'/Co=2 (atomic ratio) were contained based on the charged cobalt.

Reaction: Example 2 using 16.4 g of the catalyst solution obtained above.
Methanol was reacted with carbon monoxide and hydrogen in a similar manner. As a result, the ethanol selectivity was 77.7% at a methanol reaction rate of 29.9'4, and the selectivity for each other product was 0.54% for dimethyl ether, 0.28% for acetaldehyde, and 1.21% for methyl formate. ,
Ethyl methyl ether 0.21%, methyl acetate 0.
The contents were 42 yen, n-propertool 2.96 yen, and dimethoxyethane 1.25%. The actual methanol conversion rate at this time was 29.3 degrees, and the convertible ethanol selectivity was 80.0 degrees.

Example 4 Catalyst Preparation: 2.64 g of phenol (0,
A catalyst was prepared in the same manner as in Example 2 using 0281 mol). The catalyst liquid obtained here contains P/Co=
2 (atomic ratio) complex contained 28.9 cobalt based on the charged cobalt.

Reaction: Example 2 using the catalyst solution 17.85 obtained above
Methanol was reacted with carbon monoxide and hydrogen in a similar manner. As a result, the ethanol selectivity was 86.1% at a methanol reaction rate of 24.1%, and the selectivity for each other product was 0.99% for dimethyl ether, 0.52% for acetaldehyde, 1.07% for methyl formate, Ethyl methyl ether 0.60%, methyl acetate 0.5
1, n-propertool 2.28%, dimethoxyethane 1.264%. At this time, the actual methanol conversion rate was 23.3%, and the convertible ethanol selectivity was 90.5%.

Example 5 Catalyst preparation: A catalyst was prepared in the same manner as in Example 2 using 6.09 (0,0210 mol) of tri-n-hexylphosphine as the tertiary phosphine and 0.9 g (0,0281 mol) of methanol as the promoter. Preparation was carried out. In the catalyst solution obtained here, the complex of P/Co=2 (atomic ratio) was 29% based on the cobalt charged. (It was included.

Reaction: Example 2 using 17.8g of the catalyst solution obtained above.
Methanol was reacted with carbon monoxide and hydrogen in a similar manner. As a result, the ethanol selectivity was 79.9% at a methanol reaction rate of 27.7%, and the selectivity for each other product was 0.45% for acetaldehyde, 2.331% for methyl formate, and 0.67% for ethyl methyl ether.
H, methyl acetate 0.90 H, n-propertool 1.
It was 66.9. The actual methanol conversion rate at this time was 26. El, and the convertible ethanol selectivity is 85.
It became 3'l.

Comparative Example 1 Reaction by in 5 itu method: Internal volume 100 ml
methanol in a stainless steel tear-out type autoclave
10 g (0,312 mol), benzene 10 g (0,12 mol)
8 mol), tri-n-butylphosphine 4.75 g (
0,0234 mol) and dicobalt octacarbonyl
29 (0°00585 mol) was charged and the container was sealed. A mixed gas of hydrogen and carbon monoxide (H
2/Co = 1 molar ratio) 200 Kf/cIrL2
G was injected under pressure and reacted at 230°C for 1.5 hours.

After the reaction, the autoclave was cooled and residual gas was purged, and the reaction product liquid was analyzed using an internal standard method using a gas chromatograph. As a result, methanol reaction rate 5
．． At 72'l, the ethanol selectivity was 55°4, and the selectivity to other components was 17.3% for methyl formate,
The amount of ethyl methyl ether was 2.3. At this time, the actual methanol conversion rate was 4.70%, and the convertible ethanol selectivity was 67.0%.

Comparative Example 2 Catalyst preparation: 12.9 (0°154 mol) of benzene and 2.49 (0,007 mol) of dicobalt octacarbonyl were placed in a stainless steel tear-off type autoclave with an internal volume of 100!11.
mole) and tri-n-butylphosphine 5.66 IC
0,028 mol) and sealed without addition of accelerator. After replacing the system with N2 gas several times, the temperature was reduced to 20
Heat treatment was performed at 0°C for 3 hours. Cool the autoclave;
As a result of analyzing the taken out catalyst liquid by liquid chromatography, it was found that almost no complex of P/Co±2 (atomic ratio) was formed.

Reaction: Methanol, carbon monoxide, and hydrogen were reacted in the same manner as in Example 2 using 16.79 g of the catalyst solution obtained above. As a result, when the methanol reaction rate was 8.61%, the ethanol selectivity was 56.6%, and the selectivity for each other product was 0.45% for acetaldehyde, 5.72% for methyl formate, and 0.54 yen for methyl acetate. , n-proper tool was 2.261. At this time, the actual methanol reaction rate was 8.0%, and the convertible ethanol selectivity was 60.7%.

Comparative Example 3 Catalyst preparation: Similar to Comparative Example 2, no accelerator was added, P/C
The catalyst was prepared under the conditions of o = 1, 5 (atomic ratio). In the catalyst liquid obtained here, almost no P/Co=2 (atomic ratio) was generated.

Reaction: Example 2 using the catalyst solution 15.69 obtained above
Methanol was reacted with carbon monoxide and hydrogen in a similar manner. As a result, the methanol reaction rate was 13.0%, the ethanol selectivity was SO, S%, and the selectivity for each other product was 0.85% for acetaldehyde, 3.73% for methyl formate, and 0.98% for methyl acetate. there were.

The actual methanol reaction rate at this time was 12.4%,
The convertible ethanol selectivity was 55.6'4.

As mentioned above, from the comparison between Example 1 and Comparative Example 1, P/C
Under the condition of ow2 (atomic ratio), i
It can be seen that when the reaction was carried out by the n 5 itu method, the catalyst activity and selectivity to ethanol were extremely low.

Furthermore, from the comparison between Examples 2 to 4 and Comparative Examples 2 and 3, P
/Co == 1, 5-2 (atomic ratio) when treated without a promoter, the target P/Co = 2 (
It becomes clear that a complex with a high atomic ratio) cannot be easily obtained, and that the catalytic performance is also low.

Claims (1)

[Claims] In producing ethanol from methanol, carbon monoxide, and hydrogen, a catalyst containing cobalt carbonyl and tertiary phosphine as active ingredients is heated in an inert gas in the presence of a hydroxy compound, and then used as a catalyst. A method for producing ethanol.