JPH0723331B2 - Method for producing tertiary butanol - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a method for producing a tertiary butanol by hydrating isobutylene with a heteropoly acid as a catalyst.

Tertiary butanol is useful as various industrial raw materials,
It is used as a raw material for isobutylene, methyl methacrylate, etc., and is industrially obtained mainly by hydrating isobutylene.

(Prior Art) As a method for hydrating isobutylene, a method using an aqueous solution containing a heteropolyacid has been proposed. Japanese Patent Publication 58-39
According to the 134 publication, the reaction is less than 100 ° C, preferably
It progresses at a sufficient speed even at a low temperature of 30 to 80 ° C, especially at 80 ° C
At the following temperatures, a dimer or trimer polymer obtained by the polymerization of isobutylene or sec-time caused by the hydration of n-butene.
By-production of butanol is suppressed, and tertiary butanol can be produced with high selectivity.

(Means for Solving Problems) As a result of intensive studies on the method of further improving the hydration activity of heteropolyacid while suppressing such by-products, the present inventors have found that it is soluble in an aqueous solution containing heteropolyacid. It was found that the hydration activity of isobutylene was increased by reacting such an oxygen-containing organic solvent in the range of not exceeding 30 times the molar amount of the heteropolyacid.

That is, the present invention uses an aqueous solution containing a heteropolyacid or a salt thereof having a condensation coordination element of at least one element selected from Mo, W, and V, and hydrates isobutylene
A third characteristic feature of reacting an oxygen-containing organic solvent soluble in an aqueous solution containing a heteropolyacid or a salt thereof in the range of not exceeding 10 times the molar amount of the heteropolyacid in the production of a grade-butanol. It is a method for producing high-grade butanol.

The oxygen-containing organic solvent referred to in the present invention can be selected from oxygen-containing organic solvents that are soluble in the heteropolyacid aqueous solution. A solvent having a high reactivity with isobutylene under the present reaction conditions is economically unfavorable because it lowers the selectivity of the product tertiary butanol. Preferred solvents include isopropyl alcohol, tertiary butanol, alcohols such as 1,3-butylene glycol and diethylene glycol, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, glycol monomethyl ether and diethylene glycol monomethyl ether. There are ethers and alcohols. However, the solvent is not limited to the above. It is more preferable to use tertiary butanol, which is a hydrated product of isobutylene, as the oxygen-containing organic solvent from the viewpoint of practically not complicating separation and purification.

The hydration reaction of isobutylene is an equilibrium reaction, and it is generally considered that the presence of a product in the equilibrium reaction is disadvantageous in terms of reaction, and the present invention is based on the discovery of facts contrary to this common sense. It was done and it is amazing. The figure shows that the presence of tertiary butanol significantly enhances the hydration activity of isobutylene.

Conventionally, it has been known that an oxygen-containing organic solvent such as a tertiary butanol stabilizes a heteropoly acid.
Soushie, Earl, Contact, C. R. Academia. Science., Paris. Series.265,723 (1967) (P.
Souchay.R.Contant, CAAcad.Sci.C.265,723 (196
7))], In the present invention, the hydration activity of isobutylene is remarkably increased when a small amount of an oxygen-containing organic solvent is added, and the hydration activity is decreased when further added. Although its mechanism of action is unknown, it is presumed that the oxygen-containing organic solvent has a specific action on the heteropolyacid.

In the method of the present invention, the concentration of the oxygen-containing organic solvent coexisting in the aqueous solution of the heteropolyacid varies depending on the type of the heteropolyacid used, the concentration, and the reaction temperature, but is usually 30 times or less the molar amount of the heteropolyacid, preferably It should be 1 to 10 times mol. If the amount is 30 times or more, the hydration activity will decrease.

The method of the present invention further has the following advantages. That is, by improving the hydration reaction activity of isobutylene, it becomes possible to carry out the reaction at a lower temperature, and as a result, it is expected that the production of diisobutylene and sec-butanol can be suppressed more effectively.

Isobutylene used in the present invention is 1-butene, cis
A mixed olefin containing 2-butene, trans-2-butene, or the like may be used, and saturated hydrocarbon or aromatic hydrocarbon may coexist. For example, most of butadiene was removed from the C ₄ fraction of a fluidized catalytic reactor of petroleum, the catalytic dehydrogenation fraction of n-butane, etc., particularly the fraction having 4 carbon atoms in the naphtha cracking step. It is also possible to use, as a raw material, so-called Spent BB, which has isobutylene and n-butene as main components to be obtained later. Isobutylene is preferably supplied in liquid form, but it is also possible to supply it in vaporized gaseous form to an aqueous solution containing a catalyst.

The heteropolyacid used as a catalyst in the present invention is
The condensation coordination element contains at least one element selected from Mo, W, and V, but may further contain other elements such as Nb and Ta as the condensation coordination element. The central element of this heteropoly acid is P,
Si, As, Ge, Ti, Ce, Th, Mn, Ni, Te, I, Co, Cr, F
It is one kind selected from the group of e, Ga, B, V, Pt, Be and Zn, and the condensed coordination element / central element (atomic ratio) in the heteropolyacid is 2.5 to 12. Further, not only a heteropolyacid monomer but also a polymer such as a dimer or trimer can be used.
Specific examples of these heteropolyacids include phosphomolybdic acid, phosphotungstic acid, phosphomolybdotungstic acid, phosphomolybdopanadic acid, phosphomolybdotungstopanadic acid, phosphotungstopanadic acid, phosphomolybdoniobate, Silicotungstic acid, silicomolybdic acid, silicomolybdotungstic acid, silicomolybdo tungstopanadic acid, borotungstic acid, boromolybdic acid, boromolybdotungstic acid, boromolybdovanadic acid,
Examples thereof include humoribdotungstovanadic acid, cobalt molybdic acid, cobirtotungstic acid, arsenicmolybdic acid, and arsenictungstic acid. As long as it does not form an insoluble salt with the above-mentioned heteropolyacid, cations such as lithium, sodium, magnesium, beryllium, aluminum, nickel, copper, zinc, cobalt, tellurium, vanadium, titanium, arsenic, zirconium, iron and chromium. It can also be used as a salt of manganese or the like.

The amount of the catalyst is not particularly limited, and the higher the concentration in the aqueous solution is, the faster the reaction proceeds, which is preferable, but it is not necessary to add more than the solubility. Further, since the reaction rate decreases at an extremely low concentration, it is usually performed at a solubility of 10% by weight or more and a saturated solubility.

The catalyst used in the present invention is preferably prepared by preparing a heteropolyacid in advance, but it is also possible to separately prepare a compound containing a central element and a condensation coordination element, and to use it for the reaction while forming a heteropolyacid.

The reaction temperature is relatively low, ie less than 100 ° C, preferably 30
Perform in the temperature range of -80 ℃. At 100 ° C or higher, the hydration reaction of n-butene rapidly occurs, and oligomers or polymers such as isobutylene dimers and trimers are formed.
The purity of the tertiary butanol in the produced alcohol decreases. At 80 ° C or lower, the hydration reaction of n-butene hardly occurs, and highly pure tertiary butanol is obtained. Also, 30
When the temperature is lower than 0 ° C, the reaction rate becomes low, which is economically disadvantageous.

The pressure used in the present invention is at least the pressure at which water exists as a liquid, and particularly at least the pressure at which isobutylene exists as a liquid. In this case, the pressure can be controlled by introducing an inert gas such as nitrogen gas.

The reaction solution is usually a reaction consisting of two phases, an aqueous layer and a hydrocarbon layer.

As an embodiment of the present invention, any of a reaction vessel with a stirrer, an external circulation type reactor, a packed column type reactor, a wet wall column type reactor, a tumbler type reactor, etc. may be adopted. It may be a batch system, a continuous system, or a semi-batch system, and even in the continuous system, operations such as a countercurrent multistage continuous system are possible.

(Examples) Hereinafter, the present invention will be described with reference to Examples. The analysis of the product was carried out by gas chromatography using dimethoxyethane as an internal standard substance, diluting it about 5 times with methanol, neutralizing it with sodium hydroxide.

Examples 1 to 4, Comparative Example 1 Isobutylene 10 gr, phosphomolybdic acid 50 gr (atomic ratio phosphorus to molybdenum = 1: 12), water 100 gr, and tertiary butanol were charged in a stainless steel autoclave as shown in Table 1.
Sealed, heated to 60 ° C, reacted for 30 minutes under stirring, and the result was 1st
It was as shown in the table.

In each of Examples 1 to 4, the selectivity of tertiary butanol is 10
It was 0%, and a polymer such as a dimer or trimer of isobutylene was not detected.

Examples 5-6, Comparative Example 2 Isobutylene 40.7% by weight (hereinafter, all% by weight), 1-butene 20.6%, 2-butene 16.0%, n-butane 13.2%, i
-The so-called spent BB20gr containing butane 1.7%, phosphotungstic acid 50gr (atomic ratio phosphorus to tungsten = 1: 1
2), 100 gr of water and 6.0 gr of organic solvent as shown in Table 2 were charged into a stainless steel autoclave, sealed, and stirred at 60 ° C.
Reacted for 30 minutes. The results after the reaction are shown in Table 2.

(Effect of the Invention) It is possible to further improve the hydration activity of the heteropolyacid, that is, improve the hydration reaction activity of isobutylene and significantly increase the reaction rate (conversion rate) of isobutylene. Also,
By improving the hydration reaction activity of isobutylene, the reaction can be carried out at a lower temperature, so that by-products can be suppressed more effectively. The present invention is a novel production method capable of improving the production of tertiary butanol.

[Brief description of drawings]

The drawings are charts showing the results according to Examples 1 to 4 of the present invention.

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Claims (1)

[Claims] 1. A tertiary butanol is produced by hydrating isobutylene using an aqueous solution containing a heteropolyacid or a salt thereof having a condensation coordination element of at least one element selected from Mo, W and V. In this case, the reaction is carried out while allowing an oxygen-containing organic solvent soluble in an aqueous solution containing a heteropolyacid or a salt thereof to exist in a range not exceeding 10 times the molar amount of the heteropolyacid, and producing a tertiary butanol. Method.