JP2782871B2 - Method for producing neopentyl glycol - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing neopentyl glycol, and more particularly, to converting hydroxypivalaldehyde obtained by condensing isobutyraldehyde and formaldehyde to ruthenium-palladium ( The present invention relates to a method for producing neopentyl glycol, which comprises hydrogenating in the presence of a catalyst comprising a combination of two elements of Ru-Pd.

Neopentyl glycol has a wide range of industrial applications such as acrylic resins, polyester resins, polyurethane resins, alkyd resins, polycarbonate resins, other plasticizers, synthetic lubricating oils, textile processing agents, and surfactants. Is an extremely important intermediate material.

(Prior art and its problems) There are the following two methods for producing neopentyl glycol.

One is to convert isobutyraldehyde and formaldehyde into strong alkaline catalysts such as caustic soda, caustic potash,
In this method, a two-stage reaction of an aldol condensation reaction and a cross-Kanitzaro reaction is performed in the presence of calcium hydroxide or the like to obtain neopentyl glycol as a target product. However, this method has a drawback that since an equimolar amount of sodium formate is by-produced with the target substance, it cannot be used as an industrial method for producing neopentyl glycol unless the sodium formate is used effectively. .

Another method involves hydrogenating hydroxypivalaldehyde obtained by the reaction of isobutyraldehyde and formaldehyde in the presence of a catalyst to obtain the desired product, neopentyl glycol, without the by-product of sodium formate. It is.

Regarding this hydrogenation method, Japanese Patent Publication Nos.
3-17568, UK Patent No. 1219162, U.S. Patent No. 3,920,760
Nos., U.S. Patent No. 4021496, British Patent No. 1048530, European Patent No. 44412, and methods according to European Patent No. 44444 are known, and Raney Ni-based, Ni-Cr-based as a hydrogenation reaction catalyst, Cu-Zn system, Cu-Al system, Cu-Cr system,
And Cu-Cr-Ba series are disclosed.

However, these known catalysts do not have sufficient catalytic activity and must be reacted under high pressure conditions.
In addition, there is a problem that sufficient catalytic activity cannot be maintained for a long period of time due to the influence of trace impurities contained in the starting hydroxypivalaldehyde. In the case of Raney catalysts, in addition to the shortcomings in catalytic activity and sustainability, the preparation and handling of the catalyst are not easy, and the process is complicated due to use in the form of a slurry, which is not favorable in terms of process. Have various problems.

(Means for Solving the Problems) The present inventors have proposed a method for producing neopentyl glycol by hydrogenating hydroxypivalaldehyde,
As a result of intensive studies to solve the above-mentioned drawbacks, they have found that a catalyst comprising two elements of Pu-Pd has extremely excellent catalytic performance, and have completed the present invention.

That is, the present invention, in the presence of a Ru-Pd-based catalyst, a solvent such as water or methanol, or in the presence of a mixed solvent thereof,
Hydrogenation of hydroxypivalaldehyde obtained by condensing isobutyraldehyde and formaldehyde completes a method capable of stably producing neopentyl glycol at a high yield.

 Hereinafter, the present invention will be described in more detail.

The hydroxypivalaldehyde used in the present invention is
It can be easily obtained by an aldol condensation reaction between isobutyraldehyde and formaldehyde in the presence of a basic catalyst.

For example, the charged molar ratio of isobutyraldehyde to formaldehyde is 0.8 to 1.3 times mol, preferably 1.1 to 1.
To 1.2-fold molar and in the presence of a tertiary amine catalyst such as trimethylamine or triethylamine at 15 to 95 ° C.
The hydroxypivalaldehyde can be obtained by a method of conducting a condensation reaction at 15 to 40 ° C. in the presence of a strong alkali catalyst such as caustic soda.

Next, as the raw material hydroxypivalaldehyde used in the method of the present invention, the unreacted isobutyraldehyde and formaldehyde are removed from the above-mentioned aldol condensation reaction product solution, or the reaction product solution is used if impurities are below an allowable amount. As is applied. Alternatively, after the former treatment, a dimer of hydroxypivalaldehyde can be once crystallized in water and used as a raw material. Since this dimer takes part in the reaction as a hydroxypivalaldehyde monomer during the hydrogenation reaction, it has no problem at all and is applicable to the method of the present invention.

In carrying out the method of the present invention, an appropriate amount of water with respect to the above-mentioned hydroxypivalaldehyde, or a raw material liquid prepared by using water and alcohol as a solvent is prepared, and then Ru-Pd
The hydrogenation reaction is carried out in the presence of a system-based catalyst. The unreacted isobutyraldehyde, formaldehyde, tertiary amine and amine compounds derived therefrom, sodium formate, etc. contained in the raw material liquid are used. The amount of impurities is allowed up to 5 wt%.

When a dimer of pivalaldehyde obtained by crystallization from an aldol condensation reaction solution of isobutyraldehyde and formaldehyde is used as a raw material, it is preferable to dissolve it in a solvent. Are preferably used. When water and methanol are mixed to form a solvent, both can be mixed and used at an arbitrary ratio.

The catalyst according to the present invention is a catalyst obtained by combining two Ru-Pd elements, and exhibits a remarkable effect. That is, by using the catalyst of the present invention, Ru-based, or
All of the problems of unsatisfactory catalytic activity and life which are found in a Pd-based single catalyst, a Ru-based catalyst, or a Pd-based catalyst in which other elements are combined are eliminated.

The Ru-Pd two-element combination catalyst of the present invention is effective when both are present even in trace amounts to each other.However, as a recommended catalyst composition, when represented by a combination ratio of Ru and Pd, Weight ratio in the range of 99: 1 to 1:99, preferably 90: 1
It ranges from 10 to 10 to 90.

As the catalyst raw material in the present invention, for each such element, chlorides, nitrates, sulfates, carbonates and other inorganic hydrochloric acid, oxides and hydroxides, various organic acid salts, oxyacid salts, and carbonyl compounds and various complexes Etc. are used.

As a catalyst preparation method in the present invention, in the final use form, satisfy the combination and atomic ratio of the elements of the present invention,
In addition, any method can be adopted as long as it is in a form that can withstand use, and a catalyst carrier may or may not be used.

Next, as an example of the catalyst preparation method of the present invention, a simple supported catalyst preparation method will be described.

For example, a mixed aqueous solution in which ruthenium trichloride and palladium chloride are previously dissolved in a predetermined ratio is added to the catalyst carrier, and the mixture is heated under reduced pressure, and water is evaporated while stirring. Then, 12
After drying at a temperature of about 0 ° C., the catalyst can be prepared by calcining at the decomposition temperature of the salts used.

The carrier used in the catalyst of the present invention is silica, alumina, silica alumina, zeolite, magnesium oxide,
They are titanium oxide, zirconium oxide, diatomaceous earth, activated carbon, silicon carbide, and the like, and are not particularly limited as long as they are used as ordinary catalyst carriers.

The supported amount of the catalyst components Ru and Pd of the present invention on the catalyst carrier,
Depending on the type of carrier, each metal should be 0.01 to 20 wt.
%, Preferably in the range of 0.1 to 5% by weight.

As a method for supporting each component of the catalyst of the present invention, any method such as a method of simultaneously supporting each component on a carrier to be used or a method of sequentially supporting each component can be used.
Also, depending on the type of compound used regardless of the presence or absence of a catalyst carrier, the mixed aqueous solution is neutralized with an appropriate acid or base to precipitate a mixed metal salt, and the precipitate is filtered, washed, dried, and then dried. When an insoluble compound is used, a method in which the two components of the catalyst of the present invention are formed into a uniform slurry or kneaded to form a paste and then dried and calcined may be employed. it can.

The form of use of the catalyst according to the present invention can be appropriately selected and used, such as powder, extruded product, compression-molded tablet, or crushed product having an appropriate size.
Further, as a reaction system, any system such as a fixed bed and a fluidized bed can be adopted.

Further, the catalyst of the present invention is reduced with a reducing gas such as hydrogen,
After activation, it is applied to the hydrogenation reaction.

 The method of the present invention will be described in more detail below.

Alcohols such as water and methanol as reaction solvents,
And the amount of these mixtures used is 10 to 80% by weight as raw material hydroxypivalaldehyde concentration, preferably 15 to 60% by weight.
% By weight.

If the concentration is lower than this, it is difficult to separate the formed neopentyl glycol from the solvent, and the energy burden for evaporation and dehydration is large. This reaction is not industrially feasible because of the occurrence of the Tyshenko reaction, and by-produced neopentyl glycol hydroxypivalate.

When carrying out the method of the present invention, in the presence of hydrogen, a Ru-Pd-based catalyst is dispersed in a hydroxypivalaldehyde raw material liquid using a solvent selected from water, alcohols such as methanol, and a mixture thereof. Or suspended,
Alternatively, a hydrogenation reaction of hydroxypivalaldehyde to obtain neopentyl glycol is performed by a method of supplying a raw material liquid to a column filled with the catalyst.

The hydrogenation reaction can be performed by either a continuous method or a batch method.

The reaction temperature ranges from 60 to 200 ° C, preferably from 80 to 150 ° C.

The reaction pressure is 1 to 150 kg / cm ² , preferably 5 to 80 kg / cm 2
^2. The pressure in the reaction system is maintained by introducing hydrogen.

In the method of the present invention, the reaction proceeds even outside the above-mentioned condition range, but can be sufficiently achieved within this range.

Separation and recovery of the target product neopentyl glycol from the reaction product solution is performed by applying a distillation method, a solvent extraction method, or the like after the reaction.

(Effect of the Invention) According to the method of the present invention, in a method for producing neopentyl glycol by hydrogenating hydroxypivalaldehyde, sufficient catalytic activity and selectivity are exhibited by using a Ru-Pd-based catalyst, The industrial significance is extremely large in that a stable long-life catalyst can be realized.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited by these Examples.

In Examples and Comparative Examples, hydroxypivalaldehyde, neopentyl glycol, isobutyraldehyde, triethylamine, and hydroxypivalic acid neopentyl glycol ester were respectively HPA, NPG, IBA, TE
A, and abbreviated as HPNE.

Examples 1 to 10 A stainless steel autoclave having an internal volume of 100 ml was charged with HPA powder, or a 25 wt% solution of HPA, or an aldol condensate and a catalyst, the inside of the autoclave was replaced with hydrogen gas, and hydrogen gas was introduced to a predetermined pressure. . The autoclave was placed on a shaking table, heated, and reacted at a predetermined temperature. After completion of the reaction, the autoclave was cooled, and after purging the residual pressure, the reaction solution was analyzed by gas chromatography.

The aldol condensate is prepared by reacting 37% formalin aqueous solution with IBA and triethylamine, and adding pure water to HPA.
The concentration was adjusted to 25 wt%. Other components are IBA 0.3wt%,
TEA 0.8wt%, methanol 1.3wt%, water 68.5wt%, NPNE0.9
% Wt%, NPG 1.1 wt% and other 2.1 wt%. Table 1, Table 2 and Table 3 show the reaction conditions and results of each Example.
It was shown to.

Example 11 In a stainless steel single-tube reactor, 0.7% Ru-
The catalyst was loaded with 150 ml of 0.3% Pd-supported catalyst, the raw material HPA solution and hydrogen were continuously introduced, and a flow reaction was carried out for 30 days. material
HPA was supplied as a 25 wt% solution (water: methanol = 1: 1.6 weight ratio). Table 4 shows the reaction conditions and results. As a result, it became clear that high activity can be maintained for a long period of time.

Comparative Examples 1 to 3 Crushed activated carbon carrying 0.5% Pd as catalyst, Ru 5%
The reaction was carried out in the same manner as in Example 1 except that an alumina powder supporting the compound and activated carbon powder supporting 1% of Ru were used. Table 5 shows the reaction conditions and results of each comparative example.

Claims (1)

(57) [Claims] 1. A method for producing neopentyl glycol, which comprises using a catalyst comprising a combination of two elements, ruthenium and palladium, in synthesizing neopentyl glycol by hydrogenating hydroxypivalaldehyde.