JPS61130252A - Production of formaldehyde - Google Patents

Abstract

PURPOSE:To produce formaldehyde extremely stably in a gaseous phase in high yield, by dehydrogenating methanol in the absence of oxygen by the use of a catalyst consisting of zinc and synthetic mica. CONSTITUTION:In producing formaldehyde by dehydrogenating methanol in the absence of oxygen in a gaseous-phase flow reaction, a synthetic mica (especially preferably sodium teterasilicic mica, sodium taeniolite, or lithium taeniolite) shown by the formula (W is cation having 12 coordination number; X and Y are cations with 6 coordination number, and Z is cation with 4 coordination number) whose interlaminar W is subjected to ion exchange with zinc ion is used as a catayst. The catalyst subjected to ion exchange may be directly used, preferably it is calcined at 400-800 deg.C in air or in nitrogen air and used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing υ formaldehyde by dehydrogenating methanol-μ in a gas phase flow reaction.

More specifically, it relates to a method for producing formaldehyde characterized by using a catalyst consisting of zinc and synthetic mica. General industrial methods for producing formaldehyde include catalytic oxidative dehydrogenation using a silver catalyst or iron oxide Catalytic oxidation methods using mixtures of molybdenum oxides as catalysts are known, and in these methods formaldehyde is usually obtained as an aqueous solution. The former uses a large amount of expensive silver as a catalyst, and the reaction takes place at a high temperature of 650°C to 720°C, and is extremely sensitive to trace amounts of metals such as halogen and sulfur in the raw methanol. Because of this, it is necessary to sufficiently purify the raw material methanol, and it also has disadvantages such as the need to mix in a large amount of water vapor to extend the catalyst life. Also, in the latter case, the reaction temperature is 350 to 450 °C. Although it is low, a large excess of air and methanol vapor must be brought into contact and deliberately distributed, requiring a large investment in equipment and energy costs, and is likely to produce water and formic acid as by-products. The waste gas cannot be used as fuel and has disadvantages such as requiring special treatment. In order to recover formaldehyde as a concentrated formaldehyde aqueous solution, formaldehyde is used in the production of major industrial applications such as polyacetal resin, urea resin, and phenolformaldehyde resin.
The reality is that it requires processes such as processing and refining, resulting in a large amount of energy loss.

On the other hand, a so-called formaldehyde method using methanol dehydrogenation has been proposed. For example, a method using a catalyst consisting of copper, silver, and silicon (Japanese Patent Publication No. 41-11859),
Method using molten zinc, gallium, indium or aluminum or alloys thereof
49251), a method of contacting carbon-containing molten zinc or a mixture containing zinc and lead (Japanese Patent Application Laid-open No. 48
-97808) have been proposed. However, these methods have various drawbacks such as short catalyst life and low reaction rate, and are not satisfactory as industrial production methods. Furthermore, a method using a catalyst consisting of copper, zinc, and sulfur (Japanese Unexamined Patent Publication No. 51-4407) and a method using a catalyst consisting of copper, zinc, or copper, zinc, and sulfur are used to dehydrogenate methanol while supplying a gaseous sulfur compound. The method (Japanese Unexamined Patent Publication No. 51-76209) involves the mixing of sulfur into the reaction products or the exhaust gas, which causes various industrial problems.To improve this, a catalyst consisting of copper, zinc, and selenium is used. A mochiru method (Japanese Unexamined Patent Publication No. 52-215) has also been proposed, but it is still unsatisfactory industrially in terms of catalyst life and selectivity. The present inventor has conducted extensive research to improve these problems. As a result of repeated research, they discovered that formaldehyde can be obtained in high yield and in an extremely stable manner by dehydrogenation of methanol by using a catalyst found in zinc and synthetic mica, leading to the completion of the present invention. 0 The main component of the synthetic mica used in the present invention is an oxide (for example, a Sin4 tetrahedron) of a cation (2) with a coordination number of 4.
Mica crystals are based on regular tetrahedrons, and these tetrahedrons are connected in a hexagonal network plate shape. Between the upper and lower layers are cations with a coordination number of 6 (X
, Y) (e.g., kl'', Fe'', Mg'+, etc.) are ionically bonded. , These are layered. Between the tablets, cations with a coordination number of 12 called interlayer ion light, such as alkali metal or alkaline earth metal ions, are surrounded by oxygen and form a very weak bond. In other words, the synthetic mica used in the present invention is represented by -2: a cation with a coordination number of 4, 0: oxygen, and F: fluorine. , for example, “Na”.

K”, Ca”, Ba”, Rh”・Sr2
+, etc., as X and Y, for example, Mg, Fe
, Ni + Mn + AJ + Fe”+
, Li+, etc. 2 is, for example (A71", Si"
).

Si4+, Ga4+, A! 3+, p+
Examples include e3+ and B3+.

Specifically, these synthetic mica include fluorine phlogopite [KM
g3(AJSi30,o)F2), Potassium tetrasilicic mica (KMg.(st*o+.)F2) Na tetrasilicic mica [NaMg2.5(Si
4016)F2]Na teniolite [Na
Mg2L1 (S140+o) FJLi Taeniolite
(r,iMg2Li (S i40+o)F
z) Na hectorite [Na+Mg,;,
Lf, (Si401.)F2] ■ Li67 gates” [Li, Mg 24 Li4 (
Si・0...)F・] and so on. Among these synthetic micas, Na tetrasilicic mica 3 & teniolite, L
1. Taeniolite is particularly suitable in the present invention. 0. The catalyst used in the present invention can be prepared by any of the known ion exchange methods. Among them, zinc chloride is preferably added to a suspension of purified Na tetrasilisilisili7 quack squid.

Zinc nitrate, zinc acetate, zinc oxalate. An aqueous solution of a divalent zinc salt such as zinc formate or zinc sulfate is prepared and added, or preferably 1 mol to 20 mol of zinc is added. After that, the solid phase is filtered, washed thoroughly with water, repeated filtration, and finally Dry at appropriate temperature.

Although the obtained powder may be used as a catalyst as it is in the present invention, it is preferable to perform a calcination treatment in air or nitrogen stream at a temperature of 400'C to 400'C.

The reaction of the present invention is usually preferably carried out in a fixed bed gas phase flow system. Regarding the reaction conditions, the catalyst layer temperature is usually 45
0-650℃, right? , 500C to 600C are suitable.

Further, methanol is usually supplied to the catalyst layer in vapor form together with an inert gas or hydrogen using a vaporizer or the like. The amount of methanol supplied depends on the size, shape, etc. of the reactor, but the appropriate amount is 1 to 1007 p/hour per catalyst.If it is less than 0.17 p/hour, it is not practical and it is 1007 p/hour. If the methanol reaction rate is exceeded, the reaction rate of methanol decreases.

The product obtained according to the invention is formaldehyde 5w
t% or more, water θ˜1 wt− and the remaining methanol, the water content in the product is extremely small, and formadehyde can be obtained in high yield. Furthermore, since hydrogen can be obtained in high yield through the reaction, the off-gas from the reaction can also be effectively used as a heat source or other raw materials.

The catalyst of the present invention has a high reaction rate of methanol and an extremely high yield, and the activity of the catalyst that can obtain form μdehyde is sustained for more than 10 hours, and there is no deposition on the carbonaceous catalyst. Almost never seen. Another major feature is that the blocking phenomenon caused by fusion between catalyst pellets, which tends to occur in copper-based catalysts, does not occur at all. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these. isn't it.

Examples 1-5. Comparative Example 1 (1) Catalyst Preparation Method Catalyst A Zinc nitrate (Zn(NO3)! ・6H20) 15.0
7 F was dissolved in 200 mA pure water and 26 ml of 28 thiammonium water was added thereto to obtain solution A. On the other hand, sodium tetrasilisili 7 quaika (NaMg 2.5 (S
1.81 g of pure water is added to 200f of a 10 wt% aqueous sol solution of k40B(1)F2) and mixed, and the mixture is heated and mixed in a 40°C water bath to obtain liquid B. A to this B liquid
Add the liquid and continue heating and stirring at 40°C for 90 minutes. Thereafter, the mixed liquid was filtered and further washed with pure water, which was repeated three times, and the obtained solid was dried in an oven at 150°C for 20 hours, and then calcined at 600°C in a stream of air for 5 hours. The BIT surface area of catalyst A thus obtained was 13.2 m
'/r, Zn content is 14. It was Owt%.

Catalyst B Zinc nitrate (Zn(No3)2.6H20) 7.58f
was dissolved in 200 mJ of pure water, and 13 ml of 28 thiammonia water was added thereto to obtain Solution D. Add solution D to solution B, which has the same recipe as that used when preparing catalyst A, and continue heating and stirring at 40°C for 90 minutes. After that, the mixed liquid was filtered and further washed with pure water, which was repeated three times, and the obtained solid was dried in an oven at 150°C for 20 hours, and then calcined at 600°C for 5 hours in an air stream. ◇The BET surface area of the catalytic IIeB thus obtained is 8.8 rl, yy, Z
The n content was 7.8 wt.

Catalyst C Zinc nitrate (Zn (No, )2'6 H2O)
1. Dissolve 22.6 Of in 200 mjl of pure water. Add 89 mJ of 28 thiammonia water to this to obtain Solution D.

Add D to solution B of the same formulation used when preparing catalyst A.
Add the liquid and continue heating and stirring at 40°C for 90 minutes.

After that, the mixed liquid was filtered and further washed with pure water, which was repeated 8 times, and the obtained solid was dried in an oven at 150°C for 20 hours, and then calcined at 600°C for 5 hours in an air stream. .

Catalyst B thus obtained had a BIT surface area of 17.2 f and a Zn content of 18.9 wt.

Touch! JE, D Zinc nitrate (Zn(NO3)z ・6H20) 15.0
7t was dissolved in 200 mj of pure water to obtain liquid E. Catalyst A
Add solution E to solution B, which has the same formulation as that used when preparing , and continue heating and stirring at 40°C for 90 minutes. After that, the process of filtering this mixture and washing with pure water was repeated three times.
The obtained solid material was dried in an open air at 150°C for 20 hours, and then calcined at 600°C for 5 hours in an air stream. The BET surface area of the touch HD thus obtained is 1o, 5rr?
It, Zn content was 2.5 vt%.

Catalyst E Dissolve 8.5f of zinc chloride (ZnCJt) in 200mJO pure water and add 18ml of 1f:m of 28 thiammonia water to obtain pg0 Add solution F to solution B of the same formulation as used when preparing catalyst A. Add and continue heating and stirring at 40C for 90 minutes. Thereafter, the mixed solution was filtered and further washed with pure water, which was repeated eight times. The resulting solid was dried in an oven at 150°C for 20 hours, and then calcined at 600°C for 5 hours in an air stream. BIDT of the thus obtained tactile E.
Surface area is 9.1 m”/S', Zn content is 7.1
It was wt Chi.

Catalyst F silver nitrate (*fNo, ) 8.61 y was dissolved in 200 mJ of pure water, and 18 mA of 28 thiammonium water was added thereto to obtain liquid G. Add Solution G to Solution B, which has the same recipe as that used when preparing Catalyst A, and continue heating and stirring at 40C for 90 minutes. Thereafter, the mixed liquid was filtered and further washed with pure water three times, and the resulting solid was dried in an open air at 150° C. for 20 hours, and then calcined at 600° C. for 5 hours in an air stream. The catalyst FOT3ET thus obtained
The surface area was 18.1 m"zT.

Touch KG Cupric chloride (CuCJ*) 6.81t to 200m
Dissolve in pure water of J, add 26 m of 28 thiammonia
1 to obtain solution H. Add B solution 4CH solution having the same formulation as that used when preparing catalyst A, and continue heating and stirring at 40° C. for 90 minutes. After that, the operation of filtering this mixed liquid and washing with pure water was repeated three times, and the resulting solid matter was
After drying for 20 hours in the open at 0, dry in the air stream for 6
The catalyst G thus obtained was calcined at 00°C for 5 hours.
The BET surface area of was 18.4 yl, yy.

Catalyst H Cuprous chloride (CuCJ) 5.1Of200mjt
Dissolve in pure water and add 26 mal of 28% ammonia water to this.
t, to obtain solution I. Add the working solution to Solution B, which has the same recipe as that used when preparing Catalyst A, and continue heating and stirring at 40°C for 90 minutes. After that, this mixed liquid was filtered, and the operation of washing with pure water was repeated three times.
After drying for 20 hours in the open at 0°C, dry in an air stream for 6 hours.
Firing was performed at 00°C for 5 hours. Catalyst H thus obtained
The BUT surface area of is L8. Om? Met.

The preparation method of A-H was described above, and the prepared catalyst was molded to a particle size of 24 to 48 mesh and then stored in a desiccator.

In addition, the specific surface area was measured using Monosoap (manufactured by Quantachrome) after dehydration treatment at 200°C for 80 minutes in a nitrogen stream.On the other hand, the amount of Zn component in the catalyst (w t *) 0 (2) Catalytic reaction test catalyst 2. was measured by atomic absorption spectrometry. Of is charged into a quartz tube reactor having an inner diameter of 10%. A mixed gas of methanol and nitrogen (CH, OH/N,
= 18/82 molar ratio) was allowed to flow at 550 mmoJ/hr under conditions of normal pressure and a methanol dehydrogenation reaction was carried out at a lung temperature of 550°C.

The outlet gas of the reactor was collected using a gas sampler that was kept warm as it was.
The reaction product, formaldehyde [HCHO], was introduced into a thermal conductivity type gas chromatograph using a Gas Chromo Kogyo Co., Ltd. If column 3 m and a Molecular Sieve 13X column 2 m').

Methyl formate, dimethyl ether [DME], hydrogen [H4
F, -carbon oxide [CO3, methane [CH4] and unreacted methanol [outlet CM30H'l], nitrogen analysis fixed lid was performed.

The reaction results are shown in Table 1, and the values after the reaction was maintained for 8 to 12 hours after reaching the set temperature showed stable activity. Analysis by gas chromatography showed that almost no methyl dimethyl ether formate was produced.

Therefore, the conversion rate, yield, and selectivity were calculated using the following formula.

Claims (1)

[Claims] In a method for producing formaldehyde in a gas phase by dehydrogenating methanol in the absence of oxygen, the general formula W_1_/_3 to_1(X,Y)_2_. _5～_3(
Z_4O_1_0)F_2 (W represents a cation with a coordination number of 12, X and Y represent a cation with a coordination number of 6, and Z represents a cation with a coordination number of 4). A method for producing formaldehyde characterized by using a catalyst obtained by ion exchange with zinc ions.