JPH0710801A - Production of alpha, beta-unsaturated carboxylic acid - Google Patents

Abstract

PURPOSE:To produce an alpha, beta-unsaturated carboxylic acid in high yield by adding steam to a raw material gas in catalytically oxidizing an aliphatic saturated hydrocarbon in vapor phase in the presence of a compound metal oxide catalyst. CONSTITUTION:In producing an alpha, beta-unsaturated carboxylic acid by catalytically oxidinzing a 3-8C aliphatic saturated hydrocarbon in a vapor phase in the presence of a compound metal oxide catalyst, a gas comprising an aliphatic saturated hydrocarbon, steam and an oxygen-containing gas in the molar ratio of hydrocarbon:oxygen:a diluting gas:H2O=1:(0.1-10.0):0-20:(0.2-70) is used as a raw material gas and one or more of (i) Mo, V, Te, >=1 kind metal selected from among X<1> and oxygen, (ii) Bi, No, >=1 kind metal selected from among X<2> and oxygen, (iii) V, >=1 kind metal selected from among X<3> and oxygen and (ir)Fe, >=1 kind metal selected from among X<4> and oxygen as essential components are used as the compound metal oxide catalyst. Especially the component (i) is preferable. X<1>:Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rk, Ni, Pd, Pt, Sb, Bi, B, In, Cs;X<2>: V, Nb, Tl, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, P, B, Pb, Ga, In, Ce, Li, Na, K, Rb, Cs, Tl, Cu, Ag; X<3>: Fe, Sb, P, Li, Na, K, Rb, Cs, W, Ti, Al, Zr, Sn, Ge, In; X<4>: Sb, P, Cr, Ti, Mo, Al, Zr, Sn, Ge, In.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an α, β-unsaturated carboxylic acid by subjecting an aliphatic saturated hydrocarbon having 3 to 8 carbon atoms to a gas phase catalytic oxidation.

[0002]

2. Description of the Related Art For example, α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid are used in various synthetic resins, paints,
It is industrially important as a raw material for plasticizers. Carbon number 3
Among the 8 α, β-unsaturated carboxylic acids, the industrially important method for producing acrylic acid and methacrylic acid will be described in detail below. As a method for producing acrylic acid and methacrylic acid, a method in which an olefin such as propylene or isobutene is catalytically reacted with oxygen in the gas phase at high temperature in the presence of a catalyst is conventionally known as the most general method.

On the other hand, due to the price difference between propane and propylene or the price difference between isobutane and isobutene, an aliphatic saturated hydrocarbon such as propane and isobutane is used as a starting material in the presence of a catalyst. There is an increasing interest in developing a method for producing acrylic acid, methacrylic acid, etc. in a single step by a gas phase catalytic oxidation reaction. As an example of a report for producing acrylic acid in a single step by subjecting propane to a gas phase catalytic oxidation reaction, a Mo—Sb—P—O catalyst (European Patent No. 0
010902), VP-Te-O based catalyst (J
annual of Catalysis, vol. 1
01, p389 (1986)), a Bi-Mo-O-based catalyst and / or a VP-Te-O-based catalyst (JP-A-3-1-1).
No. 70445), on the other hand, a P-Mo-O catalyst (JP-A-63-145249) is known as an example of a report of producing methacrylic acid in a single step by subjecting isobutane to a gas phase catalytic oxidation reaction. Are known.

[0004]

However, none of these methods is sufficiently satisfactory in the yield of the desired α, β-unsaturated carboxylic acid, and the reaction system is complicated. It has drawbacks.

[0005]

The present inventors have found that the number of carbon atoms is 3
As a result of various studies on a method for producing an unsaturated carboxylic acid using 8 to 8 aliphatic saturated hydrocarbons as a raw material, in the presence of a composite metal oxide catalyst composed of a certain metal, the number of carbon atoms is 3 to 8
When vapor-phase catalytic oxidation reaction of a single aliphatic saturated hydrocarbon, for example, a lower alkane such as propane, n-butane, and isobutane, is carried out by adding water vapor to the raw material gas, the yield is significantly higher than the conventional method. The present invention has been accomplished by finding that an α, β-unsaturated carboxylic acid having the following formula can be produced.

That is, the gist of the present invention is to subject an aliphatic saturated hydrocarbon having 3 to 8 carbon atoms to a gas phase catalytic oxidation reaction in the presence of a complex metal oxide catalyst to obtain an α, β-unsaturated carboxylic acid. In the method for producing an acid, the complex metal oxide catalyst contains at least one complex metal oxide selected from the following 1) to 4), the above-mentioned saturated aliphatic hydrocarbon, steam and oxygen content as a raw material gas. Using a gas containing gas, and the composition mole fraction of the raw material gas,

[0007]

[6] (aliphatic saturated hydrocarbon) :( oxygen) :( diluting _{gas) :( H 2 O) = 1} : (0.1~10.0) :( 0~
20): (0.2 to 70), which is a method for producing an α, β-unsaturated carboxylic acid. 1) Mo, V, Te, X ¹ and oxygen as essential components (provided that X ¹ is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel,
Palladium, platinum, antimony, bismuth, boron, indium and cerium one or more elements selected from the group consisting of), the proportion of each essential component relative to the total of the above essential components except oxygen, the following formula,

[0008]

0.25 <r _Mo <0.98 0.003 <r _V <0.5 0.003 <r _Te <0.5 0.003 <r _X1 <0.5 (where r _Mo , r _V , r _Te, and r _X1 are Mo, V, and T with respect to the total number of moles of the above essential components except oxygen, respectively.
(representing the mole fraction of e and X ¹ ). 2) Bi, Mo, X ² and oxygen as essential components (provided that X ² is vanadium, niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium,
Manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, phosphorus, boron,
Lead, gallium, indium, cerium, lithium, sodium, potassium, rubidium, cesium, thallium,
Representing one or more elements selected from the group consisting of copper and silver), the proportion of each essential component relative to the total of the above essential components excluding oxygen is calculated by the following formula:

[0009]

0.25 <s _Bi <0.83 0.09 <s _Mo <0.66 0.005 <s _X2 <0.59 (where s _Bi , s _Mo , and s _X2 are oxygen, respectively) Except for the total number of moles of the above essential components, Bi, Mo and X ²
Represents the molar fraction of). 3) V, X ³ and oxygen are essential components (provided that X ³ is
Represents one or more elements selected from the group consisting of iron, antimony, phosphorus, lithium, sodium, potassium, rubidium, cesium, tungsten, titanium, aluminum, zirconium, tin, germanium and indium), and the above essential except oxygen The existence ratio of each essential component to the total of the components is the following formula,

[0010]

[Equation 9] 0.23 <t _V <1.00 <t _X3 <0.77 (where t _V and t _X3 are the mole fractions of V and X ³ with respect to the total moles of the above essential components excluding oxygen, respectively) (Representing the ratio). 4) Fe, X ⁴ and oxygen as essential components (provided that X is
⁴ represents one or more elements selected from the group consisting of antimony, phosphorus, chromium, titanium, molybdenum, aluminum, zirconium, tin, germanium and indium), and each essential component relative to the total of the above essential components except oxygen. The existence ratio of

[0011]

[Equation 10] 0.23 <u _Fe <1.00 <u _X4 <0.77 (where u _Fe and u _X4 are the mole fractions of Fe and X ⁴ with respect to the total moles of the above essential components excluding oxygen, respectively) (Representing the ratio).

The present invention will be described in detail below. The mixed metal oxide catalyst used in the present invention may include various kinds of mixed metal oxides as described above, and the mixed metal oxide preferably contains Mo, V, Te, X ¹ and oxygen. As an essential component (provided that X ¹ is selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium and cerium. Which represents one or more elements selected from the group consisting of:

[0013]

0.25 <r _Mo <0.98 0.003 <r _V <0.5 0.003 <r _Te <0.5 0.003 <r _X1 <0.5 (where r _Mo , r _V , r _Te, and r _X1 are Mo, V, and T with respect to the total number of moles of the above essential components except oxygen, respectively.
e and represents the mole fraction of X ¹ ). X ¹ is Nb among the above elements,
Ta, W and Ti are preferable, and Nb is more preferable. The mole fraction of the above essential components is usually in the above range, but X
^When Nb is used as ¹ , the range shown below is particularly preferable.

[0014]

[Formula 12] 0.35 <r _Mo <0.87 0.045 <r _V <0.37 0.020 <r _Te <0.27 0.005 <r _Nb <0.35 Further, Mo, V, Among the composite metal oxides having the above-mentioned specific compositions containing Te, X ¹ and oxygen as essential components, those having a specific crystal structure are particularly preferable. Specifically, the X-ray diffraction peak of the composite metal oxide (Cu-
The following five major diffraction peaks are observed at a specific diffraction angle 2θ as a pattern (using Kα ray).

[0015]

[Table 2] X-ray face plane ────────────────────────────── Diffraction angle 2θ (± 0.3 °) interval Median value (Å) Relative intensity 22.1 ° 4.02 100 28.2 ° 3.16 20-150 36.2 ° 2.48 5-60 45.2 ° 2.00 2-40 50.0 ° 1 The .82 2-40 X-ray diffraction peak intensity may deviate depending on the measurement conditions of each crystal, but a peak intensity of 2θ = 22.1 ° is 100.
The relative intensity in the case of is usually in the above range. Also,
In general, peak strengths of 2θ = 22.1 ° and 28.2 ° are largely expressed.

Mo, V, and T which are particularly preferable as the catalyst composition
The method for preparing the composite metal oxide composed of e and Nb is usually as follows. For example, Mo case of _{a V b Te c Nb x O} n, to an aqueous solution containing a predetermined amount of ammonium metavanadate salt, an aqueous solution of telluric acid, an aqueous solution of ammonium niobium oxalate salt and a solution or slurry of ammonium paramolybdate salt - Are sequentially added in an amount ratio such that the atomic ratio of each metal element becomes a predetermined ratio, dried by evaporation dryness method, spray drying method, vacuum drying method, etc., and finally, the remaining dried product is usually dried. 350-700 ° C, preferably 400-65
At a temperature of 0 ° C., usually 0.5 to 30 hours, preferably 1 to
It is baked for 10 hours to obtain the desired mixed metal oxide.

The firing treatment method is most commonly performed in an oxygen atmosphere, but the firing atmosphere is preferably in the absence of oxygen. Specifically, it is carried out in an atmosphere of an inert gas such as nitrogen, argon or helium, or in vacuum. The raw materials of the above-mentioned composite metal oxide are not limited to those described above, but may be, for example, MoO ₃ , V ₂ O ₅ , V ₂ O ₃ , TeO ₂ , Nb.
₂ O ₅ and other oxides, MoCl ₅ , VCl ₄ , VOCl ₃
, NbCl ₅ and other halides or oxyhalides, Mo (OC ₂ H ₅ ) ₅ , Nb (OC ₂ H ₅ ) ₅ , V
O (OC ₂ H ₅ ) ₃ , alkoxides such as molybdenum acetylacetonate, and organometallic compounds can be widely used.

The composite metal oxide thus obtained can be used alone as a solid catalyst, but it can also be used together with a well-known carrier such as silica, alumina, titania, aluminosilicate, diatomaceous earth or zirconia. . The method of the present invention, by including steam in the raw material gas in the oxidation reaction of the aliphatic saturated hydrocarbon,
This is a method of obtaining an α, β-unsaturated carboxylic acid with high selectivity.

The aliphatic saturated hydrocarbon as a raw material has a carbon number of 3 to
Although eight of them are used, the purity is not particularly limited, and no problem occurs even if a lower alkane such as methane or ethane and / or an aliphatic saturated hydrocarbon containing air, carbon dioxide or the like is used as an impurity. Absent. Further, it may be a mixture of the above-mentioned aliphatic saturated hydrocarbons having 3 to 8 carbon atoms.

Although the details of the mechanism of the oxidation reaction in the present invention are not clear, it is carried out by oxygen atoms present in the above oxides or molecular oxygen present in the feed gas. When molecular oxygen is present in the feed gas, the molecular oxygen may be pure oxygen gas, but since purity is not particularly required, it is common to use an oxygen-containing gas such as air, which is economically advantageous. is there. As the feed gas for the reaction system, a mixed gas of an aliphatic saturated hydrocarbon containing water vapor and an oxygen-containing gas is usually used, but an aliphatic saturated hydrocarbon containing water vapor and an oxygen-containing gas are alternately used in the reaction system. May be supplied to. The steam to be used may exist as steam gas in the reaction system, and its introduction form is not particularly limited.

The reaction system of the present invention may employ either a fixed bed or a fluidized bed, but the reaction temperature is easier to control in the fluidized bed system because it is an exothermic reaction. In addition, this reaction is usually carried out under atmospheric pressure, but it can also be carried out under low pressure or under reduced pressure. It is also possible to carry out a gas phase catalytic reaction with the saturated aliphatic hydrocarbon, steam and, if necessary, a diluent gas as feed gases in the presence of a stoichiometric amount or less of molecular oxygen. In such a case, it is preferable that a part of the catalyst is appropriately withdrawn from the reaction zone, the catalyst is fed into an oxidation regenerator, and after regeneration, the catalyst is re-supplied to the reaction zone. Examples of the catalyst regeneration method include oxygen, air,
Oxidizing gas such as nitric oxide to the catalyst in the regenerator,
Usually, a method of circulating at 300 to 600 ° C can be mentioned.

The case where propane is used as the saturated aliphatic hydrocarbon in the present invention will be described in more detail below. The mole fraction of the source gas is

[0023]

[Formula 13] (Propane): (Oxygen): (Diluting gas):
(H ₂ O) = 1: (0.1-10.0) :( 0-2
0): (0.2 to 70), particularly preferably,

[0024]

## EQU14 ## 1: (1 to 5.0): (0 to 10): (5 to 40). When steam is supplied to the raw material, nitrogen, argon, which was added for the purpose of diluting the raw material in the conventional technology,
Unlike the supply of helium or the like, the selectivity of acrylic acid is obviously improved, and acrylic acid can be obtained in high yield from propane simply by bringing it into contact with a single catalyst layer. However, an inert gas such as nitrogen, argon, or helium may be used together as a diluent gas for adjusting the space velocity, the oxygen partial pressure, and the water vapor partial pressure.

The reaction is usually carried out at 200 to 550 ° C, particularly preferably at 350 to 440 ° C. The gas space velocity SV in the gas phase reaction is usually 100
To 10,000 hr ^-1 , preferably 300 to 6000 hr
It is in the range of ^-1 . When the partial oxidation reaction is carried out by the method of the present invention, carbon monoxide, carbon dioxide, acetic acid and the like are by-produced in addition to acrylic acid, but the amount produced is extremely small.

Further, acrolein may be produced depending on the selection of reaction conditions. This may be carried out by the gas phase catalytic oxidation reaction again with the complex metal oxide catalyst described in the present invention, or by the known gas phase of unsaturated aldehyde. It can be easily converted into acrylic acid by carrying out the gas phase catalytic oxidation reaction again with the catalytic oxidation reaction catalyst. For other aliphatic saturated hydrocarbons, the composition of the feed gas and the reaction conditions can be selected according to the conditions for propane.

[0027]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. The conversion rate (%) and the selectivity rate (%) in the following examples
The yield (%) and the yield (%) are respectively represented by the following equations.

[0028]

## EQU15 ## Conversion (%) = (moles of saturated hydrocarbons consumed / moles of saturated hydrocarbons supplied) × 100 selectivity (%) = (moles of desired unsaturated carboxylic acid produced) / Mol of saturated hydrocarbon consumed) x (n /
m) × 100 Yield (%) = (moles of the target unsaturated carboxylic acid produced / moles of the saturated hydrocarbon fed) × (n / m)
× 100 However, m in the formula is the number of carbon atoms of the supplied saturated hydrocarbon, and n is the number of carbon atoms of the produced target unsaturated carboxylic acid.

Example 1 A composite metal oxide having the empirical formula Mo ₁ V _0.3 Te _0.23 Nb _0.12 O _n (n is determined by the oxidation states of other elements) was prepared as follows. Dissolving ammonium metavanadate (NH ₄ VO ₃₎ 15.7g hot water 325 ml, this telluric acid (H ₆ TeO ₆₎ 23.6g, ammonium paramolybdate _{((NH 4) 6 Mo 7} O 2 4 · 4H ₂ O) 7
8.9 g was added sequentially to prepare a uniform aqueous solution. Further, 117.5 g of an aqueous solution of ammonium niobium oxalate having a niobium concentration of 0.456 mol / kg was mixed to prepare a slurry. The slurry was heat-treated to remove water and obtain a solid. This solid was molded into a size of 5 mmφ × 3 mmL using a tablet molding machine and then crushed to obtain 16
The mixture was sieved to ˜28 mesh and baked in a nitrogen stream at 600 ° C. for 2 hours.

Powder X-ray diffraction measurement of the composite metal oxide thus obtained was performed (Cu-K as X-ray source).
α ray is used), 22.1 ° (10
0), 28.2 ° (57.3), 36.2 ° (16.
9), 45.1 ° (15.2), 50.0 ° (10.
A major diffraction peak was observed in 1) (the numbers in parentheses indicate relative peak intensities when the peak intensity at 22.1 ° is 100).

0.55 g of the catalyst thus obtained was charged into a reactor, the reaction temperature was 390 ° C., and the space velocity was SV1871.
Gas was supplied at a molar ratio of hr ⁻¹ and propane: air: H ₂ O = 1: 15: 14 to carry out a gas phase catalytic reaction. The results are shown in Table-1. Example 2 0.59 g of the catalyst obtained in Example 1 was charged into a reactor and gas was supplied at a reaction temperature of 380 ° C., a space velocity SV1439 hr ⁻¹ , and a molar ratio of propane: air: H ₂ O = 1: 15: 7. It was supplied and a gas phase catalytic reaction was carried out. The results are shown in Table-1.

Example 3 A reactor was charged with 0.55 g of the catalyst obtained in Example 1, the reaction temperature was 420 ° C., the space velocity was SV3247 hr ⁻¹ , and the molar ratio was propane: air: H ₂ O = 1: 15: 36. The gas was supplied to conduct a gas phase contact reaction. The results are shown in Table-1. Example 4 30 g of the catalyst obtained in Example 1 was ground in a mortar and the powder was dispersed in 100 ml of water to obtain an aqueous slurry. The powder solid was obtained by heat-treating this slurry.
This solid was molded into a size of 5 mmφ × 3 mmL using a tablet molding machine, crushed, sieved to 16 to 28 mesh, and fired at 600 ° C. for 2 hours in a nitrogen stream. The reactor thus obtained was charged with 0.61 g of the catalyst thus obtained, and the reaction temperature was 380 ° C.
Space velocity SV1861 hr ^-1 , propane: air: H ₂ O
Gas was supplied at a molar ratio of = 1: 15: 14 to carry out a gas phase catalytic reaction. The results are shown in Table-1.

Comparative Example 1 0.55 g of the catalyst obtained in Example 1 was charged into a reactor, and the gas was used at a reaction temperature of 390 ° C., a space velocity SV1871 hr ⁻¹ , and a molar ratio of propane: air: nitrogen = 1: 15: 14. Was supplied to carry out a gas phase catalytic reaction. The results are shown in Table-1.

[0034]

[Table 3] Example 5 0.5 g of the catalyst obtained in Example 1 was charged into a reactor, the reaction temperature was 410 ° C., the space velocity SV1900 hr ⁻¹ , n-butane:
Gas was supplied at a molar ratio of air: H ₂ O = 1: 24: 22 to carry out a gas phase catalytic reaction. The results are shown in Table-2.

Comparative Example 2 0.5 g of the catalyst obtained in Example 1 was charged in a reactor, gas was supplied at a space velocity SV of 1000 hr ⁻¹ and a molar ratio of n-butane: air = 1: 24 to carry out a gas phase catalytic reaction. I did. The results are shown in Table-2.

[0036]

[Table 4]

[0037]

According to the method of the present invention, the desired α, β-unsaturated carboxylic acid is produced in a high yield by a one-step method using an aliphatic saturated hydrocarbon having 3 to 8 carbon atoms as a raw material. be able to.

Claims (3)

[Claims] 1. A method for producing an α, β-unsaturated carboxylic acid by subjecting an aliphatic saturated hydrocarbon having 3 to 8 carbon atoms to a gas phase catalytic oxidation reaction in the presence of a complex metal oxide catalyst. The composite metal oxide catalyst contains at least one composite metal oxide selected from the following 1) to 4), and contains the above aliphatic saturated hydrocarbon as a raw material gas, steam and an oxygen-containing gas. The use and the composition mole fraction of the raw material gas are as follows: (aliphatic saturated hydrocarbon) :( oxygen) :( diluting gas) :( H ₂ O) = 1: (0.1-10 .0): (0 to
20): (0.2 to 70), A process for producing an α, β-unsaturated carboxylic acid. 1) Mo, V, Te, X ¹ and oxygen as essential components (provided that X ¹ is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel,
(Representing one or more elements selected from the group consisting of palladium, platinum, antimony, bismuth, boron, indium and cerium), the proportion of each essential component relative to the total of the above essential components excluding oxygen is represented by the following formula: 0.25 <r _Mo <0.98 0.003 <r _V <0.5 0.003 <r _Te <0.5 0.003 <r _X1 <0.5 (however, r _Mo , r _V , r _Te and r _X1 are each Mo, V and T with respect to the total number of moles of the above essential components except oxygen.
(representing the mole fraction of e and X ¹ ). 2) Bi, Mo, X ² and oxygen as essential components (provided that X ² is vanadium, niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium,
Manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, phosphorus, boron,
Lead, gallium, indium, cerium, lithium, sodium, potassium, rubidium, cesium, thallium,
(Representing one or more elements selected from the group consisting of copper and silver), and the existence ratio of each essential component to the total of the above essential components excluding oxygen is represented by the following formula: ## EQU3 ## 0.25 <s _Bi < 0.83 0.09 <s _Mo <0.66 0.005 <s _X2 <0.59 (where s _Bi , s _Mo , and s _X2 are Bi with respect to the total number of moles of the above essential components except oxygen, Mo and X ²
Represents the molar fraction of). 3) V, X ³ and oxygen are essential components (provided that X ³ is
Represents one or more elements selected from the group consisting of iron, antimony, phosphorus, lithium, sodium, potassium, rubidium, cesium, tungsten, titanium, aluminum, zirconium, tin, germanium and indium), and the above essential except oxygen excluding the existence ratio of each essential ingredient to the sum of components, the following equation, equation 4] _{0.23 <t V <1.0 0 <} t X3 <0.77 ( where each is t _V and t _X3 oxygen (Representing the mole fraction of V and X ³ with respect to the total number of moles of the above essential components)). 4) Fe, X ⁴ and oxygen as essential components (provided that X is
⁴ represents one or more elements selected from the group consisting of antimony, phosphorus, chromium, titanium, molybdenum, aluminum, zirconium, tin, germanium and indium), and each essential component relative to the total of the above essential components except oxygen. The abundance ratio of the following formula: 0.23 <u _Fe <1.00 <u _X4 <0.77 (where u _Fe and u _X4 are the total number of moles of the above essential components excluding oxygen, respectively) (Representing the mole fraction of Fe and X ⁴ with respect to). 2. The complex metal oxide is Mo, V, Te, X.
¹ and oxygen as essential components (provided that X ¹ is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, Which represents one or more elements selected from the group consisting of indium and cerium), and its X-ray diffraction lines (using Cu-Kα rays as an X-ray source), the main X-rays having a diffraction angle 2θ shown below. It shows a diffraction peak, The manufacturing method of the (alpha), (beta)-unsaturated carboxylic acid of Claim 1 characterized by the above-mentioned. [Table 1] Diffraction angle 2θ (± 0.3 °) ────────────── 22.1 ° 28.2 ° 36.2 ° 45.2 ° 50.0 ° 3. The saturated aliphatic hydrocarbon is propane and / or
Or it is butanes, The manufacturing method of the (alpha), (beta)-unsaturated carboxylic acid of Claim 1 or 2 characterized by the above-mentioned.