JPS58172208A - Crystalline composite vanadium-phosphorus oxide - Google Patents

Abstract

PURPOSE:To provide the titled oxide contg. quatervalent V and quinquevalent P in a prescribed ratio, having prescribed principal X-ray diffraction peaks, and useful as an intermediate of a catalyst used in the vapor phase oxidation of 4C alkane or alkene. CONSTITUTION:An aqueous soln. contg. quatervalent V and phosphoric acid is prepared, and the soln. is heated to obtain a composite oxide contg. quatervalent V and quinquevalent P in 0.8-1.5 atomic ratio of P to V and having principal X-ray diffraction peaks shown in the table. The oxide is useful as an intermediate of a catalyst used in the vapor phase oxidation of 4C alkane or alkene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an S-crystalline vanadium-phosphorus composite oxide. For more details, see the alkane t with the number of carbon atoms.
The present invention relates to a crystalline panadium-phosphorus composite oxide that is useful as an intermediate for a catalyst used in the gas phase oxidation of alkenes or alkenes.

Conventionally, one type of crystalline structure has been known for composite oxides containing vanadium and phosphorus, but even if the valence of vanadium is limited to tetravalent ones, several types of crystalline compositions are still known. It is being

Tokukai Akiko/! 4/93 describes two types of crystalline catalytic intermediates in which the atomic ratio of phosphorus to vanadium (hereinafter abbreviated as P/V) is 1. Its X-ray diffraction peaks are shown in Table 1K.

Table 1 xaaq spectrum of intermediate B described in 117 W3sx-tz4tvs (Anticathode C5-Xα) JP 58-172208C2) Phosphoric and phosphorous acids, formaldehyde and the vanadium compound are introduced together into the reaction chamber under conditions such as to give the tetravalent vanadium of the SO atoms and form the intermediate, and this It is stated that the intermediate can be produced from K by sufficiently heating the intermediate under reflux for several tens of hours. If a catalyst is to be prepared, these two intermediates are further heated at temperatures above 30C to form a catalyst precursor, and then the catalyst precursors are heated at a temperature of about 300-400C.
Bake between C.

Tokukai Akira! Goo 9! No. 90 also describes a method for producing a catalyst intermediate having an atomic ratio of 1 to 2. In the same specification, a soluble vanadium salt dissolved in a non-oxidizing acid aqueous solution such as hydrochloric acid is reacted with phosphoric acid, and the resulting soluble vanadium-phosphorus composite oxide is dissolved in water. It is manufactured by adding and precipitating it. The X1lli spectrum of this composite oxide is as shown in Table 1, but it is clearly different from the data in Table 1. This composite oxide can be made anhydrous from butane by firing if necessary! It is useful as a catalyst for producing lemon shun.

Table - xII of the composite oxide described in JP-A No. 341-9!990! Spectrum (Anticathode C1I-section α) According to the knowledge of the present inventors, the chemical composition of these composite oxides is (v
moa) (!'toe) (koH20) In addition to the crystalline composite oxides mentioned above, several vanadium-phosphorus composite oxides are known. When organized, it becomes like Table-J.

Table 3 Principal X@diffraction spectra (α for anticathode Cu) of known vanadium-phosphorus composite oxides 2, C value As described above, the chemistry of vanadium-phosphorus is extremely complicated, and the crystal manufacturing conditions must be adjusted accordingly. If not strictly followed, the reproducibility may be poor and the crystal may change to something other than the intended one.0 The inventor, Go, has conducted a detailed study on the chemistry of such complex vanadium-phosphorus composite oxide crystals. However, we have discovered a vanadium-phosphorus composite oxide that has a new crystal phase that is completely different from the various crystals mentioned above.

Although this composite oxide has a characteristic xII diffraction spectrum, it can be converted into a catalyst for the production of maleic anhydride through gas phase oxidation of C4 hydrocarbons such as butane and butene to hydrocarbons and 411 by appropriate hydrothermal treatment. There was found.

The carbon dioxide compound oxide of the present invention contains tetravalent vanadium and electric valence phosphorus, and has a main X@ rotational peak as shown in Table-D.

Table - Reference Also, φ in the composite oxide. A range of 1-11 is preferred.

This composite oxide can be produced by various methods, but a water-depleting solution containing vanadyl phosphate containing tetravalent vanadium and phosphoric acid is prepared in advance, and this is mixed with a mild KtoO5-t
Preferably, it is produced by heating at 30C.

Water is generally used as the aqueous medium.

If desired, hydrophilic organic compounds such as alcohols, carboxylic acids, ethers, and ketones may be used in combination.

Specifically, a monovalent vanadium compound such as vanadium pentoxide is mixed with hydrazine (usually hydrazine hydrate), hydroxylamine or salts thereof such as hydrochloride or phosphate, oxalic acid, milk I2 group, etc. Monovalent vanadium, represented by organic acids, is reduced with an inorganic or organic reducing agent capable of rapidly reducing it to tetravalent vanadium, and K is used simultaneously with the reduction, or tetravalent vanadium ions and phosphoric acid are reacted after reduction. let To prepare a vanadyl phosphate solution from a reaction solution containing a reducing agent with a slow reduction rate such as phosphorous acid, vanadium pentoxide, and phosphoric acid, long-term RR heating is required; Use of a reducing agent that may not be suitable for producing the novel composite oxide of the present invention with high purity, as there is a possibility that a part of the hydrothermal reaction may proceed in the reduction step and lead to a different type of compound. The stoichiometric amount required to reduce five vanadiums to tetravalent is sufficient, and usually 1? j
-/- Used in the range of excellent.

The order of addition of the reducing agent, phosphoric acid and monovalent vanadium into the aqueous medium is not limited. The amount of phosphoric acid added is P
/N' is preferably in the range where art-is,
The #I degree of phosphoric acid in the aqueous medium is preferably between s and Jg. The reaction is heated as necessary to prepare a homogeneous vanadyl phosphate-containing solution and kept in a closed container such as an autoclave. Slowly raise the temperature in the container to 100-170℃
A crystalline composite oxide can be obtained by heating for 01 to 20 hours, more preferably in a greenhouse range of toy to /SOC. It is important here to raise the temperature slowly. The heating rate should be 10C or less S degrees in 1 hour, and if the heating rate is increased, a crystal having an X-ray diffraction spectrum as shown in Table 1 can be obtained.

At first glance, this manufacturing method appears to be from Tokkai Shoj! Although this method is very similar to the method described in No.-/14/9J, there are differences in the reduction operation and hydrothermal treatment conditions, and there is a clear difference in the crystals produced.

When a solution containing vanadyl phosphate is left without being subjected to hydrothermal treatment, a different type of light-colored crystals are formed. This item has a characteristic xl as shown in Table-j.
li! IQ peak is shown.

The slurry in which the crystals are formed can be directly treated or only the crystals can be separated and subjected to hydrothermal treatment at 100 C or higher for several hours to several IO hours in a closed container in the presence of water.

It is possible to obtain a composite oxide exhibiting a characteristic thermal peak as shown in the table.

Table-S Note that in the manufacturing stage of the composite oxide, an activity promoting component of butane oxidation reaction 6 may be added.As the activity promoting component,
iron, chromium, alumnium.

Examples include titanium, cobalt, magnesium, etc., and the addition form may be an inorganic salt, an organic salt, etc., as long as it is a compound soluble in a solution.The amount of these additions is preferably in the range of aoiNa damol as metal per mole of vanadium element. The value of 10 in the X-ray concavity spectrum of the resulting composite oxide deviates slightly from the values shown in Table D, but it is within the range of 10-0.

Although the crystalline composite oxide which is a catalyst intermediate of the present invention can be obtained by the above method, several methods are possible for making this intermediate into a catalyst suitable for the oxidation of butane or butene.

One method is to directly or after separating only the crystals, hydrothermally treat the slurry containing this intermediate in a closed container at a temperature of 1,100 or more while being flushed with water. In this case, if the temperature is higher than the ice island treatment temperature tzoc, the intermediate of the present invention will be xls! as shown in Table 1. It changes into a crystal exhibiting a g11fr spectrum.

This crystal needs to be dried and molded! It can be catalyzed by firing according to the conditions. In addition, the intermediate of the present invention /10℃~1
If heat treatment is performed at a relatively high temperature of about 4!0° C., the intermediate product shown in Table 1 will be obtained.

Intermediates can be prepared by adding a complex oxide having a Xil spectrum of
It transforms into a composite oxide that exhibits a line spectrum. It is also possible to catalyze it by drying it and then firing it.

As another method, X11m shown in Table-JK for the intermediate of the present invention
It is possible to mix seed crystals exhibiting the same spectrum and subject them to hydrothermal treatment at a temperature of 110° C. or higher. Most conveniently, the intermediate of the present invention can be prepared by filtration, evaporation to dryness, etc.
It can also be activated by heating and used as a catalyst. However, in this case, somewhat unsatisfactory results are obtained in terms of activity.

As described above in detail, the present invention provides a novel composite oxide that is practical as an intermediate for a catalyst used in the gas phase oxidation of alkanes or alkenes having a large number of carbon atoms.

Example 1 1004 container Kzsgbsy with thin glass lining
@/4AjJ? kJj, tows hydrazine hydrate solution t
Prepare tttq and water 4131.

Prepare an aqueous solution and add vanadium pentoxide/Q974 under stirring.
kl was added while observing foaming.

The container was cooled by flowing a heat medium through the outer jacket of the container.

Although the liquid temperature rose by approximately AQCK, after the addition was completed, heating of the heating medium was started and 1. After confirming that bubble generation had stopped, the container was sealed. The temperature was raised to 0C over about 1 hour, and the temperature was further maintained at 0C for 7.2 hours.

A pale green crystalline precipitate was formed in the container, but a small amount was filtered off and subjected to X-ray image lIr11 determination, and it was found that the precipitate corresponded to the concavity peak shown in Table D.

Detailed example 1 &j phosphoric acid 64t70f, g! - Hydrogen hydrate J4f and 1 ton of water were mixed, and 5 Ut of vanadium pentoxide was added. Foaming decreased after about is minutes, but
The reduction was completed by boiling for an additional 70 minutes. When the obtained dark blue homogeneous solution was left at the mold temperature, a pale blue precipitate began to precipitate after several hours of ζ filtration. The mixture was heated for 411 hours to induce precipitation. Filter the crystals and
When I checked the results, I found that it matched with the 1glFr peta shown in Table-jl (shown in Table-jl).This crystal/ OffC water 6
0- was added to prepare a slurry and heated in a #wptsoc for an hour. The product was filtered and subjected to X-ray IJIII
When the sample was analyzed, it was found that the peak group shown in Table 1 completely disappeared, and the spectrum obtained was found to be almost identical to that shown in Table 1.

However, a small number of complex oxide peaks shown in Table 1 were also present, although the strength was low.

Comparison fpal After obtaining a dark blue homogeneous solution in exactly the same manner as in Example 1, it was immediately transferred to a JjO- Teflon tuttle, sealed in an autoclave, and heated to /JO'f:. It took about 30 minutes to raise the temperature. Heating continued for an additional 11 hours. The resulting slurry was filtered and subjected to XIIIWA spectrometry, and the spectrum matched the spectrum of the composite oxide shown in Table 1-A.

Example J Is it too bad? , %DL in the mixed wave of water too-
-Add and mix 10f of lactic acid t#fluid solution, 40~10OC
K-heated vanadium pentoxide/1 uff was added.

The reduction proceeded rapidly and a blue homogeneous solution could be obtained. When this solution was left at mold temperature overnight, precipitation of solid was detected. Filter this stuff and wash it.

When xII measurement was performed, the spectrum shown in Table 1 was obtained. The structural change of this crystalline product due to hydrothermal treatment was similar to that of Example C, and it was confirmed that a new crystalline phase having a main peak at -0-t/'' etc. was formed.

Reference Example 1 (Production of Intermediate) A portion of the slurry containing the crystalline precipitate obtained in Example 1 was further processed again for 0 hours. When the obtained slurry was filtered and XtlaHq was measured, it was found that it had changed to a pattern of blue discoloration + intermediate particles (roughly dispersed) as shown in the X table.As noted on the bladder, This is an intermediate described in JP-A No. 4/93, and the crystalline composite compound obtained by the present invention is a promising intermediate for producing the intermediate described in the specification. Can be an intermediate.

Reference 111 JII-JK Production of composite oxide) Implementation N
To -11 of the slurry containing the crystalline precipitate obtained in /, a small amount (/weight) of the filtered composite oxide obtained in Comparative Example 1 was added, and the mixture was heated to tsoc.

JJ Tokiya reheated and destroyed. The generated slurry is X4Il
llI? As a result of Table 1, the curved peak disappeared completely, and the diffraction peaks in Table 1 were not detected, indicating that /DO was smoothly converted to the composite oxide shown in Table JK. It was clear.

The filterability is better and the particle size is larger than that of fP4I.

Reaction Example Example 1. The slurry filtration product obtained in #Consideration 99/~ was dried and agglomerated at 300C for 1 hour under a phonetic air flow. The powder is compressed into tablets and laminated into l! Crush it into 1 ginseng - 2 ginseng pieces xs
-(zxtr Q rating) particles were obtained and used as a catalyst. Touch 1
st- was packed in a 41φ glass reactor, and an activity test was conducted using a 1g-butane/air mixed gas tGII8VcoOVa. The product was directly introduced into a gas chromatogram via a heat-retaining gas sampler and analyzed and quantified.The reaction results are as follows.

-I-Example I 4Ig3 17. Reference 1-Reference 1111/41
34I91ko 1i & Reference Example 2 DaAJ
914, t Yul Applicant Mitsubishi Chemical Industries Co., Ltd. Agent Patent Attorney Hase - 1 other person

Claims (1)

[Scope of Claims] 11) Crystalline vanadium-phosphorus composite oxide containing four vanadiums and monovalent phosphorus and exhibiting the following main XLS diffraction peaks (2) The atomic ratio of phosphorus to vanadium is from at to Oxide described in item 1