KR820000961B1 - Process for preparation of acrylonitrile and metacrylonitrle - Google Patents

Abstract

Acrylonitrile and methacrylonitrile is prepd. by ammoxidation of propylene and isobutyrene resp., using improved catalyst which can be represents as JaQ6ZcFedDeMo12Ox, where J is an alkali metal, Tl and Ag, Q is Co, Ni, Zn, Cd, Be, Mg, Ca, Sr, Ba and Ra, Z represents Ge+Sb, Cu+W, Cu+Sn, Ce+W, Pr+Mn, Sn+Mn, Mn+W, W+Sb, Cr+Sn, W+Sn, Ge+Sn, Sb+Sn, W+P, Sb+P, Cr+Cu, Mn+Cu, Sb+Cu and Mn+P, D is Bi or Te, a = 0.03-0.05, b = 4-10, C = 0.5-7, d = 0.5-5, e - 0.5-5, and x is as necessary for balance. For example, MnWo.5 (Ko.1Ni2.5Co4.5 Fe2BiMo12Ox) supported on 20% SiO2 gave acrylonitrile with 86.4% selectivity and 68.5% conversion per pass at 420≰C.

Description

[Name of invention]

Process for preparing acrylonitrile and methacrylonitrile

Detailed description of the invention

The present invention utilizes a novel catalyst with excellent catalytic performance, based on iron, bismuth, and molybdenum, and additionally containing unique promoters to oxidize, ammoxidate, dehydrogenate, and oxy various olefins. The present invention relates to a method for dehydrogenation, and more particularly, to a method for producing acrylonitrile or methacrylonitrile using propylene or isobutylene, respectively.

Catalysts used for the oxidation, ammoxidation and oxydehydrogenation of olefins are well known.

References: U.S. Pat.Nos. 3,642,930 and 3,414,631, U.S. Patent Nos. 490,532 (July 2, 1974), 308,527 (July 19, 1973), 717,838 (August 26, 1976).

The catalysts described in the above references are also preferred, but the catalysts used in the present invention have significant advantages over these catalysts.

Moreover, the catalyst used in the present invention is not only an excellent catalyst for ammoxidation for producing acrylonitrile or methacrylonitrile, but also when olefins having 4 or more consecutive carbon atoms are converted into the corresponding diolefins and by oxydehydrogenation. It shows good catalytic activity even when made from diolefins.

The improved catalyst used in the present invention has the following empirical formula.

J _a Q _b Z _c Fe _d D _e Mo ₁₂ O _x

In the above structural formula

J is an alkali metal, thallium, silver or a mixture thereof,

Q is Co, Ni, Zn, Cd, Be, Mg, Ca, Sr, Ba, Ra or mixtures thereof,

Z is Ge + Sb, Cu + W, Cu + Sn, Ce + W Pr + Mn, Sn + Mn, Mn + W, W + Sb, Cr + Sn, W + Sn, Ge + Sn, Sb + Sn, W Two or more elemental systems selected from + P, Sb + P, Cr + Cu, Mn + Cu, Sb + Cu, Mn + P or mixtures thereof, provided that when Z is Mn + P the catalyst comprises TI Do not

X is the number of oxygen needed to balance the valence of atoms of other elements in the catalyst.

In this catalyst composition, the Z component is composed of two or more unique elemental systems. Each element in the system described above is at least 1 atomic percent, preferably at least 5 atomic percent, based on the particular system selected. In this catalyst, D is preferably Bi.

The catalyst of the present invention preferably contains the components indicated above in the following amounts,

It is best to be present in the following quantities:

Especially preferred are the above preferred or most preferred catalysts comprising K, Rb and Cs and optionally Ni and Co.

It is also preferable to select Z so that the ratio of the amount of the first element to the amount of the second element of each system described above is from 1: 0.25 to 1: 0.75.

Of the above catalysts, Z is particularly good among combinations of the following elements: Ge + Sb, Cu + W, Ce + W, Pr + Mn, Sn + Mn, Mn + W, and Cu + Sn: these Of particular interest are catalysts in which Z is Ge + Sb, Cu + W, Cu + Sn and Pr + Mn.

The catalyst of the present invention, for example, makes an aqueous composition of degradable salts and oxides of metals to be combined with the catalyst and evaporates water from the aqueous composition into a dense paste to dry and then the paste is heated to an elevated temperature and oxidizing atmosphere. It is prepared by calcining (Calcining) in. Processes for making catalysts of the type described herein are well known in the literature and those skilled in the art will have little difficulty making the catalysts of the present invention.

The catalyst of the present invention is not supported or used with various conventional carriers such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , BPO ₄ , SbPO ₄ , MgO montmorillonite and the like. They are used in fixed bed reactors or fluidized bed reactors as needed. When these catalysts are used, they can simply be replaced with the catalysts used previously and reacted under the same conditions.

For example, when the catalyst of the present invention is used in the reaction of ammoxidizing propylene or isobutylene to produce acrylonitrile and methacrylonitrile, respectively, the olefins to be reacted with oxygen and ammonia in a normal ratio are usually raised at an elevated temperature, usually 200 Contact with the catalyst for a time sufficient to cause the ammoxidation reaction in a fixed or fluid-bed reactor at from 600 ° C. Similarly, when the catalyst of the present invention is used for other known reactions, the reaction conditions use syntactic conditions.

Comparative Example

80% K _0.1 Ni _2.5 Co _4.5 Fe ₃ Bip _0.5 Mo ₁₂ O _x + 20% SiO ₂

Prepare a solution of 127.1 g ammonium heptamolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O and water. To this solution was added 6.9 g of 42.5% H ₃ PO ₄ solution and 102.7 g of Nalco 40% silica sol to form a slurry. In addition, 72.7 g of iron nitrate Fe (NO ₃ ) _{3 ·} 9H ₂ O 29.1 g of bismuth nitrate Bi (NO ₃ ) ₃ · 5H ₂ O 78.6 g of cobalt nitrate Co (NO ₃ ) ₂ 6H ₂ O 43.6 g of nickel nitrate Separately prepare an aqueous solution containing Ni (NO ₃ ) ₂ .6H ₂ O and 6.1 g of 10% potassium nitrate solution.

A solution of this metal nitrate is slowly added to the slurry. The resulting slurry is evaporated to dryness and the solid obtained is heat treated at 290 ° C. for 3 hours, at 425 ° C. for 3 hours and at 550 ° C. for 16 hours.

[Examples 1 to 7]

The catalysts listed in Table I were prepared by the method described in Comparative Example A. Each catalyst of Table I and the catalyst of Comparative Example A were tested for the catalytic activity when ammoxidatively propylene to acrylonitrile. In this test, each catalyst was charged at 5 cc. Charge into a fixed-bed reactor. Samples of propylene / ammonia / oxygen / nitrogen / steam are supplied to the reactor in a quantity of 1.8 / 2.2 / 3.6 / 2.4 / 6 so that the WWH is 0.1 g propylene / 1 g catalyst / hour and the contact time is 3 seconds. The reaction temperature is maintained at 420 ° C. Table I shows the results obtained here and the results obtained when the control catalyst A was used.

TABLE I

^The reaction temperature is 430 ° C.

The brackets used in Table I and the following Table II are intended to clarify the differences between the various catalysts.

[Examples 8 to 10]

Examples were carried out to ammonia propylene to produce acrylonitrile using various catalysts prepared by the process described above. These examples are carried out in the same manner as in Examples 1 to 7, except that the reaction temperature is 430 ° C, the contact time is 6 seconds, and the catalyst support is 50% SiO ₂ . The results obtained are shown in Table II below.

TABLE II

^* 9 seconds contact time

Claims (1)

Process for drawing acrylonitrile or methacrylonitrile by reacting propylene or isobutylene, molecular oxygen and ammonia at a temperature of 200 ° C to 600 ° C in the presence of a catalyst of the structure J _a Q _b Z _c Fe _d D _e Mo ₁₂ O _x Wherein J is an alkali metal, thallium, silver or mixtures thereof, Q is Co, Ni, Zn, Cd, Be, Mg, Ca, Sr, Ba, Ra or mixtures thereof, Z is Ge + Sb, Cu + W , Cu + Sn, Ce + W, Pr + Mn, Sn + Mn, Mn + W, W + Sb, Cr + Sn, W + Sn, Ge + Sn, Sb + Sn, W + P, Sb + P, Cr Two or more elemental systems selected from + Cu, Mn + Cu, Sb + Cu, Mn + P or mixtures thereof, provided that when Z is Mn + p the catalyst does not contain TI; D is Bi or Te In the above structural formula

X is the number oxygen is needed to balance the valence of the other elements in the catalyst and each element in these two or more elemental systems is present at least 1 atomic percent based on the atoms in the system.