Claims
- 1. A process for preparing methacrylonitrile by reacting isobutylene or tertiary butanol with ammonia and oxygen in a gaseous phase, comprising:
- (A) carrying out the reaction
- (i) on a catalyst system consisting essentially of (1) 30-70% by weight of a silica catalyst carrier and (2) a catalyst having a composition represented by the following general formula:
- A.sub.a Mo.sub.12 Bi.sub.b Fe.sub.c Na.sub.d P.sub.e O.sub.x
- wherein
- A is at least one element selected from the group consisting of potassium, rubidium and cesium, and a, b, c, d, e and x are the atomic ratios of A, bismuth, iron, sodium, phosphorus and oxygen, respectively, relative to twelve atoms of molybdenum, wherein:
- a is between 0.05 and 1.0
- b is between 1 and 18,
- c is between 2 and 10,
- d is between 0 and 3.6,
- e is between 0 and 3, and
- x is the number of oxygen atoms required to satisfy the valence requirements of the other elements present, said catalyst having a surface area of 2.5-6.2 m.sup.2 /g, and a feedstock conversion rate with no substantial decrease in conversion percentage points from the initial value while producing carbon deposition of less than 0.05 g carbon/100 g catalyst, after 1000 hours of continuous use;
- (ii) at a reaction temperature of 380.degree. C. to 480.degree. C.; and
- (iii) at a contact time of 1 to 10 seconds; and
- (B) maintaining the oxygen volume concentration in the gaseous reaction mixture at the outlet of the catalyst bed below about one percent.
- 2. Process of claim 1 wherein:
- b is between 2 and 10;
- c is between 3 and 10;
- the silica constitutes between 40 and 60% by weight of the total catalyst system;
- the catalyst system demonstrates a time conversion of feedstock with no substantial decrease in conversion percentage points from the initial value;
- the reaction temperature is between about 400.degree. C. and about 460.degree. C.;
- the contact time is between about 1.5 seconds and about 8 seconds; and
- the oxygen volume concentration in the gaseous reaction mixture at the outlet of the catalyst bed is maintained below about 0.5%.
- 3. Process of claim 2 wherein A is potassium and a is between 0.1 and 1.0.
- 4. Process of claim 2 wherein A is rubidium or cesium and a is between 0.05 and 0.6.
- 5. Process of claim 3 or 4 wherein a is between 0.1 and 0.6.
- 6. Process of claim 1 wherein:
- the volume ratio of tert-butanol and/or isobutylene to ammonia in the gaseous phase is between about 1:0.9 and about 1:2.0; and
- the volume ratio of tert-butanol and/or isobutylene to oxygen in the gaseous phase is between about 1:1.8 and about 1:2.6.
- 7. Process of claim 6 wherein the volume ratio of tert-butanol and/or isobutylene to ammonia in the gaseous phase is between about 1:1 and about 1:1.6.
Priority Claims (1)
Number |
Date |
Country |
Kind |
56-170106 |
Oct 1981 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 421,072, filed Sept. 22, 1982, now abandoned.
US Referenced Citations (14)
Foreign Referenced Citations (6)
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Country |
16419 |
Jan 1972 |
JPX |
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Feb 1980 |
JPX |
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JPX |
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JPX |
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GBX |
1347175 |
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GBX |
Non-Patent Literature Citations (1)
Entry |
Brunauer et al., "Adsorption of Gases on Multimolecular Layers", J. Am. Chem. Soc., 60, 309-319 (1938). |
Continuations (1)
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Number |
Date |
Country |
Parent |
421072 |
Sep 1982 |
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