Process for producing catalyst for methacrylic acid production, catalyst for methacrylic acid production, and process for producing methacrylic acid
View Patent ↗A method for producing a catalyst containing given atoms in a given atomic proportion for use in producing methacrylic acid through gas-phase catalytic oxidation of methacrolein with molecular oxygen comprising the steps of: (i) preparing a solution or slurry containing at least molybdenum, phosphorus, and vanadium (liquid I); (ii) preparing a solution or slurry containing ammonium radical (liquid II); (iii) preparing a mixture of the liquid I and the liquid II by introducing one liquid (liquid PR) of the liquid I and the liquid II into a tank (tank A) and pouring the other liquid (liquid LA) on a continuous region in the surface of the liquid PR, the continuous region occupying 0.01 to 10% of the whole area of the surface of the liquid PR; and (iv) drying and calcining the resultant solution or slurry containing a catalyst precursor comprising all the catalyst constituents.
1. A method for producing a catalyst having a composition represented by the following formula (1) for use in producing methacrylic acid through gas-phase catalytic oxidation of methacrolein with molecular oxygen, comprising:
(i) preparing a solution or slurry comprising at least molybdenum, phosphorus, and vanadium (liquid I);
(ii) preparing a solution or slurry containing ammonium radical (liquid II);
(iii) preparing a mixture of the liquid I and the liquid II by:
introducing one of the liquid I and the liquid II (liquid PR) into a tank (tank A),
subsequently pouring the other of the liquid I and the liquid II (liquid LA) into the tank already containing the liquid PR,
the liquid LA is poured into the tank A so that when the liquid LA contacts the liquid PR the contact occurs at a continuous region on a surface of the liquid PR, and
the continuous region comprises 0.01 to 10% of an entire surface area of the liquid PR in the tank A; and
(iv) drying and calcining the resultant solution or slurry containing a catalyst precursor comprising all the catalyst constituents,
P a Mo b V c Cu d X e Y f Z g O h (1)
wherein:
P, Mo, V, Cu and O represent phosphorous, molybdenum, vanadium, copper and oxygen, respectively;
X represents at least one element selected from the group consisting of antimony, bismuth, arsenic, germanium, zirconium, tellurium, silver, selenium, silicon, tungsten and boron;
Y represents at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, cobalt, manganese, barium, gallium, cerium and lanthanum;
Z represents at least one element selected from the group consisting of potassium, rubidium and cesium;
subscripts a, b, c, d, e, f, g and h represent an atomic ratio of each element, respectively; and
when b is 12, a is in the range of from 0.5 to 3, c is in the range of from 0.01 to 3, d is in the range of from 0.01 to 2, e is in the range of from 0 to 3, f is in the range of from 0 to 3, g is in the range of from 0.01 to 3 and h represents the atomic ratio of oxygen necessary for fulfilling the requirement of the valence of each element above.
2. The method according to claim 1 , wherein the liquid LA is poured while stirring the liquid PR introduced into the tank A with a stirring power of 0.01 to 3.5 kW/m 3 .
3. The method according to claim 1 , wherein the liquid LA is poured from a height of 0.05 to 2 m above the surface of the liquid PR introduced into the tank A.