| abstract |
The present invention is a catalyst composed of a carrier having a silanol group supported by at least one first metal element selected from boron, magnesium, zirconium and hafnium, and an alkali metal element. The average particle size of the compound of the first metal element is 0.4 nm or more and 50 nm or less, the molar ratio of the alkali metal element to the first metal element is X, and the BET specific surface area of the catalyst is Y (m 2 /). g) When the number of silanol groups (pieces / nm 2 ) per unit area of the catalyst is Z, the catalyst satisfies the following formula (1). 0.9 × 10-21 (g / piece) ≦ X / (Y × Z) <10.8 × 10-21 (g / piece) ・ ・ ・ Equation (1) |