Abstract:
The invention relates to a catalyst molded body for producing maleic anhydride by gas-phase oxidation of a hydrocarbon having at least four carbon atoms, comprising a catalytically active mass, which contains vanadium, phosphorus, and oxygen. The catalyst molded body comprises a substantially cylindrical body having at least two, preferably four, inner through-bores substantially parallel to the cylinder axis of the body. The catalyst molded body has a large outer surface area, a lower pressure loss, and sufficient mechanical stability.
Abstract:
Provided is a catalyst for preparing carboxylic acids and/or carboxylic anhydrides, which has a plurality of catalyst zones arranged in series and has been produced using a vanadium antimonite having a maximum content of crystalline valentinite of 5% by weight. The present invention further provides a process for gas-phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst which has a plurality of catalyst zones arranged in series and has been produced using a vanadium antimonite having a maximum content of crystalline valentinite of 5 % by weight.
Abstract:
A catalyst for the gas phase oxidation of organic hydrocarbons comprises a multielement oxide which comprises at least one transition meal such as vanadium, wherein the catalyst has a charge transport activation energy Ec at a temperature of 375 to 425°C of less than 0 kJ/mol. The catalyst serves for preparation of maleic anhydride.
Abstract:
The invention relates to a method for producing phthalic anhydride by catalytic gas phase oxidation of o-xylol. According to said method, a gaseous mixture of o-xylol and an oxygen-containing gas is guided through at least two reaction zones in a main reactor, the temperature of said reaction zones being adjustable independently of each other, and is reacted to give a gaseous intermediate reaction product which contains unreacted o-xylol, phthalic anhydride reaction products with a lower oxidation state and phthalic anhydride, and the intermediate reaction product is introduced into a secondary reactor. The temperature in the reaction zones in the primary reactor is controlled in such a manner that the concentration of the unreacted o-xylol in the intermediate reaction product is at least 0.5% by weight. The method according to the invention allows an increase in total yield of phthalic anhydride without any or without substantial decrease in product quality.
Abstract:
Disclosed is a method for long-term operation of a heterogeneously catalyzed partial gas phase oxidation of propene to obtain acrolein, in which the propene contained in the fed reaction gas mixture is partially oxidized when said gas mixture penetrates the fixed catalyst bed that is accommodated in two spatially successive temperature zones A, B, and in order to prevent the quality of the fixed catalyst bed from deteriorating during long-term operation, the temperature in at least one of the two temperature zones is raised in such a way that the difference TB- TA becomes greater and greater, where TB is the temperature in temperature zone B and TA is the temperature in temperature zone A.
Abstract:
The invention relates to a catalyst for partially oxidizing hydrocarbons in the gas phase, containing a multi-metal oxide of the general formula (I), AgaMObVcMdOe * f H2O (I), wherein M stands for at least one element selected from among Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, B, AI, Ga, In, Si, Sn, Pb, P, Sb, Bi, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Au, Zn, Cd, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and U, a has a value of 0.5 to 1.5, b has a value of 0.5 to 1.5, c has a value of 0.5 to 1.5, a+b+c has the value 3, d has a value of less than 1, e means a number that is determined by the valence and frequency of the elements other than oxygen in the formula (I), f has a value of 0 to 20, which multi-metal oxide exists in a crystal structure, the X-ray powder diffractogram of which is characterized by diffraction reflections at a minimum of 5 lattice distances selected from among d = 4.53, 3.38, 3.32, 3.23, 2.88, 2.57, 2.39, 2.26, 1.83, 1.77 Å (± 0.04 Å).
Abstract translation:一种用于烃的气相部分氧化催化剂包括通式(I)的多金属氧化物,AgaMObVcMdOe * F H 2 O(I)其中M是其中锂,钠,钾,铷,铯,铍,镁,钙的至少一个, 锶,钡,硼,铝,镓,铟,硅,锡,铅,磷,锑,铋,Y,钛,锆,铪,钒,铌,钽,铬,钨,锰,RE,铁,钌, 锇,钴,铑,铱,镍,钯,铂,铜,金,锌,镉,镧,铈,镨,钕,钐,铕,钆,铽,镝,钬,铒,铥,镱,路, U被选择的元素,一个具有0.5至1.5的值; b为0.5〜1.5的值,c具有从0.5至1.5,A + b + C的值 是3,D具有小于1的值,例如确定由其中,F为0至20的值,式(I)中氧以外的元素的化合价和频率定义的一个数,在 的晶体结构存在,其粉末X至少为5,在D的特征在于衍射峰= 4.53,3.38,3.32,3.23,2.88,2.57,2.39,2.26,1, 83,1.77埃(±0.04 A)中的晶面间距。
Abstract:
The catalytically active mass of a catalyst molded body comprises a multi-element oxide containing vanadium and phosphorus. The specific pore volume PV (in ml/g) of the catalyst molded body, the bulk density p of the catalyst molded body (in kg/l), the geometric surface area Ageo (in mm2), and the geometric volume Vgeo (in mm3) of the catalyst molded body satisfy the condition: 0.275 geo/Vgeo. In a method for producing maleic acid anhydride by heterogeneously catalytic gas phase oxidation of a hydrocarbon, the catalyst molded body allows a lower pressure loss and a high yield.