Abstract:
The invention relates to a multi-tube fixed-bed reactor and to the use of a reactor of this type for carrying out catalytic gas phase reactions, especially for carrying out exothermic or endothermic catalytic gas phase reactions such as producing phthalic anhydride (PSA), acrylic acid (AA), methacrylic acid (MAA), acrolein, maleic anhydride (MSA), glyoxal, phosgene, hydrogen cyanide or vinyl formamide (VFA). According to the invention, in the case of larger reactors where a considerable reaction heat is produced or required and must be dissipated as a result of the numerous reaction tubes (17), the ratio of tube distribution t to tube outer diameter d?a? is made dependant on the reactor diameter or the tube bundle diameter d?RBa?. If the outer diameter of the reaction tube bundle (18) is more than 4 metres, a ratio of tube distribution t to tube outer diameter d?a? of at least 1.3 is preferred.
Abstract:
A multitube fixed bed reactor and the use of such a reactor for carrying out catalytic gas-phase reactions, in particular for carrying out exothermic and endothermic catalytic gas-phase reactions such as the preparation of phthalic anhydride (PA), acrylic acid, methacrylic acid (MAA), acrolein, maleic anhydride (MA), glyoxal, phosgene, hydrocyanic acid or vinyl formamide (VFA). In a relatively large multitube reactor in which a large amount of heat of reaction is generated owing to the numerous catalyst tubes ( 17 ) and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter d a be made dependent on the reactor diameter or on the external tube bundle diameter d RBa . At an external diameter of the catalyst tube bundle ( 18 ) of more than 4 meters, a ratio of tube spacing d to external tube diameter d a of at least 1.3 is preferred.
Abstract:
A multitube fixed bed reactor and the use of such a reactor for carrying out catalytic gas-phase reactions, in particular for carrying out exothermic and endothermic catalytic gas-phase reactions such as the preparation of phthalic anhydride (PA), acrylic acid, methacrylic acid (MAA), acrolein, maleic anhydride (MA), glyoxal, phosgene, hydrocyanic acid or vinyl formamide (VFA). In a relatively large multitube reactor in which a large amount of heat of reaction is generated owing to the numerous catalyst tubes ( 17 ) and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter d a be made dependent on the reactor diameter or on the external tube bundle diameter d RBa . At an external diameter of the catalyst tube bundle ( 18 ) of more than 4 meters, a ratio of tube spacing d to external tube diameter d a of at least 1.3 is preferred.
Abstract:
2-Pyrrolidone derivs. of formula (Ia) are new, where R'1 and R'2 = 1-4C alkyl, or CR'1R'2 is a ring, esp. with 4-7 ring C atoms; R''3 = Me ot t-Bu. Prodn. of 2-pyrrolidone derivs. of formula (I) is effected by reacting an amine of formula (II) with an alpha,beta-unsatd. carboxylic acid or nitrile deriv. of formula (III) in the presence of a radical initiator, and opt. alkylating the prod. when R'3 = H. R1 and R2 = 1-8C alkyl, 1-8C alkoxy, 3-10C cycloalkyl or 3-10C cycloalkoxy, or CR1R2 is a ring, esp. with 4-7 ring C atoms; R3 = H, 1-6C alkyl, phenyl or naphthyl; R4 and R5 = H or 1-4C alkyl; R'3 = H, t-Bu, phenyl or napthyl; Q = COX or CN; X = OR', NR'R'', NHR' or NH2; R'= 1-8C alkyl, 3-8C cycloalkyl or phenyl; Z = O or NH. Use of cpds. (I; Z = O) as basic absorbents for scrubbing gas mixts. to remove acid gases is also new. The reaction is effected at 50-200 deg.C and 1-200 bar in the presence of an alkyl perester, dialkyl peroxide, diaryl peroxide or azo cpd. Excess (II) is used as solvent.
Abstract:
A multitube fixed bed reactor and the use of such a reactor for carrying out catalytic gas-phase reactions, in particular for carrying out exothermic and endothermic catalytic gas-phase reactions such as the preparation of phthalic anhydride (PA), acrylic acid, methacrylic acid (MAA), acrolein, maleic anhydride (MA), glyoxal, phosgene, hydrocyanic acid or vinyl formamide (VFA). In a relatively large multitube reactor in which a large amount of heat of reaction is generated owing to the numerous catalyst tubes ( 17 ) and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter d a be made dependent on the reactor diameter or on the external tube bundle diameter d RBa . At an external diameter of the catalyst tube bundle ( 18 ) of more than 4 meters, a ratio of tube spacing d to external tube diameter d a of at least 1.3 is preferred.
Abstract:
A multitube fixed bed reactor and the use of such a reactor for carrying out catalytic gas-phase reactions, in particular for carrying out exothermic and endothermic catalytic gas-phase reactions such as the preparation of phthalic anhydride (PA), acrylic acid, methacrylic acid (MAA), acrolein, maleic anhydride (MA), glyoxal, phosgene, hydrocyanic acid or vinyl formamide (VFA). In a relatively large multitube reactor in which a large amount of heat of reaction is generated owing to the numerous catalyst tubes ( 17 ) and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter d a be made dependent on the reactor diameter or on the external tube bundle diameter d RBa . At an external diameter of the catalyst tube bundle ( 18 ) of more than 4 meters, a ratio of tube spacing d to external tube diameter d a of at least 1.3 is preferred.
Abstract:
Carbonyl compounds of the formulawhere R1 is a hydrogen atom or an alkyl radical having from 1 to 3 carbon atoms, R2 is a hydrogen atom, an unsubstituted or C1-C3-alkyl-monosubstituted to -trisubstituted C2-C4-alkenyl radical or a radical of the formulawhere R3 is a hydrogen atom or together with R4 is an oxygen atom, R4 is the radical OR6 or together with R3 is an oxygen atom, R5 is a hydrogen atom, an alkyl radical having from 1 to 8 carbon atoms, an unsubstituted or C1-C3-alkyl-monosubstituted to -trisubstituted C2-C4-alkenyl radical or a cyclohexyl or cyclopentyl radical and R6 is an alkyl radical having from 1 to 4 carbon atoms, a cyclohexyl or cyclopentyl radical or a radical of the formula -CH2-CHO or -CH2-CH2-O-CH2-CHO, are prepared by gas-phase oxidation of methanol or alcohols of the formulawhere R1 and R5 are as defined above, by means of an oxygen-containing gas in the presence of copper- and/or silver-containing catalysts, the catalyst system used comprising at least one phosphorus-containing copper- and/or silver-containing catalyst.