摘要:
Supported silver catalysts which contain one or more alkali metals are prepared in a two-stage process by doping a basic catalyst which contains silver in metallic form and may also contain lithium with the heavy alkali metal sodium, potassium, rubidium and/or cesium using an impregnating solution which contains the heavy alkali metal and one or more nitrates of the general formulaR.sup.+ NO.sub.3.sup.-wherein R.sup.+ is an ammonium, hydrazinium, C.sub.1 -C.sub.12 -monoalkylammonium, C.sub.2 -C.sub.12 -dialkylammonium, C.sub.3 -C.sub.12 -trialkylammonium or C.sub.4 -C.sub.12 -tetraalkylammonium cation.
摘要翻译:含有一种或多种碱金属的负载型银催化剂通过掺杂含有金属形式的银的碱性催化剂并且还可以使用重质碱金属钠,钾,铷和/或铯来包含锂,通过两步法制备。 含有重质碱金属和一种或多种通式为R + NO 3 - 的硝酸盐的浸渍溶液,其中R +是铵,肼,C1-C12-单烷基铵,C2-C12-二烷基铵,C3-C12-三烷基铵或C4-C12 四烷基铵阳离子。
摘要:
A catalyst for decomposing dinitrogen monoxide which is pure or present in gas mixtures comprises metallic silver applied to an alumina carrier with a BET surface area of from 5 to 25 m.sup.2 /g.
摘要:
Phthalic anhydride is prepared in a multiple tube reactor provided with separate salt baths, the temperature of the salt bath used for cooling the first layer of catalyst, as regarded in the direction of flow of the reaction mixture, being from 2.degree. to 20.degree. C. higher than that of the salt bath(s) associated with the following layer(s).
摘要:
A process for regenerating deactivated metal oxide catalysts comprising at least one of the elements antimony, iron, bismuth, molybdenum, vanadium, tungsten and/or uranium and a peptizable carrier, comprises the steps of:a) grinding the metal oxide catalyst in the presence of water to a particle size of from 10 nm to 10 .mu.m,b) heating the aqueous suspension of the metal oxide catalyst of stage a) to 30-100.degree. C. and adding an acid which peptizes the carrier,c) spray drying the acidic suspension of the metal oxide catalyst,d) heating the fluidizable metal oxide catalyst particles of stage c) to 500.degree.-850.degree. C.
摘要:
Pure acrylic acid is stored and/or transported by a process in which the pure acrylic acid is stored and/or transported as liquid aqueous solution at ≦15° C.
摘要:
A method is described of stabilizing (meth)acrylic esters against unwanted free-radical polymerization, in which the mixture to be stabilized has added to it a polymerization inhibitor mixture comprising at least one nitroxyl radical and/or at least one organic compound having at least one nitroso group, and at least one p-phenylenediamine.
摘要:
A process for preparing pure (meth)acrylic acid or a (meth)acrylate starting from a crude (meth)acrylic acid, which comprises the following stages: A: treating the crude (meth)acrylic acid with at least one compound which is able to remove aldehydes, to give an aldehyde-free crude (meth)acrylic acid; B: subjecting the aldehyde-free crude (meth)acrylic acid to imprecise distillation, to give a low-boiling fraction comprising (meth)acrylic acid and acetic acid and a high-boiling fraction comprising (meth)acrylic acid and high boilers; C: isolating a pure (meth)acrylic acid from the high-boiling fraction and, if desired, D: esterifying the low-boiling fraction comprising (meth)acrylic acid and acetic acid that is obtained in stage B by means of one or more alkanols, to give an esterification mixture comprising one or more (meth)acrylates, one or more acetic esters, and one or more alkanols.
摘要:
In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with alkanols having from 1 to 5 carbon atoms in a homogeneous, liquid, solvent-free phase at elevated temperature and in the presence of an acid esterification catalyst, in which the (meth)acrylic acid, the alkanol and the catalyst are fed to a reaction zone, the water formed is removed by rectification during a residence time as constituent of a mixture comprising alkanol in a rectification unit superposed on the reaction zone, the distillate thus obtained is separated into an organic phase comprising alkanol and an aqueous phase comprising water, the organic phase is returned to the rectification unit, the reaction mixture is discharged from the reaction zone and conveyed into a distillative separation zone comprising further rectification units and in the latter the alkyl (meth)acrylate formed is separated off.
摘要:
The process for the esterification of (meth)acrylic acid with an alkanol in the presence of an esterification catalyst, in which unconverted starting compounds and the (meth)acrylate to be formed are separated off by distillation and an oxyester-containing bottom product is formed and is separated off, and (a) in the bottom product separated off, the oxyesters present are cleaved, if required after the addition of (meth)acrylic acid and/or oligomeric (meth)acrylic acid, directly in the presence of acid catalysts differing from (meth)acrylic acid and/or oligomeric (meth)acrylic acid, and the cleavage products are removed, a cleavage residue remaining, or (b) the oxyesters are first removed by distillation from the cleavage product separated off, a distillation residue remaining, and the oxyesters removed are cleaved, if required after addition of (meth)acrylic acid and/or oligomeric (meth)acrylic acid, in the presence of acid catalysts differing from (meth)acrylic acid and/or oligomeric (meth)acrylic acid, and the cleavage products are removed, a cleavage residue remaining, is carried out in such a way that the cleavage residue obtained in step (a) or the cleavage residue obtained in step (b) is hydrolytically cleaved together with the resulting distillation residue in the presence of water and acids or bases.
摘要:
The disclosure is a process for preparing (meth)acrylic esters by reacting (meth)acrylic acid with C4-C6-alkanols in the presence of a strong inorganic acid or of a C4-C6-monoalkyl ester of a polybasic strong acid as catalyst, which comprises removing the unconverted alkanol from the resulting reaction mixture by distillation and thereafter removing the catalyst from the resulting mixture.