摘要:
A process for the separation by distillation of a mixture of 1,4-butanediol and at least one 4-hydroxybutyraldehyde, its cyclic hemiacetal and its cyclic full acetals with at least one further alcohol by carrying out the distillation in the presence of an alkaline compound. The mixture to be separated preferably contains a cyclic full acetal of 4-hydroxybutyraldehyde with a further alcohol which has a lower boiling point than butanediol and also the further alcohol in free form. The process is particularly suitable for the separation by distillation of mixtures formed in the hydrogenation of maleic acid derivatives.
摘要:
A process for preparing cyclopentanone and cyclopentene-1-carboxylic acid or an ester thereof of the formula I where R is hydrogen or an aliphatic radical having 1-6 carbon atoms or a cycloaliphatic, araliphatic or aromatic radical having 6-12 carbon atoms comprises heating a compound of the formula II X—(CH2)4—COOR II where X is formyl or hydroxymethyl and R is defined as above, and/or a compound which is converted into a compound of the formula II by reaction with water or alcohols ROH under the reaction conditions to from 200 to 450° C. in the gas or liquid phase in the presence of a heterogeneous oxidic catalyst.
摘要:
In a process for preparing THF (tetrahydrofuran) by reaction of a 1,4-butanediol-containing reaction mixture over an acid catalyst, the reaction mixture comprises further alcohols different from 1,4-butanediol and is essentially free of water.
摘要:
In a process for preparing alcohols by gas phase hydrogenation of carboxylic acids or esters thereof at elevated temperature and elevated pressure in the presence of catalysts consisting of or comprising, as hydrogenating components, oxides of main group VI and/or subgroup IV, the hydrogenation is carried outa) at from 250.degree. C. to 400.degree. C. and from 5 bar to 100 bar in the presence ofb) primary or secondary alcohols, the molar hydrogen/alcohol ratio being at most 800.
摘要:
A process for preparing halogen-free, reactive polyisobutene having a terminal double bond content of more than 60 mol % and an average molecular weight Mn of 800-3000 dalton by cationic polymerization in the liquid phase of isobutene over an acidic, essentially halogen-free heterogeneous catalyst, where a) a hydrocarbon mixture of essentially C4-hydrocarbons comprising isobutene in an amount of from 10 to 80% by weight is used as the starting material and b) polymerization is carried out continuously at from −30 to 0° C. with average starting material residence times of one hour or less, where the temperature and the residence time are selected such that the isobutene conversion is less than 60% and, after separation from the resulting polyisobutene, the isobutene is either enriched in the partially converted hydrocarbon mixture and returned to the polymerization or passed to another isobutene reaction coupled with the polymerization.
摘要:
A process for preparing cyclopentanone by reacting adipic esters of the formula R1OOC—(CH2)4—COOR2 I where R1 and R2 are each alkyl having from 1 to 12 carbon atoms, cycloalkyl having 5 or 6 carbon atoms, aralkyl or aryl and R2 may additionally be hydrogen, in the presence of oxidic catalysts comprises reacting adipic esters of the formula I having less than 5% by weight of by-products other than adipic esters in the gas phase in the presence of water, a carrier gas and a) from 0.01 to 10% by weight of at least one metal oxide selected from the first or second main group of the periodic table or from the group of the rare earth metals on titanium dioxide or zirconium dioxide as catalyst support, or b) from 0.01 to 50% by weight of at least one metal oxide selected from the second main group of the periodic table on zink oxide as catalyst support.
摘要:
In a process for the catalytic hydrogenation of 2,5- and 2,3-dihydrofuran with hydrogen to give tetrahydrofuran, use is made of a catalyst in which a metal or a plurality of metals have been deposited by vapor deposition or sputtering on a metal wire mesh or a metal foil as support.
摘要:
1,6-hexanediol and .epsilon.-caprolactone are prepared from a carboxylic acid mixture comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols which is obtained as a by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or oxygen-containing gases by water extraction of the reaction mixture, by esterifying and hydrogenating a substream to give hexanediol and cyclizing 6-hydroxycaproic esters to give caprolactone.
摘要:
Described is a method of producing 1,4-butanediol, the method calling for 2,3-dihydrofuran to be decomposed in a single stage over a hydrogenation catalyst in the presence of water and hydrogen at a temperature of 20 to 300.degree. C. and a pressure of 1 to 300 bar and in neutral or acid conditions.
摘要:
1,4-butanediol and THF are prepared from furan by a process which comprises converting furan in the presence of water and hydrogen but in the absence of a water-soluble acid in a single stage over a hydrogenation catalyst, the hydrogenation catalyst containing at least one element of subgroup I, V, VI, VII or VIII in the form of a compound or in elemental form and the restriction that the catalyst does not contain nickel alone being applicable.