Abstract:
A metal oxide supported palladium catalyst comprised of a β-Bi2O3/Bi2Sn2O7 hetero-junction catalyst support and palladium was developed. The catalyst was synthesized using a sol-gel technique as a nanocrystalline structure. In the presence of fluorene, an oxidant and ultraviolet irradiation, the catalyst converts the hydrocarbon to a mixture of fluorenol/fluorenone oxidation products. The close proximity between β-Bi2O3 and Bi2Sn2O7 heterojunction phases in the catalyst is thought to be responsible for the efficient charge separation and catalytic activity. An indirect chemical probe method using active species scavengers elucidated that the photo-oxidation mechanism proceeds via holes and superoxide radical (O2.−) moieties.
Abstract:
A process for the preparation of an aromatic aldehyde by means of the oxidation of the corresponding starting compound in aqueous medium, and separation of said aldehyde from said medium by pervaporation is disclosed together a plant for its carrying out. Advantageously, the process of the present invention allows control of oxidation reaction and recovery of the product with high selectivity and purity. Among others, benzaldehyde, anisaldehyde and vanillin can advantageously be prepared by this process.
Abstract:
Disclosed is a process for the production of an oxygen-containing organic compound by oxidizing an organic compound with molecular oxygen in a liquid phase in the presence both of a catalytic nitrogen-containing cyclic compound and a catalyst including a solid superacid and, supported thereon, a transition metal compound, in which the nitrogen-containing cyclic compound contains, as a ring constituent, a skeleton represented by following Formula (1), wherein X represents an —OR group, and wherein R represents hydrogen atom or a hydroxyl-protecting group. The process gives the oxygen-containing organic compound in a high yield and enables easy recovery and reuse of the catalyst.
Abstract:
A catalyst of the invention includes an imide compound having a N-substituted cyclic imide skeleton represented by following Formula (I): wherein R is a hydroxyl-protecting group. Preferred R is a hydrolyzable protecting group. R may be a group obtained from an acid by eliminating an OH group therefrom. Such acids include, for example, carboxylic acids, sulfonic acids, carbonic acid, carbamic acid, sulfuric acid, nitric acid, phosphoric acids and boric acids. The catalyst may include the imide compound and a metallic compound in combination. In the presence of the catalyst, (A) a compound capable of forming a radical is allowed to react with (B) a radical scavenging compound and thereby yields an addition or substitution reaction product of the compound (A) and the compound (B) or a derivative thereof. This catalyst can produce an organic compound with a high selectivity in a high yield as a result of, for example, an addition or substitution reaction under mild conditions.
Abstract:
The present invention relates to a novel method for preparing a catalyst for partial oxidation of methylbenzenes, comprising, (a) a step of preparing a solution or slurry of the compounds comprising tungsten; (b) a step of supporting the solution or slurry obtained in the step (a) on inorganic carrier; (c) a step of drying the catalyst obtained in the step (b); and (d) a step of calcining the dried catalyst obtained in the step (c), characterized in that the ratio of the pore volume of inorganic carrier and the volume of the solution or slurry in the step (b) is 1:0.9˜1.1, and the catalyst provides superior aromatic aldehydes selectivity to those prepared by the conventional impregnation or heat evaporation method over a wide range of conversion rate.
Abstract:
A shell-and-tube heat exchanger-type reactor including one or more catalytic tubes, each including a first-step reaction zone and a second-step reaction zone, wherein at least one of the first-step reaction zone and the second-step reaction zone is divided into two or more shell spaces by a partition; each of the divided shell spaces is independently heat-controlled; and a heat transfer medium having a temperature from the lowest active temperature of a catalyst layer in a reaction tube corresponding to the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone to the lowest active temperature of the catalyst layer plus 20° C.; and the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone is controlled so as to provide a reactant conversion contribution per length of 1.2˜2.5.
Abstract:
The invention relates to mixed oxide catalysts for the catalytic gas-phase oxidation of olefins and methylated aromatics, processes for producing the catalysts and the reaction with air or oxygen in the presence of inert gases in various ratios at elevated temperatures and pressure to form aldehydes and carboxylic acids.
Abstract:
The present invention relates to a method and an apparatus for continuously separating aromatic dialdehyde from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene. The method for continuously separating aromatic dialdehyde includes the steps of congealing aromatic dialdehyde by cooling the gas-phase reaction mixture including the aromatic dialdehyde, which is obtained by gas-phase oxidation of dimethylbenzene, to 5-70° C. and separating the congealed aromatic dialdehyde from the remaining reaction mixture. Using the method and apparatus in accordance with the present invention, aromatic dialdehyde can be effectively and selectively separated from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene in high yield.
Abstract:
The present invention relates to a method for preparing an aromatic dialdehyde, comprising, a) a step of gas phase oxidation reaction for preparing aromatic dialdehyde from dimethyl benzene; b) a step of separation for selectively recovering crude aromatic dialdehyde of molten phase from the reaction product of the step (a); and c) a step of purification for obtaining highly pure aromatic dialdehyde by purifying said crude aromatic dialdehyde, and a manufacturing system used for the preparation method. The method for preparation of the aromatic dialdehyde according to the present invention is simple, effective, and advantageous in that highly pure aromatic dialdehyde can be continuously prepared.
Abstract:
The present invention relates to a method and an apparatus for continuously separating aromatic dialdehyde from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene. The method for continuously separating aromatic dialdehyde includes the steps of congealing aromatic dialdehyde by cooling the gas-phase reaction mixture including the aromatic dialdehyde, which is obtained by gas-phase oxidation of dimethylbenzene, to 5-70° C. and separating the congealed aromatic dialdehyde from the remaining reaction mixture. Using the method and apparatus in accordance with the present invention, aromatic dialdehyde can be effectively and selectively separated from a reaction mixture obtained by gas-phase oxidation of dimethylbenzene in high yield.