There is provided a catalyst that enables the production of isobutylene with a high selectivity in the production of isobutylene by dehydration of isobutanol. The catalyst according to the present invention contains at least one metal selected from Group 6 to Group 14 metal elements in Period 4 to Period 6 of the periodic table, in alumina which includes alumina consisting of one or more crystal phases of a monoclinic crystal phase, a tetragonal crystal phase, and a cubic crystal phase.

There is provided a catalyst that enables the production of isobutylene with a high selectivity in the production of isobutylene by dehydration of isobutanol. The catalyst according to the present invention contains at least one metal selected from Group 6 to Group 14 metal elements in Period 4 to Period 6 of the periodic table, in alumina which includes alumina consisting of one or more crystal phases of a monoclinic crystal phase, a tetragonal crystal phase, and a cubic crystal phase.

A method includes supplying a gas containing acrolein to a fixed bed reactor including a reaction tube to produce acrylic acid by vapor phase catalytic oxidation of acrolein. The reaction tube is packed with catalysts having different activities in such a way that catalyst layers are formed in a tube axis direction. A catalyst X having the highest activity among the catalysts contained in all the catalyst layers is placed in the whole or a part of a section up to 30% of a length of all the catalyst layers from a rearmost portion on a gas outlet side toward a gas inlet side. A catalytically active component x in the catalyst X has Mo, V, and optionally Cu. When Cu is included, its amount is 0.8 mol or less per 12 mol of Mo. A specific surface area of the catalytically active component x is 15-40 m.sup.2/g.

A method includes supplying a gas containing acrolein to a fixed bed reactor including a reaction tube to produce acrylic acid by vapor phase catalytic oxidation of acrolein. The reaction tube is packed with catalysts having different activities in such a way that catalyst layers are formed in a tube axis direction. A catalyst X having the highest activity among the catalysts contained in all the catalyst layers is placed in the whole or a part of a section up to 30% of a length of all the catalyst layers from a rearmost portion on a gas outlet side toward a gas inlet side. A catalytically active component x in the catalyst X has Mo, V, and optionally Cu. When Cu is included, its amount is 0.8 mol or less per 12 mol of Mo. A specific surface area of the catalytically active component x is 15-40 m.sup.2/g.

A strengthening oxidation system of the external micro-interfacial unit for producing PTA with PX is provided, including: a reactor, a circulating heat exchange device and a micro-interfacial unit. The reactor includes an outer casing and an inner cylinder disposed concentrically inside the outer casing. The circulating heat exchange device is disposed at an exterior of the reactor, and is connected with the outer casing and the inner cylinder respectively, for regulating reaction temperatures of the first reaction zone, the second reaction zone and the third reaction zone inside the reactor in a reaction process of producing PTA with PX. the micro-interfacial unit is connected between the reactor and the circulating heat exchange device, and connected with an external feed pipe of the reactor, for crushing a gas phase material into micro bubbles with a diameter greater than or equal to 1 μm and less than 1 mm and for mixing the micro bubbles with a liquid phase material to form an emulsion at the exterior of the reactor before a reaction material enters each of the reaction zones inside the reactor.

A strengthening oxidation system of the external micro-interfacial unit for producing PTA with PX is provided, including: a reactor, a circulating heat exchange device and a micro-interfacial unit. The reactor includes an outer casing and an inner cylinder disposed concentrically inside the outer casing. The circulating heat exchange device is disposed at an exterior of the reactor, and is connected with the outer casing and the inner cylinder respectively, for regulating reaction temperatures of the first reaction zone, the second reaction zone and the third reaction zone inside the reactor in a reaction process of producing PTA with PX. the micro-interfacial unit is connected between the reactor and the circulating heat exchange device, and connected with an external feed pipe of the reactor, for crushing a gas phase material into micro bubbles with a diameter greater than or equal to 1 μm and less than 1 mm and for mixing the micro bubbles with a liquid phase material to form an emulsion at the exterior of the reactor before a reaction material enters each of the reaction zones inside the reactor.

A method is described for producing a catalyst having a high raw material conversion rate and a high product selectivity, as well as an excellent yield of unsaturated carboxylic acid, the catalyst being used in a vapor-phase catalytic oxidation reaction for producing an unsaturated carboxylic acid such as acrylic acid or methacrolein from an unsaturated aldehyde such as acrolein or methacrolein. The method includes a molding process of molding a powder containing a catalyst component element to produce a catalyst precursor, where a sulfur-containing inorganic compound is added to the powder, and the powder is molded in the molding process.

A method is described for producing a catalyst having a high raw material conversion rate and a high product selectivity, as well as an excellent yield of unsaturated carboxylic acid, the catalyst being used in a vapor-phase catalytic oxidation reaction for producing an unsaturated carboxylic acid such as acrylic acid or methacrolein from an unsaturated aldehyde such as acrolein or methacrolein. The method includes a molding process of molding a powder containing a catalyst component element to produce a catalyst precursor, where a sulfur-containing inorganic compound is added to the powder, and the powder is molded in the molding process.

The present application relates to a compound of the following formula (I)

##STR00001## in which —R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represent independently of each other H or a (C.sub.1-C.sub.30) alkyl group, the total sum of the number of carbon atoms of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 being equal to 6+4x, x being a whole number of between 1 and 6, provided that: at most two of the groups R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are H, R.sup.5 represents H, OR, or NR′R″ R, R′ and R″, identical or different, represent H, a (C1-C10) alkyl group, at least one of groups R.sup.1, R.sup.2, R.sup.3 or R.sup.4 comprises or is a tertiobutyl group. (I) the method for preparing same and the uses thereof as a plasticising lubricant, surfactant or in a cosmetic composition.

The present application relates to a compound of the following formula (I)

##STR00001## in which —R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represent independently of each other H or a (C.sub.1-C.sub.30) alkyl group, the total sum of the number of carbon atoms of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 being equal to 6+4x, x being a whole number of between 1 and 6, provided that: at most two of the groups R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are H, R.sup.5 represents H, OR, or NR′R″ R, R′ and R″, identical or different, represent H, a (C1-C10) alkyl group, at least one of groups R.sup.1, R.sup.2, R.sup.3 or R.sup.4 comprises or is a tertiobutyl group. (I) the method for preparing same and the uses thereof as a plasticising lubricant, surfactant or in a cosmetic composition.