The present disclosure relates to the recovery of an alkoxide catalyst used in a process depolymerizing a polyester to form a diacid or diester and a diol. The present disclosure also relates to the recovery of an alkoxide catalyst used in a process depolymerizing polyethylene terephthalate to form dimethyl terephthalate and mono ethylene glycol.

The present disclosure relates to the recovery of an alkoxide catalyst used in a process depolymerizing a polyester to form a diacid or diester and a diol. The present disclosure also relates to the recovery of an alkoxide catalyst used in a process depolymerizing polyethylene terephthalate to form dimethyl terephthalate and mono ethylene glycol.

The invention provides a process for regenerating a catalyst used for the ring hydrogenation of an aromatic species, especially an aromatic ester, wherein a gas stream containing a particular amount of oxygen is used for the regeneration.

The present disclosure is directed to a non-destructive process for removing metals, metal ions and metal oxides in alumina-based materials without destroying alumina, allowing the regeneration of alumina-based catalysts. The non-destructive process uses an extracting agent that sequesters metals, metal ions and/or metal oxides present in alumina-based materials without destroying the alumina, allowing the regeneration of alumina-based catalysts.

The present disclosure is directed to a non-destructive process for removing metals, metal ions and metal oxides in alumina-based materials without destroying alumina, allowing the regeneration of alumina-based catalysts. The non-destructive process uses an extracting agent that sequesters metals, metal ions and/or metal oxides present in alumina-based materials without destroying the alumina, allowing the regeneration of alumina-based catalysts.

Embodiments provide a method for determining a chloride content of an alumina-based catalyst used for catalytic reforming. The method includes the step of combining nitric acid, isopropanol, and the alumina-based catalyst such that the alumina-based catalyst is dissolved in the nitric acid and the isopropanol to form a homogenized mixture. The alumina-based catalyst include chloride. The method includes the step of taking a conductivity measurement of the homogenized mixture using a pair of electrodes. The method includes the step of introducing a titrant solution comprising silver nitrate to the homogenized mixture such that a precipitate of silver chloride is formed. The method includes the step of determining a chloride concentration of the homogenized mixture based on the conductivity measurement of the homogenized mixture. The method includes the step of determining the chloride content of the alumina-based catalyst based on the chloride concentration of the homogenized mixture.

Embodiments provide a method for determining a chloride content of an alumina-based catalyst used for catalytic reforming. The method includes the step of combining nitric acid, isopropanol, and the alumina-based catalyst such that the alumina-based catalyst is dissolved in the nitric acid and the isopropanol to form a homogenized mixture. The alumina-based catalyst include chloride. The method includes the step of taking a conductivity measurement of the homogenized mixture using a pair of electrodes. The method includes the step of introducing a titrant solution comprising silver nitrate to the homogenized mixture such that a precipitate of silver chloride is formed. The method includes the step of determining a chloride concentration of the homogenized mixture based on the conductivity measurement of the homogenized mixture. The method includes the step of determining the chloride content of the alumina-based catalyst based on the chloride concentration of the homogenized mixture.

The present invention addresses to a method of maintaining the activity of pre-reform catalysts in hydrogen production units, in order to avoid deactivation by oxidation or coke deposition of pre-reform catalysts in the absence of hydrogen in the feed consisting of hydrocarbon and water vapor.

The present invention addresses to a method of maintaining the activity of pre-reform catalysts in hydrogen production units, in order to avoid deactivation by oxidation or coke deposition of pre-reform catalysts in the absence of hydrogen in the feed consisting of hydrocarbon and water vapor.

Realized is a method for restoring the activity of a catalyst for producing a carbonate ester by a simple technique with no use of a complicated step such as calcining or the like to allow the catalyst to be reusable, and a method for producing a carbonate ester at a high yield by use of the catalyst thus regenerated. The above-described problem has been solved by a method for regenerating a catalyst containing CeO.sub.2, the catalyst being usable for a carbonate ester generation reaction of generating a carbonate ester from carbon dioxide and an alcohol, the method comprising (a) a separation step of separating the catalyst as a crude catalyst from a reaction solution of carbon dioxide and the alcohol; and (b) a catalyst processing step of washing the crude catalyst with a washing alcohol to provide a purified catalyst.