摘要:
The invention relates to a method for regenerating acidic cation exchangers, which are used as catalysts in the reaction of phenols with aldehydes or ketones to give bisphenols, in particular to give bisphenol A, with acids, with the proviso that, in the method according to the invention, these cation exchangers experience very little mechanical damage due to swelling processes during the regeneration process.
摘要:
The invention relates to a method for regenerating acidic cation exchangers, which are used as catalysts in the reaction of phenols with aldehydes or ketones to give bisphenols, in particular to give bisphenol A, with acids, with the proviso that, in the method according to the invention, these cation exchangers experience very little mechanical damage due to swelling processes during the regeneration process.
摘要:
Processes for producing bisphenols (e.g., bisphenol A (BPA)) having a purity greater than 99.7% are described, such processes including reacting a phenol and acetone in the presence of an acidic catalyst to form a product mixture comprising a bisphenol; removing at least a portion of the bisphenol from the product mixture in the form of a bisphenol/phenol adduct by crystallization, filtration and washing to provide bisphenol/phenol adduct crystals; and removing at least a portion of the phenol from the bisphenol/phenol adduct crystals to provide the bisphenol having a purity of more than 99.7%; wherein the crystallization comprises continuous suspension crystallization and is carried out in at least three crystallization devices arranged such that the product mixture is first cooled in a first stage of the crystallization to a temperature of 50 to 70° C. in a first crystallization device and a second crystallization device connected in parallel, and subsequently cooled in a second stage of the crystallization to a temperature of 40 to 50° C. in a third crystallization device connected downstream in series to the first and second crystallization devices, and wherein a total dwell time of the product mixture in the crystallization is more than 4 hours.
摘要:
A process for the storage or transportation of pretreated, conditioned ion exchangers as catalysts for chemical reactions is disclosed. The preconditioned ion-exchange resin is kept as preconditioned ion-exchange resin suspension in a storage or transporting container. The container with the preconditioned ion-exchange resin suspension is transported to either a storage site for storage or to a reactor for transfer of the resin to the reactor.
摘要:
The invention relates to a composition containing at least one microgel, at least one carbon nanotube and at least one organic medium. Said organic medium can be cross-linked or non cross-linked.
摘要:
The present invention relates to a process for the production of carbon nanotubes by decomposition of hydrocarbons on a heterogeneous catalyst in a fluidized bed reactor, wherein the reactor can be operated batchwise or continuously, and in the case of continuous operation discharge can take place with sifting or without sifting.
摘要:
Process for the continuous production of catalysts which are useful for the production of carbon nanotubes by decomposition of gaseous carbon compounds.
摘要:
The present invention relates to an aromatic branched polycarbonate, produced via melt transesterification of a bisphenol with a diaryl carbonate in the presence of a branching agent, wherein the aromatic branched polycarbonate comprises branching point structures and structures of formula (D) wherein X is a single bond, C1- to C6-alkylene, C2- to C5-alkylidene or C5- to C6-cycloalkylidene, optionally substituted by C1- to C6-alkyl; wherein the amount of D in the aromatic branched polycarbonate is in the range of from 5 to 450 mg per kg of the aromatic branched polycarbonate; and wherein the ratio of the total branching point structures to the total structures of the formula D in the aromatic branched polycarbonate is in the range of from 8 to 200.
摘要:
The present invention relates to a process for the production of carbon nanotubes, in particular those having a diameter of 3-150 nm and an aspect ratio of length:diameter (L:D)>100, by decomposition of hydrocarbons on a heterogeneous catalyst which comprises Mn, Co, preferably also molybdenum, and an inert support material, and the catalyst and the carbon nanotubes themselves and the use thereof.
摘要:
The present invention is directed to a composition comprising a tris-hydroxyaryl compound having a metal ion impurity content of less than 10 ppm and to a process for the purification of tris-hydroxyaryl compound having a metal ion impurity, comprising at least the following steps: a) conditioning a sulphonic acid group-containing active ion exchanger with a solvent which is suitable for the handling of the tris-hydroxyaryl compounds, b) producing a solution of the tris-hydroxyaryl compounds to be purified in a solvent which is suitable for the handling of the tris-hydroxyaryl compounds, c) contacting the tris-hydroxyaryl compound-containing solution from b) with the conditioned ion exchanger from a), d) separating the tris-hydroxyaryl compound-containing solution from c) from the conditioned ion exchanger, e) removing at least part of the solvent from the solution of the tris-hydroxyaryl compound separated in d) under low temperature stress.