Abstract: Processes for recovering 4,4'-dimethyl bibenzoate (DMBB) from byproduct streams of dimethyl terephthalate (DMT) production are disclosed. The byproduct streams are treated to produce an overhead stream which includes DMBB. In one aspect of the invention, the overhead product stream is added to an organic solvent under conditions sufficient to rapidly form a suspension of crystallized DMBB. In another aspect of the invention, the overhead is dissolved in an appropriate organic solvent and cooled to form a suspension of DMBB crystals in the solvent. A portion of the suspension is removed, and the remaining portion of the suspension centrifuged to recover DMBB crystals. In still another aspect of the invention, the overhead stream is treated with an organic solvent to form a slurry of DMBB crystals, and the resultant slurry thermally treated to increase the concentration of DMBB crystals therein while also solubilizing any organic contaminants.

Abstract: A valve for obtaining a sample from a continuous flow of fluid includes a primary flow path for directing a continual flow of the fluid through the valve, a valve stem which engages a passage in a valve seat for metering a sample of fluid passing through the primary flow path out through a separate outlet passage in the valve. The valve further includes a passage separate from the primary flow path for injecting a purge gas into the sample outlet passage to remove any sample fluid contained in the outlet passage after the sample valve has been closed and before the sample container is taken off-line so as to avoid atmospheric emissions of the sample fluid.

Abstract: A valve for metering a slurry includes a primary flow path for directing a continual flow of slurry through the valve, a valve stem which extends through the primary flow path and engages a passage in a valve seat for metering a portion of slurry passing through the primary flow path out through a second outlet in the valve. A portion of the valve stem which engages the valve seat passage is cut-away and when placed in communication with the primary flow path allows the flushing of accumulated solids through the valve seat passage to avoid persistent plugging of the valve.

Abstract: A continuous process is disclosed for the acylation or alkylation of aromatic compounds in hydrogen fluoride. The aromatic compound is sufficiently insoluble in hydrogen fluoride that a two phase reaction medium forms. However, surprisingly, the product acylated or alkylated aromatic compound is soluble in hydrogen fluoride. The present invention particularly relates to use of a continuous, multi-stage process for carrying out the acylation or alkylation reaction. In the multi-stage process, the continuous phase can be either the hydrogen-fluoride rich phase or the aromatic compound-rich phase. The movement of the continuous phase relative to the non-continuous (dispersed) phase can be countercurrent or concurrent. The multi-stage process can be operated in a manner such that the aromatic compound feed to the reaction is entirely consumed or such that unreacted aromatic compound is recycled.

Abstract: A continuous process is provided for the production of 4'-isobutylacetophenone (4-IBAP) comprising feeding liquid hydrogen fluoride (HF) and an acetylating agent into an extractor-reactor to form a first, HF-rich phase containing the acetylating agent, feeding isobutylbenzene (IBB) to the extractor-reactor to form a second, IBB-rich phase which is contacted with said first, HF-rich phase in a manner such that the acetylating agent reacts with IBB to form 4-IBAP which is extracted into the first, HF-rich phase, and a light IBB-rich second phase containing the bulk of unreacted IBB, externally recycling said second, IBB-rich phase to the IBB feed point in combination with fresh IBB to make up for IBB consumed in the reaction and that and dissolved in the HF-rich phase, and withdrawing HF-rich phase containing 4-IBAP from the extractor-reactor.