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Class 203/75 - And return of distillation product to a previous distillation zone


Subclass of Class 203 - Distillation: processes, separatory
Definition: Processes in which a product from a later distillation operation
No. of patents: 140
Last issue date: 04/01/2008


1        
NumberTitleIssue Date
7351311Method for purifying tetrahydrofuran by distillation
Crude water-containing tetrahydrofuran is purified by passing the crude tetrahydrofuran through three distillation columns, withdrawing water from the bottom of the first column, recycling water-containing tetrahydrofuran from the top of the second column into the f...
04/01/2008
7339088Alkylbenzene refining process and apparatus
Improved processes and apparatus use a finishing column with a mid-cut that provides alkylbenzene products of high purity containing less than about 1 ppmw benzene and less than about 50 ppmw heavies while accommodating enhancements in the efficiencies and the capac...
03/04/2008
7329330Method and device for the distillative processing of 1,6-hexanediol, 1,5-pentanediol and caprolactone
A process for working up by distillation the crude products obtained in the process according to DE-A 196 07 954 and containing 1,6-hexanediol (HDO), 1,5-pentanediol (PDO) or caprolactone (CLO) in order to obtain the corresponding pure products, the working-up by di...
02/12/2008
7311813Distillation sequence for the purification and recovery of hydrocarbons
This invention is an improved distillation sequence for the separation and purification of ethylene from a cracked gas. A hydrocarbon feed enters a C2 distributor column. The top of the C2 distributor column is thermally coupled to an ethylene distributor column, an...
12/25/2007
7268194Continuous slurry polymerization process and apparatus
A process of converting a loop reactor into multiple loop reactors comprising starting with a loop reactor comprising at least 8 vertical legs, at least two non-vertical conversion runs, each non-vertical run connected in fluid flow communication with two vertical l...
09/11/2007
7264696Dividing-wall column with feed in whole or in part in the vaporous state and/or side stream take off in whole or in part in the vaporous state
A dividing-wall column having a dividing wall which is essentially disposed along the long direction of the column is proposed, which divides the column interior into a feed part, a take off part, an upper shared column part and a lower shared column part, with feed...
09/04/2007
7249469Method for separating a multicomponent stream
This invention relates to a method for separating a stream having benzene, toluene and alkyl benzene, said method comprising: feeding the stream into a first distillation column, wherein the stream comprises between about 60 mole percent to about 85 mole percent tol...
07/31/2007
7241928Process for the manufacture of halocarbons and selected compounds and azeotropes with HF
A liquid phase process is disclosed for producing halogenated alkane adducts of the formula CAR1R2CBR3R4 (where A, B, R1, R2, R3, and R4 are as defined in the specification) whic...
07/10/2007
7189311Purification of difluoromethane
A method for separating difluoromethane from a mixture of difluoromethane and at least one impurity, the method involving extractively distilling the mixture using dichloromethane as an extractive agent to recover a product stream of purified difluoromethane having ...
03/13/2007
7169267Method and device for carrying out the distillative separation of C cuts
A process is proposed for the separation of C5+ cuts by distillation into a low-boiler (A), a medium-boiler (B) and a high-boiler fraction (C) in one or more dividing-wall columns (TK), in which a dividing wall (T) is arranged in the longitudinal directio...
01/30/2007
7147757Method for separating an azepine derivative out of a mixture containing an amine an azepine derivative
The invention relates to a method for separating by distillation a portion or the entirety of an azeptine derivative (III), which is selected from the group consisting of aminohexylidene imine, tetrahydroazepine, hexylhexahydroazepine and of aminohexylhexahydroazepi...
12/12/2006
7132038Method and device for obtaining 1,3 pure butadiene from 1,3 raw butadiene by distillation
A process for obtaining pure 1,3-butadiene from crude 1,3-butadiene by distillation is carried out in a dividing wall column in which a dividing wall is located in the longitudinal direction of the column to form an upper common column region, a lower common column ...
11/07/2006
7128813Process for manufacturing high purity methacrylic acid
A process for the high yield production of high purity glacial methacrylic acid (“HPMAA”) with minimization of decomposition of hydroxy isobutyric acid (HIBA). The HPMAA is substantially pure, specifically 99% pure or greater with a water content of 0.05% or les...
10/31/2006
7074971Recovery of ethylene and propylene from a methanol to olefin reaction system
The present invention provides new highly-efficient separation processes and systems for separating polymerization-grade ethylene and propylene from an initial effluent stream comprising ethane, ethylene, propylene, dimethyl ether, and one or more of propane, acetyl...
07/11/2006
6998026Method for producing tertiary C-C-alkyl esters of (meth)acrylic acid
A tert-C4–C8-alkyl (meth)acrylate is prepared by reacting (meth)acrylic acid with an olefin of the formula where R1 and R2, which may be i...
02/14/2006
6977235Catalyst systems comprising a calcined chromium catalyst and a non-transition metal cyclopentadienyl cocatalyst
According to an embodiment, catalyst systems for polymerizing olefins include a catalyst comprising chromium and a cocatalyst comprising a substituted or unsubstituted non-transition metal cyclopentadienyl compound (Cp). The catalyst also comprises an inorganic oxid...
12/20/2005
6972075Method for removing 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine
The invention relates to a method for removing, by distillation, 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine, by a) removing the hexamethylenediamine from the mixture while obtaining a mixture (I) that ...
12/06/2005
6926868Continuous slurry polymerization volatile removal
A process/apparatus is disclosed for continuously separating a liquid medium comprising diluent and unreacted monomers from a polymerization effluent of a slurry loop reactor containing a flow of slurry therein, comprising a discharge conduit extending a distance in...
08/09/2005
6896772Method for separating ammonia from solutions containing caprolactam and ammonia
A process for distillative removal of ammonia from solutions (I) which include a lactam and ammonia comprises effecting said removal in a distillation apparatus (a) at an absolute pressure of less than 10 bar. ...
05/24/2005
6846389Method for distillative separation of mixtures containing tetrahydrofuran, γ-butyrolactone and/or 1,4-butanediol
In a process for the continuous fractional distillation of mixtures comprising tetrahydrofuran, γ-butyrolactone and/or 1,4-butanediol to give at least three fractions, the fractionation is carried out in an assembly of distillation columns comprising at least one d...
01/25/2005
6692616Method for purifying trimethylolpropane, which is produced by hydrogenation, by means of continuous distillation
A process is disclosed for the purification, by distillation, of trimethylolpropane originating from the hydrogenation of 2,2-dimethylolbutanal, said process including the following steps: (a) reaction of n-butyraldehyde with formaldehyde in the presence o...
02/17/2004
6632330Process for purification of alkyl alkanoate
A process for the recovery of substantially pure alkyl alkanoate, such as ethyl acetate, from an impure feedstock. The impure feedstock is contacted with a selective hydrogenation catalyst in the presence of hydrogen in a selective hydrogenation zone main...
10/14/2003
6599398Recovery of adiponitrile from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine
Process for the recovery of a purified adiponitrile (ADN) from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine, utilizing two sequential distillations: (1) a first distillation in which the mixture is distilled in a distillation colu...
07/29/2003
6508916Process for recovering processing liquids
A process for recovering processing liquids such as gas-treating liquids wherein a feed mixture containing the processing liquid, water, and optionally additional components that are more volatile than the processing liquid and components that are less vo...
01/21/2003
6500310Process for the treatment of waste water
A process for treating waste water streams containing at least hydrocarbons and salts to yield a clean water product, a concentrated brine product and a hydrocarbon-rich product, which process includes the steps of: (a) feeding the waste water feed into a...
12/31/2002
6488817Purification of hydrofluorocarbons
A process for the purification of difluoromethane comprising: (a) subjecting a mixture comprising at least difluoromethane (HFC-32) and dichlorodifluoromethane (CFC-12) to a first distillation step in which a majority of either CFC-12 or HFC-32 is concentrated...
12/03/2002
6472568Reaction and distillation device and etherification process
The invention relates to a process for preparing at least one aliphatic monoalcohol, generally in excess, and at least one olefin. The process is performed in a distillation and reaction device having a reaction section and a distillation-reaction section...
10/29/2002
6444096Process for the recovery and purification of cyclobutanone
A process for the recovery and purification of cyclobutanone from a crude product mixture obtained from an oxidation product mixture resulting from the oxidation of cyclobutanol to cyclobutanone in the presence of water. The process provides for the recov...
09/03/2002
6299734Preparation of an aqueous solution of free hydroxylamine
An aqueous solution of free hydroxylamine is prepared by treating a hydroxylammonium salt with ammonia by the countercurrent method in a stripping column by a process in which hydroxylamine is liberated and at the same time the solution obtained is separa...
10/09/2001
6296739Operation of heads column
A process for the enhanced recovery and operation of hydrogen cyanide (HCN) / heads column obtained from the reactor effluent of an ammoxidation reaction of propane, propylene or isobutylene by reducing the polymer formation above the feed tray in the hea...
10/02/2001
6252110Methods for recovering acrylic acid
A method for recovering acrylic acid from high boiling impurities containing acrylic acid dimer, acrylic acid and maleic acid at high efficiency with stability which includes the steps of (1) introducing said high boiling impurities containing acrylic aci...
06/26/2001
6214173On-site manufacture of ultra-high-purity nitric acid
Provided is a novel on-site system and method for providing ultra-high-purity nitric acid to a point of use. The system includes a source of nitric acid at a concentration greater than 68 wt %; a reflux distillation column having an inlet in communication...
04/10/2001
6214172Preparation of methylglyoxal dimethyl acetal
In a process for the preparation of methylglyoxal dimethyl acetal from methylglyoxal and methanol in the presence of an acidic ion exchanger, water is introduced in an amount sufficient to form an acidic reaction mixture in which the acetal product and wa...
04/10/2001
6210583Spent caustic pretreatment and enhanced oxidation process
A process for pre-treating a spent caustic stream prior to oxidation which includes countercurrent multi-stage elevated temperature solvent extraction of dissolved organic material from the spent caustic using a solvent to yield a spent caustic raffinate ...
04/03/2001
6159344Reaction and distillation device
The invention relates to a distillation and reaction device having a reaction section and a distillation-reaction section. The distillation-reaction section has a distillation zone with at least one device for circulation of the effluent from the reaction...
12/12/2000
6160185Process for purification of methylal
Provided is a process for high purification of methylal by removing water and methanol present as impurities from the methylal. The process for purification of methylal comprises subjecting a methylal gas containing water and methanol and a polyalkylene g...
12/12/2000
6106674Operable and efficient distillation schemes for multicomponent separations
The present invention teaches an efficient and easier to operate distillation system to separate mixtures containing three or more components into streams enriched in one of the components. In this invention, a liquid stream enriched in the least volatile...
08/22/2000
6048441Isolation of neopentyl glycol hydroxypivalate (NGH)
Neopentyl glycol hydroxypivalate (NGH) is isolated from a mixture containing NGH, lower- and higher-boiling products and inorganic salts and purified in a two-stage process, wherein in a first separation stage, the inorganic salts and part of the higher-b...
04/11/2000
6015875Process for making acetals
Acetals are produced from the reaction of aldehydes and alcohols, e.g. methylal by the reaction of methanol and formaldehyde, by the reaction in a reaction distillation column of the alcohol and aldehyde in the presence of a catalyst and the concurrent fr...
01/18/2000
5993608Process for recovering processing liquids
A process for recovering processing liquids such as gas-treating liquids wherein a feed mixture containing the processing liquid and components or impurities that are more volatile and less volatile than the processing liquid is initially heated in a firs...
11/30/1999
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