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Class Information
Number: 203/75
Name: Distillation: processes, separatory > Plural distillations performed on same material > One a distillation under positive pressure or vacuum > Distillation of initial distillate > And return of distillation product to a previous distillation zone
Description: Processes in which a product from a later distillation operation is returned in terms of the process to a distillation zone prior to the distillation zone in which the product was produced.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7553397 |
Process |
Jun. 30, 2009 |
| 7501047 |
Method for purifying caprolactam |
Mar. 10, 2009 |
| 7468119 |
Separation of 6-aminocapronitrile and hexamethylenediamine from a mixture comprising hexamethylenediamine, 6-aminocapronitrile and tetrahydroazepine |
Dec. 23, 2008 |
| 7351311 |
Method for purifying tetrahydrofuran by distillation |
Apr. 1, 2008 |
| 7339088 |
Alkylbenzene refining process and apparatus |
Mar. 4, 2008 |
| 7311813 |
Distillation sequence for the purification and recovery of hydrocarbons |
Dec. 25, 2007 |
| 7147757 |
Method for separating an azepine derivative out of a mixture containing an amine an azepine derivative |
Dec. 12, 2006 |
| 7128813 |
Process for manufacturing high purity methacrylic acid |
Oct. 31, 2006 |
| 7074971 |
Recovery of ethylene and propylene from a methanol to olefin reaction system |
Jul. 11, 2006 |
| 6998026 |
Method for producing tertiary C.sub.4-C.sub.8-alkyl esters of (meth)acrylic acid |
Feb. 14, 2006 |
| 6972075 |
Method for removing 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine |
Dec. 6, 2005 |
| 6896772 |
Method for separating ammonia from solutions containing caprolactam and ammonia |
May. 24, 2005 |
| 6846389 |
Method for distillative separation of mixtures containing tetrahydrofuran, .gamma.-butyrolactone and/or 1,4-butanediol |
Jan. 25, 2005 |
| 6692616 |
Method for purifying trimethylolpropane, which is produced by hydrogenation, by means of continuous distillation |
Feb. 17, 2004 |
| 6632330 |
Process for purification of alkyl alkanoate |
Oct. 14, 2003 |
| 6599398 |
Recovery of adiponitrile from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine |
Jul. 29, 2003 |
| 6508916 |
Process for recovering processing liquids |
Jan. 21, 2003 |
| 6500310 |
Process for the treatment of waste water |
Dec. 31, 2002 |
| 6488817 |
Purification of hydrofluorocarbons |
Dec. 3, 2002 |
| 6472568 |
Reaction and distillation device and etherification process |
Oct. 29, 2002 |
| 6444096 |
Process for the recovery and purification of cyclobutanone |
Sep. 3, 2002 |
| 6299734 |
Preparation of an aqueous solution of free hydroxylamine |
Oct. 9, 2001 |
| 6296739 |
Operation of heads column |
Oct. 2, 2001 |
| 6252110 |
Methods for recovering acrylic acid |
Jun. 26, 2001 |
| 6214173 |
On-site manufacture of ultra-high-purity nitric acid |
Apr. 10, 2001 |
| 6214172 |
Preparation of methylglyoxal dimethyl acetal |
Apr. 10, 2001 |
| 6210583 |
Spent caustic pretreatment and enhanced oxidation process |
Apr. 3, 2001 |
| 6159344 |
Reaction and distillation device |
Dec. 12, 2000 |
| 6160185 |
Process for purification of methylal |
Dec. 12, 2000 |
| 6106674 |
Operable and efficient distillation schemes for multicomponent separations |
Aug. 22, 2000 |
| 6048441 |
Isolation of neopentyl glycol hydroxypivalate (NGH) |
Apr. 11, 2000 |
| 6015875 |
Process for making acetals |
Jan. 18, 2000 |
| 5993608 |
Process for recovering processing liquids |
Nov. 30, 1999 |
| 5985100 |
Process for separating butanol and dibutyl ether by means of dual-pressure distillation |
Nov. 16, 1999 |
| 5948213 |
Processes for the manufacture and purification of 1,1,2,2,3,3,4,4-octafluorobutane and by-products, and azeotropes with HF |
Sep. 7, 1999 |
| 5908964 |
Process for preparing alkyl ethers and mixtures thereof |
Jun. 1, 1999 |
| 5885422 |
Spent caustic (pre)treatment process |
Mar. 23, 1999 |
| 5853551 |
Process for the separation of alpha-olefins by distillation of an effluent comprising ethylene and 1-butene |
Dec. 29, 1998 |
| 5804040 |
Purification process for silane compound |
Sep. 8, 1998 |
| 5779861 |
Method for treating process condensate |
Jul. 14, 1998 |
| 5723026 |
Process for recovering pure benzene and pure toluene from aromatic hydrocarbon products |
Mar. 3, 1998 |
| 5707497 |
Process for the separation of hydrogen fluoride and of difluoromethane |
Jan. 13, 1998 |
| 5705039 |
Process for purifying a 2,6-dialkylphenol |
Jan. 6, 1998 |
| 5700358 |
Recovery of caprolactam from oligomers and/or polymers of caprolactam |
Dec. 23, 1997 |
| 5679223 |
Method for separating and purifying catechol mixtures |
Oct. 21, 1997 |
| 5675054 |
Low cost thermal coupling in ethylene recovery |
Oct. 7, 1997 |
| 5643420 |
Method for treating process condensate |
Jul. 1, 1997 |
| 5635590 |
Process and polycondensation apparatus for the treatment of contaminated ethylene glycol |
Jun. 3, 1997 |
| 5587047 |
Method for separating boric acid |
Dec. 24, 1996 |
| 5534151 |
Process for separating and recovering halocarbons from mixtures thereof |
Jul. 9, 1996 |
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