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Class Information
Number: 203/78
Name: Distillation: processes, separatory > Plural distillations performed on same material > One a distillation under positive pressure or vacuum > And returning distillation product to a previous distillation zone
Description: Processes in which a product from a later distillation operation is returned in term 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 |
| 7619126 |
Method for obtaining crude 1,3-butadiene from a C.sub.4 fraction |
Nov. 17, 2009 |
| 7575660 |
Process for the distillative separation of aqueous amine solutions |
Aug. 18, 2009 |
| 7563360 |
Mercury-removal process in distillation tower |
Jul. 21, 2009 |
| 7560590 |
Rectificative separation of an acrylic acid-containing liquid |
Jul. 14, 2009 |
| 7553397 |
Process |
Jun. 30, 2009 |
| 7468119 |
Separation of 6-aminocapronitrile and hexamethylenediamine from a mixture comprising hexamethylenediamine, 6-aminocapronitrile and tetrahydroazepine |
Dec. 23, 2008 |
| 7449088 |
Process for obtaining fatty acids with improved odor, color and heat stability |
Nov. 11, 2008 |
| 7416645 |
Continuous process for recovering acetone from a waste stream resulting from acetone purification |
Aug. 26, 2008 |
| 7410556 |
Purification of aqueous solutions of organic acids |
Aug. 12, 2008 |
| 7384518 |
Method for purifying lactams |
Jun. 10, 2008 |
| 7351311 |
Method for purifying tetrahydrofuran by distillation |
Apr. 1, 2008 |
| 7339088 |
Alkylbenzene refining process and apparatus |
Mar. 4, 2008 |
| 7329330 |
Method and device for the distillative processing of 1,6-hexanediol, 1,5-pentanediol and caprolactone |
Feb. 12, 2008 |
| 7309403 |
Method for avoiding corrosion |
Dec. 18, 2007 |
| 7169268 |
Color stabilization of amines |
Jan. 30, 2007 |
| 7169267 |
Method and device for carrying out the distillative separation of C.sub.5+ cuts |
Jan. 30, 2007 |
| 7157610 |
Process for recovering methanol |
Jan. 2, 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 |
| 6998026 |
Method for producing tertiary C.sub.4-C.sub.8-alkyl esters of (meth)acrylic acid |
Feb. 14, 2006 |
| 6986833 |
Process for fractionating water-containing crude amine mixtures from amine synthesis |
Jan. 17, 2006 |
| 6982026 |
Azeotropic distillation process for producing organic acids or organic acid amides |
Jan. 3, 2006 |
| 6972075 |
Method for removing 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine |
Dec. 6, 2005 |
| 6969446 |
Method for producing concentrated nitric acid and installation for carrying out a method of this type |
Nov. 29, 2005 |
| 6955743 |
Method for producing furfural, acetic acid and formic acid from spent pulp-cooking liquor |
Oct. 18, 2005 |
| 6946060 |
Purification of N,N-dimethylacetamide |
Sep. 20, 2005 |
| 6913674 |
Process for fractionating water-containing crude amine mixtures from amine synthesis |
Jul. 5, 2005 |
| 6896772 |
Method for separating ammonia from solutions containing caprolactam and ammonia |
May. 24, 2005 |
| 6863778 |
Separation of tertiary butyl alcohol from diisobutylene |
Mar. 8, 2005 |
| 6849161 |
Process for the production of anhydrous hydrazine and device for its implementation |
Feb. 1, 2005 |
| 6849162 |
Method for the production of propylene oxide |
Feb. 1, 2005 |
| 6846389 |
Method for distillative separation of mixtures containing tetrahydrofuran, .gamma.-butyrolactone and/or 1,4-butanediol |
Jan. 25, 2005 |
| 6843890 |
Purification and recovery of acetonitrile from waste solvent acetonitrile |
Jan. 18, 2005 |
| 6835287 |
Apparatus, method for enrichment of the heavy isotope oxygen and production method for heavy oxygen water |
Dec. 28, 2004 |
| 6821396 |
Process for fractionating water-containing crude amine mixtures from amine synthesis |
Nov. 23, 2004 |
| 6821382 |
Method and arrangement for cleaning contaminated condensate including a combined stripper/condenser |
Nov. 23, 2004 |
| 6793777 |
Method for separating and purifying an aqueous mixture that mainly consists of acetic acid and formic acid |
Sep. 21, 2004 |
| 6758946 |
Recycling hydroxylamine-containing stripper solutions |
Jul. 6, 2004 |
| 6695952 |
Method for the separation of and purification of an aqueous mixture consisting of the main components acetic acid and formic acid |
Feb. 24, 2004 |
| 6692616 |
Method for purifying trimethylolpropane, which is produced by hydrogenation, by means of continuous distillation |
Feb. 17, 2004 |
| 6689251 |
Cycled-concentration distiller |
Feb. 10, 2004 |
| 6685802 |
Process and apparatus for removing dissolved and undissolved solids from liquids |
Feb. 3, 2004 |
| 6679975 |
Process for recovering the methanol contained in a liquid hydrocarbon feed |
Jan. 20, 2004 |
| 6635151 |
Lactam dehydration method |
Oct. 21, 2003 |
| 6632330 |
Process for purification of alkyl alkanoate |
Oct. 14, 2003 |
| 6605193 |
Recovery of HFC-32 |
Aug. 12, 2003 |
| 6605192 |
Method for producing highly pure monoethylene glycol |
Aug. 12, 2003 |
| 6599398 |
Recovery of adiponitrile from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine |
Jul. 29, 2003 |
| 6547933 |
Process for the purification of aromatic polyamines |
Apr. 15, 2003 |
| 6527917 |
Process for preparing pentafluoroethane |
Mar. 4, 2003 |
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