| Patent Number |
Title Of Patent |
Date Issued |
| 7540884 |
Method for performing the purifying separation of crystals out their suspension in a mother liqu |
June 2, 2009 |
| A process for purifying removal of crystals from their suspension in mother liquor by means of a washing column having forced transport in which the process chamber is encased by a metal wall which, on its side facing away from the process chamber, is heated at least along the length |
| 7393436 |
Thermal separating process for removing at least one stream containing enriched (meth) acrylic m |
July 1, 2008 |
| A thermal separating process for removing a stream containing enriched (meth)acrylic monomers from a mixture containing (meth)acrylic monomers, in which the liquid phases retained in the separating space at high temperature and high (meth)acrylic monomer content are minimized. |
| 7323016 |
Regulation of a wash column in a melt crystallization process |
January 29, 2008 |
| The present invention relates to the use of an optical line detector for regulating the position of the wash front and/or of the build-up front of the crystal bed of a wash column in a melt crystallization process and a corresponding regulation method. The line detector, for example a CC |
| 7319166 |
Method of purifying a raw melt of at least one monomer by crystallization |
January 15, 2008 |
| The invention relates to a method for purifying a raw melt of at least one monomer by crystallization, wherein suspension crystallization is initially used and the resulting remaining melt or the suspension crystals that have been molten once again and separated are subjected to a me |
| 7307189 |
Method for discontinuous purification of crude acrylic acid by means of crystallization |
December 11, 2007 |
| Crude acrylic acid is purified batchwise by crystallization by a process which comprises at least one purification stage and at least one stripping stage and in which at least the first stripping stage is carried out in a different crystallizer from the first purification stage. |
| 7129376 |
Method for the production of a purified melt of at least one monomer |
October 31, 2006 |
| The invention relates to a method for the production of a purified melt of a monomer melt obtained by condensation, absorption or extraction in a crystallizer, wherein the inlet to the crystallizer is subjected to a mechanical solid/liquid separation operation. |
| 7112695 |
Method for the purification of a crude acrylic acid melt |
September 26, 2006 |
| In a process for the purification of a crude acrylic acid melt, the crude acrylic acid melt is converted, under the action of low temperatures, into a crude acrylic acid suspension consisting of acrylic acid crystals and residual melt, and the acrylic acid crystals of the crude acrylic |
| 6921837 |
Process for the purification and preparation of acrylic acid or methacrylic acid |
July 26, 2005 |
| Acrylic acid or methacrylic acid is purified by crystallization to obtain crystals and a mother liquor, by a process in which the crystals are washed with a wash liquid containing the acid and having a temperature from 15 to 40.degree. C. Furthermore, a process for the preparation of |
| 6852881 |
Purification method for (meth)acrylic acid |
February 8, 2005 |
| (Meth)acrylic acid is purified by crystallization by a process in which the (meth)acrylic acid is purified by a combination of at least two different dynamic crystallization processes, in particular a suspension crystallization and a layer crystallization. |
| 6703511 |
Method for obtaining pure n-vinyl pyrrolidone |
March 9, 2004 |
| The invention describes a process for the isolation of pure N-vinylpyrrolidone from N-vinylpyrrolidone-containing crude products, comprising a single-stage or multistage crystallization process, which comprises passing the mother liquor from the first crystallization stage either to |
| 6700016 |
Method of purifying and producing acrylic acid or methacrylic acid |
March 2, 2004 |
| Acrylic acid or methacrylic acid is purified be crystallization to obtain crystals and a mother liquor, by a process in which the crystals are washed with a was liquid containing the acid and having a temperature from 15 to 40.degree. C. Furthermore, a process for the preparation of acry |
| 6646161 |
Method for the fractional condensation of a hot gas mixture containing acrylic acid or methacryl |
November 11, 2003 |
| A process for the fractional condensation of a gas mixture which, in addition to acrylic acid or methacrylic acid, also contains at least one further condensable component and additionally a high proportion of one or more noncondensable components, wherein the gas mixture is passed throu |
| 6596901 |
Method for purifying acrylic acid and methacrylic acid |
July 22, 2003 |
| A process for preparing acrylic acid or methacrylic acid comprises (a) preparing a gaseous product mixture having essentially the composition of a reaction mixture of the catalytic gas phase oxidation of C.sub.3 -/C.sub.4 -alkanes, -alkenes, -alkanols and/or -alkanals and/or precursors |
| 6541665 |
Method for purifying acrylic acid or methacrylic acid by crystallization and distillation |
April 1, 2003 |
| In a process for the purification of acrylic acid or methacrylic acid by crystallization and distillation, the following steps are carried out: (a) crystallization of a mixture containing the acrylic acid or methacrylic acid with formation of product crystals having a higher concentration |
| 6448439 |
Method for producing acrylic acid and methacrylic acid |
September 10, 2002 |
| A process for preparing acrylic acid or methacrylic acid comprises preparing a gaseous product mixture having essentially the composition of a reaction mixture of the catalytic gas phase oxidation of C.sub.3 -/C.sub.4 -alkanes, -alkenes, -alkanols and/or -alkanals and/or precursors t |
| 6433222 |
Method for producing acrylic acid |
August 13, 2002 |
| A process for the preparation of acrylic acid by: (a) preparation of a gaseous product mixture which essentially has the composition of a reaction mixture of catalytic gas-phase oxidation of C.sub.3 -alkanes, C.sub.3 -alkenes, C.sub.3 -alkanols and/or C.sub.3 -alkanals and/or intermed |
| 6414190 |
Purification of acrylic acid by crystallization by means of vacuum evaporation |
July 2, 2002 |
| In a process for purifying acrylic acid by crystallization by means of vacuum evaporation, a solution which contains acrylic acid and water and may contain further components is crystallized by means of vacuum evaporation with formation of a liquid phase, consisting of a mother liquo |
| 6242639 |
Preparation of neopentyl glycol hydroxyprivalate granules |
June 5, 2001 |
| A method for preparing neopentyl glycol hydroxypivalate granules by application of a neopentyl glycol hydroxypivalate melt (1) onto a cooling belt (6) on which the melt solidifies, wherein the melt contains at least so 3 wt % of neopentyl glycol hydroxypivalate crystals, based on the tot |
| 6051736 |
Preparation of (meth)acrylic acid |
April 18, 2000 |
| The invention is directed toward preparation of (meth)acrylic acid, comprising condensation of a gas comprising (meth)acrylic acid, absorption with water, and extraction with an aqueous solution forming a miscibility gap. |
| 6026656 |
Crystallization by evaporation and vapor condensation |
February 22, 2000 |
| In a process for crystallizing material to be isolated, fluid is vaporized from a melt or a solution comprising the material to be isolated and the fluid and the vaporized fluid is condensed or absorbed in a liquid material to form a liquid mixture, wherein the fluid components to be |
| 5831124 |
Purification of acrylic acid and methacrylic acid |
November 3, 1998 |
| Acrylic acid or methacrylic acid is purified by(a) subjecting a mixture comprising the acrylic acid or methacrylic acid to a sharply defined separation process essentially in the absence of an organic solvent, with the composition of the phase in which the acrylic acid or methacrylic aci |
| 5755975 |
Separation of substances from a liquid mixture by crystallization |
May 26, 1998 |
| In a process for separating substances from a liquid mixture by crystallization in a crystallizer, a two-phase seed layer in the form of a melt or solution of the mixture to be separated, with crystals suspended therein, is applied, prior to the crystallization, to those surfaces of |
| 5710284 |
Purification of N-vinylpyrrolidone by crystallization |
January 20, 1998 |
| In a process for purifying N-vinylpyrrolidone by crystallization in a crystallizer, those surfaces of the crystallizer from which crystals grow during the crystallization are covered with an N-vinylpyrrolidone seed layer before the crystallization. |
