公开(公告)号：DE2646804A1

公开(公告)日：1978-04-20

申请号：DE2646804

申请日：1976-10-16

Applicant: BASF AG

Inventor： GETTERT HANS DIPL CHEM DR ,  FROMM HERMANN DIETER DIPL CHEM ,  MOLZAHN MARTIN DIPL ING DR ,  SCHIER ERNST-JUERGEN DIPL CHEM ,  SCHNEEHAGE HANS HENNIG DIPL CH

IPC: B01D53/14 ,  C01C1/12

Abstract: To isolate ammonia from gas mixtures containing ammonia and carbon dioxide, the gas mixture is first partially absorbed in a solvent, with residence times of at most 0.1 second, and the non-absorbed gas is then separated from the solution obtained. The solution is then subjected to a first desorption stage, in which only the ammonia present in an excess over a molar ratio of 3 parts of ammonia to 1 part of carbon dioxide is expelled by heating, and the entrained carbon dioxide is washed out of the expelled ammonia by means of solutions containing free ammonia. The solution remaining after the first desorption stage is substantially freed from ammonia and carbon dioxide in a second desorption stage and the expelled gas, containing solvent, together with fresh gas mixture is fed to the adsorption stage, while the solvent obtained from the second desorption stage is employed for the absorption.

公开(公告)号：DE3138419A1

公开(公告)日：1983-04-14

申请号：DE3138419

申请日：1981-09-26

Applicant: BASF AG

Inventor： FROMM DIETER DIPL CHEM DR ,  SCHIER ERNST-JUERGEN DIPL CHEM ,  SCHNEEHAGE HANS HENNING DIPL C ,  VODRAZKA WOLFGANG DIPL CHEM DR

IPC: B01J21/20 ,  B01J38/06 ,  C07B61/00 ,  C07D251/60 ,  C07D251/62

Abstract: In the synthesis of melamine by conversion of urea in a fluidized catalyst bed, the melamine quality is improved by reactivating the catalyst by treating it, in the fluidized bed, with gases containing steam, in the absence of oxygen, at from 250 DEG to 450 DEG C.

公开(公告)号：DE2345461A1

公开(公告)日：1975-03-27

申请号：DE2345461

申请日：1973-09-08

Applicant: BASF AG

Inventor： SCHIER ERNST-JUERGEN DIPL CHEM ,  NOHE HEINZ DIPL-CHEM DR ,  BECK FRITZ DIPL-CHEM DR ,  DIETMAR WERNER DIPL-CHEM DR

IPC: C25B3/29 ,  C07C31/20

Abstract: Pinacol is prepd. by the electrolhydro-dimerisation of acetone in partitioned cell using as electrolyte a catholyte contg. 10-90 wt % acetone, 1-60 wt % water and 1-50 wt % to a quat. ammonium salt. The pref. amts. are 40-80 wt %, 5-30 wt % and 5-20 wt % respectively. The cell is pref. divided by porous membranes of cation exchangers e.g. sulphonated reticulated polystyrene. The anode may be Pb coated with PbO2, graphite or Ti esp. in combination with 1-10 wt % H2SO4 as anolyte. The cathode may be Cu, Ag, Cd, Zn, Sn, Pb, Tl or Hg but is pref. graphite or a plastic matl. filled with graphite. The quat. cpd. is e.g. of formula (I): (where R1-4 are each 1-6C alkyl, aryl or aralkyl and X- is an anion such as sulphate, alkylsulphate, phosphate, carbonate, tosylate, BF4-, SiF6- halide or perchlorate). Process may be continuous or discontinuous, give improved yields per unit of current over known methods and avoids the necessity of neutralising acids in soln.

公开(公告)号：DE3041324A1

公开(公告)日：1982-06-16

申请号：DE3041324

申请日：1980-11-03

Applicant: BASF AG

Inventor： BLANCK KLAUS DIPL CHEM DR ,  DETHLEFSEN WINFRIED DIPL CHEM ,  JUNGBAUER ANTON DIPL CHEM DR ,  LEUTNER BERND DIPL CHEM DR ,  SCHIER ERNST-JUERGEN DIPL CHEM ,  SCHLIMPER HANS-ULRICH DIPL CHE ,  SCHNEEHAGE HANS DIPL CHEM DR

IPC: C07D251/60 ,  B01D53/86 ,  B01J23/00 ,  B01J23/72 ,  B01J23/745 ,  C01C1/12 ,  C07B61/00 ,  B01D53/36

Abstract: The reaction off-gas from the synthesis of melamine consists, after separating off the melamine, mainly of ammonia and carbon dioxide, with traces of hydrogen cyanide, isocyanic acid, urea and residual melamine. To remove these trace components, the off-gas is passed over a catalyst, containing copper oxide and/or iron oxide, in the presence of steam at from 100 DEG to 500 DEG C.

公开(公告)号：DE3031124A1

公开(公告)日：1982-04-08

申请号：DE3031124

申请日：1980-08-18

Applicant: BASF AG

Inventor： BORHO KLAUS DIPL ING DR ,  FROMM DIETER DIPL CHEM DR ,  SCHIER ERNST-JUERGEN DIPL CHEM ,  SCHNEEHAGE HANS HENNING DIPL C ,  WIDMANN ALFRED DIPL ING DR

IPC: C07C273/10 ,  C07C67/00 ,  C07C239/00 ,  C07C273/12 ,  C07C273/16 ,  C07D251/62 ,  C07D251/60

Abstract: A process for isolating liquid urea and its thermal decomposition products from the off-gas of melamine synthesis, which gas has been freed from melamine by fractional condensation and then been washed with molten urea, wherein the off-gas, containing 2-10 kg of melt per kg of pure gas, is passed at 8-30 m/sec tangentially into the upper part of an axially symmetrical separation zone. As a result of the rotation imparted to the gas/liquid mixture, the two phases are separated from one another, and both pass downward through the separation zone. The gas and liquid are separately taken off at the bottom end of the separation zone. The residence time of the gas mixture in the separation zone is not less than 0.5 second.