- Email: [email protected]
Electrodialysis in fibres manufacture
Patents
gas separation. Patent number: EP 382356 Date: 16 August 1990 Inventor: H.M. Colquhoun, T.M. Taylor Applicant: Imperial Chemical Industries PLC
Semipermeable membrane A homogeneous polymer mixture is used which contains, as major components, polyvinylpyrrolidone and an
aromatic polyamide. The latter compound has the general formula (CO-E1-CONH-E2-NH) where E 1 and E 2 are aryl groups or aryl-X-aryl groups. The aryl functional groups are substituted 1,2-, 1,3- or 1,4-phenylene units. The linkage X can be a single bond, oxygen, C(CF~)2, or one of several other alternatives. The membrane can be used as a carrier for enzymes or anticoagulants as it has good hydrophilic properties and resists microorganisms. Its other properties include resisting oxidising or saponifying agents, and it can be used as a carrier for thin (< 1 pm thickness)
permselective polymers. Patent number: EP 382009 Date: 16 August 1990 Inventor: M. Haubs, W. Kreuder, C.P. Krieg, J. Wildhardt Applicant: Hoechst AG
Electrodialysis in fibres manufacture Wet spinning of synthetic fibres into a precipitation bath gives an
Dialyser and electrode layout
feed stream
I!
() r
t
clear strear :oncen~ lectrode compartment feed
14
Membrane Technology
Patents
Reaction scheme for production of a polyimide/polyester copolymer, and showing its structure. O I
O II
.o~c c-o-c-c,..c-o~c C-OH, 2 o:c.N-~c.,-~>-,.c.o Polyethylene Adlpate
H
0 U
MDI
0
0
0
o - c - , ~ ", ~ ' N - C - o ~ c o ~ c . o - ~ c - o - c' - c , - c' - o ~ c c - o - c '- ~" ' - " MDI
PEA
MDI
I
Cl MOCA
Urethane O H
O H
,,
-O--(CC-O-C-C~-C-O~CC ~ O - C - N ~ ~ N - C - N ~.A
/ ~ q,
Cl
Urea
i" . i . . . .O ,, ! II HI,.=.~ I- . . . .
.I
.-.~H
O
;
O
II H ! , ~ ,~x H I H ,~x ~ C ~ N - C - N ~ C H
. . . . . .
...DI
-
CI
.o,
CI
,oc, |
J
V
Soft Segment
Hard Segment
Membrane Technology
Polyimide/ aliphatic polyester copolymers A new copolymer composition is claimed with alternating 'soft' and 'hard' segments. The 'soft' element is an oligomeric aliphatic polyester and the 'hard' part is a polyimide. The terms 'hard' and 'soft' arise from the difference in the glass transition temperature Tg: the 'hard' polyimide transition temperature is greater than 130°C, that of the 'soft' constituent is lower. Depending on the precise composition, the membrane is stable at temperatures up to 150°C. The polyimide is derived from a diamine of 2-30 carbon chain length and from a dianhydride of 8-20 carbon chain length. The
O
~ H II 2~-(~./~N-C--
%
V
aqueous solution containing metal salts. Reuse of the solution requires the ionic concentration to be controlled. The present invention employs electrodialysis, with the addition of a water-miscible organic solvent, to lower the salt content of the solution. The electrodialysis apparatus electrodes are rinsed with an electrolyte solution free from sulphate ions, such as an aqueous solution of sodium acetate. The membrane material is based on a styreneodivinylbenzene copolymer with an ionic capacity of 0.8-3 milliequivalents/g. Current density is 1-200 A/m 2 and operation is at ambient temperature. After electrodialysis the organic solvent solution is distilled. Patent number: EP 381134 Date: 8 August 1990 Inventor: M. Schneider, G.E. Miess Applicant: Hoechst AG
o~ ~" . ~ . c . o
,~,
polyester can be a polymalonate, polyglutarate, polyadipate or polysuccinate, preferably one of the last two. The diagram shows the outline reaction scheme and structure in one embodiment of the invention, in which the diamine is methylene diooo chloroaniline. The particular application of the membrane is to separate aromatic compounds from aliphatics or other non-aromatic compounds, an operation in which membranes can have energy and selectivity advantages over distillation. There are clear opportunities in the petroleum and petrochemical industries. One suggested use is in recovering large substituted aromatics from catalytic naphtha streams. Patent number: US 4944880 Date: 31 July 1990 Inventor: W.S. Ho, G. Sartori, W.A. Thaler, D.C. Dalrymple Appficant: Exxon Research & Engineering Co.
15
gas separation. Patent number: EP 382356 Date: 16 August 1990 Inventor: H.M. Colquhoun, T.M. Taylor Applicant: Imperial Chemical Industries PLC
Semipermeable membrane A homogeneous polymer mixture is used which contains, as major components, polyvinylpyrrolidone and an
aromatic polyamide. The latter compound has the general formula (CO-E1-CONH-E2-NH) where E 1 and E 2 are aryl groups or aryl-X-aryl groups. The aryl functional groups are substituted 1,2-, 1,3- or 1,4-phenylene units. The linkage X can be a single bond, oxygen, C(CF~)2, or one of several other alternatives. The membrane can be used as a carrier for enzymes or anticoagulants as it has good hydrophilic properties and resists microorganisms. Its other properties include resisting oxidising or saponifying agents, and it can be used as a carrier for thin (< 1 pm thickness)
permselective polymers. Patent number: EP 382009 Date: 16 August 1990 Inventor: M. Haubs, W. Kreuder, C.P. Krieg, J. Wildhardt Applicant: Hoechst AG
Electrodialysis in fibres manufacture Wet spinning of synthetic fibres into a precipitation bath gives an
Dialyser and electrode layout
feed stream
I!
() r
t
clear strear :oncen~ lectrode compartment feed
14
Membrane Technology
Patents
Reaction scheme for production of a polyimide/polyester copolymer, and showing its structure. O I
O II
.o~c c-o-c-c,..c-o~c C-OH, 2 o:c.N-~c.,-~>-,.c.o Polyethylene Adlpate
H
0 U
MDI
0
0
0
o - c - , ~ ", ~ ' N - C - o ~ c o ~ c . o - ~ c - o - c' - c , - c' - o ~ c c - o - c '- ~" ' - " MDI
PEA
MDI
I
Cl MOCA
Urethane O H
O H
,,
-O--(CC-O-C-C~-C-O~CC ~ O - C - N ~ ~ N - C - N ~.A
/ ~ q,
Cl
Urea
i" . i . . . .O ,, ! II HI,.=.~ I- . . . .
.I
.-.~H
O
;
O
II H ! , ~ ,~x H I H ,~x ~ C ~ N - C - N ~ C H
. . . . . .
...DI
-
CI
.o,
CI
,oc, |
J
V
Soft Segment
Hard Segment
Membrane Technology
Polyimide/ aliphatic polyester copolymers A new copolymer composition is claimed with alternating 'soft' and 'hard' segments. The 'soft' element is an oligomeric aliphatic polyester and the 'hard' part is a polyimide. The terms 'hard' and 'soft' arise from the difference in the glass transition temperature Tg: the 'hard' polyimide transition temperature is greater than 130°C, that of the 'soft' constituent is lower. Depending on the precise composition, the membrane is stable at temperatures up to 150°C. The polyimide is derived from a diamine of 2-30 carbon chain length and from a dianhydride of 8-20 carbon chain length. The
O
~ H II 2~-(~./~N-C--
%
V
aqueous solution containing metal salts. Reuse of the solution requires the ionic concentration to be controlled. The present invention employs electrodialysis, with the addition of a water-miscible organic solvent, to lower the salt content of the solution. The electrodialysis apparatus electrodes are rinsed with an electrolyte solution free from sulphate ions, such as an aqueous solution of sodium acetate. The membrane material is based on a styreneodivinylbenzene copolymer with an ionic capacity of 0.8-3 milliequivalents/g. Current density is 1-200 A/m 2 and operation is at ambient temperature. After electrodialysis the organic solvent solution is distilled. Patent number: EP 381134 Date: 8 August 1990 Inventor: M. Schneider, G.E. Miess Applicant: Hoechst AG
o~ ~" . ~ . c . o
,~,
polyester can be a polymalonate, polyglutarate, polyadipate or polysuccinate, preferably one of the last two. The diagram shows the outline reaction scheme and structure in one embodiment of the invention, in which the diamine is methylene diooo chloroaniline. The particular application of the membrane is to separate aromatic compounds from aliphatics or other non-aromatic compounds, an operation in which membranes can have energy and selectivity advantages over distillation. There are clear opportunities in the petroleum and petrochemical industries. One suggested use is in recovering large substituted aromatics from catalytic naphtha streams. Patent number: US 4944880 Date: 31 July 1990 Inventor: W.S. Ho, G. Sartori, W.A. Thaler, D.C. Dalrymple Appficant: Exxon Research & Engineering Co.
15