GB2229180A - Novel polyimides and diamines - Google Patents

Novel polyimides and diamines Download PDF

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GB2229180A
GB2229180A GB9000616A GB9000616A GB2229180A GB 2229180 A GB2229180 A GB 2229180A GB 9000616 A GB9000616 A GB 9000616A GB 9000616 A GB9000616 A GB 9000616A GB 2229180 A GB2229180 A GB 2229180A
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general formula
polymer
membrane
diamine
independently
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Robin Edward Richards
Nevin John Stewart
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BP PLC
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C217/00—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton
    • C07C217/78—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of six-membered aromatic rings of the same carbon skeleton
    • C07C217/80—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of six-membered aromatic rings of the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of non-condensed six-membered aromatic rings
    • C07C217/82—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of six-membered aromatic rings of the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of non-condensed six-membered aromatic rings of the same non-condensed six-membered aromatic ring
    • C07C217/90—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of six-membered aromatic rings of the same carbon skeleton having amino groups and etherified hydroxy groups bound to carbon atoms of non-condensed six-membered aromatic rings of the same non-condensed six-membered aromatic ring the oxygen atom of at least one of the etherified hydroxy groups being further bound to a carbon atom of a six-membered aromatic ring, e.g. amino-diphenylethers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/62—Polycondensates having nitrogen-containing heterocyclic rings in the main chain
    • B01D71/64—Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • C08G73/1046—Polyimides containing oxygen in the form of ether bonds in the main chain

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

Abstract

a polymer having repeating units of general formula: <IMAGE> where A is <IMAGE> and -Z- is -O-, -CO-, C(CF3)2-, -SO2, -C(CH3)2- or -S-; and -X- is -O- or -C(CH3)2-, -Y- is -O- or -C(CH3)2- and -X- and -Y- are different; and -Ra is -CH3 or -CF3; and -Rb is -Cl, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and -Rc is -CH3 or -CF3 and m, n, p are independently 0, 1, 2, 3 or 4. The polymer may be used in gas separation membranes. The polymers are prepared from novel diamines.

Description

NOVEL POLYIMIDE The present invention relates to novel polyimides and to gas separation membranes comprising such polyimides.
The separation of gas mixtures into their individual components has numerous applications and the development of membrane gas separation processes has become of increasing importance. The use of membrane processes for gas separation has certain advantages over alternative techniques, for example, those based on adsorption, absorption and liquefaction. These advantages include potential energy efficiency, compactness, relative simplicity and ease of operation.
United States patent number US 4,717,394 discloses a process for separating gases comprising bringing two or more gases under pressure into contact with a membrane formed of an aromatic polyimide comprising units of the formula
where -Ar- is
or mixtures thereof, R is
mixtures thereof, Ar' is
or mixtures thereof
or mixtures thereof
where n L O to 4, alkylene radicals of 1 to 3 carbon atoms or mixtures thereof, -X, -X1, -X2 and -X3 are independently alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl or aromatic groups of 6 to 13 carbon atoms, -Z is -H, -X, -X1, -X2, or -X3 W is 5Z to 100X, Q is 5Z to 100X Y is 100% minus W, V is 100X minus V, Y plus V is at least 5Z whereby at least one of said gases is enriched upon permeating the membrane.
United States patent number US 6,746,901 relates to copolyimides consisting essentially of chemically combined recurring units of the formulas:
wherein R may differ between the recurring units and is an aromatic tetravalent radical; and wherein Z1 is a bridged radical of the formula;
where Y may differ within the radical and is selected from the group consisting of -O-, -S-, -CO-, -NH-, -SO-, -OPR'-, -C(CF3)2-, -C(CH)2-, where R' is alkyl or aryl and m is 0, 1, 2 or 3 and wherein Z2 is of the formula
where -Z is selected from the groups consisting of -Br, -C1, -F, -CF3, aryl, or alkyl.
Japanese patent application number JP 62-57421 relates to colourless, transparent polyimide mouldings which have at least one repeating unit which can be represented by general formula (I) repeating unit which can be represented by general formula (II) and repeating unit which can be represented by general formula (III) for their main constituents.
where -X1 to -X4 are -H, -CH3, -C2,H5, -NO2, -F, -COOH or -C1.
where -X6- is -SO2-, -C(CH3)2-, or -C(CF3)2 United States patent number US 4,681,928 relates to a thermoplastic polyimide, poly(amide-imide), poly(esterimide), polyamide acid, poly(amide-amide acid) or poly(esteramide acid) composition which contains at least about 10 per cent of the reaction product of an aromatic or alphatic tetracarboxylic dianhydride or acid tricarboxylic acid anhydride and an aromatic diamine having the formula:
wherein R1, R2 and R3 each independently is hydrogen, halogen or unsubstituted or substituted hydrocarbyl, X1 and X2 each independently is substituted or unsubstituted branched linear or cyclic alkylene or alkenylene of 1 to about 30 carbon atoms, -S-, or -0- with the proviso that X1 and X2 are not both concurrently -S- or -0- and n, n' and n each independently is an integer of 1 to 4.
Exemplary of suitable diamino compounds US 4,681,928 mentions 4-(p-aminophenoxy)-p-aminophenyl) cumene but no details of how such a compound might be prepared are given nor taught towards.
It has been found in membranes formed of polyimide polymer chains having 3-ring diamine units, that by selecting the meta-para positions of the bonds between the rings, by selecting the pendant groups on the rings, and by selecting suitable groups between the rings, membranes particularly suitable for gas separation may be obtained.
Thus, according to the present invention there is provided a polymer having repeating units of the general formula:
and -Z- is -O-, -CO-, -C(CF3)2-, -S02, -C(CH3)2- or -S-; and -X- is -O- or -C(CH3)2-, -Y- is -O- or -C(CH3)2-and -X- and -Yare different; and -Ra is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms;and -Rc is -CH3 or -CF3; and m, n, p are independently 0, 1, 2, 3 or 4. Preferably m, n, p are independently 0 or 1 and most preferably if -X- is -C(CH3)2- then m is 0 and if -Y- is -C(CH3)2the p is 0. Different repeating units may be present in the polymer.
According to the present invention there is also provided a gas separation membrane comprising a polymer as hereinbefore described.
Different repeating units may be present in the polymer. The membrane may comprise a blend of polymers as hereinbefore described.
Also, according to the present invention there is provided a process for separating gases comprising passing a mixture comprising two or more gases through a membrane, as hereinbefore described, there being a differential pressure across the membrane whereby the gases of the gas mixture are separated by their relative permeation rates through the membrane.
By gas it is intended to include vapours.
The gas separation process according to the present invention may be used to separate carbon dioxide/methane mixtures; oxygen/nitrogen mixtures; helium/methane mixtures; carbon monoxide/methane mixtures; hydrogen/methane mixtures, carbon monoxide/hydrogen mixtures and the like. The process may also be used for dehydration and for the removal of hydrogen sulphide gas from natural gas and the like.
According to the present invention there is also provided apparatus for separating gases comprising means for passing a mixture comprising two or more gases through a gas separation membrane as hereinbefore described with a differential pressure across the membrane so that the gases separate by their relative permeation rates through the membrane.
According to the present invention there is provided a process for making a polymer as hereinbefore described, the method comprising the steps of reacting a diamine having the general formula:
where -X- is -O- or -C(CH3)2-, -Y- is -O- or -C(CH3)2- and -X- and -Y- are different; and -Ra is -CH3 or -CF3; and -Rc is -CH3 or CF3; and -Rb is -C1, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m, n, p are independently p, 1, 2, 3 or 4, with a bisanhydride having the general formula:
and -Z- is -O-, -CO-, -C(CF3)2-, -S02-, -C(CH3)2- or -S Preferably m, n, p are independently 0 or 1 and most preferably if -X- is -C(CH3)2- then m is 0 and if -Y- is -C(CH3)2- the p is 0.
Preferably, the process is conducted with equimolar quantities of the bisanhydride and diamine. Preferably, equimolar quantities of bisanhydride and diamine is refluxed in a solvent (for example m-cresol and toluene) with a Dean-Stark trap to remove water eliminated in the reaction and then the trap is replaced with a calcium hydride trap followed by further reflexing. The polymers may be isolated by precipitating into methanol, filtering and drying under vacuum.
According to the present invention there is also provided a diamine having the general formula:
where -Ra is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and -Rc is -CH3 or -CF3; and m, n and p are independently, 0, 1, 2, 3 or 4.
Preferably m, n, p are independently 0 or 1 and most preferably m is 0.
According to the present invention there is also provided a process for making a diamine having the general formula (IV) as hereinbefore defined, the process comprising the steps: (a) reacting a compound having the general formula:
where -Ra is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m and n are independently 0, 1, 2, 3 or 4, with a compound having the general formula:
where -Rc is -CH3 or -CF3; and p is 0, 1, 2, 3 or 4, to give a compound having the general formula:
where -Ra is -CH3 or -CF3; and -Rc is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m, n and p are independently 0, 1, 2, 3 or 4 and (b) reducing the product of step (a).Preferably, m, n, p are independently 0 or 1 and most preferably m is O.
The invention will now be described by way of example only and with reference to the drawings. Figures 1 and 2 represent in side elevation and cross-section respectively, apparatus used to measure the permeability of membranes according to the present invention.
Preparation of Diamines Example 1 Ereparation of 2-(4-aminonhenol)-2- r 4-(4-aminonhenoxv) phenoll- profane (reference name: AIV Diamine) 2-(4-hydroxyphenyl)-2-(4-aminophenyl)propane (65.0g, 0.286 mol, prepared by the method disclosed in GB 1,028,156), l-chloro-4-nitrobenzene (45.1g, 0.28mol), potassium carbonate (base) (24.7g, 0.179mol), N,N-dimethylacetamide (300ml) (solvent) and toluene (150ml) (azeotropic agent to facilitate removal of water) were charged to a one litre flask fitted with a thermometer, overhead stirrer, Dean and Stark apparatus and condenser, and nitrogen inlet/outlet tubes. The reaction mixture was heated to boiling over 0.75 hours with stirring under nitrogen. After 7 hours at 138-C no further water collected in the trap.Toluene (150ml) was removed by distillation and the flask contents were allowed to cool to room temperature. The flask contents were then added slowly to vigorously stirred water (600ml) and a dark red solid was collected by filtration. Three recrystallisations of this solid from methanol gave pale yellow crystals of 2-(4-aminophenyl)-2-[4-(4-nitrophenoxy) phenyl] propane (72.2g, 72Z) m.p.93.5-94.0C (GB 1,248,027 m.p.96C).
2-(4-aminophenyl)-2-[4-(4-nitrophenoxy) phenyl] propane (70.0g, 0.201mol) dissolved in ethyl acetate (250ml) was transferred, with 5Z palladium on carbon catalyst (Pd/C) (4.28g, lmolZ Pd), to a 500ml rocking hydrogenator and heated with agitation at 90'C for 6.5 hours under 300psig (20.7 barg) of hydrogen. The catalyst was removed by filtration and the solvent distilled off under reduced pressure to give a solid which was recrystallised from toluene (100ml) to give pink crystals of 2-(4-aminophenyl)-2- [ 4 (4-aminophenoxy) phenyl] propane (51.2g, m.p. 108-llO'C. The structure of this product was confirmed by 1H and 13C n.m.r.
spectroscopy (proton and carbon-thirteen nuclear magnetic resonance spectroscopy).
Example 2 Preparation of 2-(4-aminoohenyl)-2- [ 3-(4-aminophenoxy) phenoll- propane (reference name: AIVa Diamine).
2-(3-hydroxyphenyl)-2-(4-aminophenyl)propane (100.0g, 0.440mol, a product of Mitsui Petrochemical Industries Ltd, Tokyo, Japan), l-chloro-4-nitrobenzene (69.4g, 0.440mol), potassium carbonate (37.2g, 0.269mol) (base), N,N-dimethylacetamide (300ml) (solvent) and toluene (300ml) (azeotropic agent) were charged to a one litre flask fitted with a thermometer, overhead stirrer, Dean and Stark apparatus and condenser, and nitrogen inlet/outlet tubes. The reaction mixture was heated to boiling over 0.75 hours with stirring under nitrogen and held at 130C for 5 hours. Toluene (150ml) was then removed by distillation and the mixture heated at 140it for a further 7.5 hours.After this time the remaining toluene was removed by distillation and the flask contents allowed to cool to room temperature. The flask contents were then added slowly to vigorously stirred water (800ml) and an orange solid was collected by filtration. The solid was recrystallised from a mixture of cyclohexane (1000ml) and ethyl acetate (50ml) to give 2-(4-aminophenyl)-2-[3-(4-nitrophenoxy) phenyl] propane (138.0g, 90Z) as lustrous orange crystals.
2-(4-aminophenyl)-2-13-(4-nitrophenoxy) phenyl] propane (138.0g, 0.396mol) dissolved in warm ethyl acetate (300ml) was transferred, with 5S Pd/C catalyst (8.4g, lmol x Pd), to a 500ml rocking hydrogenator and heated with agitation for 6 hours at 90C under 300psig (20.7 barg) of hydrogen. The catalyst was removed by filtration and the solvent distilled off under reduced pressure to give 2-(4-aminophenyl)-2- [ 3-(4-aminophenoxy)phenyl ] propane (123g, 98S) as an orange-red glassy product. The structure of this product was confirmed by n.m.r. spectroscopy.
Example 3 PreParation of 2-(4-aminohenyl )-2- [ 4- (amino-2-trifluoromethvl- phenoxv)phenoll propane (reference name: AV Diamine).
2-(4-hydroxyphenyl)-2-(4-aminophenyl)propane (50.3g, 0.221mol), 2-chloro-5-nitrobenzotrifluoride (49.9g, 0221mol), potassium carbonate (19.lug, 0.138mol)(a base), N,N-dimethylacetamide (170ml) (solvent) and toluene (170ml) (azeotropic agent) were charged to a one litre flask fitted with a thermometer, overhead stirrer, Dean and Stark apparatus and condenser, and nitrogen inlet/outlet tubes.
The reaction mixture was heated to boiling over 0.67 hours with stirring under nitrogen. After 4.33 hours at 129*C no further water collected in the trap. Toluene (145ml) was removed by distillation, (final flask temperature 146it) and the flask contents were allowed to cool to room temperature. The flask contents were then added slowly to vigorously stirred water (400ml) and a dark red oil layer formed. This oil was collected,washed with water and dried under high vacuum to give a dark red brittle glassy product. The product was purified by high performance liquid chromatography in 8g (crude product) batches by passage through a silicon column (Waters Associates Prep PAK 500 (Trade Mark), 5.7cm ID x 30 cm silicon catridge) eluted with a 50:50 volume:volume) mixture of diethyl ether: 40-60 (boiling range) petroleum spirit. The main fraction from each batch was collected and combined. Solvent was removed under high vacuum to give the product 2-(4-aminophenyl)-2- [ 4 -(4nitro- 2-trifluoromethylphenoxy)phenyl] propane (69.5g, 752) as a dark red-orange brittle glassy product.
2-(4-aminophenyl )-2- [ 4-(4-nitro-2-trifluoromethylphenoxy)- phenyl] propane (68.7g, 0.165mol) dissolved in ethyl acetate (300ml) was transferred, with 5Z Pd/C catalyst (3.5g, lmolZ Pd), to a 500ml rocking hydrogenator and heated with agitation at 500C for 6.5 hours and at 90C for 11 hours under 345psig (23.8 barg) of hydrogen. The catalyst was removed by filtration and the solvent distilled off under reduced pressure to give a yellow glassy product (62.lg).
This product was purified by high performance liquid chromatography in 15g crude batches by passage through a reverse-phase column (Waters Associates, Prep PAK (Trade Mark) 500/C18 5.7cm ID x 30cm reverse-phase cartridge) eluted with a 15:85 (volume:volume) mixture of water:methanol. The main fraction from each batch was collected and combined. Solvent was removed under high vacuum to give the product 2-(4-aminophenyl)-2- [ 4-(4-amino-2-trifluoromethylphenoxy)- phenyl] propane (33.0g, 47Z) as a glassy product. The structure of this product was confirmed by 1H and 13C n. m. r. spectroscopy.
Example 4 Preparation of 2- (4-aminophenyl )-2- 3-(4-amino-2- trifluoromethvlphenoxy) phengl ] propane (reference name: AVa Diamine) 2-(3-hydroxyphenyl)-2-(4-aminophenyl)propane (90.0g, 0.396mol), 2-chloro-5-nitrobenzotrifluoride (89.5g, 0.396mol), potassium carbonate (34.3g, 0.248mol) (base), N,N-dimethylacetamide (300my) (solvent) and toluene (300ml) (azeotropic agent) were charged to a one litre flask fitted with a thermometer, overhead stirrer, Dean and Stark apparatus and condenser, and nitrogen inlet/outlet tubes.
The reaction mixture was heated to boiling over 0.75 hours with stirring under nitrogen and held at 127iC for 3 hours. Toluene (300ml) was then removed by distillation and the flask contents allowed to cool to room temperature. The flask contents were then added to vigorously stirred water (800ml) and a dark red oil layer formed. This was collected, washed with water and dried under high vacuum to give a dark red brittle glassy product. This product was purified by high performance liquid chromotography in 14g (crude product) batches by passage through a silicon column (Waters Associates, Prep PAK 500 (Trade Mark), 5.7cm ID x 30cm silicon cartridge) eluted with a mixture of 30:70 (volume:volume) ethyl acetate:40-60 (boiling range) petroleum spirit. The main fraction from each batch was collected and combined.Solvent was removed under high vacuum to give the product 2-(4-aminophenyl)-2 [ 3-(4-nitro-2-trifluoromethylphenoxy)phenyl ] propane (128.0g, 78%) as a dark red glassy product. The structure of this product was confirmed by 13C n. m. r. spectroscopy.
2-(4-aminophenyl)-2- [ 3-(nitro-2-trifluoromethylphenoxy)- phenyl ] -propane (139go 0.334mol) dissolved in ethyl acetate (300ml) was transferred, with 5X Pd/C catalyst (8.5g, 1.2mol Z Pd), to a 500ml rocking hydrogenator and heated with agitation for 6 hours at 90'C under 300 psig (20.7 barg) hydrogen. The catalyst was removed by filtration and the solvent distilled off under reduced pressure to give 2-(4-aminophenyl)-2- [ 3-(4-amino-2-trifluoromethylphenoxy)- phenyl ] propane (127.4g, 99Z) as an orange glassy product. The structure of this product was confimed by 13C n. m. r. spectroscopy.
Preparation of polymers In a typical process for preparing polymers equimolar quantities of bisanhydride and diamine (0.02 moles) were refluxed in m-cresol (35 cm3) and toluene (15 cm3), using a Dean-Stark trap to remove water eliminated on imidization. After 2-3 hours, when most of the water had been eliminated, the simple Dean-Stark trap was replaced with one in which the vapours refluxed through calcium hydride.
Refluxing was continued for 3 hours. Polymers were isolated by precipitating into methanol, filtering and drying under vacuum. The polymers were reprecipitated into methanol from chloroform solution. All polymerisation mixtures had become very viscous when the polymerisation was terminated. Polymer molecular weights were determined by gel permeation chromatography relative to polystyrene equivalent using tetrahydrofuran as solvent (see Table l).Polymers were made from the four diamines, the preparation of which has been described hereinbefore and a 6-Fluorobisanhydride (available from Riedel - De Haen, Hoechst) having the formula:
Example 5 The 6-Fluorobisanhydride was reacted with AIV diamine to give a polymer having repeating units of the formula::
Example 6 The same 6-Fluorobisanhydride as was used in Example 5 was reacted with AIVa diamine to give a polymer having repeating units of the formula:
Example 7 The same 6-Fluorobisanhydride as was used in Example 5 was reacted with AV diamine to give a polymer having repeating units of the formula:
Example 8 The same 6-Fluorobisanhydride as was used in Example 5 was reacted with AVa diamine to give a polymer having repeating units of the formula:
PreParation of Membranes Several membranes films were prepared using the polymers made in Examples 7 to 8 as follows: (i) Approximately 0.5g of polymer was dissolved in tetrahydrofuran (20cm3) (ii) The resulting solution was passed through a Millipore prefilter (type AP15) onto a clean glass Petri dish.
(iii) The solvent was allowed to evaporate to produce a dense tough flexible membrane readily removed from the glass Petri dish.
(iv) The polymer membranes were pretreated to remove solvent by annealing at 200it for 7 days (except film AS for 6 days, and film A9 for 3 days).
Gas Permeability Measurements The constant volume, variable pressure apparatus used to measure gas permeabilities of the membranes is shown in Figures 1 and 2.
Figure 1 shows the constant volume, variable pressure apparatus assembled and Figure 2 shows two parts of the apparatus in cross-section and disassembled. The apparatus comprised a cell (14) having a base (1) and a top (2), both of stainless steel. The base had a recess (3) and outlet (4). The recess (3) was capable of receiving a wire mesh support (5), a sample of membrane (6), a rubber gasket (7) and an indium wire sealing ring (8). The top (2) had a gas inlet (10) and was shaped so that it could be assembled with the base to form a gas-tight seal with the membrane and the O-ring (11). The assembled cell could be maintained at a constant temperature by an insulated heat block (12) and was mounted on a frame (13).The inlet (10) was connected to a constant volume connected to a constant volume receiver (20) (shown schematically) which was provided with means (not shown) for applying a vacuum or for applying a constant volume of gas to the inlet side of the membrane. The outlet (4) was connected to a constant volume receiver (21) (shown schematically) which was provided with means (not shown) for applying vacuum to the outlet side of the membrane.
The inlet and outlet were connected to pressure transducers (22) (shown schematically) for measuring pressure.
In use, a sample (6) was cut from an annealed polymer membrane and placed in the cell (14). The membrane was pretreated in the apparatus overnight be applying vacuum to both inlet (10) and outlet (4) of the cell with the membrane at 35'C. A constant volume of gas (purity > 99%) was applied to the inlet side of the membrane at known pressure, and a vacuum was applied to the outlet side of the membrane. The pure gas permeability was determined under steady-state conditions, i.e. gas permeation varying linearly with time where the outlet pressure is negligible compared with the inlet pressure. The pressure on the outlet side of the membrane was measured by the pressure transducer (22) and recorded on a chart recorder (not shown). Gas permeabilities were determined for, individual gases, He, C02, CO, 02, N2 and CH4 in the applied pressure range 100 to 700 kPa.
Example 9 Polymer from 6-Fluorobisanhydride + AIV Diamine Film thickness (A27) 48 x 10-4 cm (A9) 48 x 10-4 cm Example 10 Polymer from 6-Fluorobisanhydride + AIVa Diamine Film thickness (A48) 57 x 10-4 cm Example 11 Polymer from 6-Fluorobisanhydride + AV Diamine Film thickness (A18) 47 x 10-4 cm Example 12 Polymer from 6-Fluorobisanhydride + AVa Diamine Film thickness (A45) 53 x 10-4 cm (A5) 46 x 10-4 cm The results are shown in Table 2.
Experiment Not According To The Present Invention A gas separation membrane not according to the present invention was prepared from the same 6-Fluorobisanhydride as was used in Examples 5 to 8 and a diamine having the formula:
by the polyamic acid route which preparation route is described in Macromolecular Synthesis Volume 3 1968 page 83 by C E Scroog and comprised a polymer in which the repeating unit is:
A membrane film 76 micrometres thick (reference number B38) was prepared and permeabilities were measured at 35it, 650 kPa in the same way as for the previous films. The results are shown in Table 3.
TABLE 1
Expts Number Average Weight Average Peak Molecular Molecular Molecular Weight Weight Weight Mn Mw M"/MV 5 34000 84000 2.5 56000 6 25000 72000 2.8 53000 7 37000 117000 3.1 68000 8 29000 97000 3.3 58000 TABLE 2 Permeability results at 35 C and 650kPa
Separation Factors Example Film Permeability (ratios of permeabilities) (film Thickness (Barrers) No.) (micrcmetres) (cm3(STP) cm cm- s-1 cmHg-1 x 10-10) CO2 O2 He He &alpha; &alpha; &alpha; &alpha; CH4 N2 CH4 CO PCO2 PCH4 PO2 PN2 PHe PCO 9 (A27) 48 18.6 0.656 - - 37.5 - 28 - 57 (A9) 48 19.2 0.633 4.34 0.868 - - 30 5.0 - 10 (A48) 57 5.95 0.158 1.61 0.275 25.1 - 38 5.9 159 11 (A18) 47 29.6 1.05 6.99 1.57 57.3 - 25 4.5 55 12 (A45) 53 9.84 0.290 2.77 0.507 39.7 - 34 5.5 137 (A5) 46 - 0.280 - - 44.6 0.666 - - 159 67 TABLE 3 Experiment Not According To the Present Invention 76 micrometre film B38 35 C 650 kPa gas pressure
Gas Permeability Separation Factors (Barrers) (Ratios of permeabilities) CO2 29.8 CO2 - - 22 CH4 1.33 CH4 02 7.47 02 - 4.6 N2 1.61 N2

Claims (15)

Claims
1. A polymer having repeating units of general formula:
and -Z- is -O-, -CO-, -C(CF3)2-, -S02, -C(CH3)2- or -S-; and -X- is -O- or -C(CH3)2-, -Y- is -O- or -C(CH3)2-and -X- and -Yare different; and -Ra is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms;and -Rc is -CH3 or -CF3; and m, n, p are independently 0, 1, 2, 3 or 4.
2. A polymer having repeating units of general formula (I) as defined in claim 1 with the provisos that if -X- is -C(CH3)- then m is 0 and if -Y- is -C(CH3)- then p is 0.
3. A polymer as claimed in any of claims 1 or 2 in which the polymer has different repeating units of general formula (I) as defined in claim 1.
4. A gas separation membrane comprising a polymer as claimed in any of claims 1 to 3.
5. A gas separation membrane comprising a blend of polymers as claimed in any of claims 1 to 3.
6. A process for separating gases comprising passing a mixture comprising two or more gases through a membrane as claimed in any of claims 4 to 5, there being a differential pressure across the membrane whereby the gases of the gas mixture are separated by their relative permeation rates through the membrane.
7. Apparatus for separating gases comprising means for passing a mixture comprising two or more gases through a gas separation membrane as claimed in any of claims 4 to 5, with a differential pressure across the membrane so that the gases separate by their relative permeation rates through the membrane.
8. A process for making a polymer having repeating units of general formula (I) as defined in claim 1, the method comprising the stews of reacting a diamine having the general formula:
where -X- is -O- or -C(CH3)2-, -Y- is -O- or -C(CH3)2- and -X- and -Y- are different; and -Ra is -CH3 or -CF3; and -Rc is -CH3 or CF3; and -Rb is -Cl, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m, n, p are independently 0, 1, 2, 3 or 4, with a bisanhydride having the general formula:
and -Z- is -O-, -CO-, -C(CF3)2-, -S02-, -C(CH3)2- or -S
9.A diamine having the general formula:
where -Ra is -CH3 or -CF3; and -Rb is -Cl, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and -Rc is -CH3 or -CF3; and m, n and p are independently, 0, 1, 2, 3 or 4.
10. A diamine having the general formula (IV) as defined in claim 9 with the proviso that m, n p are independently 0 or 1.
11. A diamine having the general formula:
12. A process for making a diamine having the general formula (IV) as defined in claim 9, the process comprising the steps: (a) reacting a compound having the general formula:
where -Ra is -CH3 or -CF3; and -Rb is -C1, -F or -Br, or is alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m and n are independently 0, 1, 2, 3 or 4, with a compound having the general formula:
where -Rc is -CH3 or -CF3; and p is O, 1, 2, 3 or 4, to give a compound having the general formula:
where -Ra is -CH3 or -CF3; and -Rc is -CH3 or -CF3; and -Rb is -Cl, -F or -Br, or is an alkyl or cycloalkyl group having between 1 and 6 carbon atoms; and m, n and p are independently 0, 1, 2, 3 or 4 and (b) reducing the product of step (a).
13. A polymer substantially as hereinbefore described and with reference to Examples 5 to 8.
14. A gas separation membrane substantially as hereinbefore described and with reference to Examples 9 to 12.
15. A diamine substantially as hereinbefore described and with reference to Examples 1 to 4.
GB9000616A 1989-01-14 1990-01-11 Novel polyimides and diamines Withdrawn GB2229180A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0488341A2 (en) * 1990-11-30 1992-06-03 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Polyimide gas separation membranes and process of using same
WO1992012120A1 (en) * 1991-01-10 1992-07-23 E.I. Du Pont De Nemours And Company Bis(aminophenoxy)naphthalenes and bis(nitrophenoxy)naphthalenes
US5178650A (en) * 1990-11-30 1993-01-12 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes and process of using same
EP0565352A2 (en) * 1992-04-07 1993-10-13 MITSUI TOATSU CHEMICALS, Inc. Aromatic diamine and polyimde, and preparation process of same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4681928A (en) * 1984-06-01 1987-07-21 M&T Chemicals Inc. Poly(amide-amide acid), polyamide acid, poly(esteramide acid), poly(amide-imide), polyimide, poly(esterimide) from poly arylene diamine

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4681928A (en) * 1984-06-01 1987-07-21 M&T Chemicals Inc. Poly(amide-amide acid), polyamide acid, poly(esteramide acid), poly(amide-imide), polyimide, poly(esterimide) from poly arylene diamine

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0488341A2 (en) * 1990-11-30 1992-06-03 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Polyimide gas separation membranes and process of using same
EP0488341A3 (en) * 1990-11-30 1992-07-01 E.I. Du Pont De Nemours And Company Polyimide gas separation membranes and process of using same
US5178650A (en) * 1990-11-30 1993-01-12 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes and process of using same
WO1992012120A1 (en) * 1991-01-10 1992-07-23 E.I. Du Pont De Nemours And Company Bis(aminophenoxy)naphthalenes and bis(nitrophenoxy)naphthalenes
EP0565352A2 (en) * 1992-04-07 1993-10-13 MITSUI TOATSU CHEMICALS, Inc. Aromatic diamine and polyimde, and preparation process of same
EP0565352A3 (en) * 1992-04-07 1994-01-19 Mitsui Toatsu Chemicals
US5354839A (en) * 1992-04-07 1994-10-11 Mitsui Toatsu Chemicals, Incorporated Polyimide and preparation process of same

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GB8900805D0 (en) 1989-03-08

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