FR2542211A1 - SELECTIVE PERMEABLE MEMBRANE FOR GAS SEPARATIONS - Google Patents

Abstract

SELECTIVE PERMEABLE MEMBRANE FOR GAS SEPARATION. THIS MEMBRANE CONSISTS OF A POLYPHOSPHAZENE CONTAINING A REPEATED PATTERN OF GENERAL FORMULA: (CF DRAWING IN BOPI) IN WHICH X AND X REPRESENT EACH, INDEPENDENT OF THE OTHER, AN ALCOXY GROUP, AMINO, ARYLOPEXY, A MOUTIVE ORGANOSILANE OR A GROUP CONTAINING AN ORGANOSILOXANE PATTERN.

Description

2542211.

  The present invention relates to a selective permeable membrane for gas separations and, more particularly, to a selective permeable membrane for

  concentrate the oxygen from the air.

  It has long been known that a membrane

  polymer material can be used to separate and concentrate a

  gaseous mixture This technique has recently stimulated

  considerable interest because of research aimed at

  In fact, if one could easily obtain

  low cost and continuous air with high oxygen concentration from normal air by separation on a membrane,

  this process would be of great interest The oxygen used today

  for medical applications, for example for incubators for premature infants or for the care of patients with

  Respiratory disease consists of pure oxygen from a

  The use of this oxygen has serious drawbacks as well, for example, it requires inconvenient manipulations; oxygen

  can not be provided continuously and must be diluted before use.

  If a high-efficiency membrane capable of supplying oxygen in the concentrated state from air was available, these drawbacks could be remedied and it would even be possible to use this oxygen at home, using a simple device, this

  which would constitute a great medical improvement.

  On the other hand, if one could easily

  and continuously, using a membrane, oxygen enriched air in various combustion systems now in use such as industrial boilers and furnaces, iron blast furnaces, internal combustion engines for vehicles and household water heaters, combustion efficiency would be better

  and fuel consumption could be reduced, that is,

  to say that we would save energy by remedying simultaneously

  problems of environmental pollution caused by

  Incomplete supply Easy and inexpensive supply of enriched air

  in oxygen using a membrane would bring even more people

  in areas such as the food industry

  aquaculture and waste disposal.

  The polymer materials known at present are more or less permeable to gases, but in order to be able to use a membrane capable of concentrating oxygen industrially, the material used must have a permeation rate that is sufficiently high for oxygen and has a high selectivity. for this gas, compared to nitrogen It is known that the rate of permeation of a gas is proportional to the permeation coefficient

  (usually called P and expressed in cm 3 (at temperature and

  normal pressure TPN) cm / cm s cmHg) which is particular to each polymeric substance, at the pressure difference between the two faces of the membrane, and inversely proportional to the thickness of the membrane The selectivity of the oxygen at 1 nitrogen depends on the ratio (O / PN) between the permeation coefficient for

O 2 2

  the oxygen (PO) and the nitrogen permeation coefficient (P) peculiar to the polymeric substance. If it is desired to achieve a practical permeation rate, then a material having a high PO must be selected or otherwise it will be necessary to increase the pressure difference or membrane surety of increased dimensions and a complicated structure of the apparatus using the membrane.

  Moreover, if we want to achieve a sufficient concentration of oxy-

  gene, it is necessary to choose a polymer material for which the ratio

  P 2 / PN is strong The thickness of the mem-

  In order to achieve as high a rate of permeation as possible and therefore the mechanical strength of the material must be strong In addition, the material of the membrane must be durable enough to withstand long-term use and it must be sufficiently Oxidically stable to withstand continuous contact with high concentration oxygen Thus, therefore, commercially available oxygen enrichment membrane materials must have a high P a high PO / P ratio, and excellent properties of mechanical strength, durability 2

and oxidation stability.

  There is practically no known polymeric material which meets all these requirements. Many attempts have already been made to improve the known polymeric materials in this respect and none of these attempts has been entirely satisfactory. below the values of

Z 54221

  PO and PN for some known polymeric substances.

PO 2 PN 2

  (cm 3 mcm) 02 N Polymer material PO (cm 3 (TPN) cm 2 cm 2 cm Hg) P 0 / Polydimethylsiloxane 3.5 x 10 8 1.9 Poly-4-methylpentene-1 3.0 x 10 9 2 , 9 Natural rubber 2.3 x 10 '9 2.4 Low polyethylene 2.9 x 1010 2.9 density Cellulose acetate 43 x 10 3.0 There is only an extremely limited number of known polymeric P of 109 or more:

  these are, for example, polydimethylsiloxane, poly-4'-methyl-

  Pentene-1 and Natural Rubber Most other polymeric substances have a PO of 1010 or less, so that it is impossible to obtain a membrane with a permeate rate convenient from these materials unless a membrane is used. extremely large Even among high polymers with a P no lower than 109, natural rubber has a poor Po 2

  durability (especially due to poor oxy-

  dation) due to the presence of -C = C double bonds in the chain

  main and its mechanical strength is also insufficient.

  Poly-4-methylpentene-1, which is a polyolefin, has a high mechanical strength but its stability to oxidation is poor due to the presence of an atom of

  tertiary carbon in the main chain, so that its use

  under severe industrial conditions (eg at high temperature) poses problems among the polymeric substances

  polydimethylsiloxane has the highest permeability

  gas resistance, but its mechanical strength is poor and it is extremely difficult to form a membrane of lower thickness

  to 20 p m, so we can not achieve a speed of

  practice despite the high PO value of this material.

  If it is reinforced with a filler and crosslinking agent, the mechanical strength can be improved to a certain extent, but these treatments affect the film-forming properties, and it is

  difficult to obtain a very thin membrane On the other hand, the poly-

  Dimethylsiloxane has serious drawbacks: its PO PO ratio is low and its selectivity for oxygen, compared to nitrogen, is poor. We have already tried to improve the permeability

  polydimethylsiloxane gases and to improve its mechanical strength.

  Thus, for example, several attempts have been made to improve the mechanical strength by forming a block copolymer of polydimethylsiloxane and another component in the United States patent.

  No. 3,189,662, a block copolymer of polydimethyl-

  siloxane and a polycarbonate The mechanical strength of this copo-

  The block polymer is somewhat improved due to the introduction of the polycarbonate patterns, but its solvent resistance is reduced so that it can be degraded by the oil of a pump; on the other hand, compared to polydimethylsiloxane alone, the value of P is lowered. Many attempts have been made to modify the organopolysiloxanes by reacting them with others.

  These attempts have all come up against the same

  When the silicon siloxane content of the polymer is lowered, the characteristic property of the polyorganosiloxanes, ie the strong PO, is reduced even if the mechanical strength is improved. In summary, the known high polymers and their modifications have not been reduced.

  still meets the requirements of the introduction.

  The present invention relates to a novel permeable membrane selective for gas separation.

  according to the invention makes it possible to enrich a gas with oxygen because it pre-

  high P values and the P / PN ratio and elsewhere

2 2 2

  excellent characteristics of mechanical strength, durability,

  resistance to chemicals and oxidation stability.

  The gas-permeable and selective membrane of the invention comprises a polyphosphazene containing a repeating unit which has the following general formula:

X

  where X and X ', which may have the same or different meanings, each independently of one another represents an alkoxy group, an amino group, an aryloxy group, a group containing an organosilane unit or a group containing an organosiloxane unit, and ns which represents the average degree of polymerization, is usually in the range of

at 70,000.

  Details will now be given on the meaning

  the symbols X and X 'of the general formula (I) above.

  Of the alkoxy groups, those having the general formula -OR wherein R is C 1 -C 20 alkyl are preferred. Among the preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, sec-butoxy pentyloxy,

  2-methylpentyloxy, neopentyloxy, hexyloxy, decyloxy and dodecyloxy.

  Alkoxy groups in which one or more hydrogen atoms have been replaced by one or more halogen atoms than chlorine, bromine and fluorine, amino, phenyl, nitro and methoxy groups are also preferred.

  mercapto We particularly appreciate the groups in which hydro-

  The term "gene" in any position other than the alpha position has been replaced. When referring to the present application alkoxy groups, the term also applies to substituted alkoxy groups which have been referred to as exemplary substituted alkoxy groups. mention will be made of 2-chloroethoxy, 3-chloropropoxy, 2-bromethoxy, 2-fluorethoxy, phenylmethoxy, p-chlorophenylmethoxy, 2-phenylethoxy, 3-phenylpropoxy, p-butylphenylmethoxy, 2-dimethylaminoethoxy,

  2-methylaminoethoxy, 4-methoxybutoxy, 2-mercaptoethoxy and 2-nitro-

  ethoxy. The fluoroalkoxy groups corresponding to the general formula -OCH 2 (CF 2) -Z in which m is a 2 2 m number from 1 to 10 and Z represents hydrogen or fluorine are also preferred.

  for example 2,2,2-trifluoroethoxy, 2,2,3,3,3-pentafluoro-

  propoxy, 2,2,3,3,4,4,4-heptafluorobutoxy, 2,2,3,3-tetrafluoropropoxy,

  2,2,3,3,4,4,5,5-octafluoropentyloxy and 2,2,3,3,4,4,5,5,6,6,7,7-dodecyl

cafluoroheptyloxy.

  The amino groups referred to above are those which correspond to the general formula -NR 1 R 2 in which

  R 1 and R 2, which may have identical or different meanings.

  Rents, preferably each represent a hydrogen atom, a C 1 -C 10 alkyl group, a substituted C 1 -C 10 alkyl group;

  which several hydrogen atoms have been replaced by one or more

  halogen atoms, fluorine, chlorine or bromine atoms, phenyl groups, C 1 -C 4 alkoxy groups, nitro, cyano, C 1 -C 4 alkylamino or C 1 -C 4 alkylacetoxy groups. C 4; phenyl groups, substituted phenyl groups in which

  one or more hydrogen atoms have been replaced by one or more

  halogens that include fluorine, chlorine or bromine atoms, C 1 -C 28 alkyl groups, C 1 -C 4 alkoxy groups, phenoxy, phenyl, nitro, cyano and C 4 alkylamino groups; 1-C 4; cyano groups; nitro groups; C 1 -C 4 alkylamino groups; alkylcarbamate groups; pyridyl groups

or imidazolyl groups.

  As preferred examples of the amino groups,

  there will be mentioned amino, alkylamino groups such as methylamino, ethyl-

  amino, n-propylamino, n-butylamino, sec-butylamino, n-hexylamino,

  cyclohexylamino, octylamino, decylamino, dimethylamino, diethyl

  amino, methylethylamino and piperidino; alkylemino groups

  substituted such as benzylamino, 2-phenylethylamino, 2,2-trifluor-

  ethylamino, 2,2,33,3,4,4-heptafluorobutylamino and ethylacetoamino arylamino groups such as phenylamino, 3-fluorophenylamino,

  4-fluorophenylamino, 3-chlorophenylamino, 4-chlorophenylamino, 3-

  methylphenylamino, 4-methylphenylamino, 4-ethylphenylamino, 4-n-

  butylphenylamino, 4-methoxyphenylamino, perfluorophenylamino,

  chlorophenylamino, and biphenylamino; pyridylamino groups such

  that 2-pyridylamino and 5-methyl-2-pyridylamino; imidazo groups

  lyle; alkylcarbazate groups such as methylcarbazate and ethyl-

  carbazate; amino groups derived from methylhydrazine and ethylhydrazine; amino groups containing cyano groups such as cyanamide and dicyandiamide groups; and amino groups

containing nitro groups.

  Preferred examples of aryloxy groups are phenoxy and substituted phenoxy groups in which one or more hydrogen atoms have been replaced by one or more straight or branched chain C 1 -C 20 alkyl groups, alkoxy groups.

  C 1 -C 20 straight or branched chain, aryl groups, halogen atoms,

  genes, alkylamino groups containing chain alkyl groups

  straight or branched C -Clo, cyano and nitro groups.

  More specifically, among the preferred aryloxy groups, there will be mentioned phenoxy groups; 3-naphthoxy; alkyl-substituted aryloxy groups such as 4-methylphenoxy, 3-methylphenoxy,

  2,6-dimethylphenoxy, 4-ethylphenoxy, 4-n-propylphenoxy, 4-isopropyl-

  phenoxy, 4-sec-phenoxy, 4-tert-butylphenoxy, 2,4-ditert-butylphenoxy, 3,5-di-tert-butylphenoxy, 4-n-pentylphenoxy, 4-2-ethylhexylphenoxy,

  4-nonylphenoxy, 4-n-dodecylphenoxy, 4-hexadecylphenoxy, 4-phenyl-

  methylphenoxy and 4-trifluoromethylphenoxy; alkoxy-substituted aryloxy groups such as 4-methoxyphenoxy, 3-methoxyphenoxy,

  4-ethoxyphenoxy, 4-n-butoxyphenoxy, 4-sec-butoxyphenoxy and 4-hexyloxy-

  phenoxy; aryloxy-substituted aryl groups such as 4-phenyl-

  phenoxy; aryloxy groups with halogen substituents such as 4-

  chlorophenoxy, 4-bromophenoxy, 4-fluorophenoxy, 3-chlorophenoxy, 2,4-

  dichlorophenoxy, 2,4-dibromophenoxy, 2,4,6-trichlorophenoxy, 2-chloro

  4-methylphenoxy, perchlorophenoxy and perfluorophenoxy; alkylamino substituted aryloxy groups such as 4-dimethylaminophenoxy, 4-diethylaminophenoxy, 4-propylaminophenoxy and 4-butylaminophenoxy; cyano substituted aryloxy groups such as cyanophenoxy; and nitro-substituted aryloxy groups such as 2-nitrophenoxy,

  2. Nitro-4-methylphenoxy, 4-nitrophenoxy and 2-chloro-4-nitrophenoxy.

  The group containing organosilane units has the following general formula A Si Rla R 3 (II) wherein A represents an atom or group which relates to the silane unit having the general formula - Si R 1 R 2 R 3 to the phosphorus atom of the main polyphosphazene chain; the nature of this atom or group is not especially limited: it suffices that it connects the organosilane unit to the phosphorus atom and

  for example: -O-, -NH-, -S-, -CH 2 -CH 2 m O-, O 2 CH -CH-O-

(CH 2) XH

  -NH 4 CH 2 -O-, -NH 4 CH NH-, o 4 'J 2 o H 2 H' 2 m

(CH 2) H

2 m CH

-0, - (CH -) - 0 O CH -

<NH <(CH 2 NH-

  in which m and t each represent a number from 1 to 4.

  In the general formula -Si R 1 R 2 R 3, R 1, 2 and R 3 which may have identical or different meanings each independently of one another is hydrogen, a C 1 -C 4 alkyl group, a substituted C 1 -C 4 alkyl group in which one or more hydrogen atoms have been replaced by one or more halogen atoms such as atoms

  fluorine, chlorine and bromine, cyano, nitro, alkylamino-

  at CC 4, phenyl groups, substituted phenyl groups in which one or more hydrogen atoms have been replaced by one or more halogen atoms than fluorine, chlorine and bromine atoms, cyano, nitro and C1-C4 alkylamino halogen atoms than chlorine, fluorine or bromine atoms; C 1 -C 4 alkylamino groups, cyano groups; or some

vinyl groups.

  Among the organosilane units which are preferred, mention may be made of organosilyl groups of various types such as

  dimethylsilyl, trimethylsilyl, triethylsilyl, tert-butyldimethyl

  silyl, chloromethyldimethylsilyl, trifluoropropyldimethylsilyl,

  cyanoethyldimethylsilyl, dimethylaminoethyldimethylsilyl, cyano-

  propyldimethylsilyl, phenyldimethylsilyl, perfluorophenyl dimethyl

  silyl, 4-dimethylaminophenyldimethylsilyl, dimethylaminodimethyl-

  silyl, methylchlorodimethylaminosilyl, dimethylchlorosilyl and

  vinyldimethylsilyl; the dimethylsilyl and triethyl groups are preferred.

methylsilyl.

  The group containing an organism pattern

  siloxane responds to the following general formula

4 6

B Si if -Y (III) <RS J p R 7

R%

  wherein B represents an atom or group which connects the organosiloxane moiety to the phosphorus atom of the polyphosphazene main chain; its nature is not especially limited; it is sufficient that it connects the organosiloxane motif to the phosphorus atom;

CH CH

, 3 C, 3

  for example, -O-, -NH-, -O (CH 2 O-, -O-CH-, -O-CH 4 CH 2 d, -O "CH 2 CH C, o C 2

(2H) 9H ((CHO CH + CH-

(CH 2 H (C Hk H

NH, -NH H

OCH 2 m CH 2 m 2, H-

(CH 2) e H

  in which m and t each represent a number from 1 to 4.

  In the organosiloxane pattern responding

R, 4> 6 R

  with the general formula Si O if Y, R R 5 R and A, R 5 p R 7

  which may have identical or different meanings,

  each a hydrogen atom, a C 1 -C 4 alkyl group or a C 1 -C 4 haloalkyl group in which one or more hydrogen atoms have been replaced by one or more halogen atoms such as fluorine, chlorine and bromine atoms; a phenyl group; or a vinyl group, Y is hydrogen, a C 1 -C 4 alkyl group, a haloalkyl group in which one or more

  hydrogen atoms have been replaced by one or more halo-

  only fluorine, chlorine and bromine atoms; a hydroxyalkyl group; phenyl, vinyl; a halogen such as fluorine, chlorine or bromine; a hydroxy group, an amino group, a C 1 -C 4 alkylamino, epoxy; -4 CH + O-Si (CH 3) 3 or-2 H-Si (CH 3) 3, in 1 4-1 2 m or 3 2 in 33 where m is a number from 1 to 4 and p is a number from 1 to 1000 The following are preferred examples of groups containing an organosiloxane unit:

254221 1

  H CH f H CH CH / i 3) | 3 3 1 H 3 / ci 3

  If Si-CH Si-Ot Si-OH, -O (CH Si-

  CH + 3 '24 mt 3 p CH 3 CH 3 p CH 3 CH 3 p

CH / CH 2 CH CH

1 3/1 3 '1 3

-Si C 3 H 2 OH, CH 3 CH 3 CH 3 CH

1%

CH 3 CH 3

/ i h} 3.

-O O Si-O-t Si-CH 3,

JP CH 3

i-CH 3, -O

H 3 CH 2 -CH 2-CH 2-

  In the general formula I, the symbols X and X 'may have identical or different meanings but, in the case where they are substituent groups containing the organosilane or organosiloxane units, the ratio of the total of the n -Si-CH CH 3 CH 3 lu, organosilane units and / or organosiloxane units to the total polymer

  advantageously in the range of 10 to 90% and, preferably,

  from 20 to 80% by weight. If this ratio is less than 10%,

  gas permeability can not be improved and if it is superior

  At 90%, the final polymer will have a poor mechanical strength and will not allow to obtain a thin membrane. Thus, with the reports coming out of the interval which has just been defined, it is impossible to remedy the disadvantages encountered. with rubber

  silicone, and the goals sought in the invention are not achieved.

  The polyphosphazenes which make it possible to obtain a particularly efficient oxygen enriching membrane, that is to say a membrane which has a very selective oxygen permeability, namely a high PO / PN ratio, are those in which 10 to 90% of the substituent groups are alkoxy groups and the remaining 90 to 10% are amino, aryloxy, ether-oxy, alkyl, alkenyl and / or aryl groups. Alkoxy, amino groups

  and aryloxy in question are as defined above.

  The ether-oxy group has the general formula R (OR ') n O wherein R represents a C 1 -C 20 alkyl, aryl, alkylaryl or arylalkyl group and R' represents a C 1 -C 4 alkylene group. the most appreciated are CH 3 (OC 2 H 4) n O-,

  CH 3 (OC 4 H) n 0-, CH 3 (OC-CH-C 2 H 4) n O-, C 2 H 5 (c OC 2 H 4) n O nC 4 H 9 (OC 2 H 4) n 0-

  CH 3 K> C 2 i 4) n O, D-CH 2 OC 2 H 4) n Oet 2 m + 1 CM C o 2 4) n in which m and N are numbers ranging respectively from 1 to 12

and from 1 to 70.

  These alkyl groups are preferably straight-chain or branched C 1 -C 12 alkyl groups, for example methyl, ethyl, propyl, butyl, sec-butyl, tert-butyl, pentyl,

  neopentyl, hexyl, cyclohexyl, octyl, decyl and dodecyl.

  The alkenyl groups preferably consist of those which correspond to the general formula -CH = CC 2 R "in which R" represents hydrogen or a straight or branched chain alkyl group or a C 1 -C 12 aryl group, for example Example 2-chlorethenyl, 2-chloropropenyl, 2-chloro-1-butenyl, 2-chloro-3-methyl-1-butinyl, 2-chloro-1-hexenyl, 2-chloro-3-methyl-1heptenyl, 2-chloro -l-octenyl,

  2-chloro-1-decenyl, 2-chloro-2-phenylethenyl, 2-chloro-4-tert-

  butylphenyl) ethenyl and 2-chloro-2-naphthylethenyl.

  The aryl groups are substituted or unsubstituted.

  For example, phenyl, 4-methylphenyl, 3-ethyl-

  phenyl, 4-tert-butylphenyl, 3-methoxyphenyl, 4-butoxyphenyl and 4phenylphenyl. In the general formula (I), N is a

  number ranging from 20 to 70 000, so that the polymer is usually

  In the form of a rubber or flexible elastic solid substance. If N is less than 20, the polymer has poor mechanical strength and does not provide a membrane.

  sufficiently resistant for practical use If N is greater than

  At 70,000, it is difficult to prepare the polymer because of its too high molecular weight and it is difficult to form a membrane because of the high viscosity of the solution which serves to form the membrane. not less than 20, depending on the particular nature of the substituents, an oily liquid may be obtained, but a polyphosphazene may be naturally used, containing in part such substituents and forming the

  impregnating a porous substance of the liquid polymer.

  The polyphosphazene according to the invention can be prepared by known processes (see, for example, Allcock et al., Inorg Chem, 5, 1716 (1966)). Thus, for example, the polydichlorophosphazene itself obtained by polymerization is reacted.

  heat of a cyclic chlorophosphazene such as hexachlorocyclo

  triphosphazene or octachlorocyclotetraphosphazene, or a chloro-

  linear low molecular weight phosphazene in a perfect

  anhydrous, in the presence or absence of a catalyst, with

  a reagent for forming the group X and / or the group X '.

  A polyphosphazene containing

  alkoxy groups by reacting a polydichlorophosphazene

  with an alkali metal alcoholate (eg sodium, potassium

  sium or lithium) of the corresponding alcohol It can also be prepared by heating polydichlorophosphazene with alcohol

  corresponding in the presence of a tertiary amine such as tri-amine

  ethylamine. Amino, aryloxy and the like can be introduced into the polyphosphazene molecule in the same manner as described hereinafter. The amino groups Polychlorophosphazene is reacted and

  the corresponding amine in the presence or absence of a tertiary amine.

such as triethylamine.

  The aryloxy groups The polydichlorophosphazene is reacted with an alkali metal (eg sodium, potassium or lithium) phenol phenol or corresponding substituted phenol. The polydichlorophosphazene can also be reacted with phenol or

  substituted phenol corresponding to hot in the presence of a tertiary amine

such as triethylamine.

  Groups containing an organosilane unit In a process, some or all of the chlorine atoms of the polydichlorophosphazene are replaced by hydroxy, amino or mercapto groups, or a polyphosphazene substituted with a hydroxy, amino or mercapto group is substituted. at a place

  other than the bond with the phosphorus atom, and one submits to sily-

  with a coupling agent of the silane type containing the

corresponding organosilyl group -

  In another process, some or all of the chlorine atoms of the polydichlorophosphazene are replaced

  by an alcoholate of the corresponding silyl alcohol.

  In another process, the groups

  alkoxy of a polyalkoxyphosphazene with transesterification with a

  of the corresponding silyl alcohol in the presence of an alkaline catalyst. Groups Containing Organosiloxane Units In a process, some or all of the chlorine atoms of the polydichlorophosphazene are replaced by an alkoxide of a polyorganosiloxane having hydroxy end groups or by a polyorganosiloxane having terminal groups

amino or epoxy.

  In another process, some or all of the alkoxy groups of a transesterification polyalkoxyphosphazene are subjected to an alcoholate of a polyorganosiloxane.

hydroxy end groups.

  In another process, a polyphosphazene bearing a substituent group which contains an unsaturated bond is first prepared and then a polyhydrosiloxane is fixed on this unsaturated bond, using a catalyst such as chloroplatinic acid.

carrying an active hydrogen.

  The ether-oxy groups The polydichlorophosphazene is reacted with an alkali metal alcoholate (for example sodium, potassium

  sium or lithium) of the corresponding ether-alcohol (R (OR ') n OH) or is reacted with the corresponding hot ether-alcohol in the presence

  a tertiary amine such as triethylamine.

  The alkenyl groups The polydichlorophosphazene and the corresponding alkyne are reacted in the presence of a tertiary amine such as

triethylamine.

  Alkyl and aryl groups A trimer or tetramer of a cyclophosphazene with an alkyl or aryl substituent (for example, monomethylpentachlorocyclotriphosphazene) is thermally polymerized while hot.

  reacting a polydifluorophosphazene obtained from

* fluorocyclotriphosphazene with an organometallic compound containing the alkyl or aryl group to be introduced (for example an aryl-lithium

or a dialkyl magnesium).

  In the case where only one type of reagent, for example an alcohol, is used, a homopolymer represented by the formula NPX 2 is obtained and in the case where two types of

  reagents, there is obtained a copolymer containing, in statistical distribution,

  tick the following three types of repeated patterns

N = P, N = N = P

X

254221 1

  When three or more reagent types are used, a copolymer containing these three or more substituents in random distribution is obtained.

  For example, to prepare a poly-

  phosphazene containing 10 to 90% of an alkoxy group and 90 to 10% of another substituent group, it is possible to adopt a process in which a polyphosphazene containing the desired proportion of the alkoxy group is first prepared as described above; the remaining chlorine atom which is not substituted by the substituent group desired as described above is replaced. A method may also be adopted in which a polyphosphazene having a substituent other than the alkoxy group is first prepared and then replacing the chlorine atom. remaining by

  In another process, the alkoxy group is reacted simultaneously.

  with the polydichlorophosphazene the alkoxy-introducing reactant and the substituent introducing a substituent other than

  alkoxy group The optimal process depends on the reactivity of the

  starting point and we can therefore choose the most appropriate method

  asked for the copolymer we want to obtain.

  In the polyphosphazene according to the invention, part of the substituent groups X and X 'may be replaced by

  a crosslinkable group, for example an allylalkoxy or allylalkoxy group;

  phenoxy, which then allows the crosslinking with the aid of a peroxide, sulfur, etc. One can also leave a part of the chlorine atoms of polydichlorophosphazene for crosslinking It goes without

  say that these polymers are also part of the poly-

phosphazenes according to the invention.

  The permeable membrane selective for sepa-

  The gas ration consisting of polyphosphazene according to the invention has a high gas permeation rate and a remarkable selectivity. For example, for the enrichment of oxygen in the air, PO reaches values of 10 9 to 10 With the exception of polyorganosiloxanes, macropolymers having such PO values are not known. In addition, the PO 2 / PN 2 ratio is not less than 2.0 and preferably not less than 3.0. , while he

  is 1.9 for the polyorganosiloxanes On the other hand, the polyphosphoric acid

  phazene as a material for the preparation of the membrane

  gas separator according to the invention may vary from the state of

  elastic rubber in the state of plastic material according to the nature and

  proportion of substituent groups In all these states, the poly-

  Phosphazene possesses remarkable properties of resistance to solvents, heat and oxidation. Therefore, problems such as membrane degradation are not encountered.

  under the action of the oil of a pump, degradation by the use

  This is also a remarkable characteristic of the membranes according to the invention. On the other hand, the polyphosphazene according to the invention has high temperature or oxidative degradation due to the continuous contact with oxygen at high concentrations.

  remarkable film-forming properties, which is a major advantage

  when you want to form a gas separation membrane.

  The gas separation membrane of polyphosphazene according to the invention having these remarkable characteristics can easily be obtained by any of the known techniques for the formation of membranes and, for example, by the casting technique Solubility in solvents varies depending on the nature of the substituent groups, but a casting solution can be prepared using a solvent suitable for the polyphosphazene used and then pouring the solution on an ice or on a surface

  likewise followed by drying and removal of soil

  efore; Thus, a homogeneous membrane is obtained. Among the solvents which are suitable and which differ according to the nature of the substituent groups as we have just mentioned, mention may be made of aromatic hydrocarbons such as benzene and toluene, alcohols in the case of a

  polydiethoxyphosphazene and ketones and ethers such as methyl-

  ethyl ketone and tetrahydrofuran in the case of polydifluoro-

  ethoxyphosphazene or a polybisphenoxyphosphazene The concentration of the solution to be cast is preferably from 0.5 to 30% 7, preferably from 1 to 20%, and a membrane having a thickness in the range of 0.01 can then be obtained. at 200, pm If one wants to achieve a strong

  gas permeation, the membrane must be as thin as possible

  and, therefore, the thickness of the membrane will preferably be in the range of 0.05 to 30 μm. A membrane with a thickness of less than 1 e can be obtained by using a process known in the industry and in wherein a solution is dissolved in a hydrophobic solvent on the surface of the water, and after evaporation of the solvent, the thin film is applied to a porous mineral or organic carrier. The membrane according to the invention can be used directly as a homogeneous membrane or can be put under the

  form of a composite membrane reinforced by application to a sup-

  porous polymer port consisting for example of cellulose acetate,

  polyamide, polycarbonate, polysulfone, polyether-sulfone or poly-

  olefin, or on a porous inorganic support such as glass or alumina, or a woven or non-woven fabric. In addition, the membrane of the invention may take the form of a sheet, a tube,

  another hollow form or any other form.

  Finally, it is also possible to use a membrane made of a mixture of polymers obtained by mixing the

  polyphosphazene with another macropolymer, for example a poly-

olefin or a polyorganosiloxane.

  As already mentioned, the selective permeable membrane for gas separation comprising the polyphosphazene according to the invention is an upper membrane having high values of PO and PO / PN; usable for oxygen enrichment

2 2 N 2

  and having high qualities of mechanical strength, solvents, heat and oxidation; it can be used in

  various combustion systems for medical, industrial and

  In addition, the membrane according to the invention can serve not only to enrich oxygen in the air but also to separate mixtures of various gases, for example hydrogen, carbon monoxide, anhydride. carbonic acid, helium, argon, hydrogen sulphide, ammonia or light hydrocarbons such as methane, ethane, propane, butane, ethylene, propylene and butene. The following examples illustrate the invention

  without, however, limiting its scope; in these examples, the indica-

  Parts and percentages are by weight unless otherwise indicated.

EXAMPLE 1

  Hexachlorocyclotriphosphazene at 250 ° C. is heated in a glass ampoule under vacuum for 20 h. A solution of the polydichlorophosphazene obtained in benzene is then added dropwise to a solution of sodium trifluoroethylate in tetrahydrofuran at room temperature and then heated to room temperature. reflux for 30 h; a polydifluoroethoxyphosphazene is obtained which is carefully purified by removal of the accompanying sodium chloride, unconverted monomers and low molecular weight oligomers. On this purified polydifluorethoxyphosphazene, the average molecular weight, by weight, is then determined by the diffraction method of light; there is approximately 1,500,000 This value corresponds to an average degree of polymerization

  (n of formula I) of about 6,100.

  This polymer is dissolved at the concentration of% in methyl ethyl ketone. This solution is then poured on an ice, setting at a casting thickness of 0.4 mm using a scraper blade. After a day's rest at room temperature ,

  a translucent membrane having a thickness of 12 μm is obtained.

  This membrane, which is as thin as it is, has sufficient mechanical strength to withstand stretching. It is placed in a gas permeability cell. Air is passed from one side of the membrane to the manometer pressure of 2. bars and the rate of permeation and the composition of the oxygen-enriched air that has passed through the membrane are measured by analysis, from which P and P are deduced.

02 N 2

  obtains the following results which show that the membrane e poly-

  difluoroethoxyphosphazene has a superior enrichment

  Oxygen: OD 7.1 x 109 cm (TPN) cm / cm s cm Hg

2 -

P 2.7 x 109 02.2 Po 2 / PN 2,

EXAMPLE 2

  A solution of polydichlorophosphazene in benzene prepared as described in Example 1 is added dropwise to a solution of sodium methoxide in methanol at room temperature over 2 hours and then refluxed for

  38 h A polydimethoxyphosphazene is obtained Carefully purified

  This polymer is removed by removing the sodium chloride formed as a side product, the unconverted monomer and the low molecular weight oligomers, and then the average weight average molecular weight is measured by the light diffraction method; there is 950 000 This value corresponds to an average degree of polymerisation

(n of formula I) of 8,900.

  This polymer is dissolved at a concentration of 1% in methanol. This solution is applied in a thin layer to a porous sintered alumina plate pre-impregnated with paraffin oil, 7.4 cm in diameter, and dried. then the resulting membrane, with the carrier, in n-hexane to remove the paraffin oil After drying for one day at room temperature, the permeability of the membrane to oxygen is determined as described in Example 1 ; the following results are obtained: Permeation rate of oxygen: 5.0 x 10-6 cm 3 (TPN) / cm 2 s cm Hg Permeation rate of nitrogen: 1.9 x 106 cm 3 (TPN) / cm 2 cm Hg With a membrane of approximate thickness 1> O ym obtained by the gravimetric method and taking into account the pqrosity of% of the sintered alumina support, P 0, PN and PO / PN are determined;

2 'N 2 2 N 2

  the results obtained are the following:

9 3 2

  1.1 x 109 cm (TRPN) cm / cm s cm Hg P 02 42 x 10-1 PN 2 Po 2 / P N 26

12 N 2

  They show that the polydimethoxyphosphazene membrane has a

  superior ability to enrich oxygen.

EXAMPLE 3

  Polydichlorophosphazene is prepared by polymerization

  30 hours as described in Example 1 and add drop to

  drop a solution of the polymer in benzene to a solution of ethyl-

  sodium acetate in ethanol at room temperature over 2 h. Refluxed for 30 h; a polydiethoxyphosphazene is thus obtained which is carefully purified by removing the sodium chloride formed

  in particular, the unconverted monomer and the oligomers

  Low molecular weight metals and the average weight average molecular weight is determined by the diffraction method of light; there is 2,800,000, which corresponds to an average degree of polymerization (n of formula I) of 20,000.

  This polymer is dissolved in toluene in the concentration

  6% and pour the solution on an ice setting the casting thickness of 1 mm with a scraper blade After resting for one day at room temperature, detach the film

  with care of the ice; it's a transparent film of thick

  35 'is determined PO' PN and PO, as described in

2 2 2

  Example 1 The following results show that the polyethoxyphosphazene membrane has a superior oxygen enrichment capacity:

-8 3 2

  P 1.4 x 10 cm (TPN) cm / cm s cm Hg P 02 PN 5.8 x 109 2.2

PO 2 / PN 2 4

EXAMPLE 4

  Polydichlorophosphazene is prepared as described in Example 3 and a solution of this polymer in benzene is added dropwise to a solution containing amounts.

  equimolecular levels of 2,2,2,3,3,4,4- 2,2,2-trifluoroethyl

  sodium heptafluorobutylate in tetrahydrofuran at room temperature for 3 h; then refluxing for 20 h; can obtain a copolymer of fluoroalkoxyphosphazene After careful purification

  by removal of by-product sodium chloride, mono-

  unconverted mother and low molecular weight oligomers, it is

  the average molecular weight of the copolymer by the method of

  fraction of light; we find 5 100 000, which corresponds to

  an average degree of polymerization (n of formula (I)) of 15,000.

  This copolymer is dissolved in a tri-solvent mixture

  chlorofluoroethane / acetone 9: 1 at a concentration of 2% With this solutin, a film is formed on a porous plate of sintered alumina as described in Example 2 and the permeability to oxygen is determined. The following examples show that the fluoroalkoxyphosphazene copolymer membrane has a

  superior oxygen enrichment.

-8 3 2

  PO at 1.7 x 10 cm (TPN) cm / cm s cm Hg PN 7.4 x 10 -9

PO / IN 2.3

2 2

EXAMPLE 5

  A droplet of a 1% solution of the poly-

  diethoxyphosphazene of Example 3 in toluene at the surface of

  water placed in a glass container and kept at 10%.

  The droplet spreads immediately with the formation of a film of liquid on the surface of the water. By keeping the surface of the liquid as fixed as possible, the benzene is allowed to evaporate and then it is removed.

  the thin film by taking it under it with a film

  porous polypropylene cartridge (Juraguard 2500

the company Polyplastics Co).

  After a day's rest to drain the water, the membrane is placed in the cell of Example 1 and passed through

  of the primary side of the membrane a gaseous mixture of carbon dioxide

  nitrogen and nitrogen at the gauge pressure of 2 bar to determine

  P Co / PN; The effect of separation on a gaseous mixture of helium and nitrogen is also measured. P He / PN = 10.6 For comparison, a membrane of m 2 of silicone rubber (polydimethylsiloxane) crosslinked with bis-2,4-dichlorobenzyl peroxide is formed and determined for this purpose. PCO / PN and P He / PN membrane; we find respectively

  6.5 and 1.2 This result shows that the polydiethoxyphosphate

  phazene has a gas separation capacity much higher than that

  of the silicone rubber membrane.

EXAMPLE 6

  Hexachlorocyelotriphosphazene is polymerized at 250 ° C. in a glass ampoule under vacuum for 24 hours and a solution of the polydichlorophosphazene obtained in benzene is added dropwise to a solution of dimethylamine in benzene over 4 hours while maintaining the temperature at a temperature of maximum of 5 C Then continue the reaction

  at 25 C for 24 hours; a polybisdimethylamino-

  phosphazene This polymer is purified by removing the unconverted amine,

  dimethylamine hydrochloride and low molecular weight oligomers

  then the average molecular weight is determined by the diffraction method of light; 780,000, which corresponds to an average degree of polymerization (n of formula I) of 5,800. A 2% solution of this polymer is then prepared in trifluoroethanol and applied to a porous polypropylene film. (Jurucard 2500 commercial product, from Polyplastics Co, thickness 25 μm, porosity 45%), then left

  dry for one day at room temperature.

  composite brane obtained in a permeability measuring cell

  gas and air is passed over the primary face of the membrane at a pressure of 3 bar; under these conditions, the flow rate and the composition of the air enriched with oxygen at atmospheric pressure having passed through the membrane are measured; The following results are obtained: Permeation rate of oxygen 3.1 x 106 cm 3 (TPN) / cm 2 cm Hg Nitrogen permeation rate: 0.82 x 10-6

  2 N 2 These results show that the dimethyl-

  Aminophosphazene has a good ability to enrich oxygen.

EXAMPLE 7

  A benzene solution of the polydichlorophosphazene prepared in Example 6 is added dropwise to a solution of aniline in tetrahydrofuran at room temperature for 4 hours, and the reaction is then continued for 4 hours under reflux; we obtain

  phenylaminophosphazene This polymer is purified by eliminating the

  unconverted line, aniline hydrochloride and oligomers of low molecular weight, then the molecular weight is determined by the light diffraction method. There are 1,720,000, which corresponds to an average degree of polymerization (n of the Formula I) 7500 A 2% solution of the polymer in benzene is then prepared and this solutin is applied to the Juraguard 2500 film as described in Example 6. On the composite membrane obtained, the permeation rates of the oxygen and nitrogen; the results obtained are as follows: Oxygen permeation rate: 6.3 x 10 6 cm 3 (TPN) / cm 2 cm -1 Hg -6 Nitrogen permeation rate: 1.5 x 10 "

P 2 / PN 2: 4.2

  These results show that the polybisphenylaminophosphazene membrane has a higher enrichment capacity

oxygen.

EXAMPLE 8

  A solution is added dropwise to the tetra-

  hydrofuran of the polydichlorophosphazene prepared in Example 6

  to a solution of diethylamine in tetrahydrofuran at room temperature

  After 2 hours at room temperature, the resulting polymer is thoroughly purified and its composition is determined by elemental analysis.

  in the polymer structure, 50% of the chlorine atoms of the polydim-

  rophosphazene were replaced by diethylamino groups, the remaining 50% of chlorine remained unaffected. A solution of the polymer in tetrahydrofuran was then added dropwise.

  to a solution of n-butylamine in tetrahydrofuran at room temperature

  room temperature in 2 hours, then continue the reaction for 2 days

  at room temperature; a copolymer of n-butylamino is obtained

  diethylaminophosphazene in which equal amounts of diethylamino and n-butylamino groups have been introduced after purification

  by removal of the unconverted amine, n-butylhydrochloride

  amine and high molecular weight oligomers, the polymer has an average molecular weight of 170,000 and a degree of polymerization

average of 890.

  A 2% solution of this polymer is prepared in

  benzene and, with the aid of a micropipett,

  lette the solution on the surface of clean water maintained at 5 C in a container; A thin film is formed on the surface of the water. This thin film is carefully removed by taking it back on a film of Juraguard 2500. On the composite membrane obtained, the permeation rates of oxygen and carbon are measured. nitrogen like

  d written in example 6; the following results are obtained.

  Oxygen permeation rate: 4.7 x 10 -4 cm 3 (TPN) / 2 C m Hg Oxygen permeation rate 4 e 7 x 10 cm (T Ff O cm s cm Hg Permeation rate of nitrogen: 1.2 x 10 cm (TPN) / cm s cmg

P 2 / P 2 3 '9

  o 2 /: 3, These results show that the copolymer membrane

  n-butylaminodiethylaminophosphazene has a superior

richness of oxygen.

EXAMPLE 9

  In a toluene solution of polydichloro

  phosphazene prepared in Example 6, triethylamine is added

  As a reaction accelerator we add to the same solution

  a solution of 2-amino-4-picoline is added dropwise at room temperature over 4 hours and the reaction is continued for 5 days at reflux temperature; The polymer is purified by removal of the unconverted amine, triethylamine, the hydrochlorides of these amines and the oligomers, and a 10% solution of the purified polymer is prepared in the course of the reaction. dioxane, which is poured on an ice setting the casting thickness of 0.3 mm using a scraper blade; air dried for 1 day at room temperature; we obtain

  a transparent transparent homogeneous film of thickness 20 m.

  The flow rate and the composition of the oxygen-enriched air passing through this film are determined as described in Example 6, from which P and PN are deduced. The following results are obtained:

02 N 2 -9 3 2

  PO 1.3 x 10 cm (TPN) cm / cm s cm Hg P 02 P 3.2 x 10-10

P / P 4.1

02 N 2

  These results show that the polyaminophosphazene membrane has a

  superior ability to enrich oxygen.

EXAMPLE 10

  The membrane prepared in Example 8 is placed in the cell of Example 6 and a gaseous mixture of carbon dioxide and nitrogen is passed from the primary side of the membrane at a pressure of 2 bars; PCO / PN is determined; 24.3 The same measurements are made for a gaseous mixture.

  helium and nitrogen; a value of 13.7 is obtained for P He / PN.

Hey

Z 542211

  For comparison, a 30 μm thick membrane of silicone rubber (polydimethylsiloxane) crosslinked with bis-2,4-dichlorobenzoyl peroxide is formed and the ratios are determined.

  PCO / PN and P He / PN; these are 6.5 and 1.2 respectively.

  States show that the polyethoxyphosphazene membrane has a capacity of

  higher gas separation than silicon rubber

cone.

EXAMPLE 11

  Hexachlorocyclotriphosphazene at 250 ° C. is heated in a glass ampoule under vacuum for 24 hours; a polydichlorophosphazene is obtained which is dissolved in toluene; we add

  the solution dropwise to a solution of 4-ethylphenate

  diol in dimethyl ether glycol A 90 C in 1 h The temperature is then raised to 115 ° C and the reaction is continued for 30 h; polybis (4-ethylphenoxy) phosphazene is obtained. This polymer is purified by removing by-product sodium chloride, unconverted phenate and low molecular weight oligomers and the molecular weight is determined by gel permeation chromatography ( with polystyrene calibration curve) 1,200,000, corresponding to an average degree of polymerization of about 4,200 (n of Formula I). This polymer is dissolved in tetrahydrofuran at a concentration of 15%. Pour the solution on an ice setting the casting thickness of 0.3 mm with a scraper blade After drying for 1 day at room temperature, the film is carefully detached from the ice This film is transparent and resistant and its thickness is pm This film is placed in a cell l measurement of the gas permeability and air is passed on the primary face of the membrane at a pressure manomâtriqu e of 2 bars; the flow velocity and the composition of the oxygen-enriched air passing through the membrane, from which P and PN are deduced, are obtained, the results obtained being the following: P 2.0 × 10 -9 cm 3 ( TPN) cm / cm s cm Hg, 9x10- 9 N 2

P 2 / PN 3

  These results show that the membrane of polybis (4-ethylphenoxy) -

  phosphazene has a superior oxygen enrichment capacity.

EXAMPLE 12

  Polybisphenoxyphosphazene is prepared as described in Example 11 but replacing sodium 4-ethylphenate with sodium phenate. Molecular weight and mean degree of polymerization (n) are respectively 900,000 and 3900. The polymer is dissolved. at the concentration of 18% in tetrahydrofuran and the solution is applied to a porous polypropylene film (commercial product Juraguard 2500 from Polyplastics Co, thickness: 25 μm, porosity 45%) and allowed to dry at rest for one night The calculated composite film thickness was 22 m based on the weight, area and density of the applied polymer. PO and N 2 were then determined as described in Example 11; we get the results

O 2 2

following:

9 3 2

  P 02 7.1 x 10-9 cm (TPN) cm / cm 2 s cm Hg PO 2 P 2.0 x 10-9 N 2

02 N 2 3 5

  These results show that the polybisphenoxyphosphazene membrane

  a superior capacity for oxygen enrichment.

EXAMPLE 13

  Polybis (4-chlorophenoxy) phosphazene is prepared

  as described in Example 11, but by polymerizing hexachlorotrichloride

  phosphazene for 48 h and using sodium 4-chlorophenate

  instead of sodium 4-ethylphenate A molecular weight is found

  The polymer was dissolved at a concentration of 5% in tetrahydrofuran and the solution was applied to ice as described in Example 11; a resistant membrane of 10 μm thickness is obtained. On this membrane, P and PN are determined as described in Example 11; we obtain the following results

-93 2

  PF 5.3 x 10 cm (TPN) cm / cm s cm Hg 02 1 9 l -'- 1 ^ i 91 r 2 L, J_) P 2 / Pl 3.8

02 N 2

  These results show that the membrane of polybis (4-chlorophenoxy) -phosphoric acid

  phazene has a superior ability to enrich oxygen.

EXAMPLE 14

  Hexachlorocyclotriphosphazene at 2500 ° C was heated in a glass ampoule under vacuum for 30 h. Polydichlorophosphazene was added dropwise a solution of this polymer in toluene to a solution containing equimolar amounts of sodium phenate and 4- sodium sec-butylphenate in glycol dimethyl ether at 90 ° C. and in 2 hours. The temperature is then brought to 115 ° C. and the reaction is continued for 30 hours; a polyaryloxyphosphazene copolymer containing phenoxy and 4-sec-butylphenoxy groups in equal amounts is obtained. The average molecular weight and the degree of polymerization

  average (n) are 1,800,000 and 6,200, respectively.

  This copolymer is dissolved at the concentration of% in tetrahydrofuran and the solution is applied to a film of Juraguard 2500 as described in Example 12; The film thickness calculated on the basis of the weight of the polymer applied to the support film is 24 μm. P and PN are determined for this composite membrane as described in Example 11; the following results are obtained:

9 3 2

  PO 2.5 x 10-9 cm (TPN) cm / cm s cm Hg 6.7 x 10-10

P 02 / P 2

  These results show that the polyaryloxy copolymer membrane

  phosphazene has a superior oxygen enrichment capacity.

EXAMPLE 15

  A composite membrane consisting of

  polyaryloxyphosphazene copolymer containing 4-methoxy groups

  phenoxy and 4-tert-butylphenyl, and equal amounts on Juraguard 2500 film support in the cell of Example 11, and a gaseous mixture of carbon dioxide and nitrogen is passed on the primary side of the membrane. under these conditions, the ratio PCO / PN is determined; 20.1 The same is done for the determination of the separation effe on a gaseous mixture of helium and nitrogen; PH Ie / PN = 12.3 For comparison, a membrane is prepared

  2 m thick silicone rubber (polydimethyl-

  siloxane) crosslinked with bis-2,4-dichlorobenzoyl peroxide and PCO / PN and P He / PN determined; we find respectively 6.5

2 2

  and 1.2 These results show that the composite membrane according to the invention has a gas separation capacity much greater than

  that of the silicone rubber membrane.

EXAMPLE 16

  Hexachlorocyclotriphosphazèng at 250 OC was heated in a glass ampoule under vacuum for 20 h; Thus a solution of this polymer in toluene at 95 ° C. is added dropwise to a solution of the monosodium salt of bisphenol A in dimethyl glycol ether.

  prepared from bisphenol A and sodium in the corresponding quantities

  at 4 and 3 moles, respectively, relative to the di-

  chlorophosphazene The temperature is then brought to 115 ° C. and the reaction is continued for 30 hours; a polyphosphazene is obtained with the following structure: CH 1 NP (o C Q 011) 2 In CH 3

  The average degree of polymerization N is 9,700.

  This polymer is then slowly reacted with an excess of trimethylchlorosilane in the tetrahydrofuran containing triethylamine, thereby causing the trimethylsilylation of the polyphosphazene hydroxyl groups. After purification, the silicon content of the polymer is determined, from which the content is deduced. in

  trimethylsilyl groups: 19% is found.

This polymer is dissolved in tetrahydrofuran at a concentration of 8%; the solution is poured on ice, adjusting to a thickness of 0.2 mm and then air-dried for one day;

  a film 7 μm thick is obtained.

  in a gas permeability measuring cell, air is passed over the primary face of the membrane at a pressure of 2 bar; under these conditions, the flow rate and the composition of the oxygen-enriched air passing through the membrane are determined; we deduce PO and PN; the following results are obtained: tnddi and N

02 2 -8 3 2

  PO 2.3 x 10 cm (TPN) cm / cm s cm Hg P 02 2 -9 f PN 9.1 x 109

P "/ PN 2, 5

  222.5 These results show that the polymer prepared above can be easily diluted compared with polydimethylsiloxane and that the membrane formed from this polymer has a remarkable capacity for oxygen enrichment, having a P / PN ratio. superior

  to that of polydimethylsiloxane which is 1.9.

EXAMPLE 17

  A polyphosphazene tert-butyldimethylsilyld was prepared as described in Example 16 but starting from the polymer of CH Example 16 (1NP (O H) 2 In) and using

CH 3

  as a coupling agent for tert-butyldimethylchlorosilane

  The tert-butyldimethylsilyl group content of the polymer is 29%.

  The polymer is dissolved at the concentration of 10% in tetrahydro-

  furan, and pour the solution on ice into a film of 15 μm thick

  PO and PN are determined for this film as described in

02 N 2

  Example 16; the following results are found: PO 1.6 x & & 8 3 2 PO 1.6 x 10 8 cm (TPN) cm / cm s cm Hg

2 9

PN 2 5.7 x 10 N 2

P / P 2.8

02 / N 2

N 2.8

EXAMPLE 18

  A solution in benzene of the polydichlorophosphazene prepared in Example 2 is added dropwise at room temperature.

  Example 16 to a solution in trisethylene tetrahydrofuran

  sodium fluoromethylate in an equimolar amount relative to the dichlorophosphazene units and then the reaction is continued for 30 h at the reflux temperature; Polyphosphazene partially substituted by trifluoroethoxy groups is obtained. A solution of the polymer in tetrahydrofuran is added dropwise to a solution in the solvent mems of the monosodium alcoholate of 1,4-butanediol and of excess 1,4-butanediol in excess. relative to the chlorine remaining in the polymer, and heated to reflux; a polyphosphazene of structure 1NP (OCH 2 CF 3) (O-C 4 H 8 -OH) is formed. The average degree of polymerization of this polymer is 5 300.

  slowly this polymer with an excess of 3,3-trifluoropropyldimethyl

  chlorosilane in tetrahydrofuran containing triethylamine; a trifluoropropyldimethylsilylated polymer with a content of

  trifluoropropyldimethylsilyl groups of 38%.

  This polymer is dissolved in tetrahydrofuran at a concentration of 2%; the solutin is applied to a porous polypropylene film (commercial product Juraguard 2500 from Polyplastics Co) and air dried; a composite film is obtained on the basis of the measurements carried out as described in Example 16 and taking into account the film thickness (2 m, calculated from the weight of the polymer supported on the Juraguard film and the porosity of the Juraguard, P and N are determined;

02 N 2

  the following results are found: PO 1.3 x 108 cm (TPN) cm / cm s cm Hg N 5, 2 x 109 2 N 2

PO / PN 2.5

02 N 2

EXAMPLE 19

  The polydichlorophosphazene prepared in Example 16 is reacted with diethylamine in tetrahydrofuran; we

  obtains a polydiethylaminochlorophosphazene.

  in tetrahydrofuran and the solution is added dropwise to a solution of ammonia in tetrahydrofuran; after removal of unconverted ammonia, allowed to react at 0 ° C for 4 h; The amino groups of this trimethylsilylated polymer are then subjected to trimethylchlorosilane in tetrahydrofuran containing triethylamine. The average degree of polymerization and the trimethylsilyl group content of the polymer obtained are, respectively, 670.degree.

and 35%.

  The polymer is dissolved in tetrahydrofuran at the concentration of 10, and the solution is applied to ice at the thickness of 0.1 mm, and allowed to air dry for one day; a film of 8> of thickness is obtained. On this membrane, PO and PN are determined as described in Example 16;

02 N 2

  the following results are obtained: Po O 1.1 x 10-8 cm (TPN) cm / cm s cm Hg

P 02

I Ni 3.7 x 10 o N PO It '-3.0

02 / N 2

EXAMPLE 20

  A toluene solution of the polydichlorophosphazene prepared in Example 16, at 95 ° C., is added dropwise to a solution containing equimolar amounts of sodium phenate.

  and sodium ortho-allylphenate in dimethyl glycol ether.

  The temperature is then raised to 95 ° C. and allowed to react for 24 hours; a polyphosphazene of structure NPl (O, l) (O C) ln is obtained

CH 2-CH = CH

  The average degree of polymerization of the polymer is 9,200. This polymer is then reacted with pentamethyldisiloxane in toluene in the presence of chloroplatinic acid as a catalyst; a polymer carrying a siloxane group attached to the

  allyl group The siloxane unit content of the polymer is 34%.

  This polymer is dissolved in tetrahydrofuran at

  concentration of 10%. Using this solution, a film is formed.

  extremely thin surface of the water as described in

  Example 19 and the film is taken up on a Juraguard film.

  On the thin membrane obtained, permeation rates are determined.

  oxygen and nitrogen; The following results are found: Oxygen permeation rate: 7.8 x 10-4 cm 3 (TPN) / cm 2 cm -1 Hg Permeation rate of nitrogen: 3.0 x 10-4 "Po 2 / PN 2: 2.6

  2 N 2

  These results show that the polyphosphazene prepared as described above makes it possible to easily obtain an ultra-thin membrane having remarkable properties, for example a strong

  oxygen permeation rate and a high P / PN ratio.

EXAMPLE 21 2 2

  Polydichlorophosphazene prepared as described in Example 16 is reacted with an alcoholate itself obtained by reacting sodium and a polydimethylsiloxane endblocked silanol (MW 3200) with a hydroxy group blocked with trimethylchlorosilane in tetrahydrofuran at room temperature. reflux for h, in order to introduce a polydimethylsiloxane group into the polymer. The chlorine remaining in the polymer is then replaced by a trifluoroethoxy group by reacting with sodium trifluoroethylate. The average degree of polymerization and the content of polydimethylsiloxane units of the polymer are respectively 11,000 and 73%. This polymer is dissolved in 1,2-dichloroethane at

  concentration of 10%; pour this solution on ice

  0.2 mm and allowed to air dry; a film of 20 μm thickness is obtained. On this membrane, P and PN are determined.

02 N

  as described in Example 16; the following results are obtained: O 2.9 x 10 cm (TPN) cm / cm s cm Hg P 02 P 1.2 x 10-8 N 2 2, Po / PN 2.4 2 2

EXAMPLE 22

  Polyphosphazene containing poly-

  diphénylsiloxanne and trifluoroethoxy groups as described in Example 21 but using a silanol endblocked polydiphenylsiloxane The content of the siloxane unit polymer is 59% From a 10% solution of this polymer, it is formed on

  15 μm thick film which gives the following values:

boasting PO and PN:

02 2

  Po 1.1 x 108 cm (TPN) cm / cm s cm Hg N.2 4.2 x 109 2, 6 Po / PN 2 26

EXAMPLE 23

  The polydichlorophosphazene prepared in Example 16 is reacted with a monoalcoholate itself obtained from sodium and a hydroxyl group of a carbinol-terminated polydimethylsiloxane (molecular weight 2400) in refluxing tetrahydrofuran in 30 hours; a polydimethylsiloxane group is thus introduced leaving a carbinol group on the opposite side.

  chlorine remaining in the polymer by a trifluoroethoxy group in

  The average molecular weight and the polydimethylsiloxane unit content of the polymer are 10 300 and 48% respectively. This polymer is dissolved at the concentration of 10% in tetrahydrofuran and with the aid of this method.

  solution, a film 10 μm thick is formed on ice.

  On this membrane, PO and PN are determined as described in Example 16. The following results are found:

-8 3 2

PO 2.0 x 10 cm (TPN) cm / cm s cm Hg

02 9

N, 8.1 x 10 N

PO / PN 2.5

2 2

EXAMPLE 24

  The trimethylsilyl polyphosphazene membrane of Example 16 is placed in the cell of the same example and is passed through

  the primary face of the membrane a gaseous mixture of carbon dioxide

  nitrogen and nitrogen at the gauge pressure of 2 bar; under these conditions, the PCO / PN ratio is determined; 15.1. The same tests were carried out with a gaseous D mixture of helium and nitrogen; we find a ratio P He / PN of 7.4 A for comparison, we

  forms a 30 m membrane of silicone rubber (polydimethyl-

  siloxane) crosslinked with bis-2,4-dichlorobenzoyl peroxide and the PCO / PN and P He / PN ratios are determined; we find respectively

2 2 2

  6.5 and 1.2 These results show that the polydiethylene oxide membrane

  phosphazene has a very superior gas separation capability

  to that of the silicone rubber membrane.

EXAMPLE 25

  On the polyphosphazene membrane obtained in Example 23, for which polydimethylsiloxane units were introduced into the side chain, PC / P and P / PN were determined as described in Example 24; 10.3 to 4.9 are found respectively

  are much higher than those obtained when using polydi

  Methylsiloxane ec prove that the membrane has a good ability to

separation of gases.

EXAMPLE 26

  Hexachlorocyclophosphazene is heated to 250 C in

  a vacuum glass bulb for 20 hours. A poly-

  dichlorophosphazene dissolved in tetrahydrofuran; the solution is added dropwise at room temperature to a solution in tetrahydrofuran containing an excess of diethylamine and allowed to react at room temperature for 3 days, a diethylamino-substituted polymer is obtained. Elemental analysis shows

  that in the structure of this polymer, half of the chlorine of the poly-

  dichlorophosphazene was replaced by diethylamino groups. A solution of this intermediate polymer in tetrahydrofuran, at room temperature, was added dropwise to a solution in tetrahydrofuran containing an excess of sodium trifluoroethylate and the reaction was terminated by refluxing. from 8 pm Analysis

  elementary shows that in the structure of the polymer, after purification

  cation, the relative proportions of the substituents are 30% of

  trifluoroethoxy groups, 50% diethylamino groups and 20% chlorine.

  The average degree of polymerization is 1200.

  This polymer is dissolved at a concentration of 2% in tetrahydrofuran and the solution is applied to the Juraguard 2500 commercial porous polypropylene film and then dried for one day; a composite membrane is obtained which is placed in a gas permeability measuring cell and air is passed over the primary face of the membrane at the pressure of the pressure gauge.

  2 bars; under these conditions, the flow and the composi-

  oxygen enriched air passing through the membrane; The following results are obtained: Permeation rate of oxygen: 5.3 x 10 5 cm 3 (TPN) / cm 2 cm Hg Permeation rate of nitrogen: 1.5 x 10-5 Po / PN: 3, 5

2 2

EXAMPLE 27

  In a benzene solution of the polydichlorophosphazene prepared in Example 26, a solution in tetrahydrofuran containing 60 mol%, relative to the dichlorophosphazene units, of an alcoholate which was prepared from 4-hydroxybiphenyl and 4-hydroxybiphenyl was slowly added at room temperature. sodium, and refluxed for 4 h. A solution in tetrahydrofuran containing an excess of ethylate is added dropwise to the reaction mixture.

  of sodium and refluxed for 35 hours to complete the reaction.

  The elemental analysis shows that, in the polymer structure, after purification, the relative proportions of the substituent groups

  are 70% ethoxy groups and 30% 4-phenylphenoxy groups.

  The average degree of polymerization is 4800.

  Using a 2% solution of this polymer in tetrahydrofuran, a film is formed on Juraguard film

  as described in Example 26; permeate velocities are determined

  oxygen and nitrogen; the following results are obtained:

6.2 5 3 2

  Oxygen permeation rate: 6.2 x 10-5 cm (TPN) / cm 2 cm Hg Nitrogen permeation rate: 1.6 x 10-5 "

P 2 / PN 3.8

EXAMPLE 28

  A polyphosphazene is prepared as described in Example 27

  containing 50% phenoxy groups and 50% butoxy substituted groups

  The average degree of polymerisation is 5200 A membrane formed from a 2% solution of this polymer on film

  Juraguard gives the following results: -

-5 3 2

  Oxygen permeation rate: 8.1 x 105 cm (TPN) / cm 2 cm Hg Permeation rate of nitrogen: 2.2 x 105 "

P 02 / PN 2: 3.6

2 2

EXAMPLE 29

  Polydichlorophosphazene is prepared as described in Example 1, but with a polymerization time of 40 hours. The polymer is then dissolved in tetrahydrofuran containing an excess of

  trifluorethanol and 2- (2-phenoxyethoxy) ethanol in equiva-

  Then, triethylamine was added as a reaction accelerator and allowed to react at 120 ° C. for 40 hours. The analysis showed that 48% of trifluoroethoxy groups and 52% of polyamine were introduced into the polyamer. 2- (2-phenoxyethoxy) ethoxy groups as substituents.

  The average degree of polymerization is 11,000.

  This polymer is dissolved in tetrahydrofuran at a concentration of 2% and a droplet of this solution is dropped onto the surface of clean water held in a container; a thin film is formed which is carefully taken up on Juraguard film and dried. The permeation rates of oxygen and nitrogen are measured as described in Example 26; The following results are obtained: Permeation rate of oxygen: 2.1 x 10 -4 cm (TPN) / cm 2 cm Hg Permeation rate of nitrogen: 6.2 x 10 -5

PO 2 / PN: 3.4

2 2

EXAMPLE 30

  Prepared polydichlorophosphazene is reacted as

  described in Example 29, in chloroform, with phenylacetyl

  and trifluoroethanol in equimolar amounts and in excess

  relative to the dichlorophosphazene units in the presence of diethyl

  amine which serves as a reaction accelerator The elemental analysis shows that in the polymer obtained, 39? of 2-chloro-2-phenylethenyl groups and 61% of trifluoroethoxy groups as

than substituent groups.

  From this polymer, a 20-μm thick membrane is formed on which the permeation rates of oxygen and nitrogen are determined, from which P and PN are deduced.

P 02 N 2

-9 3 2

  P 02 7.8 x 109 cm (TPN) cm / cm s cm Hg P 2.0 x 10-9 N 2

PO / PN 339

2 2

EXAMPLE 31

  Monoethylpentachlorocyclotriphosphazene is polymerized at 250 ° C. under vacuum for 24 hours. The polymer is then dissolved in tetrahydrofuran and this solution is added dropwise.

Z 542211

  room temperature to a solution in tetrahydrofuran

  Sodium 2,2,3,3-tetrafluoropropylate and sodium trifluoroethylate in equimolar amounts and in excess, then the reflux is continued for 24 hours to complete the reaction. The polymer obtained has an average degree of polymerization of 2200 and contains in its 17% structure / methyl substituent groups, 40% of substituent groups

  fluoropropoxy and 43% fluorethoxy substituent groups.

  Using a 3% solution of this polymer in the tetra-

  hydrofuran, a thin film is formed on Juraguard film

  as described in Example 26 and permeate rates are determined.

  oxygen and nitrogen; the following results are obtained:

-4 3 2

  Oxygen permeation rate: 1.2 x 104 cm (TPN) / cm 2 cm Hg Nitrogen permeation rate: 3.9 x 105 "

2 / N 2

EXAMPLE 32

  The polydifluorophosphade prepared as described by Alcock et al (Inorg Che, 11, 1120 (1972)) and phenyl lithium are reacted in tetrahydrofuran at room temperature at room temperature. A reaction solution at room temperature is then added dropwise to the reaction mixture at room temperature. sodium hexylate in tetrahydrofuran and refluxing was continued for 60 h. Finally sodium methylate was added to the reaction mixture and the reaction was completed by 24 h reflux. The analysis showed that the polymer obtained had a degree of average polymerization of 2600 and as substituent groups 50% of phenyl groups, 16% of hexyloxy groups,

  % of methoxy groups and 4% of chlorine.

  Using a 3% solution of this polymer in the tetra-

  hydrofuran, a thin film is formed on Juraguard film

  as described in Example 26 and permeation rates are measured.

  oxygen and nitrogen; the following results are obtained: Speed of -53 2 Rate of permeation of oxygen: 7.8 x 105 cm (TPN) / cm 2 s cmi {g Rate of permeation of nitrogen: 2.1 x 10-5 Po 2 / PN: 3.7

02 2

EXAMPLE 33

  The membrane obtained in Example 32 is used to separate a gaseous mixture of carbon dioxide and nitrogen; we

  for the P Co / PN ratio, a value of 19.3 is obtained.

  separation of a mixture of helium and nitrogen; a value of 12.2 is obtained for the ratio P He / PNI He

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Claims (20)

R E V E N D I C A T IO N S ___________________________   1 Selective permeable membrane for gas separation,   it consists of a polyphosphazene containing a repeating unit corresponding to the general formula __x   Wherein X and X 'each represent, independently of one another, a group selected from alkoxy groups, amino groups, aryloxy groups, organosilane moiety-containing groups;   and groups containing an organosiloxane moiety.   2 selective permeable membrane according to claim 1, characterized in that the average degree of polymerization in   The number of polyphosphazene is in the range of 20-70,000.   Selective permeable membrane according to claim 1, characterized in that X and X 'are both alkoxy groups. Selective permeable membrane according to claim 1, characterized in that X and X 'are both groups amino.   A selective permeable membrane according to claim 1, wherein X and X 'are both aryloxy groups. Selective permeable membrane according to claim 1, characterized in that X represents a group containing an organosilane unit and X 'is selected from alkoxy groups, the groups   amino groups, aryloxy groups, groups containing an organo   silane and the groups containing an organosiloxane unit.   Selective permeable membrane according to claim 1, characterized in that X represents a group containing an organosiloxane unit and X 'represents a group selected from alkoxy groups, amino groups, aryloxy groups, groups containing   an organosilane unit and the groups containing an organo-organo   siloxane. Selective permeable membrane according to Claim 1, characterized in that the alkoxy groups represent from 10 to 90% d of all substituent groups.   Selective permeable membrane according to claim 8, characterized in that the alkoxy groups represent from 10 to 90% of the substituent groups, and one or more groups selected from amino groups, aryloxy groups, ether-oxy groups,   the alkyl groups, the alkenyl groups and the aryl groups feel from 90 to 10%.   Selective permeable membrane according to any one of   Claims 1, 3 and 6 to 9, characterized in that the alkoxy group   is a group of general formula -OR in which R is a group C 1 -C 20 alkyl. 1 20 '   Selective permeable membrane according to any one of claims 1, 3 to 6, characterized in that the alkoxy group is a fluoroalkoxy group of the general formula -OCH 2 (CF 2) Z wherein 2 2 m   m is 1 to 10 and Z is hydrogen or fluorine.   Selective permeable membrane according to claim 10, characterized in that the alkoxy group is a methoxy, ethoxy group,   propoxy, butoxy, sec-butoxy or neopentyloxy.   Selective permeable membrane according to Claim 11, characterized in that the fluoroalkoxy group is a group -OCH 2 CF 3, -OCH 2 C 2 F 5, -OCH 2 C 3 F 7 or -OCH 2 (CF 2) 3 CF H. 14 Selective permeable membrane according to any one of   claims 1, 4, 6, 7 or 9, characterized in that the group   amino is a group in which R 1 and R 2 each represent hydro-   gene or a C 1 -C 4 alkyl group.   A selective permeable membrane according to claim 14, characterized in that the amino group is a group -NHCH 3, -NHC 2 H 5, -N (C 2 H 5) 2, -NHC 3 H 7, -NHC 4 H 9 or -NH 16 selective permeable membrane according to any one of   Claims 1, 5 to 7 or 9, characterized in that the aryloxy group   is a phenoxy group or a group-substituted phenoxy group C 1 -C 20 alkyl. 1 20 '   Selective permeable membrane according to claim 16, characterized in that the phenoxy group substituted by a group   alkyl is a tert-butylphenoxy group.   Selective permeable membrane according to claim 6 or 7, characterized in that the organosilane at 90% of the weight of the polymer.   Selective permeable membrane according to claim 6 or 7, characterized in that the total of organosilane units and   Organosiloxane units represent from 10 to 90% of the weight of the polymer.   Selective permeable membrane according to any one of   claims 1, 6 or 7, characterized in that the group contains   An organosilane moiety is a group of the general formula -A-Si R 1 R 2 R 3 wherein A is an atom or group which connects the organosilane moiety to the phosphorus atom in the polyphosphagen main chain. , and R 1, R 2 and R 3 each represent hydrogen or a C 1 -C 4 alkyl group.   Selective permeable membrane according to claim 20, characterized in that A represents -O (CH 2 M, -NH (CH 2 m, -O)   or -0 in which m is a number from 1 to 4.   Selective permeable membrane according to any one of   claims 18 to 21, characterized in that the organism pattern   silane corresponding to the general formula -Si R 1 R 2 R 3 is a unit -Si (CH 3) 3.   23 Selective permeable membrane according to any one of   claims 1, 6 or 7, characterized in that the group contains   An organosiloxane unit is a group of the general formula / 4> 6   -B Si Si Y in which B is an atom or group 7   which connects the organosiloxane unit to the phosphorus atom in the polyphosphazene backbone, R 4, RS, R 6 and 7 each represent hydrogen or a C 1 -C 4 alkyl group or a hydroxy group   and p is a number from 1 to 1000.   Selective permeable membrane according to claim 23, characterized in that B represents -O (CH 2 ml, -NHCH 2) m, -0 o   or -0 in which m is a number from 1 to 4.   Selective permeable membrane according to any one of   claims 18, 19 or 23, characterized in that the pattern   of organosiloxane corresponding to the general formula 4 1 6 R R i 0 If Y 3 3,3, 3   is a reason Si O if CH 3 or if O if OH CH 3 CH 3 CH 3 CH 3