JPH0321332A - Highly selective gas separation composite membrane - Google Patents

Abstract

PURPOSE:To enhance gas permselectivity by forming a composite membrane by applying a metal phthalocyanine or naphthalocyanine derivative to a membrane containing a repeating unit of fumaric diester represented by a specific general formula by vapor deposition. CONSTITUTION:A compound containing a repeating unit of fumaric diester represented by formula I (wherein R1 and R2 are a 3-12C branched alkyl group, a 3-12C cycloalkyl group or a 2-6C substituted alkyl group having a substituent having a 3-14C ring structure) is formed into a membrane by employing a solvent casting method or a water surface developing method. Subsequently, a metal phthalocyanine or naphthalocyanine derivative is applied to the membrane by vapor deposition using an ion sputtering apparatus to form a highly selective gas separation composite membrane. The thickness of this membrane is pref. about 100-1000Angstrom , especially pref., about 20-100Angstrom .

Description

Detailed Description of the Invention Industrial Field of Application The present invention relates to a highly selective gas separation composite membrane, and more specifically, the present invention relates to a highly selective gas separation composite membrane. The present invention relates to a highly selective gas separation membrane having a functional membrane formed by vapor-depositing metal phthalocyanine derivatives.

<Prior art> Gas separation 'a-condensation' performed using polymeric membranes has recently attracted attention from the viewpoint of resource and energy conservation. In particular, if oxygen-enriched air with increased oxygen concentration could be obtained from air cheaply and continuously, it would be of great value, and great effects could be expected from medical to industrial uses. Incidentally, an industrially practical oxygen enrichment membrane must have a high oxygen permeation rate and high selectivity to oxygen. The gas permeation rate is determined by the permeability coefficient (usually expressed as P, unit: cs (STP)), which is a value specific to polymeric substances.
・cs/al-sec-anHg) has been shown to be proportional to the differential pressure between both sides of the membrane and the surface area of the membrane, and inversely proportional to the membrane thickness. In addition, the selectivity of oxygen to nitrogen is determined by the oxygen permeability coefficient (Pop) and the nitrogen permeability coefficient (Pop).
PN2) (PO, /PN!, hereinafter abbreviated as α). To obtain a practical permeation rate, a material with a large PO2 is required, and in order to obtain a high oxygen concentration, a material with a large α is required. A polymer must be selected. In order to obtain an even higher permeation rate, the film thickness must be made sufficiently thin, and a material with high mechanical strength is desired. In other words, as industrially practical membrane materials for oxygen enrichment, po and α
A material with a large diameter and excellent mechanical strength and durability is required. However, there are almost no existing polymer materials that meet these requirements, and although many attempts have been made to modify or improve conventional polymers, none of them have been able to fully achieve their goals. Among the polymers known so far, there are only a limited number of polymers with a po of 10-3 or more, and only a few include polydimethylsiloxane, poly-4-methylbentene-
1 (Japanese Unexamined Patent Publication No. 55-41809), natural rubber, polyacetylene derivatives, etc., all of which have an α value of about 3. For example, natural rubber has a small α value and has double bonds in its main chain, so it has problems with durability, especially oxidation stability and heat resistance. Similarly, PO8, a polyacetylene derivative, has amazing permeability, but its gas selectivity is too low (less than 2), its mechanical strength is low, and it is difficult to form a thin film, making it impractical. There are many problems. Also, because it has a conjugated double bond in its main chain, there are concerns about its chemical stability (oxidative stability). In addition, poly-4-methyl-pentene-1 has excellent mechanical strength, chemical stability, and relatively high gas selectivity, but it has poor gas permeability compared to the three types of polymers mentioned above. Due to its low solubility in solvents, it is not suitable for conventional thin film formation techniques, making it difficult to form thin films.
Although polydimethylsiloxane has high gas permeability, it is extremely difficult to create a membrane with weak mechanical strength <20μ or less, and its α value is the lowest at 1.9, making it difficult to fabricate a membrane with a weak mechanical strength of less than 20μ. The reality is that it cannot be used for applications that require enriched air. On the other hand, instead of developing polymeric materials with high gas permeability, attempts have been made to overcome gas permeability by making thin films of materials with relatively large α and excellent mechanical strength. Particularly, as a method for producing a homogeneous thin film, a thin film is produced by dissolving a polymer in a suitable solvent and coating it on a smooth flat surface with a spin coating, or by a water surface spreading method. Alternatively, a polymer solution is cast onto a smooth flat surface, some of the solvent is evaporated in a kiln, and this part is immersed in a non-solvent to gel, forming a homogeneous thin film on a relatively thick porous layer. A method has been developed to create a highly asymmetric membrane (called a ``lobed membrane''). Other methods that have been developed include graft copolymerization of molecules with different chemical compositions onto the surface of a porous substrate using gamma rays or other methods, and plasma polymerization using radio frequency.

However, the method described above has various problems.
For example, in the solvent casting method, advanced technology is required to form a thin film of 10 μm or less, which poses problems for industrial use. Also, “lob-type membrane” (Tsuyoshi Matsuura: [Basics of synthetic membranes) P.
53, 1981, Kitami Shobo) is suitable for dialysis membranes or reverse osmosis membranes, but it is not suitable for the purpose of gas separation.6 Furthermore, the water surface development method is However, in order to reduce defects in the membrane, it is necessary to increase the number of laminations, resulting in a relatively thick membrane, which has the disadvantage that a sufficient permeation rate cannot be obtained. Graft copolymerization using gamma rays and plasma polymerization are also being considered, but the reality is that it is not only difficult to control the film thickness, but also requires large equipment to produce large films. Therefore, the development of a material that has a practical value of P02 of 10-9 or more, a sufficiently large strength and α value, and can be made into a thin film without membrane defects, and a gas separation membrane obtained by thinning the film. is strongly desired.

<Problems to be Solved by the Invention> An object of the present invention is to provide a highly permselective gas separation composite membrane that has excellent gas selective permselectivity, is easy to form into a thin film, and has practical mechanical strength. It is in.

<Means for Solving the Problems> According to the present invention, the following general formula (I) (wherein R1 and R2 are the same or different groups, and at least one of R1 and R2 has 3 to 3 carbon atoms) 12
A branched alkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and a substituent having a ring structure having 3 to 14 carbon atoms.
6 substituted alkyl group, a substituted cycloalkyl group having 3 to 10 carbon atoms or a siloxane hydrocarbon group having a substituent in the ring structure, each of the groups may contain a heteroatom, A highly selective gas separation composite having a functional membrane formed by depositing a metal capped cyanine or naphthalocyanine derivative on a thin membrane containing a repeating unit of fumaric acid diester (which may also be substituted with a halogen atom). A membrane is provided. The present invention will be explained in more detail below. The highly selective gas component Jv composite film of the present invention is characterized by having a functional film formed by depositing a metal phthalocyanine derivative (including a naphthalocyanine derivative) on a thin film containing repeating units of a specific fumaric acid diester. Suppose that In the present invention, the repeating unit of fumaric acid diester can be represented by the following general formula (summer), in which R1 and R
2 are the same or different groups, and at least one of R and R is a branched alkyl group having 3 to 12 carbon atoms,
A cycloalkyl group having 3 to 12 carbon atoms, a substituted alkyl group having 2 to 6 carbon atoms having a substituent having a ring structure having 3 to 14 carbon atoms, and a substituted cycloalkyl group having 3 to 10 carbon atoms having a substituent having the above ring structure. group or a siloxane-based hydrocarbon group.
Each of the above groups may contain a heteroatom such as a nitrogen atom, an oxygen atom, a phosphorus atom, a sulfur atom, or the like, or may be substituted with a halogen atom.

At this time, production is difficult if R1 and R2 are outside the range of carbon numbers of each group. In addition, when only one of R1 and R2 is the hydrocarbon group, the other group has 1 carbon number.
-12 alkyl groups and cycloalkyl groups having 3 to 12 carbon atoms are preferable.

Examples of the fumaric acid diester having a structural unit represented by the general formula (I) include diisobutyl fumarate, di-tert-butyl fumarate, dicyclohexyl fumarate, di-sea monobutyl fumarate, and di-tert-butyl fumarate.
-Methyl-2-pentyl, isoprobyl fumarate
rt-butyl, isopropyl-isoamyl fumarate, isopropyl-4-methyl-2-pentyl fumarate, isopropyl-2-ethylhexyl fumarate, isopropynonyl fumarate, fumarfil-tert-butyl-sec-butyl, fumaric acid -tert-butylisoamyl, monotert-butyl-4-methyl-2-fumarate
Fumaric acid diesters with hydrocarbon groups such as pentyl, fumaric acid mono-tert-butyl-2-ethylhexyl, methyl-(trimethylsilyl) mono-fumarate, ethyl-(
trimethylsilyl) monofumarate, isoprobyl (trimethylsilyl) monofumarate, cyclohexyl(trimethylsilyl) monofumarate, tert-butyl(trimethylsilyl) monofumarate, isoprovil [3-tris(trimethylsiloxy)silyl]provir fumarate, isoprobyl- Fumaric acid diesters having a siloxane hydrocarbon group such as 3-[(pentamethyl)disiloxanyl]propylphumarate, N,N-dimethylaminoethyl-isoprobyl fumarate, tert-butyl-1-butoxy-2-probyl fumarate fumaric acid diesters with heteroatoms such as 2-cyanoethyl-isoprobyl fumarate, glycidy-isoprobyl fumarate, diethylphosphonomethyl-isopropylphumarate, 2-methylthioethyl-isoprobyl fumarate, perfluorooctyl ethyl Ru-isopropyl fumarate, trifluoromethyl-isobrobyl fumarate,
Pentafluoroethyl isoprobyl fumarate, hexafluoroisopropyl isoprobyl fumarate, 1
Examples include fumaric acid diesters having a halogen-substituted hydrocarbon group such as -chloropropyl-isopropyl fumarate. In the present invention, the general formula (I)
In order to produce a fumaric acid diester polymer having a repeating unit of fumaric acid diester represented by, fumaric acid diesters can be synthesized by a conventional radical polymerization method. As the polymerization initiator used in the polymerization, one or more of organic peroxides and azo compounds having a selected 10-hour half-life temperature of 120° C. or less can be used. Specifically, for example, benzoyl peroxide, diisopropylberoxycarbonate, tart-butylperoxy-2-ethylhexanoate, tart-butylperoxypiparate, tart-butylperoxydiisobutyrate, lauroyl peroxide, azobis Examples include isobutyronitrile. The amount of the polymerization initiator used is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of the raw material monomer. Mata II
I performance, especially mechanical strength, l! From the viewpoint of membrane properties, gas permeability, etc., the molecular weight of the fumaric acid diester polymer used is preferably higher, and is preferably 10,000 to 1,000,000. In addition, the polymerization conditions are at a low temperature of about 10 to 60°C,
Moreover, it is desirable that the polymerization be carried out at a high concentration of fumaric acid diester, for example, 60 mol% or more. In the present invention, in order to prepare a thin film containing the repeating unit of fumaric acid diester represented by the general formula (visual), the fumaric acid diester polymer is coated with the fumaric acid diester polymer by, for example, a solvent casting method, a water surface spreading method, a spin coating method, etc. can be done,
The obtained thin membrane can be used as it is as a separation membrane, but depending on the purpose, it may be made of a strong material such as boris sulfone, polyether sulfone, cellulose, polytetrafluoroethylene, etc., to increase its mechanical strength. It is also possible to form a composite film by applying the thin film on a support film that can be used. In addition, from the viewpoint of gas permeation rate, the support membrane is made of a porous organic polymer formed of, for example, polyacrylonitrile, polysulfone, polyamide, polyimide, polyvinylidene fluoride, polypropylene, polycarbonate vinyl chloride-acrylonitrile copolymer, cellulose derivative, etc. It is preferable to use a membrane, and it is also possible to use a commercially available porous organic polymer membrane such as an ultrafiltration membrane. On the other hand, if the surface of the porous organic polymer membrane is rough and the pores are quite large, a highly gas-permeable polymer thin membrane such as polybutadiene or polydimethylsiloxane is first prepared using a water surface development method or the like. It is preferable to laminate one to three layers on a high-quality organic polymer film to make the surface relatively smooth, and then form the thin film into a composite. At this time, the thickness of the polyfumarate film is preferably 100 to 5,000.

In the present invention, as the metal cap cyanine derivative to be deposited on the thin film containing repeating units of fumaric acid diester, for example, compounds represented by the following general formula (II) or (m) can be preferably mentioned. In the formula, R is not particularly limited, but includes, for example, a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, an aryl group, an alkoxyl group having 1 to 22 carbon atoms, and a carbon atom. cycloalkoxyl group of number 4 to 1o,
Preferred examples include polyalkylene glycol groups, hydroxyl groups, carboxyl groups, amino groups, and alkylamino groups, where n represents 0 or 1. Further, M is a central metal, and can be selected from various types depending on the type of gas to be separated. Specifically, when creating a so-called oxygen-enriched membrane or a nitrogen-enriched membrane for separating oxygen and nitrogen, for example, silicon having an affinity for either oxygen or nitrogen is used. Preferred examples include metals such as iron, copper, zinc, nickel, cobalt, and panadium. In particular, in order to increase selectivity without reducing gas permeability, it is most desirable to use silicon.
Examples of the metal phthalocyanine derivative include bis[
Tri(n-propyl)siloxy] cap cyanate silicone, bis[tri(isobrobyl)siloxy] phthalocyanate silicone, bis[tri(n-butyl)siloxy] cap cyanate silicone, bis[tri(methyl)siloxy] cap cyanate silicone, bis[tri(ethyl)siloxy] cap cyanate silicone, bis[tri(see-butyl)siloxy] phthalocyanate silicone, bis[tri(n-butyl)siloxy] naphthalocyanate silicone, bis[tri(methyl)siloxy] ) Siloxy] naphthalocyanate silicone, iron phthalocyanine, nickel phthalocyanine, copper phthalocyanine, iron naphthalocyanine, cobalt phthalocyanine, magnesium phthalocyanine, zinc phthalocyanine, chromium phthalocyanine, cobalt naphthalocyanine, magnesium naphthalocyanine, zinc naphthalocyanine, chromium naphthalocyanine, etc. It can be mentioned preferably.

In the present invention, in order to produce the highly selective gas separation composite membrane of the present invention by depositing the metal cap cyanine derivative on ARF4 containing a repeating unit of fumaric acid diester, an ion sputtering device, a plasma processing device, etc. This can be carried out by a known method such as a vacuum evaporation method using a reactor such as the above. Next, a preferred example of the vacuum evaporation method will be specifically explained with reference to FIG. In FIG. 1, reference numeral 1 denotes a reactor. First, a thin film 3 containing repeating units of fumaric acid diester was placed on a sample stage 2 inside the reactor 1, and a recess provided in the upper center of a heating furnace 4 was placed. , metal phthalocyanine derivative 5
After charging the reactor 1, the interior of the reactor 1 is brought to a high vacuum using a pump 6 such as a rotary pump or an oil diffusion pump. Next, an electric current is passed through the electrode 7 to heat the heating furnace 4 and vaporize the metal lid cyanine derivative 5. The conditions for vaporization vary depending on the melting point of the metal phthalocyanine derivative.
Also, due to the relationship between the defects in the film obtained and the film formation rate,
The rate of vaporization can be determined as appropriate, but preferably the heating temperature is 100-500°C and the vaporization rate is 0.5-500°C.
It is desirable that it be 1000 mg/hr. The vaporized metal phthalocyanine derivative reaches the surface of the thin film 3 while being directed by the covers 8 provided along both sides of the reactor 1, and transfers a certain functional film from the metal lid cyanine derivative to the thin film 3. The highly selective gas separation composite Jll of the present invention can therefore be obtained. The thickness of the functional membrane can be selected depending on the purpose in relation to gas permeation rate and strength, but it is preferably in the range of 100 to 1000, particularly preferably in the range of 20 to 100.

<Effects of the Invention> Since the highly selective gas component II composite membrane of the present invention has a thin film containing repeating units of fumaric acid diester, it has excellent film formability,
The oxygen permeability coefficient can also be made very high. Furthermore, since the composite film of the present invention has a functional film formed by vapor-depositing a metal capped cyanine derivative on the thin film, the value of the oxygen to nitrogen permeability coefficient ratio α (PG2/PI-) is 4 or more. It has excellent gas selectivity.

<Examples> The present invention will be explained in more detail below using Examples and Reference Examples, but the present invention is not limited thereto.

Toyo [1 raw L diisobutylphumarate in a glass ampoule log]
Then, 0.1 g of azobisisobutyronitrile was added as a radical polymerization initiator, and the inside of the ampoule was repeatedly purged with nitrogen and degassed, then sealed, and bulk polymerization was carried out at 40°C for 48 hours. After polymerization, the contents are dissolved in benzene,
The polymer was poured into a large amount of methanol to precipitate, separated by filtration, thoroughly washed with methanol, and dried under reduced pressure to obtain poly(diisoprobyl fumarate) with a molecular weight of 235,000.
(hereinafter abbreviated as PDIPF) was obtained. First of all, the porous support membrane is a porous polypropylene support membrane made by stacking three layers of polybutadiene water surface spreading membrane on a polypropylene porous membrane to make the surface smooth! 1IIL, T. That is, a cyclohexane solution containing 5 wt% poly(cis-1,4-butadiene) was gently dropped onto a clean water surface to create a water surface spreading film, and then a porous polypropylene film attached to a smooth glass plate was gently dropped onto the water surface. The surface was smoothed by stacking three layers of water surface spreading membrane on the porous polypropylene membrane by pressing it against the developing membrane. Next, PDi prepared in Reference Example 1
A thin film was prepared by spreading a toluene solution containing 5 tgt% PF on the water surface in the same manner as described above, and 101 layers of the thin film were accumulated on the porous membrane to prepare a polymer membrane having a support membrane. After thoroughly drying the obtained polymer film to completely evaporate the toluene, it was placed in a vacuum evaporator and the pressure was sufficiently reduced to 10"
When the temperature is below cnHg, bis[tri(n-propyl)siloxy] cyanate silicone (■) (hereinafter abbreviated as Pc (Si)) is heated to generate molecular vapor, which is then deposited on the polymer film. A highly selective gas separation composite membrane was created by depositing a metal phthalocyanine membrane to a uniform thickness of 60λ. When the gas selective permeation rate of the obtained composite membrane was measured using a high vacuum method for oxygen and nitrogen, the permeation rate (QO.) = 3.5 x 1 0-'. QN. =
7.6 X10″″@aJ (STP)/aJ-sec
・Table 1 shows the vapor deposition conditions and gas permeability results, which were cs+Hg (25°C). 4vt% of poly(di-t-butyl fumarate) (hereinafter abbreviated as PDtBF) was added instead of PDiPF on the polypropylene porous membrane obtained in the same manner as in Example 1.
The thin film obtained by developing the toluene solution on the water surface was 10WI
A polymer film was produced by accumulating and further vacuum-depositing Pc(Si). Next, a composite membrane was prepared in the same manner as in Example 1, and the gas permeability of the composite membrane was measured. Table 1 shows the deposition conditions and gas permeability results. In Example 3, instead of PDtBF used in Example 2, poly(dicyclohexyl fumarate) (hereinafter referred to as P D c H
In Example 4, poly(fumaric acid di-11
In Example 5, poly(di-4-methyl-2-pentyl fumarate)
In Example 6, poly(tert-butyl-sea-butyl fumarate) (hereinafter referred to as PDMPF) was used.
In Example 7, poly(
tert-butylisoamyl fumarate) (hereinafter P t
In Example 8, poly(tart-butyl-4-methyl-2-pentyl fumarate) (hereinafter abbreviated as PtB/MPF) was used, and in Example 9, poly(tert-fumarate) was used. butyl-2-ethylhexyl) (hereinafter abbreviated as PtB/EHF), in Example 10 poly(isopropyl-perfluorooctylethyl fumarate) (hereinafter abbreviated as P i P / F, F), and in Example 11 Poly(isopropyl fumarate-hexafluoroisoprobyl) (hereinafter abbreviated as PiP/iP-F,F), and in Example 12, poly(isopropyl fumarate-1-chloropropyl-isobutyl fumarate) (hereinafter abbreviated as PDCliPF), In Example 13, poly(N,N-dimethylaminoethylisopropyl fumarate) (hereinafter abbreviated as PAE/iPF) was used, and in Example 14, poly(I-butoxy-2-propyl-tert-butyl fumarate) (hereinafter pnptB) was used.
In Example 15, poly(isoprobyl-[
In Examples 16 to 19, poly(di-t-butyl fumarate) (hereinafter abbreviated as PDtBF) was used. Furthermore, a composite membrane was prepared in the same manner as in Example 2, except that the cumulative number of membranes, conditions, and metal capped cyanine derivatives shown in Table 1 were used! 11 was made. Next, the gas permeability of the obtained composite membrane was measured. Results and Table 1 Bis[tri(methyl)siloxy]naphthalocyanate silicon iron phthalocyanine nickel phthalocyanine copper phthalocyanine iron naphthalocyanine

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a reactor used in the vacuum evaporation method. 1. Reactor, 3. Thin film, 5. Metal lid cyanine derivative.

Claims (1)

[Claims] The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼... (I) (In the formula, R_1 and R_2 are the same or different groups, and at least one of R_1 and R_2 The group is a branched alkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a substituted alkyl group having 2 to 6 carbon atoms having a substituent having a ring structure having 3 to 14 carbon atoms, and the above ring structure. represents a substituted cycloalkyl group or siloxane hydrocarbon group having 3 to 10 carbon atoms, each of which may contain a hetero atom or be substituted with a halogen atom. ) A highly selective gas separation composite membrane having a functional membrane formed by depositing a metal phthalocyanine or a naphthalocyanine derivative on a thin membrane containing a repeating unit of a fumaric acid diester represented by: