CA2045511A1 - Organic modified silicic acid heteropolycondensates - Google Patents
Organic modified silicic acid heteropolycondensatesInfo
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- CA2045511A1 CA2045511A1 CA002045511A CA2045511A CA2045511A1 CA 2045511 A1 CA2045511 A1 CA 2045511A1 CA 002045511 A CA002045511 A CA 002045511A CA 2045511 A CA2045511 A CA 2045511A CA 2045511 A1 CA2045511 A1 CA 2045511A1
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- formula
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- heteropolycondensate
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
- B01J20/28042—Shaped bodies; Monolithic structures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/26—Synthetic macromolecular compounds
- B01J20/262—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon to carbon unsaturated bonds, e.g. obtained by polycondensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/26—Synthetic macromolecular compounds
- B01J20/265—Synthetic macromolecular compounds modified or post-treated polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
- B01J20/28011—Other properties, e.g. density, crush strength
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
- B01J20/28057—Surface area, e.g. B.E.T specific surface area
- B01J20/28064—Surface area, e.g. B.E.T specific surface area being in the range 500-1000 m2/g
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/281—Sorbents specially adapted for preparative, analytical or investigative chromatography
- B01J20/282—Porous sorbents
- B01J20/283—Porous sorbents based on silica
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C1/00—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
- C03C1/006—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels to produce glass through wet route
- C03C1/008—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels to produce glass through wet route for the production of films or coatings
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C11/00—Multi-cellular glass ; Porous or hollow glass or glass particles
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/02—Polysilicates
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/06—Preparatory processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/80—Aspects related to sorbents specially adapted for preparative, analytical or investigative chromatography
- B01J2220/82—Shaped bodies, e.g. monoliths, plugs, tubes, continuous beds
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Abstract
Organic modified silicic acid heteropolycondensates can be upgraded by removal of residual silanol or hydrolyzable groups. The upgrading process is conducted by contacting the condensate with a supercritical fluid at elevated temperature and pressure. Upgraded products in the form of powders can be dissolved in an organic solvent and used to produce coatings which have improved oxygen permeability. Upgraded products have also been made in non-comminuted, solid form such as rods. These articles are useful as adsorbents.
Description
W0 90/08169 2 ~ ~ Pcr/usgo/00ls8 ORGAyIC ~ODIFIF,~_~ILI~IC
ACID~@~TE~OPQI~CQND~NS~S
Technical Ei~
This invention relates to improved 8iliCiC
acid heteropolycondensates which contain organic radicals. It al90 pertain~ to a method for their formation, and the use of ~uch condensates.
~ckground ~
Silicic acid heteropolycondensates have been known in the art for quite some time. In general, '' these products are produced by a low or mild temperature process, which comprise~ hydrolysis and condensation. The proces3 i-s performed using one or more silanes (having 2-4 hydrolyzable groups~ as the starting material. The process is illustrated below u~ing a triethoxysilane as the raw material on which the proces~ i8 conducted. In the equations which follow, R i8 a non-hydrolyzable organic group, such as an alkyl or aryl group.
(1) nRSi(OC2~s)3 3n~20 ~ nRSi(0~)3 + 3 2 ~2) RSi - OH + ~0 - Si - R ~ > RSi - O - SIR + H20 Equation (1~ illustrates complete hydrolyæis of the triethoxysilane. As shown, for each molar equivalent of trialkoxysilane which i8 completely hydrolyzed, three molar equivalents of water are consumed. The hydrolyzed product''is'compiratively unstable; it tends to rapidly undergo-the': - ~
condenæation-proces~ illustrated by;Equa~ion (2). It -i8 known in the~art that condensation càn begin to occur before all three alko~ide groups are hydrolyzed.
WO 90/08169 PCr/US90/OOtS8".~
5 ~ ~ -2-Eguation (2) is an oversimplification. It illustrate~ condensation between two silanol groups, each of which were formed in step (l). As shown by the unsatisfied valences, further condensation between other groups can occur. It i8 known in the art that ~uch continued condensation result~ in products ~nown as sol-gels. Eor the purpo~e of this invention, the term "801 - gel" refers to a glasgy solid mixture of organic-modified 8iliCiC acid heteropolycondensates formed by the hydrolysis and condensation of one or more silanes which contain one or two non hydrolyzable groups (such as R in the equations above), and in which the remainder of silicsn valences are satisfied by hydrolyzable groups. In general, these polycondensate products comprise a network of interconneeted silicon-containing chains, wherein the silicon atoms are connected by oxygen. These products are polymeric; but because they are in the solid ~tate, molecular weight determinations cannot be made. As shown by Equation (~), each condensation of two ~ilanol group~ results in the splitting out of one molecule of water. Thi~ will be ti~cus~ed in more detail below.
Linear polycondensates are produced from reactants ~olely compo~et of silane~ having two hydrolyzable groups per molecule. On the other hand, starting materials which contain one or ~ore silane~ -with three or four hydrolyzable groups yield crosslinked polycondensates.
Cros~-linking ca~ make it difficult for , .. , ,, . ~ . . . . . .
complete hydrolysis and/or condensation to take place, since groups.within.~ithree~dimensional` --polymeric network may not~readily react~because o~
steric h~ndrance. Thus,:under conditions--employed in :
prior art processe~, cro~slinked, 8ilicic acid . .... . . . . . .
.
, . - . . . . .
condensates can contain residual hydrolyzable group~
(e.g., alkoxy radicals~ or re~idual ~ilanol group3.
It is known in the art that qilicic acid heteropoly-condensates (which are not organic modified, i.e., which do not contain organic groups) can be dried using fluits above their supercritical temperatures;
Tewari et al, Mate~ial~_Let~er~, Vol. 3, number 9, 10, pp. 363-367 (July, 1985), and Laudi3e et al, Journal of Non~rystalline So~iial~, pp. 155-164 (1986) pertains to the supercritical drying of alko~ide silica gels using ~ystems containing ethanol. Monolithic non-organic modified silica gelQ
have also been made uYing hypercritical solvent evacuation; Pra~sas et al, ~our.~.al of Materials Science 19, pp. 1656-1665 (1986).
U.S. 2,967,168 di~close~ the ~ormation of - .
vinyl substituted aerogels suitable for use to prepare synthetic rubber copolymers. The preparative process comprises treatment of a vinyl - substituted aerogel with an alkanol above the critical pressure and temperature of the alcohol. A similar supercritical process for the preparation of a Qub~tantially crack-free transparent block from a tetralkoxysilane is disclosed in U.S. 4,402,927.
Neither reference disclo~es the use of a supercritical fluid with an aerogel having alkyl or aryl groups, or the fact that o~ygen permeability can be achieved with treatment by such a fluid. U.S.
4,017,528, discloses preparation of porou~ silicon dioxides in which the radical R of the unit Si-R may be phenyl. Thi~ reference, like the other reference~
disclosed above, does not pertain to the treatment of silicon-containing product~ having enhanced oxygen permeabili~y, and which are suitable for use in measurement of oxygen concentration.
.
S~
. . ~
-3d--Disclosure of Invention A problem with prior art silicic acid heteropolycondensates is they contain re~idual sila~ol groups and residual hydrolyzable groups of the type discussed above. Such groups can have a deleterious effect on the materials of the prior art. We have discovered that this problem can be `
solved by removal of such groups by treating heteropolycondensates with a fluid in the supercritical state. We have also discovered that surprisingly, use of the supercritical liquid does not remove organic groups which are bonded to ~ilicon atoms in such condensates by a silicon-to-carbon bond. We have also di~covered that the organic modified 8ilicic acid heteropolycondensates produced by our "upgrading process", i.e. our process for removing silanol and/or alkoxy groups, resulting e.g.
in products having enhanced oxygen permeabili~y, `
maXes products useful for forming films for use in oxygen permeable systems. We have also discovered that monolithic glassy, porous solids can be produced by a process which comprises :~
`:
'., ,_",~:,t.`--`
.. , ,.. : ...... .. .. . .. . . ...
WO 90/08169 PCr/US90/00158 ~
ACID~@~TE~OPQI~CQND~NS~S
Technical Ei~
This invention relates to improved 8iliCiC
acid heteropolycondensates which contain organic radicals. It al90 pertain~ to a method for their formation, and the use of ~uch condensates.
~ckground ~
Silicic acid heteropolycondensates have been known in the art for quite some time. In general, '' these products are produced by a low or mild temperature process, which comprise~ hydrolysis and condensation. The proces3 i-s performed using one or more silanes (having 2-4 hydrolyzable groups~ as the starting material. The process is illustrated below u~ing a triethoxysilane as the raw material on which the proces~ i8 conducted. In the equations which follow, R i8 a non-hydrolyzable organic group, such as an alkyl or aryl group.
(1) nRSi(OC2~s)3 3n~20 ~ nRSi(0~)3 + 3 2 ~2) RSi - OH + ~0 - Si - R ~ > RSi - O - SIR + H20 Equation (1~ illustrates complete hydrolyæis of the triethoxysilane. As shown, for each molar equivalent of trialkoxysilane which i8 completely hydrolyzed, three molar equivalents of water are consumed. The hydrolyzed product''is'compiratively unstable; it tends to rapidly undergo-the': - ~
condenæation-proces~ illustrated by;Equa~ion (2). It -i8 known in the~art that condensation càn begin to occur before all three alko~ide groups are hydrolyzed.
WO 90/08169 PCr/US90/OOtS8".~
5 ~ ~ -2-Eguation (2) is an oversimplification. It illustrate~ condensation between two silanol groups, each of which were formed in step (l). As shown by the unsatisfied valences, further condensation between other groups can occur. It i8 known in the art that ~uch continued condensation result~ in products ~nown as sol-gels. Eor the purpo~e of this invention, the term "801 - gel" refers to a glasgy solid mixture of organic-modified 8iliCiC acid heteropolycondensates formed by the hydrolysis and condensation of one or more silanes which contain one or two non hydrolyzable groups (such as R in the equations above), and in which the remainder of silicsn valences are satisfied by hydrolyzable groups. In general, these polycondensate products comprise a network of interconneeted silicon-containing chains, wherein the silicon atoms are connected by oxygen. These products are polymeric; but because they are in the solid ~tate, molecular weight determinations cannot be made. As shown by Equation (~), each condensation of two ~ilanol group~ results in the splitting out of one molecule of water. Thi~ will be ti~cus~ed in more detail below.
Linear polycondensates are produced from reactants ~olely compo~et of silane~ having two hydrolyzable groups per molecule. On the other hand, starting materials which contain one or ~ore silane~ -with three or four hydrolyzable groups yield crosslinked polycondensates.
Cros~-linking ca~ make it difficult for , .. , ,, . ~ . . . . . .
complete hydrolysis and/or condensation to take place, since groups.within.~ithree~dimensional` --polymeric network may not~readily react~because o~
steric h~ndrance. Thus,:under conditions--employed in :
prior art processe~, cro~slinked, 8ilicic acid . .... . . . . . .
.
, . - . . . . .
condensates can contain residual hydrolyzable group~
(e.g., alkoxy radicals~ or re~idual ~ilanol group3.
It is known in the art that qilicic acid heteropoly-condensates (which are not organic modified, i.e., which do not contain organic groups) can be dried using fluits above their supercritical temperatures;
Tewari et al, Mate~ial~_Let~er~, Vol. 3, number 9, 10, pp. 363-367 (July, 1985), and Laudi3e et al, Journal of Non~rystalline So~iial~, pp. 155-164 (1986) pertains to the supercritical drying of alko~ide silica gels using ~ystems containing ethanol. Monolithic non-organic modified silica gelQ
have also been made uYing hypercritical solvent evacuation; Pra~sas et al, ~our.~.al of Materials Science 19, pp. 1656-1665 (1986).
U.S. 2,967,168 di~close~ the ~ormation of - .
vinyl substituted aerogels suitable for use to prepare synthetic rubber copolymers. The preparative process comprises treatment of a vinyl - substituted aerogel with an alkanol above the critical pressure and temperature of the alcohol. A similar supercritical process for the preparation of a Qub~tantially crack-free transparent block from a tetralkoxysilane is disclosed in U.S. 4,402,927.
Neither reference disclo~es the use of a supercritical fluid with an aerogel having alkyl or aryl groups, or the fact that o~ygen permeability can be achieved with treatment by such a fluid. U.S.
4,017,528, discloses preparation of porou~ silicon dioxides in which the radical R of the unit Si-R may be phenyl. Thi~ reference, like the other reference~
disclosed above, does not pertain to the treatment of silicon-containing product~ having enhanced oxygen permeabili~y, and which are suitable for use in measurement of oxygen concentration.
.
S~
. . ~
-3d--Disclosure of Invention A problem with prior art silicic acid heteropolycondensates is they contain re~idual sila~ol groups and residual hydrolyzable groups of the type discussed above. Such groups can have a deleterious effect on the materials of the prior art. We have discovered that this problem can be `
solved by removal of such groups by treating heteropolycondensates with a fluid in the supercritical state. We have also discovered that surprisingly, use of the supercritical liquid does not remove organic groups which are bonded to ~ilicon atoms in such condensates by a silicon-to-carbon bond. We have also di~covered that the organic modified 8ilicic acid heteropolycondensates produced by our "upgrading process", i.e. our process for removing silanol and/or alkoxy groups, resulting e.g.
in products having enhanced oxygen permeabili~y, `
maXes products useful for forming films for use in oxygen permeable systems. We have also discovered that monolithic glassy, porous solids can be produced by a process which comprises :~
`:
'., ,_",~:,t.`--`
.. , ,.. : ...... .. .. . .. . . ...
WO 90/08169 PCr/US90/00158 ~
2~ 4- :
contacting an organic modified 8iliCiC acid 801 in a ~
mold with a fluid above its critical temperature and pressure.
Thu~, this invention has several aspects.
First, it pertains to a method of upgrading an organic modified silicic acid heteropolycondensate by removal of residual silanol and/or hydrolyzable grbups, said method comprising contacting the ~ ~ :
polyconden~ate to be upgraded with a fluid above the critical temperature and pressure of the fluid, for a time sufficient to remove silanol or hydrolyzable groups from the condensate. In one embodiment, the hydrolyzable groups that are removed are alkoxide groups, and the supercritical fluid i~ the alcohol ',~
15 corresponding to the al~o~ide radicals. - ' ,~
The products of the upgrading proce~s are free or substantially free of ~ilanol and hydrolyzable groups. For the purpose of this:
invention, llsub~tantially free" mean~ that no more than about 5X of the groups bonded to silicon are hydrolyzable or silanol group~.
In a second aspect, this invention comprises a preparative process. The prèparative process of this invention comprises a hydrolysisicondensatio~
reaction of the type eæemplifie~ by Equations (1) and (2) above, followed by an upgrating process which remove~ residual hydrolyzable a~d silanol groups ~rom the polycondensate intermediate. T~e upgrading process of this embodi~ent i8 of the type described above. , The p,reparative and upgrating embodiments of this invention are directed,to the preparation'of'' orga~ic modified,,.,silicic acid heteropolyco~den's'ates ,products of,two types.which compr.i~e at''third`
,embodiment;of the-invention, the first type-of-' ~ -,,, , p,roduct"are powters.-~- In these powders-:a~ least about WOgo/08169 PcT/usso/oo1~8 -5~
90~/O of the repeating silicon-containing units have at least one organic group (R) bonded to the silicon atom.
In the ~hird embodiment, the aecond type of product~ are porous/ glas~y monolithic solids. For the purpo~e of this invention, "monolithic" means ca~t or otherwise formed in a single piece. The monoliths of thi~ invention can be in the form o~
rods or have another shape, e.g., lenticular. The monoliths of this invention are glass-like, (i.e., non-crystalline) opaque or transparent ~olid bodie~. -A typical rod ha~ a diameter of 0.5 to 25 millimeters and a length of 10 to 125 millimeters. Products outside o~ the 8ize range can be produced.
In the monolith~, there are two main types of repeating units; viz, repeating unit~ having the formulas Si~, and RSi- wherein R i8 a non-hydrolyzable, organic group bonded through carbon to the ~ilicon atom. In the monoliths, from about 5 to about 35 mole percent of the repeating units have the formula RSi_. ThuR, the monoliths of this invention are mostly composed of repeating units having the formula Si_. They may have up to about 5% of repeating units with the formula RSi- wherein R has the same significance as above. The monoliths of this invention can be used as adsorbents, e.g., as ~ubstrates ~or chromatographic separations.
Although the process o~ this invention i8 -: :
primarily directed to~the remo~al of hydrolyzable and/or ~ilanol grOUps in crosslinked heteropolycon~
densates, it-i~ to be understood that the process can al80 be employed-to remove such groups from Iinear poly~condensates; m . . . , . . . ~ , . , , . - i , , ~;
. ` ~; .. .. .....
.. , - :
.
,, , . , . , ,, . ., . . . . , , ( , , . , , - ,. . ..... . .. . .. .. . . .
: ~ ' ' ~, '' " :" ' ' ', ' : ' ; ' : .' . j , ' ' ' .: . `; ' ', ` ' ':, :~' . ' ' ' .:
woso/o8169 PCT/US90/00158 Brief Desc~iption of Draw~ng The Figure in the drawing i8 a plot, graphically comparing o~ygen permeability of a non-monolithic product of thi~ invention, with a similar material which has not upgraded by the proce~ provided herein. 02ygen permeability values are on the "y" a~is, while the oxygen concentration values are plotted along the "~" a~ie. A ~hown, an organic modified ~ilicic acid heteropolycondensate (i) containing phenyl groups, and (ii) produced by the proce~s of this invention, ha~ a much greater oxygen permeability when compared to the permeability of a ~imilar material not ~ubjected to the upgrading process of this invention.
~owever, the linearity of re~pon~e with the product of this invention appear~ to be slightly less than with the compari~on material. Thi6 slight decrease in linearity does not materially det~act from the utility of the product.
Best Mode-fg~5~LoL~ 2ye~e I~enti~
In one em~odiment, this invention comprises a method for upgrading an organic modified 8ilicic acid heteropolycondensate by reducing the number of hydrolyzable groups and/or ~ilanol radicals in the condensate. This method comprises heating-said condengate at an elevatet temperature, in contact with a fluid which is-under high pressure, for a time ¦~
~ufficient to remove ~uch groups. The process i3 conducted above the critical temperature and pressure of th~ fluid. The product can be:recovered by -separating the-,fluid and the volatile product(s) formed during removal of the hydrolyzable group`s.-~
As indicated above, for the purpo~e of , description of thi~ invention, the proCeES o~ this embodiment iB referred to as the "upgrading process"
of this invention. The upgrading proce~s can be conducted on a wide variety of organomodified silicic - . . . , ~ . . .
.
WO~0/0~169 PCT/US90/00158 _7- 2 ~ .L
acid heteropolycondensates. The applicability of the upgradin~ proce~s of this invention i~ independent of the method employed for producing the condensate to be upgraded, provided that the polycondensate to be treated contains hydrolyzable andlor silanol groups which can be removed.
Also aa indicated above, a second embodiment of this invention i8 described herein as the ~preparative proce~ or the "preparative process of this invention." The preparative method comprises:
(a) formation of an srganic modified silicic acid condensate by a reaction which comprises hydrolysi 8 and condensation of an or~anosila~e, followed by (b) removal of residual hydrolyzable and/or silanol group~ with a supercritical fluid.
Step (b) comprises the upgrading process of this invention.
A preferred process within the preparative embodiment of this invention compriaes:
a method for preparing an organic motified silicic acid heteropolycondensate (i) having ~.
repeating silane unit~ with the formula RSi- such ~:
that the free valences in said formula are interconnected by o~ygen~ and (ii) being characterized by being ~ubstantially free of hydrolyzable and ~ilanol groups, said method compri 8 in~
(A) forming an intermediate 8ilicic aci~
condensate by reacting water with a silane:at:a .:
lo~ to mild temperature, and in the presence of a low boili~g ~olvent for said ~ilane, said silane : :
having the formula. ~ Si(OR')4 ~,~wherein R i8~
a~ al~yl or.~aryl radical-having~up to:about 20 .-:.~ carbon atoms, R' i8 an alkyl radical of up-~o~
about 4 carbon atoms, and X i B equal to 1 or-2;
W090/08169 PCTlUS90/00158 ~ ~
2 ~ ~ ~ 3~
(B) heating the reaction mixture thereby ~
produced at a pressure and temperature above the critical temperature and pres~ure of said solvent, for a time sufficient to remove substantially all residual R'0- and ~ilanol groups from said intermediate condensate, and form alka~ol from.said R'0- groups; and (C) removing said alkanol and solvent from the organic modified silicic acid heteropolycondensate thereby produced.
In the particular embodiment set forth immediately above, the combination of process ~teps ~A) and (B) comprise a preparati~e proeess of this invention. Step (B) i8 an upgrading process of the 15 type referred to above. Step (C) compri~es a product recovery step. Such a step is a desirable, bu~ not a critical feature of the invention.
The third embodiment of this invention comprises an organic group-containing, porou~
20 monolithic glassy body containing the repeating units Si_ and RS_, wherein R i8 a stable organic group, .~
such that (a~ Prom about 5 to about 35 mole percent ~ :
of said units are RSi_, (b) said RSi_ units are substantially uni~ormly dispersed throughout said 25 body, and (c) sait repeating units are interco~nected - ~ .
by oxygen; ~aid body hav ng a surface area of from about 500 to about 800 m.tg, an.:apparent density of : about 0.25 to about 0.40 g/ml, and being su~bstantially.free.of residual.silanol.and 30 hydrolyzable groups. - - -As part~of..this embodiment:,--thi~ invention . provides a process.:for producing^a monolithic body of : the type.~described~above,.~aid.proc~ss comprisi~g contac*ing~a-precursor polycontensate in.a-mold with :
35 a.~fluid above.the critical temperature;and-pressure of.said fluid!..for a time sufficient^to remove ':
:aùF . .
I
- : :: . : :: . .
-9- 2~
substantially all residual silanol and hydrolyzable groups from said 801, and sub~equently venting and cooling to separate said body from ~aid fluid and volatile by-products formed upon remo~al of said groups from said precursor polycondensate;
said precur~or condensate havi~g been produced by hydroly~is and conden~ation of a mi~ture of silanes having the formula SiX4 and the formula RSiX3, wherein from about 5 to about 35 mole percent of said silanes in said mixture have the formula RSiX3, and wherein each X in said formulae is a hydrolyzable group, and R i8 a non-hydrolyzable organic group.
The products of this invention are organic 15 modified; i.e., they contain organic groups. They '-are polymeric in nature. Li~ear polymers produced by this invention generally are composed of repeati~g units having the formula -0-Si-0-. The crosslinked R
polymers are composed of repeating units having the formula -o-si-o-, or -0-Si-G-. It i8 not nece~ary that the eros~linked products be solely composed of ~hese groups. As set forth more fully below, the product3 of this invention may ~e modified by the inclusion o~ other silicon-contai~ing radical~, albeit in comparatively minor amounts. Con~equently,' the productæ of this inventio~ can be considered as heteropolycondensate~ derived from ~ila~es-ha~ing'the ~ormula ~ SiX4_x, wherein'.X =-0 to 2,'~with'the'~
pro~iso that not all of-the starting material is composed-of silanes wherein X i8: equal to 0.
:,..... -- : -.~e .
. . , I, , .
: . : ' .
' ' ': . . ~ . . ~ . ' ' .
Woso/o8l69 ~ PCT/US90~00158 As stated above, crosslinked, organic modified ~ilicic acid heteropolycondensates, which are up~raded by a proce~a of this invention, have the repeating unit RSi--, wherein the unsati~fied s valences are interconnected through osygen. As discussed, these repeating unit~ can be formed by a hydrolysis and condensation reaction using one or more silanes having the formula:
RSiX3 - (I) -wherein R is an or~anic radical bonded to silicon through carbon, and the radical~ indicated by X are alike or different and selected from hydrolyzable groups, such as alkoxides, (e.g., the alkoxide radicals referred to above), arylo~ites, : -alkylalkoxide, alkoxyalkoxide3, halides, and the like. The heteropolycondensates may al80 contain groups derived from one or more silanes ha~ing the formulas:
SiX4 and R2Si~2 (II) (III) wherein X and R have the same significance as above.
When preparing powders according to this -in~ention,-only a relatively-small number of the silicon containing units will:be derived fro~ silanes .of,!For~ulas II~and III, or: mixtures thereof. This is borne out in more detail by the followi~g discussion.
. Turnin~first:to the compounds-~of Formula`
II, they~can be added to th~-reaction ~isture to increase hardnesg or abrasion resista~ce in the ; .,. .,. . ... . : ~ . . .
~ 2 ~ ~i 3 ~
product heteropolycondensates. It i8 preferred that the ~ormula II compounds be alkogides, i.e., that they have the formula Si(OR'~4. It i8 al80 preferred that all of the alkoxide groups represented by X or (OR') be the same, because such tetraalkoxides are readily inexpensive and, in general, are more readily available. Howe~er, mixed alkoxides, i.e., silicon alkogides having two, three, - :
or four different alkoxide groups, can be used if desired, -There i~ no limitation on the type of group bonded to the oxygen atoms in the alkoxide, provided, however, that the alkoxide group~ terived therefrom are hydrolyzable under the reaction conditions 15 employed. Thus, the organic radical ean be a short ~-. --or long alkyl chain, either branched or unbranched, unsubstituted or substituted with groups such as alkoxy, halogen (Cl, Br or I), or amine, or the like. More typically, they are short, unbranched, or 20 slightly branched lower hydrocarbyl alkyl group~, . -i.e., alkyl groups that are solely composed of carbon :
and hydrogen, and which contain up to about 4 car~on atoms. Thus, for example, alkoæide group6 within materials of Formula II are illustrated by the following non-limiting e~ample~:
metho~ide .ethoxide : .
- .- iso-propo~ide :
. . tert-butoxide - -.
sec-butoxide ~
- -- -. . .- A ~ost pref.erred alkoxide of this type i~C
tetrametho~ysilane;.-however, other--compounds of--thi~
type; such as~tetra~thoxysilane,~can al80 be used'~
contacting an organic modified 8iliCiC acid 801 in a ~
mold with a fluid above its critical temperature and pressure.
Thu~, this invention has several aspects.
First, it pertains to a method of upgrading an organic modified silicic acid heteropolycondensate by removal of residual silanol and/or hydrolyzable grbups, said method comprising contacting the ~ ~ :
polyconden~ate to be upgraded with a fluid above the critical temperature and pressure of the fluid, for a time sufficient to remove silanol or hydrolyzable groups from the condensate. In one embodiment, the hydrolyzable groups that are removed are alkoxide groups, and the supercritical fluid i~ the alcohol ',~
15 corresponding to the al~o~ide radicals. - ' ,~
The products of the upgrading proce~s are free or substantially free of ~ilanol and hydrolyzable groups. For the purpose of this:
invention, llsub~tantially free" mean~ that no more than about 5X of the groups bonded to silicon are hydrolyzable or silanol group~.
In a second aspect, this invention comprises a preparative process. The prèparative process of this invention comprises a hydrolysisicondensatio~
reaction of the type eæemplifie~ by Equations (1) and (2) above, followed by an upgrating process which remove~ residual hydrolyzable a~d silanol groups ~rom the polycondensate intermediate. T~e upgrading process of this embodi~ent i8 of the type described above. , The p,reparative and upgrating embodiments of this invention are directed,to the preparation'of'' orga~ic modified,,.,silicic acid heteropolyco~den's'ates ,products of,two types.which compr.i~e at''third`
,embodiment;of the-invention, the first type-of-' ~ -,,, , p,roduct"are powters.-~- In these powders-:a~ least about WOgo/08169 PcT/usso/oo1~8 -5~
90~/O of the repeating silicon-containing units have at least one organic group (R) bonded to the silicon atom.
In the ~hird embodiment, the aecond type of product~ are porous/ glas~y monolithic solids. For the purpo~e of this invention, "monolithic" means ca~t or otherwise formed in a single piece. The monoliths of thi~ invention can be in the form o~
rods or have another shape, e.g., lenticular. The monoliths of this invention are glass-like, (i.e., non-crystalline) opaque or transparent ~olid bodie~. -A typical rod ha~ a diameter of 0.5 to 25 millimeters and a length of 10 to 125 millimeters. Products outside o~ the 8ize range can be produced.
In the monolith~, there are two main types of repeating units; viz, repeating unit~ having the formulas Si~, and RSi- wherein R i8 a non-hydrolyzable, organic group bonded through carbon to the ~ilicon atom. In the monoliths, from about 5 to about 35 mole percent of the repeating units have the formula RSi_. ThuR, the monoliths of this invention are mostly composed of repeating units having the formula Si_. They may have up to about 5% of repeating units with the formula RSi- wherein R has the same significance as above. The monoliths of this invention can be used as adsorbents, e.g., as ~ubstrates ~or chromatographic separations.
Although the process o~ this invention i8 -: :
primarily directed to~the remo~al of hydrolyzable and/or ~ilanol grOUps in crosslinked heteropolycon~
densates, it-i~ to be understood that the process can al80 be employed-to remove such groups from Iinear poly~condensates; m . . . , . . . ~ , . , , . - i , , ~;
. ` ~; .. .. .....
.. , - :
.
,, , . , . , ,, . ., . . . . , , ( , , . , , - ,. . ..... . .. . .. .. . . .
: ~ ' ' ~, '' " :" ' ' ', ' : ' ; ' : .' . j , ' ' ' .: . `; ' ', ` ' ':, :~' . ' ' ' .:
woso/o8169 PCT/US90/00158 Brief Desc~iption of Draw~ng The Figure in the drawing i8 a plot, graphically comparing o~ygen permeability of a non-monolithic product of thi~ invention, with a similar material which has not upgraded by the proce~ provided herein. 02ygen permeability values are on the "y" a~is, while the oxygen concentration values are plotted along the "~" a~ie. A ~hown, an organic modified ~ilicic acid heteropolycondensate (i) containing phenyl groups, and (ii) produced by the proce~s of this invention, ha~ a much greater oxygen permeability when compared to the permeability of a ~imilar material not ~ubjected to the upgrading process of this invention.
~owever, the linearity of re~pon~e with the product of this invention appear~ to be slightly less than with the compari~on material. Thi6 slight decrease in linearity does not materially det~act from the utility of the product.
Best Mode-fg~5~LoL~ 2ye~e I~enti~
In one em~odiment, this invention comprises a method for upgrading an organic modified 8ilicic acid heteropolycondensate by reducing the number of hydrolyzable groups and/or ~ilanol radicals in the condensate. This method comprises heating-said condengate at an elevatet temperature, in contact with a fluid which is-under high pressure, for a time ¦~
~ufficient to remove ~uch groups. The process i3 conducted above the critical temperature and pressure of th~ fluid. The product can be:recovered by -separating the-,fluid and the volatile product(s) formed during removal of the hydrolyzable group`s.-~
As indicated above, for the purpo~e of , description of thi~ invention, the proCeES o~ this embodiment iB referred to as the "upgrading process"
of this invention. The upgrading proce~s can be conducted on a wide variety of organomodified silicic - . . . , ~ . . .
.
WO~0/0~169 PCT/US90/00158 _7- 2 ~ .L
acid heteropolycondensates. The applicability of the upgradin~ proce~s of this invention i~ independent of the method employed for producing the condensate to be upgraded, provided that the polycondensate to be treated contains hydrolyzable andlor silanol groups which can be removed.
Also aa indicated above, a second embodiment of this invention i8 described herein as the ~preparative proce~ or the "preparative process of this invention." The preparative method comprises:
(a) formation of an srganic modified silicic acid condensate by a reaction which comprises hydrolysi 8 and condensation of an or~anosila~e, followed by (b) removal of residual hydrolyzable and/or silanol group~ with a supercritical fluid.
Step (b) comprises the upgrading process of this invention.
A preferred process within the preparative embodiment of this invention compriaes:
a method for preparing an organic motified silicic acid heteropolycondensate (i) having ~.
repeating silane unit~ with the formula RSi- such ~:
that the free valences in said formula are interconnected by o~ygen~ and (ii) being characterized by being ~ubstantially free of hydrolyzable and ~ilanol groups, said method compri 8 in~
(A) forming an intermediate 8ilicic aci~
condensate by reacting water with a silane:at:a .:
lo~ to mild temperature, and in the presence of a low boili~g ~olvent for said ~ilane, said silane : :
having the formula. ~ Si(OR')4 ~,~wherein R i8~
a~ al~yl or.~aryl radical-having~up to:about 20 .-:.~ carbon atoms, R' i8 an alkyl radical of up-~o~
about 4 carbon atoms, and X i B equal to 1 or-2;
W090/08169 PCTlUS90/00158 ~ ~
2 ~ ~ ~ 3~
(B) heating the reaction mixture thereby ~
produced at a pressure and temperature above the critical temperature and pres~ure of said solvent, for a time sufficient to remove substantially all residual R'0- and ~ilanol groups from said intermediate condensate, and form alka~ol from.said R'0- groups; and (C) removing said alkanol and solvent from the organic modified silicic acid heteropolycondensate thereby produced.
In the particular embodiment set forth immediately above, the combination of process ~teps ~A) and (B) comprise a preparati~e proeess of this invention. Step (B) i8 an upgrading process of the 15 type referred to above. Step (C) compri~es a product recovery step. Such a step is a desirable, bu~ not a critical feature of the invention.
The third embodiment of this invention comprises an organic group-containing, porou~
20 monolithic glassy body containing the repeating units Si_ and RS_, wherein R i8 a stable organic group, .~
such that (a~ Prom about 5 to about 35 mole percent ~ :
of said units are RSi_, (b) said RSi_ units are substantially uni~ormly dispersed throughout said 25 body, and (c) sait repeating units are interco~nected - ~ .
by oxygen; ~aid body hav ng a surface area of from about 500 to about 800 m.tg, an.:apparent density of : about 0.25 to about 0.40 g/ml, and being su~bstantially.free.of residual.silanol.and 30 hydrolyzable groups. - - -As part~of..this embodiment:,--thi~ invention . provides a process.:for producing^a monolithic body of : the type.~described~above,.~aid.proc~ss comprisi~g contac*ing~a-precursor polycontensate in.a-mold with :
35 a.~fluid above.the critical temperature;and-pressure of.said fluid!..for a time sufficient^to remove ':
:aùF . .
I
- : :: . : :: . .
-9- 2~
substantially all residual silanol and hydrolyzable groups from said 801, and sub~equently venting and cooling to separate said body from ~aid fluid and volatile by-products formed upon remo~al of said groups from said precursor polycondensate;
said precur~or condensate havi~g been produced by hydroly~is and conden~ation of a mi~ture of silanes having the formula SiX4 and the formula RSiX3, wherein from about 5 to about 35 mole percent of said silanes in said mixture have the formula RSiX3, and wherein each X in said formulae is a hydrolyzable group, and R i8 a non-hydrolyzable organic group.
The products of this invention are organic 15 modified; i.e., they contain organic groups. They '-are polymeric in nature. Li~ear polymers produced by this invention generally are composed of repeati~g units having the formula -0-Si-0-. The crosslinked R
polymers are composed of repeating units having the formula -o-si-o-, or -0-Si-G-. It i8 not nece~ary that the eros~linked products be solely composed of ~hese groups. As set forth more fully below, the product3 of this invention may ~e modified by the inclusion o~ other silicon-contai~ing radical~, albeit in comparatively minor amounts. Con~equently,' the productæ of this inventio~ can be considered as heteropolycondensate~ derived from ~ila~es-ha~ing'the ~ormula ~ SiX4_x, wherein'.X =-0 to 2,'~with'the'~
pro~iso that not all of-the starting material is composed-of silanes wherein X i8: equal to 0.
:,..... -- : -.~e .
. . , I, , .
: . : ' .
' ' ': . . ~ . . ~ . ' ' .
Woso/o8l69 ~ PCT/US90~00158 As stated above, crosslinked, organic modified ~ilicic acid heteropolycondensates, which are up~raded by a proce~a of this invention, have the repeating unit RSi--, wherein the unsati~fied s valences are interconnected through osygen. As discussed, these repeating unit~ can be formed by a hydrolysis and condensation reaction using one or more silanes having the formula:
RSiX3 - (I) -wherein R is an or~anic radical bonded to silicon through carbon, and the radical~ indicated by X are alike or different and selected from hydrolyzable groups, such as alkoxides, (e.g., the alkoxide radicals referred to above), arylo~ites, : -alkylalkoxide, alkoxyalkoxide3, halides, and the like. The heteropolycondensates may al80 contain groups derived from one or more silanes ha~ing the formulas:
SiX4 and R2Si~2 (II) (III) wherein X and R have the same significance as above.
When preparing powders according to this -in~ention,-only a relatively-small number of the silicon containing units will:be derived fro~ silanes .of,!For~ulas II~and III, or: mixtures thereof. This is borne out in more detail by the followi~g discussion.
. Turnin~first:to the compounds-~of Formula`
II, they~can be added to th~-reaction ~isture to increase hardnesg or abrasion resista~ce in the ; .,. .,. . ... . : ~ . . .
~ 2 ~ ~i 3 ~
product heteropolycondensates. It i8 preferred that the ~ormula II compounds be alkogides, i.e., that they have the formula Si(OR'~4. It i8 al80 preferred that all of the alkoxide groups represented by X or (OR') be the same, because such tetraalkoxides are readily inexpensive and, in general, are more readily available. Howe~er, mixed alkoxides, i.e., silicon alkogides having two, three, - :
or four different alkoxide groups, can be used if desired, -There i~ no limitation on the type of group bonded to the oxygen atoms in the alkoxide, provided, however, that the alkoxide group~ terived therefrom are hydrolyzable under the reaction conditions 15 employed. Thus, the organic radical ean be a short ~-. --or long alkyl chain, either branched or unbranched, unsubstituted or substituted with groups such as alkoxy, halogen (Cl, Br or I), or amine, or the like. More typically, they are short, unbranched, or 20 slightly branched lower hydrocarbyl alkyl group~, . -i.e., alkyl groups that are solely composed of carbon :
and hydrogen, and which contain up to about 4 car~on atoms. Thus, for example, alkoæide group6 within materials of Formula II are illustrated by the following non-limiting e~ample~:
metho~ide .ethoxide : .
- .- iso-propo~ide :
. . tert-butoxide - -.
sec-butoxide ~
- -- -. . .- A ~ost pref.erred alkoxide of this type i~C
tetrametho~ysilane;.-however, other--compounds of--thi~
type; such as~tetra~thoxysilane,~can al80 be used'~
3~ i Compounds .o~. Formula-Ir whieh arê u~efui in this invention i~clude aryloxides; Th-us, compounds .. ... ...... , .~ ., .. ~. ...
WO~0/08169 PCT/US90/00158 2~
such as tetraphenoxysilane and diethoxydiphenoxy-~ilane can be used in this invention. Generally speakin~, the aryloxy groups can be the phenoxy group or alkylphenoxy groups having up to about 14 carbon atoms. The alkyl sub~tituents may be of the type~
discussed above. Eor powdered, i.e., non-monolithic, products the amount of Formula II compounds used in this invention i8 set forth in Table I.
One or more materials having ~ormula III can be added. These materials can be included within the reaction mi~ture to add linearity to the resultant heteropolycondensate, or to add more organic groups :' to the finished product. For examiple, with regard to usin~ materials of Formula III to add organic groups, 1~ the combination of one molecule of Formula II and one molecule of Formula III contains twv organic group~
(indicated by R above~. ~ence, when it i8 desired to add a material of Formula II to improve hardne~s, 2 molar equivalent of a compound of Formula III can (o~tionally) be added 80 that the resultant product has as many organic groups as a condensate made solely from RSiX3 compound(s). This can be a useful expedient when the organic group confers a highly desirous property on the heteropolycondensate such as enhanced oxygen permeability. Of the compounds of Formula III, the alko~ides having the formula R2Si(OR')2 are preferred. For non-monolithic products, typiGal amounts of R2SiX2 compound(s) added to the reaction mixture are set forth in Table I.~ -In the Table, the Column "General Use Range"shows that compounds of Formula~. TI and III neet not be~inclu'ded in,het,er.opolyco~densates-produ'ced'by the method. o~ this in,vention..- ~owever,-.whe~ these 3S optio~al inig,red,ients:are employed,.they.-are generally-~used.i~ an amount up,to-about the higher ~alue-in '~' Column 5.
: -.- !
., . _,, .. , .. _ . ., .. . .. ,. ., . , , ~
WO 90/08169 ~ S90/00158 --13--~ ~3 L~
Tabl~
Fo~ula Mole Percent (1~ (2) (3) (4) (5) Preferred Silane General Pre~erred GeneralAmount Tvpe EQ~ Sil~ne~_ Use Ran~m~lQy~* ~-10~ SiX4 Si(9R~4 0 10 1-5 (I) ~Si~3 Rsi(oRl)3 60-100Remainder (III) R2SiX2 R2Si(OR')2 0-25 10-20 * Mole %
Thus, for e~ample, when one or more materials within For~ula II are e~ployed, they are used in an amount up to about 10 mole percent:based on the total amount of silane employed within the reaction mixture. Turning now to column 5, when one or more compounds o~ Formula II i8 utilized, it is preferred that it be employed in a range of from ::
about 1 to about 5 mole percent. Similarly, when a compound of Formula III i8 utilized, it i8 u~ually employed in an amount up to about 25 mole perce~t, or preferably within the range of from about 10 to about 20 mole percent. The Table clearly indicates that ~ -when one or more silanes (other than molecule~ within - Formula I are employed) that the amount of Formula I
material i8 generally about 60 ~ole percent, or greater~
; As stated above, the amou~ts set forth in , Table 1 are generally useful when it ~ desiràbleAto prepare organic,:modified: ~ilicic`acid heteropôly-` :
conde~ates-in;the f.or~- of. a powder:or si~ilar comminuted-material.. When it- iB desired- to prepare a ~: -, ~
Woso/08169 ~ PCT/US90/00158,~
sol-gel product in the form of a rod or similar non-comminuted article, then one employY a silane startin~ mi~ture which contains compound(s) of Formula II in an amount o$ at least about 65 mole percent, more preferably at lea~t about 70 mole percent. The remainder o~ the silane mixture i6 preferably one or more compounds of Formula I.
~owever, a small amount, ~ay up to about 5 mole percent, can be selected from compounds of Formula III.
We have made rods using methoxide~, such as a mixture of such compounds as exemplified by Example III.
It iB to be understood that the monolith~c products of this invention are not limited to rods or rod-like shapes. The shaped articles of this invention generally conform to the ~hape of the :
ves~el in which the reaction mixture is subjected to the hypercritical drying step illustrated by Example 3. U~e of vessels (with other than a tubular shape) to hold the reaction mixture will result in dif~erent shaped products, e.g., spheres. The rods or other shaped products can be comminuted after preparation by hammering, grinding or similar techniques, if desired.
As pointed out above, the silanes of Formulas I and III all contain at least one organo ,group bonded to silicon through a carbon bond. In general, there is no l~mitation on the size or type of the organie group employed. Preferably, the group is "stable"; i.e., it does not undergo an untoward amount of decomposition.during~the preparati~e or 3 ,upgrading~,process,o~-this i~ventio~. More- -preferably,,.the organic.group~ relatively inexpensive. rThirdly, it:.is.,also-,preferred thàt the . organic group be~not. 80 bulky as to unduly~retard the - - . -, . . .. ,. .: .- . . ,. . , . . . ~ ....... ~ , . ,. . : .. . . . ......
., .. , . . - . . . . . ~ . . . . . . . . . . . . . .
W~90/08l69 - PCTtUS90/001~8 2 ~
proce~ by ~teric hindrance, or by entering into an ..
untoward amount of undesirable side reactions.
Alkyl radical~ of the straight- or branched-chain type represent one type of organic group which can be pre~ent within the silane~ employed in thi~
invention. More preferably, the alkyl radicals contain from about 1 to about 20 carbon atoms, and most preferably from 1 to about 10 carbon a~oms. Of particular intere~t are the lower alkyl radicals in which the radicals eontain up to about 6 carbon atoms. Examples of lower alkyl radicals which may appear within the silanes employed in this invention are methyl, ethyl, isopropyl, ~-butyl, ~-butyl, ~ butyl, n-pentyl, and n-hexyl. .: - -Aryl radicals repre~ent another type of ~.
organic group which may be bonded to silicon in the silanes employed in this invention. Of particular interest are the hydrocarbyl aryl radicals which contain from about 6 to about 20 carbon atoms, more preferably from 6 to about 14 carbon atoms, and even more.preferably from 6 to about lO carbon atoms. ::.
Specific examples are phenyl, naphthyl, biphenyl, and the like. (~ydrocarbyl radicals are solely composed .. --of carbon and hydroge~
The radical(~) inticated by R in the above :
formulas may also be an al~enyl radical, e.g., a ~.`
straight- or branched-chai~ radical containing ~rom 2 :~.
to about 20 carbon atoms, and more preferably, l - carbon-to-carbon double bont. - Specific e~amples of 30 alkyl.radical~ of thig type are the ethylenyl, alIyl, : .
ant vinyl ~roups:.. .. ~-~ ,To produce.the organic modified 3ilicic;acid :
heteropolycondensate, the starti~g co~ponent (or~~ .
mixture o~ starting compone~ts) ig contacted with water. Preferably,.the.sila~e o~ mixture o~ silanes .ig firs dissolved;in:an organic solvent. Suitable --': .
WO 90/08169 PCl'tUS90/00158, t`
2~3~3~ 6-sol~ents are alcohol8, pre~erably the lower alcohol~
having from 1 to about 4 carbon atoms and e~emplified by methanol, ethanol, isopropanol, and isobutyl alcohol. The solvent may also be selected from ketones, particularly ~rom lower dialkyl ketones.
Solvents of this type include acetone and methyl isobutyl ketone. In addition, the solvent may be an ether, ~uch ae diethyl ether or another lower dialkyl ether. Alternatively, the solYent may be an amide, such as dimethylamide. A skilled practitioner will recognize that the above list of solvents is illustrative but not limiting, and that other solventQ of the general type described above can also be utilized in this invention. Moreover, a mixture Of solve~ts can be used. Preferably, the solvent i~
a lower alcohol.
The starting material(s), preferably in an organic solvent, i8 mixed with water in order to cauQe the reaction to proceed. Preferably, the amount of water is at least the guantity required to -hydrolyze the hydrolyzable groups that are present.
For example, if the silane starting material used in the preparation process of this invention i9 composed of one or more compounds of Eormula I, i.e., compounds having the formula RSi~3, then at least three mole~ of water i8 used, even though 1.5 mole equi~alents of w~ter are theoretically reguired to be added. Although three mole~ of water are~required to hydrolyze each o~ the hydrolyzable groups, Equation 2 show~ that in each conden3ation between silanol groups one mole equivalent of water is for~edO This mole of water formed in the overall^hydrolysis-condensation process~is available for the hydrolysis 35 ;r!. Hence, i~ thi~ example,-the amount of water : -to ~e addet-to the reaction:mixture.is two thirds of : ' . ; :,: : ' : :,, , ' ,', ' ~"', ': ' ' '' . ' ' ', ' ' , " ', ': ; '~ ' ' ' . ', . '.'~ `,, ' ':' ' . ' WOgo/08169 PCT/US90tOo158 -17~
the amount required to hydrolyze the hydrolyzable groups within the materialg to be reacted.
It i~ not necessary that an exactly ~toichiometsic amount of water be used. Thus, an 5 e~ce~s of water can be employed. ~owe~er, the amount of water added should not be too great 8 ince the monomer~ are not water miscible. Furthermore, if the amou~t of water is beyond a desired amount, the more -~
reactive material~ or groups will be more completely hydrolyzed and condensed before the le~s xeactive group~ have a chance to react. Thus, if an e~ces~ of water i8 employed, only up to about a fivefold molar excess (500 mole %) i8 preferably used.
It i~ preferred that the water be 810wly 15 added to be reaction zone. Accordingly, it i~ -:
preferred that the water be added a~ a 8iow stream or in a drop-wise ~ashion. Addition of the water in this manner helps prevent unchec~ed hydrolysis and/or condensation of the more reactive groups within the 20 material being reacted.~ -The preparative process of this invention can be conducted with water alone, o~ in the presence of a catalyst. Suitable catalysts are acidic or basi~ substances. Examples of suitable acid 25 catalysts are strong, non-o~idizing, inorganic acids, ~ -:
such aQ hydrochloric acid, sulfuric acid, acetic acid, and the like. These preferred acids have a PKa of at least about 5.
Alternatively a catalyst may be a non-oxidizing alkali~e substance, such as~sodium hydroxide, potassium hydroxide, or a lower alkylamine, such as triethylamine Xa~ing a PKb of~
at least 5.
It is preferred that their~reaction be ` , -:
conducted in the presence of a catalyst.- It i8 also . . .
preferred,that an acidic cataly~ bë-employed.- When ''''~''.
. .- . .
WO90/08169 r l~ PCI/US90/00158 ._~
2~
a catalyst i9 used, it i~ usually employed in an amount up to about 5 weight percent based on the total weight of the reaction mi~ture.
The hydrolysis and condensation reactions within the preparative process of this invention are normally carried out at mild to slightly elevated temperature~. Generally, reaction i8 conducted at a temperature within the range of fxom about 10C to about 130C. Pre~erably, the reaction i8 conducted at a temperature within the range of from about 25C
to about 65~C, The formation of an organic modified 8iliCiC
acid heteropolycondensate by hydrolysi~/condensation is preferentially conducted at atmospheric pres~ure.
~owever, it is to be understood that other pressureY
can be employed. Thus, for example, it i8 pos~ible to use slightly lower or higher pres~ure~, say, pre~sures within the range from about 0.5 to $
atmospheres.
The ~ormation of organic modified 8iliCiC
acid heteropolycondensates in this invention is conducted for a time whick. affords a desired s~ate of reaction. In a preferred embodiment the process is conducted for from about l minute to 24 hours. When a cataly8t i8 employed, the reaction can be completed in a shorter time.
After a 301 -gel i8 prepared as discussed above, it can be upgraded or i~proved by use of the upgrading process of thi8 invention. For the upgrading, it is not necessary to remove any solvent that was employed in the:preparative step. Stated another way, the upgrading step can be performed using the reaction mi~ture produced in the-`-~preparation step.
j - To upgrade an organic modified 8ilicic acid heteropolycondensate according to this invention, the ~,.
.
Wo90/08169 PCT/US90/00158 --1 9~ , j' h ~ ~
condensate to be upgraded iQ treated with an egtractant fluid at a supercritical temperature and pressure above stmospheric, 80 that 8ila~01 group~
and hydrolyzable groups are removed from the polyconden~ate. By-products which are produced, e.g., water and alcohol, become admixed with, absorbed, or dissolved in the e~tracta~t fluid.
Sub~equently, the pre~sure is reduced a~d the fluid removed from the condensate 80 that the by-products are separated with the e~tractant fluid.
The operating temperature ia at or preferably somewhat above the critical temperature of the $1uid which ia used, e.g., methanol or ethanol.
The operati~g pressure i8 al80 above the critical pressure of the fluid.
The upgrading i8 conducted at a temperature wi hin the range o~ from about 200-C to the decomposition temperature of the heteropolyconden-sate, more preferably at a temperature of from about 250C to about 350-C. It i5 to be understood that temperatures outsite of this range can be used. The operator will select a temperature which is sufficient to give a reasonable process rate, but not 80 high as to cause an intolerable amount of unwanted decomposition~
The upgrading process i8 al80 conducted at an elevated pressure. In general, one u~ies a pressure higher than about 1000 p8i. Thu8, the upgrading is usually conducted at a presBure of from about 1000 to about 5000 ps i .
The upgrading may be conducted in the presence of a simalI ~mount o~ water to removë any hydrolyiable~ gr0UpB which may ~till remain in the , .. . ..... . ...
polycondensate. Thu8, one usually employs from about ..
0.5 to about 1.5-time~ the amount of water theoretically re~uired-to hydrolyze all of the .' .:
WO90~08169 - PCT/US90/00158--, 2 ~ 20--hydrolyzable group~ in the starting Rilanes. A
skilled practitioner will understand that ~reater or lesser amounts of water can be used. In general, one uses enough water to conduct the desired a~ount o hydrolysis, but not 80 much water as to cau~e the proces~ to proceed in an undesirable manner.
The upgrading step i8 conducted for a time suffieient to give the desired ~mount of hydrolysis or condensatio~. In general, one uses- a reaction time of from about 3 to about 20 hours The reaction time i8 not a truly independent variable, but i8 dependent at leaxt to some extent on the other reaction conditions employed. For example, higher reaction temperatures generally require shorter reaction time~.
A skilled practitioner will recognize that the processes of this invention involve a considerable ~umber of process and eomposition ~ariables to select $rom. ConQeg~ently, the invention includes an ability to-"tailor-make" or ~fine-tune" a heteropolycondensate compositio~ 80 that it has a desixed set o properties. Thi~ offers considerable at~antage when it i~ desired to produce a composition havin~ preselected performance criteria. When a practitioner wishes to produce-a hetesopolyconten~ate according to the teachings of this invention, he or she can be guided by the description above and the examples which follow. ~ -- ~ y ~ ,~
~XRmG~
In a 250 mL, 3-neck, round-bottom fla~k equipped with a mechanical stirrer and reflux condensor~were placed 40 mL (0.17 mol) o~
phenyltriethoxygilane, 6.6 mL (0.031 mol~.of ~~
35- dichIorodiphenylsilàne, 2.3 mL (O.Olp mol)~of tetraethoxysilane, and 49~mL oflethanol.- This .. ,~ ....... .. . . .
, WO 90/08169 P~`/US90/00158 .
mixture wa~ stirred at 60C in a constant temperature :-.
bath while 10.8 mL (0.60 mol) of 0.15 M ~Cl was added dropwise. Th~ reRulting solution wa~ ~tirred at 60C . .
for 1 hour, allowed to 8tand over~ight at ambient temperature, and then stirred an additional 4 hours at 60C. ..
The procedure de cribed above ca~ be modified to produce a variety of compositions ~imply by varying the monomers. The amount of ethanol which :
is added may be in equal ~olume to the silane monomer~. The ~mount of water added, in the form of 0.15 M ~Cl, for e~ample, may be equal to the number of moles of hydrolyzable groups on the 8 ilane monomers.
In some in~tances, the organic ~odified 8iliCiC acid heteropolycondensates produced by the above process were isolated from the ethanol ~olu~ion in which they were made. This was accomplishe:d by pouring the ethanol solution of the condensate into an exce3s of water. The conden~ate separated as a viQcous oil which could be collected, dried (in a vacuum oven), and dissolved in methylene chloride.
To produce a material with a high enough molecular weight to be isolated in this manner, a suitable reaction time is employed. In general, three hours of stirring at 60C after addition of the aqueou3 ~Cl was suffioient. - ~ :-~eteropolycondensates made according to the proces~ illu~trated~by this E~a~ple can be upgraded by heating them at an elevated te~perature-and-presBure a8.(discussed above and) illustrated by the following E~ample.~
~ xam~le 2~; ~
, ~ Phenyltrietho~y~llane~(~0 ml, 0.25 ~oi) was -~
polymerized according to t~e procedure--set-forth in ..
' ' ; , ,. . . ,, :, ' , ., !
W09OtO8169 PCT/US90/00158 _~
~ ~3 ~ 22-Example 1 u~ing 46.7 ml of ethanol and 13.4 ml (0.75 mol) of water. No acid catalyst was employed.
The ethanolic ~olution of the 8 i 1 i C i C acid heteropolycondensate produced was transferred to a stainless steel reaction vessel and dried by heating above the critical temperature of ethanol as in Example 3.
This was accomplished by raising the temperature of the solution at a rate of 100C/hr. to 280C and a pressure of 2000-2500 psi. At that point the reactor was vented and swept with nitrogen. The product was allowed to 810wly cool to ambient temperature over a time span of about 16 hours.
After removing the sample tube from the reactor, a powder was obtained. This powder was found to be æoluble in organic solvents, such as C~C13 or toluene. A portion of this powder was '-dissolved in CDC13 and a 29SiNMR spectrum :
obtained. This spectrum clearly ~howed that >95%
of the silicon atoms had ~ully condensed and had no residual silanol bands. Silicon atoms with one ~ , remaining -OR group were barely detectable above baseline noise.
Peak poisitions in 29SiNMR spectra - 82 ppm vs. SiO2 ~ -112 ppm-- indicated that the phenyl groups remained. This fact was confirmed by infrared spectro~copy with ba~ds at 3050, 2920, 1600, 1435, ,730, 690 cm l, and,as broad band,at llOO cm 1 due to Si~O-Si~. These,bandi~ clearly confirm the pre~ence ; , -of the phenyl group. , -;, The phenyl group-containing, 8ilicic acid heteropolycondensate produced by the~process-of this Exa~ple i8 a produ~t of this invention.
A method of-upgr,ading an organic modified 35 ,silicic acid heteropolycondensate,-such'that a product-.in the for,m-of a rod.is obtai~ed, i~ '' '~ ;
iilustrated by the following example. ~'' .. . ,.. . - .... , . , , : . . , . , ., . ,: , .
WO 90/08169 PCl`tUS90/001!j8 : ~ .
--23-- ~ j 3 ~amP
In a 250 ml, 3-neck, round-bottom flask equipped with a mechanical ~tirrer and reflu~
eonden30r were placed 30 ml of tetramethosysilane, 8.6 ml of phenyltrietho~ysilane, and 30 ml of methanol. The flask wa~ placed in a 60C constant tempe~ature bath and 26.5 ml of distilled water ~ere added dropwise with stirring. After the ~2 addition, stirring was maintained ~or two hours at 60OC before removing from the bath. The reaction mi~ture contained 15 mole percent phenyltriethoxy-silane based on the total moles of silane employed.
The olution of organic modified 8iliCiC .: .
acid heteropolycondensate was added to a ~lass tube 25.2 cm long with a 7 mm inner diameter. The tube was placed in a stainle~s steel reactor and charged with N2 to about 800 p8i. ~he temperature of the :
ve~sel was then increased at a rate of lOO-C/h~. to 240-250~C with a se~ulting pre~sure of 2000 p8i.
20 This created a supercritical fluid ~above the :
critical point of methanol). At this point, the reactor was vented and swept five times with N2 and then 810wly allowed to cool to ambient temperature.
The product wa~ isolated in the ~orm of a rod which readily 8ep8rated from the walls o~ the glas~ tube. The rod was slightly opaque.
The process was repeated U8i~g the following ~tarting-compositions which contaîn about 15 and 5 mole percent respectively of phenyltri~ethoxysilane.
- - ~
257Q Phen 23.2 ml tetramethoxy~ilane `
12.6 ml~phënyltrietho~ysila~e ~30~rml méthanol ~ ¦
35~ 15.1;ml ~2 ; ~
,, . ,., . . , . , ., .. ~ .. . . .
5% Phenvl 30 ml tetramethoxysilane 2.47 ml phenyltriethoxysilane 30 ml methanol 15.1 ml H20 The following demonstrates the utility of upgraded organic modified silicic acid heteropolycondensates of this invention in oxygen sensing-Example 4 To demonstrate utility of the non-monolithic products of this invention, stock solutions were prepared by dissolving one gram of organic modified silicic acid heteropolyconden~ates in,lO,mL of C~2C12 in which one milligram of PtOEP (platinum octaethylporphyrin) wa~ added. Light was excluded from the stoc~ solution. In thi~ study, an optical fiber spectrometer (Guided Wave Model 200) wa~ used to measure the phosphorescence intensity. Thi~
commercial in~trument is equipped with a bifurcated fiber with one input fiber in the center a~i~ to guide light to the sample and si~ output fibers along the edge to collect the scattered light and guide it back to ~he spectrometer. The fibers are terminated in a stainless ~teel probe. A polycarbonate or polymethacrylate barrel was screwed with dichloromethane. The 25 mil thick plate p$ace~ the I -dye in the cro~s section of the exciting beam and the field of view definet by the numerical aperture of the optical fibers, maximizing the observable phosphore~cence. The PtOEP/sol-gel wa~ firs~ drop coated on.the circular glas~ plate. This coating was the~ processed at 60C to 120C for one to four 35 hours. After cooling to room,temperature, thi~ glas~ I
plate wa~ "glued" to the,bar~el. During the ' -- .
-25- 2 ~ ~ .$ ~
mea~iurement, the fiber waæ kept in a glas~ bottle which is connected to two ~lowmieter~. The two flowmeters were u~ed to control the ratio of compre~ed nitrogen and air partial pres~ure, while keeping the total pressure constant. The dye/polymer was excited with a tungsten lamp and an Ealing interfesence filter which pa3sed wavelengths <550 nm.
The phosphorescence was monitored at 642 Dm with a bandwidth of l0 nm. Pho~phorescence lifetimes were ..
l0 estimated from recorded decay curves by nonlinear .~ .
curve fitting. Visible absorption spectra were taken with an ~-4850A W -VIS spectrometer.
The ~lope of a plot of tI(N2)/I(O2)-l] : :
V8. Pox i~ proportional to the product of the life~ime ~t and the permeability P~
The drawing in the Figure shows that an organic modi~ied silicic acid heteropolycondensate mate from phenyltriethozysilane according to the method of Example 2, is significantly more permeable 20 to oxygen than a polyconden~ate material made from . . .
the same silane but which was not upgraded by the process of this invention. As shown by the Figure, the material made by the process of E~ample 2 has 80me nonlinear response in permeability to oxygen relative to o2ygen concentration over the range examined.
During the course of work conducted in the development o~ this. inventionj it was noted that the photostability of PtOEP in heteropolycondensates iB
not permanent, and that the phosphorescence of incorporated PtOEP decreased with time when exposed to light and oxygen. It was al~o observed that-the PtOEP incorporated..in a heteropolycondensate of~
.. . , ~ ... . ...
Ezample 2 had..a relatively 810w; degradation..rate.-J
35 .This ! demonstrate~anothe~-advantage~of.~this~.inventionE
..~.
- . .. ,... , . , ,,, , , . . ~ i ~ , , ... . . . . . . . .
WO90/08169 PCT/US90~001~8 2~ - Films and other articles made from the materials of this invention may be u~ed in other applications beside~ ogygen ~ensing. For example, they may be used wherever enhanced oxygen permeability i8 required, e.g., in gas sepasating application~, or in the construction of devices or materials to be applied to animal or human skin or other external human membranes. Thus, they may be used in the fabrication of contact len3es, for example.
It is to be understood that the materials of this invention need not be solely composed of 8ilicic .
acid heteropolycondensates such as described above.
They may al80 be modified to contain other metal oxide units in the polymeric matrix. For such modification, the raw material composition used in the.preparative proce~s of thi~ invention ~ay be modified to contain up to about 80 mole percent, and more preferably up to about 50 mole percen~ of one or more hydrolyzable materials, such as the alko~ides of titanium, molybdenum, lead, geranium,-zironium or vanadium. Modified condensates compri 3 ing metal oxide units derived from such materials have utilities similar to those discussed above.
Because the method i~ accordance with thi 8 invention removes residual silanol groups and hydro}yzable groups, it improves the properties of 8ilicic acid condensates.- For example, becau~e the method..of thi8 inve~tion lmprove8 the!o~ygen ~
permeability of such condensates, it makes such materials more useXul in applications 3uch as oxygen sensingjiwhere it ~ eceQsary to have utilize a substance that-is permeable to~oxygen; Al~, since the upgrading method of'this i~vention~does ~ot ~~
35 ~remove~organic~groups:bo~det to silicQn through Si-C
bonds, it can be used to improve the o~ygen woso/o8l69 PCT/US90/00158 -27- 2 ~
permeability of organic--modified ~ilicic~acid heteropolycondensate~ without decomposition of their organic substituents. In addition, as provided by this invention, u~e of the ~upercritical flu~d with an organic modified heteropolycondensate in a closed mold provide~ a new type of gla88y porou~ solid.
Such material8 with organic groups bo~ded to silicon atoms by Si-C bonds have never been made before.
They are useful in ~any application~, for e~ample as absorbents.
-, . ~
~. '.. ~ .
.
~5 .. . .
, . ~ ! . ~ . . . ' . . . ... . . : -\
- -. . .. . .
.: . . :.. _ . .. - . - .
,.: :, , , , . , . . ` ' .. - , , .
WO~0/08169 PCT/US90/00158 2~
such as tetraphenoxysilane and diethoxydiphenoxy-~ilane can be used in this invention. Generally speakin~, the aryloxy groups can be the phenoxy group or alkylphenoxy groups having up to about 14 carbon atoms. The alkyl sub~tituents may be of the type~
discussed above. Eor powdered, i.e., non-monolithic, products the amount of Formula II compounds used in this invention i8 set forth in Table I.
One or more materials having ~ormula III can be added. These materials can be included within the reaction mi~ture to add linearity to the resultant heteropolycondensate, or to add more organic groups :' to the finished product. For examiple, with regard to usin~ materials of Formula III to add organic groups, 1~ the combination of one molecule of Formula II and one molecule of Formula III contains twv organic group~
(indicated by R above~. ~ence, when it i8 desired to add a material of Formula II to improve hardne~s, 2 molar equivalent of a compound of Formula III can (o~tionally) be added 80 that the resultant product has as many organic groups as a condensate made solely from RSiX3 compound(s). This can be a useful expedient when the organic group confers a highly desirous property on the heteropolycondensate such as enhanced oxygen permeability. Of the compounds of Formula III, the alko~ides having the formula R2Si(OR')2 are preferred. For non-monolithic products, typiGal amounts of R2SiX2 compound(s) added to the reaction mixture are set forth in Table I.~ -In the Table, the Column "General Use Range"shows that compounds of Formula~. TI and III neet not be~inclu'ded in,het,er.opolyco~densates-produ'ced'by the method. o~ this in,vention..- ~owever,-.whe~ these 3S optio~al inig,red,ients:are employed,.they.-are generally-~used.i~ an amount up,to-about the higher ~alue-in '~' Column 5.
: -.- !
., . _,, .. , .. _ . ., .. . .. ,. ., . , , ~
WO 90/08169 ~ S90/00158 --13--~ ~3 L~
Tabl~
Fo~ula Mole Percent (1~ (2) (3) (4) (5) Preferred Silane General Pre~erred GeneralAmount Tvpe EQ~ Sil~ne~_ Use Ran~m~lQy~* ~-10~ SiX4 Si(9R~4 0 10 1-5 (I) ~Si~3 Rsi(oRl)3 60-100Remainder (III) R2SiX2 R2Si(OR')2 0-25 10-20 * Mole %
Thus, for e~ample, when one or more materials within For~ula II are e~ployed, they are used in an amount up to about 10 mole percent:based on the total amount of silane employed within the reaction mixture. Turning now to column 5, when one or more compounds o~ Formula II i8 utilized, it is preferred that it be employed in a range of from ::
about 1 to about 5 mole percent. Similarly, when a compound of Formula III i8 utilized, it i8 u~ually employed in an amount up to about 25 mole perce~t, or preferably within the range of from about 10 to about 20 mole percent. The Table clearly indicates that ~ -when one or more silanes (other than molecule~ within - Formula I are employed) that the amount of Formula I
material i8 generally about 60 ~ole percent, or greater~
; As stated above, the amou~ts set forth in , Table 1 are generally useful when it ~ desiràbleAto prepare organic,:modified: ~ilicic`acid heteropôly-` :
conde~ates-in;the f.or~- of. a powder:or si~ilar comminuted-material.. When it- iB desired- to prepare a ~: -, ~
Woso/08169 ~ PCT/US90/00158,~
sol-gel product in the form of a rod or similar non-comminuted article, then one employY a silane startin~ mi~ture which contains compound(s) of Formula II in an amount o$ at least about 65 mole percent, more preferably at lea~t about 70 mole percent. The remainder o~ the silane mixture i6 preferably one or more compounds of Formula I.
~owever, a small amount, ~ay up to about 5 mole percent, can be selected from compounds of Formula III.
We have made rods using methoxide~, such as a mixture of such compounds as exemplified by Example III.
It iB to be understood that the monolith~c products of this invention are not limited to rods or rod-like shapes. The shaped articles of this invention generally conform to the ~hape of the :
ves~el in which the reaction mixture is subjected to the hypercritical drying step illustrated by Example 3. U~e of vessels (with other than a tubular shape) to hold the reaction mixture will result in dif~erent shaped products, e.g., spheres. The rods or other shaped products can be comminuted after preparation by hammering, grinding or similar techniques, if desired.
As pointed out above, the silanes of Formulas I and III all contain at least one organo ,group bonded to silicon through a carbon bond. In general, there is no l~mitation on the size or type of the organie group employed. Preferably, the group is "stable"; i.e., it does not undergo an untoward amount of decomposition.during~the preparati~e or 3 ,upgrading~,process,o~-this i~ventio~. More- -preferably,,.the organic.group~ relatively inexpensive. rThirdly, it:.is.,also-,preferred thàt the . organic group be~not. 80 bulky as to unduly~retard the - - . -, . . .. ,. .: .- . . ,. . , . . . ~ ....... ~ , . ,. . : .. . . . ......
., .. , . . - . . . . . ~ . . . . . . . . . . . . . .
W~90/08l69 - PCTtUS90/001~8 2 ~
proce~ by ~teric hindrance, or by entering into an ..
untoward amount of undesirable side reactions.
Alkyl radical~ of the straight- or branched-chain type represent one type of organic group which can be pre~ent within the silane~ employed in thi~
invention. More preferably, the alkyl radicals contain from about 1 to about 20 carbon atoms, and most preferably from 1 to about 10 carbon a~oms. Of particular intere~t are the lower alkyl radicals in which the radicals eontain up to about 6 carbon atoms. Examples of lower alkyl radicals which may appear within the silanes employed in this invention are methyl, ethyl, isopropyl, ~-butyl, ~-butyl, ~ butyl, n-pentyl, and n-hexyl. .: - -Aryl radicals repre~ent another type of ~.
organic group which may be bonded to silicon in the silanes employed in this invention. Of particular interest are the hydrocarbyl aryl radicals which contain from about 6 to about 20 carbon atoms, more preferably from 6 to about 14 carbon atoms, and even more.preferably from 6 to about lO carbon atoms. ::.
Specific examples are phenyl, naphthyl, biphenyl, and the like. (~ydrocarbyl radicals are solely composed .. --of carbon and hydroge~
The radical(~) inticated by R in the above :
formulas may also be an al~enyl radical, e.g., a ~.`
straight- or branched-chai~ radical containing ~rom 2 :~.
to about 20 carbon atoms, and more preferably, l - carbon-to-carbon double bont. - Specific e~amples of 30 alkyl.radical~ of thig type are the ethylenyl, alIyl, : .
ant vinyl ~roups:.. .. ~-~ ,To produce.the organic modified 3ilicic;acid :
heteropolycondensate, the starti~g co~ponent (or~~ .
mixture o~ starting compone~ts) ig contacted with water. Preferably,.the.sila~e o~ mixture o~ silanes .ig firs dissolved;in:an organic solvent. Suitable --': .
WO 90/08169 PCl'tUS90/00158, t`
2~3~3~ 6-sol~ents are alcohol8, pre~erably the lower alcohol~
having from 1 to about 4 carbon atoms and e~emplified by methanol, ethanol, isopropanol, and isobutyl alcohol. The solvent may also be selected from ketones, particularly ~rom lower dialkyl ketones.
Solvents of this type include acetone and methyl isobutyl ketone. In addition, the solvent may be an ether, ~uch ae diethyl ether or another lower dialkyl ether. Alternatively, the solYent may be an amide, such as dimethylamide. A skilled practitioner will recognize that the above list of solvents is illustrative but not limiting, and that other solventQ of the general type described above can also be utilized in this invention. Moreover, a mixture Of solve~ts can be used. Preferably, the solvent i~
a lower alcohol.
The starting material(s), preferably in an organic solvent, i8 mixed with water in order to cauQe the reaction to proceed. Preferably, the amount of water is at least the guantity required to -hydrolyze the hydrolyzable groups that are present.
For example, if the silane starting material used in the preparation process of this invention i9 composed of one or more compounds of Eormula I, i.e., compounds having the formula RSi~3, then at least three mole~ of water i8 used, even though 1.5 mole equi~alents of w~ter are theoretically reguired to be added. Although three mole~ of water are~required to hydrolyze each o~ the hydrolyzable groups, Equation 2 show~ that in each conden3ation between silanol groups one mole equivalent of water is for~edO This mole of water formed in the overall^hydrolysis-condensation process~is available for the hydrolysis 35 ;r!. Hence, i~ thi~ example,-the amount of water : -to ~e addet-to the reaction:mixture.is two thirds of : ' . ; :,: : ' : :,, , ' ,', ' ~"', ': ' ' '' . ' ' ', ' ' , " ', ': ; '~ ' ' ' . ', . '.'~ `,, ' ':' ' . ' WOgo/08169 PCT/US90tOo158 -17~
the amount required to hydrolyze the hydrolyzable groups within the materialg to be reacted.
It i~ not necessary that an exactly ~toichiometsic amount of water be used. Thus, an 5 e~ce~s of water can be employed. ~owe~er, the amount of water added should not be too great 8 ince the monomer~ are not water miscible. Furthermore, if the amou~t of water is beyond a desired amount, the more -~
reactive material~ or groups will be more completely hydrolyzed and condensed before the le~s xeactive group~ have a chance to react. Thus, if an e~ces~ of water i8 employed, only up to about a fivefold molar excess (500 mole %) i8 preferably used.
It i~ preferred that the water be 810wly 15 added to be reaction zone. Accordingly, it i~ -:
preferred that the water be added a~ a 8iow stream or in a drop-wise ~ashion. Addition of the water in this manner helps prevent unchec~ed hydrolysis and/or condensation of the more reactive groups within the 20 material being reacted.~ -The preparative process of this invention can be conducted with water alone, o~ in the presence of a catalyst. Suitable catalysts are acidic or basi~ substances. Examples of suitable acid 25 catalysts are strong, non-o~idizing, inorganic acids, ~ -:
such aQ hydrochloric acid, sulfuric acid, acetic acid, and the like. These preferred acids have a PKa of at least about 5.
Alternatively a catalyst may be a non-oxidizing alkali~e substance, such as~sodium hydroxide, potassium hydroxide, or a lower alkylamine, such as triethylamine Xa~ing a PKb of~
at least 5.
It is preferred that their~reaction be ` , -:
conducted in the presence of a catalyst.- It i8 also . . .
preferred,that an acidic cataly~ bë-employed.- When ''''~''.
. .- . .
WO90/08169 r l~ PCI/US90/00158 ._~
2~
a catalyst i9 used, it i~ usually employed in an amount up to about 5 weight percent based on the total weight of the reaction mi~ture.
The hydrolysis and condensation reactions within the preparative process of this invention are normally carried out at mild to slightly elevated temperature~. Generally, reaction i8 conducted at a temperature within the range of fxom about 10C to about 130C. Pre~erably, the reaction i8 conducted at a temperature within the range of from about 25C
to about 65~C, The formation of an organic modified 8iliCiC
acid heteropolycondensate by hydrolysi~/condensation is preferentially conducted at atmospheric pres~ure.
~owever, it is to be understood that other pressureY
can be employed. Thus, for example, it i8 pos~ible to use slightly lower or higher pres~ure~, say, pre~sures within the range from about 0.5 to $
atmospheres.
The ~ormation of organic modified 8iliCiC
acid heteropolycondensates in this invention is conducted for a time whick. affords a desired s~ate of reaction. In a preferred embodiment the process is conducted for from about l minute to 24 hours. When a cataly8t i8 employed, the reaction can be completed in a shorter time.
After a 301 -gel i8 prepared as discussed above, it can be upgraded or i~proved by use of the upgrading process of thi8 invention. For the upgrading, it is not necessary to remove any solvent that was employed in the:preparative step. Stated another way, the upgrading step can be performed using the reaction mi~ture produced in the-`-~preparation step.
j - To upgrade an organic modified 8ilicic acid heteropolycondensate according to this invention, the ~,.
.
Wo90/08169 PCT/US90/00158 --1 9~ , j' h ~ ~
condensate to be upgraded iQ treated with an egtractant fluid at a supercritical temperature and pressure above stmospheric, 80 that 8ila~01 group~
and hydrolyzable groups are removed from the polyconden~ate. By-products which are produced, e.g., water and alcohol, become admixed with, absorbed, or dissolved in the e~tracta~t fluid.
Sub~equently, the pre~sure is reduced a~d the fluid removed from the condensate 80 that the by-products are separated with the e~tractant fluid.
The operating temperature ia at or preferably somewhat above the critical temperature of the $1uid which ia used, e.g., methanol or ethanol.
The operati~g pressure i8 al80 above the critical pressure of the fluid.
The upgrading i8 conducted at a temperature wi hin the range o~ from about 200-C to the decomposition temperature of the heteropolyconden-sate, more preferably at a temperature of from about 250C to about 350-C. It i5 to be understood that temperatures outsite of this range can be used. The operator will select a temperature which is sufficient to give a reasonable process rate, but not 80 high as to cause an intolerable amount of unwanted decomposition~
The upgrading process i8 al80 conducted at an elevated pressure. In general, one u~ies a pressure higher than about 1000 p8i. Thu8, the upgrading is usually conducted at a presBure of from about 1000 to about 5000 ps i .
The upgrading may be conducted in the presence of a simalI ~mount o~ water to removë any hydrolyiable~ gr0UpB which may ~till remain in the , .. . ..... . ...
polycondensate. Thu8, one usually employs from about ..
0.5 to about 1.5-time~ the amount of water theoretically re~uired-to hydrolyze all of the .' .:
WO90~08169 - PCT/US90/00158--, 2 ~ 20--hydrolyzable group~ in the starting Rilanes. A
skilled practitioner will understand that ~reater or lesser amounts of water can be used. In general, one uses enough water to conduct the desired a~ount o hydrolysis, but not 80 much water as to cau~e the proces~ to proceed in an undesirable manner.
The upgrading step i8 conducted for a time suffieient to give the desired ~mount of hydrolysis or condensatio~. In general, one uses- a reaction time of from about 3 to about 20 hours The reaction time i8 not a truly independent variable, but i8 dependent at leaxt to some extent on the other reaction conditions employed. For example, higher reaction temperatures generally require shorter reaction time~.
A skilled practitioner will recognize that the processes of this invention involve a considerable ~umber of process and eomposition ~ariables to select $rom. ConQeg~ently, the invention includes an ability to-"tailor-make" or ~fine-tune" a heteropolycondensate compositio~ 80 that it has a desixed set o properties. Thi~ offers considerable at~antage when it i~ desired to produce a composition havin~ preselected performance criteria. When a practitioner wishes to produce-a hetesopolyconten~ate according to the teachings of this invention, he or she can be guided by the description above and the examples which follow. ~ -- ~ y ~ ,~
~XRmG~
In a 250 mL, 3-neck, round-bottom fla~k equipped with a mechanical stirrer and reflux condensor~were placed 40 mL (0.17 mol) o~
phenyltriethoxygilane, 6.6 mL (0.031 mol~.of ~~
35- dichIorodiphenylsilàne, 2.3 mL (O.Olp mol)~of tetraethoxysilane, and 49~mL oflethanol.- This .. ,~ ....... .. . . .
, WO 90/08169 P~`/US90/00158 .
mixture wa~ stirred at 60C in a constant temperature :-.
bath while 10.8 mL (0.60 mol) of 0.15 M ~Cl was added dropwise. Th~ reRulting solution wa~ ~tirred at 60C . .
for 1 hour, allowed to 8tand over~ight at ambient temperature, and then stirred an additional 4 hours at 60C. ..
The procedure de cribed above ca~ be modified to produce a variety of compositions ~imply by varying the monomers. The amount of ethanol which :
is added may be in equal ~olume to the silane monomer~. The ~mount of water added, in the form of 0.15 M ~Cl, for e~ample, may be equal to the number of moles of hydrolyzable groups on the 8 ilane monomers.
In some in~tances, the organic ~odified 8iliCiC acid heteropolycondensates produced by the above process were isolated from the ethanol ~olu~ion in which they were made. This was accomplishe:d by pouring the ethanol solution of the condensate into an exce3s of water. The conden~ate separated as a viQcous oil which could be collected, dried (in a vacuum oven), and dissolved in methylene chloride.
To produce a material with a high enough molecular weight to be isolated in this manner, a suitable reaction time is employed. In general, three hours of stirring at 60C after addition of the aqueou3 ~Cl was suffioient. - ~ :-~eteropolycondensates made according to the proces~ illu~trated~by this E~a~ple can be upgraded by heating them at an elevated te~perature-and-presBure a8.(discussed above and) illustrated by the following E~ample.~
~ xam~le 2~; ~
, ~ Phenyltrietho~y~llane~(~0 ml, 0.25 ~oi) was -~
polymerized according to t~e procedure--set-forth in ..
' ' ; , ,. . . ,, :, ' , ., !
W09OtO8169 PCT/US90/00158 _~
~ ~3 ~ 22-Example 1 u~ing 46.7 ml of ethanol and 13.4 ml (0.75 mol) of water. No acid catalyst was employed.
The ethanolic ~olution of the 8 i 1 i C i C acid heteropolycondensate produced was transferred to a stainless steel reaction vessel and dried by heating above the critical temperature of ethanol as in Example 3.
This was accomplished by raising the temperature of the solution at a rate of 100C/hr. to 280C and a pressure of 2000-2500 psi. At that point the reactor was vented and swept with nitrogen. The product was allowed to 810wly cool to ambient temperature over a time span of about 16 hours.
After removing the sample tube from the reactor, a powder was obtained. This powder was found to be æoluble in organic solvents, such as C~C13 or toluene. A portion of this powder was '-dissolved in CDC13 and a 29SiNMR spectrum :
obtained. This spectrum clearly ~howed that >95%
of the silicon atoms had ~ully condensed and had no residual silanol bands. Silicon atoms with one ~ , remaining -OR group were barely detectable above baseline noise.
Peak poisitions in 29SiNMR spectra - 82 ppm vs. SiO2 ~ -112 ppm-- indicated that the phenyl groups remained. This fact was confirmed by infrared spectro~copy with ba~ds at 3050, 2920, 1600, 1435, ,730, 690 cm l, and,as broad band,at llOO cm 1 due to Si~O-Si~. These,bandi~ clearly confirm the pre~ence ; , -of the phenyl group. , -;, The phenyl group-containing, 8ilicic acid heteropolycondensate produced by the~process-of this Exa~ple i8 a produ~t of this invention.
A method of-upgr,ading an organic modified 35 ,silicic acid heteropolycondensate,-such'that a product-.in the for,m-of a rod.is obtai~ed, i~ '' '~ ;
iilustrated by the following example. ~'' .. . ,.. . - .... , . , , : . . , . , ., . ,: , .
WO 90/08169 PCl`tUS90/001!j8 : ~ .
--23-- ~ j 3 ~amP
In a 250 ml, 3-neck, round-bottom flask equipped with a mechanical ~tirrer and reflu~
eonden30r were placed 30 ml of tetramethosysilane, 8.6 ml of phenyltrietho~ysilane, and 30 ml of methanol. The flask wa~ placed in a 60C constant tempe~ature bath and 26.5 ml of distilled water ~ere added dropwise with stirring. After the ~2 addition, stirring was maintained ~or two hours at 60OC before removing from the bath. The reaction mi~ture contained 15 mole percent phenyltriethoxy-silane based on the total moles of silane employed.
The olution of organic modified 8iliCiC .: .
acid heteropolycondensate was added to a ~lass tube 25.2 cm long with a 7 mm inner diameter. The tube was placed in a stainle~s steel reactor and charged with N2 to about 800 p8i. ~he temperature of the :
ve~sel was then increased at a rate of lOO-C/h~. to 240-250~C with a se~ulting pre~sure of 2000 p8i.
20 This created a supercritical fluid ~above the :
critical point of methanol). At this point, the reactor was vented and swept five times with N2 and then 810wly allowed to cool to ambient temperature.
The product wa~ isolated in the ~orm of a rod which readily 8ep8rated from the walls o~ the glas~ tube. The rod was slightly opaque.
The process was repeated U8i~g the following ~tarting-compositions which contaîn about 15 and 5 mole percent respectively of phenyltri~ethoxysilane.
- - ~
257Q Phen 23.2 ml tetramethoxy~ilane `
12.6 ml~phënyltrietho~ysila~e ~30~rml méthanol ~ ¦
35~ 15.1;ml ~2 ; ~
,, . ,., . . , . , ., .. ~ .. . . .
5% Phenvl 30 ml tetramethoxysilane 2.47 ml phenyltriethoxysilane 30 ml methanol 15.1 ml H20 The following demonstrates the utility of upgraded organic modified silicic acid heteropolycondensates of this invention in oxygen sensing-Example 4 To demonstrate utility of the non-monolithic products of this invention, stock solutions were prepared by dissolving one gram of organic modified silicic acid heteropolyconden~ates in,lO,mL of C~2C12 in which one milligram of PtOEP (platinum octaethylporphyrin) wa~ added. Light was excluded from the stoc~ solution. In thi~ study, an optical fiber spectrometer (Guided Wave Model 200) wa~ used to measure the phosphorescence intensity. Thi~
commercial in~trument is equipped with a bifurcated fiber with one input fiber in the center a~i~ to guide light to the sample and si~ output fibers along the edge to collect the scattered light and guide it back to ~he spectrometer. The fibers are terminated in a stainless ~teel probe. A polycarbonate or polymethacrylate barrel was screwed with dichloromethane. The 25 mil thick plate p$ace~ the I -dye in the cro~s section of the exciting beam and the field of view definet by the numerical aperture of the optical fibers, maximizing the observable phosphore~cence. The PtOEP/sol-gel wa~ firs~ drop coated on.the circular glas~ plate. This coating was the~ processed at 60C to 120C for one to four 35 hours. After cooling to room,temperature, thi~ glas~ I
plate wa~ "glued" to the,bar~el. During the ' -- .
-25- 2 ~ ~ .$ ~
mea~iurement, the fiber waæ kept in a glas~ bottle which is connected to two ~lowmieter~. The two flowmeters were u~ed to control the ratio of compre~ed nitrogen and air partial pres~ure, while keeping the total pressure constant. The dye/polymer was excited with a tungsten lamp and an Ealing interfesence filter which pa3sed wavelengths <550 nm.
The phosphorescence was monitored at 642 Dm with a bandwidth of l0 nm. Pho~phorescence lifetimes were ..
l0 estimated from recorded decay curves by nonlinear .~ .
curve fitting. Visible absorption spectra were taken with an ~-4850A W -VIS spectrometer.
The ~lope of a plot of tI(N2)/I(O2)-l] : :
V8. Pox i~ proportional to the product of the life~ime ~t and the permeability P~
The drawing in the Figure shows that an organic modi~ied silicic acid heteropolycondensate mate from phenyltriethozysilane according to the method of Example 2, is significantly more permeable 20 to oxygen than a polyconden~ate material made from . . .
the same silane but which was not upgraded by the process of this invention. As shown by the Figure, the material made by the process of E~ample 2 has 80me nonlinear response in permeability to oxygen relative to o2ygen concentration over the range examined.
During the course of work conducted in the development o~ this. inventionj it was noted that the photostability of PtOEP in heteropolycondensates iB
not permanent, and that the phosphorescence of incorporated PtOEP decreased with time when exposed to light and oxygen. It was al~o observed that-the PtOEP incorporated..in a heteropolycondensate of~
.. . , ~ ... . ...
Ezample 2 had..a relatively 810w; degradation..rate.-J
35 .This ! demonstrate~anothe~-advantage~of.~this~.inventionE
..~.
- . .. ,... , . , ,,, , , . . ~ i ~ , , ... . . . . . . . .
WO90/08169 PCT/US90~001~8 2~ - Films and other articles made from the materials of this invention may be u~ed in other applications beside~ ogygen ~ensing. For example, they may be used wherever enhanced oxygen permeability i8 required, e.g., in gas sepasating application~, or in the construction of devices or materials to be applied to animal or human skin or other external human membranes. Thus, they may be used in the fabrication of contact len3es, for example.
It is to be understood that the materials of this invention need not be solely composed of 8ilicic .
acid heteropolycondensates such as described above.
They may al80 be modified to contain other metal oxide units in the polymeric matrix. For such modification, the raw material composition used in the.preparative proce~s of thi~ invention ~ay be modified to contain up to about 80 mole percent, and more preferably up to about 50 mole percen~ of one or more hydrolyzable materials, such as the alko~ides of titanium, molybdenum, lead, geranium,-zironium or vanadium. Modified condensates compri 3 ing metal oxide units derived from such materials have utilities similar to those discussed above.
Because the method i~ accordance with thi 8 invention removes residual silanol groups and hydro}yzable groups, it improves the properties of 8ilicic acid condensates.- For example, becau~e the method..of thi8 inve~tion lmprove8 the!o~ygen ~
permeability of such condensates, it makes such materials more useXul in applications 3uch as oxygen sensingjiwhere it ~ eceQsary to have utilize a substance that-is permeable to~oxygen; Al~, since the upgrading method of'this i~vention~does ~ot ~~
35 ~remove~organic~groups:bo~det to silicQn through Si-C
bonds, it can be used to improve the o~ygen woso/o8l69 PCT/US90/00158 -27- 2 ~
permeability of organic--modified ~ilicic~acid heteropolycondensate~ without decomposition of their organic substituents. In addition, as provided by this invention, u~e of the ~upercritical flu~d with an organic modified heteropolycondensate in a closed mold provide~ a new type of gla88y porou~ solid.
Such material8 with organic groups bo~ded to silicon atoms by Si-C bonds have never been made before.
They are useful in ~any application~, for e~ample as absorbents.
-, . ~
~. '.. ~ .
.
~5 .. . .
, . ~ ! . ~ . . . ' . . . ... . . : -\
- -. . .. . .
.: . . :.. _ . .. - . - .
,.: :, , , , . , . . ` ' .. - , , .
Claims (7)
1. A process for improving the oxygen permeability of an organic modified silicic acid heteropolycondensate powder in which 60-100 mole percent of the silane units have the formula RSi?, and wherein the free valences in said formula are interconnected by oxygen, and R is a stable organic group selected from alkyl or aryl groups having up to about 20 carbon atoms, said process being characterized in that said heteropolycondensate is contacted for 3-20 hours with a fluid above the critical pressure and temperature of said fluid to remove silanol or alkoxy groups from said heteropolycondensate, said fluid being the alcohol corresponding to said alkoxy groups;
and subsequently removing said fluid from the organic modified silicic acid hteropolycondensate product thereby produced;
said process being further characterized by said heterpolycondensate having increased oxygen permeability compared to the oxygen permeability of said starting heteropolycondensate.
and subsequently removing said fluid from the organic modified silicic acid hteropolycondensate product thereby produced;
said process being further characterized by said heterpolycondensate having increased oxygen permeability compared to the oxygen permeability of said starting heteropolycondensate.
2. The process of Claim 1 wherein R is aryl.
3. The process of Claim 2 wherein R is phenyl.
4. The process of Claim 1 wherein at least about 90% of the repeating silicon-containing units have said formula RSi?.
5. The process of Claim 1 wherein said fluid is an alcohol having one to four carbon atoms.
6. The process of Claim 5 wherein said alcohol is selected from methanol and ethanol.
7. The process for producing a monolithic body, said process comprising contacting a sol in a mold for 3-20 hours with a fluid above the critical temperature and pressure of said fluid, for a time sufficient to remove substantially all residual silanol and hydrolyzable groups from said sol, and subsequently cooling and venting to separate said body from said fluid and volatile by-products formed upon removal of said groups from aid sol;
said sol having been produced by hydrolysis and condensation of a mixture of silanes having the formula SiX4 and the formula RSiX3, wherein from about 5 to about 35 mole percent of said silanes in said mixture have the formula RSiX3, and wherein each X in said formulae is a methoxy group, and R is an organic grup, selected from alkyl and aryl gorups having up to 20 carbon atoms;
said process being further characterized by said fluid being methanol, said temperature 200°-350°C, and said pressure being 1000-5000 psi.
said sol having been produced by hydrolysis and condensation of a mixture of silanes having the formula SiX4 and the formula RSiX3, wherein from about 5 to about 35 mole percent of said silanes in said mixture have the formula RSiX3, and wherein each X in said formulae is a methoxy group, and R is an organic grup, selected from alkyl and aryl gorups having up to 20 carbon atoms;
said process being further characterized by said fluid being methanol, said temperature 200°-350°C, and said pressure being 1000-5000 psi.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US30009489A | 1989-01-19 | 1989-01-19 | |
| US300,094 | 1989-01-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2045511A1 true CA2045511A1 (en) | 1990-07-20 |
Family
ID=23157681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002045511A Abandoned CA2045511A1 (en) | 1989-01-19 | 1990-01-16 | Organic modified silicic acid heteropolycondensates |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0454761A1 (en) |
| JP (1) | JPH04502779A (en) |
| CA (1) | CA2045511A1 (en) |
| WO (1) | WO1990008169A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19545042A1 (en) * | 1995-12-02 | 1997-06-05 | Studiengesellschaft Kohle Mbh | Amorphous microporous mixed oxide catalysts with controlled surface polarity for selective heterogeneous catalysis adsorption and material separation |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2680696A (en) * | 1951-02-14 | 1954-06-08 | Du Pont | Method of esterifying the surface of a silica substrate having a reactive silanol surface |
| US2967168A (en) * | 1954-11-12 | 1961-01-03 | Gen Electric | Vinyl-substituted silica aerogels |
| DE2357184A1 (en) * | 1973-11-16 | 1975-05-22 | Merck Patent Gmbh | PROCESS FOR THE PRODUCTION OF ORGANICALLY MODIFIED SILICON DIOXIDES |
| DE2758415A1 (en) * | 1977-12-28 | 1979-07-12 | Fraunhofer Ges Forschung | SILICIC ACID HETEROPOLYCONDENSATES, PROCESS FOR THEIR PRODUCTION AND THEIR USE AS MEMBRANES AND ADSORBENTS |
| US4402927A (en) * | 1980-04-22 | 1983-09-06 | Dardel Guy Von | Silica aerogel |
| FR2601017B1 (en) * | 1986-07-02 | 1988-09-23 | Centre Nat Rech Scient | NOVEL COMPOSITIONS BASED ON SILICA DERIVATIVES MODIFIED BY ORGANIC GROUPS, THEIR PREPARATION AND THEIR APPLICATION, IN PARTICULAR AS PROTONIC CONDUCTORS |
-
1990
- 1990-01-16 WO PCT/US1990/000158 patent/WO1990008169A1/en not_active Application Discontinuation
- 1990-01-16 CA CA002045511A patent/CA2045511A1/en not_active Abandoned
- 1990-01-16 JP JP2502456A patent/JPH04502779A/en active Pending
- 1990-01-16 EP EP90902451A patent/EP0454761A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04502779A (en) | 1992-05-21 |
| EP0454761A1 (en) | 1991-11-06 |
| WO1990008169A1 (en) | 1990-07-26 |
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