U.S. patent application number 17/826599 was filed with the patent office on 2022-09-15 for method of preparing pentachlorodisilane purified reaction product comprising same.
This patent application is currently assigned to Jiangsu Nata Opto-Electronic Materials Co. Ltd.. The applicant listed for this patent is Jiangsu Nata Opto-Electronic Materials Co. Ltd.. Invention is credited to Barry KETOLA, Noel MOWER CHANG, Jeanette YOUNG, Xiaobing ZHOU.
Application Number | 20220289580 17/826599 |
Document ID | / |
Family ID | 1000006362473 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220289580 |
Kind Code |
A1 |
KETOLA; Barry ; et
al. |
September 15, 2022 |
METHOD OF PREPARING PENTACHLORODISILANE PURIFIED REACTION PRODUCT
COMPRISING SAME
Abstract
A method of preparing pentachlorodisilane is disclosed. The
method comprises partially reducing hexachlorodisilane with a metal
hydride compound to give a reaction product comprising
pentachlorodisilane. The method further comprises purifying the
reaction product to give a purified reaction product comprising the
pentachlorodisilane. The purified reaction product comprising
pentachlorodisilane formed in accordance with the method is also
disclosed.
Inventors: |
KETOLA; Barry; (Wilmington,
DE) ; MOWER CHANG; Noel; (Wilmington, DE) ;
YOUNG; Jeanette; (Wilmington, DE) ; ZHOU;
Xiaobing; (Wilmington, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jiangsu Nata Opto-Electronic Materials Co. Ltd. |
Suzhou |
|
CN |
|
|
Assignee: |
Jiangsu Nata Opto-Electronic
Materials Co. Ltd.
Suzhou
CN
|
Family ID: |
1000006362473 |
Appl. No.: |
17/826599 |
Filed: |
May 27, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16635442 |
Jan 30, 2020 |
11370666 |
|
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PCT/US18/44390 |
Jul 30, 2018 |
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17826599 |
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62538858 |
Jul 31, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C01B 33/10778 20130101;
B01D 3/14 20130101 |
International
Class: |
C01B 33/107 20060101
C01B033/107; B01D 3/14 20060101 B01D003/14 |
Claims
1-14. (canceled)
15. A purified reaction product comprising: pentachlorodisilane
formed by: partially reducing hexachlorodisilane with a metal
hydride compound to give a reaction product comprising
pentachlorodisilane; and purifying the reaction product to give a
purified reaction product comprising the pentachlorodisilane.
16. The purified reaction product of claim 15, comprising
pentachlorodisilane in an amount of at least 95 wt. % based on the
total weight of the purified reaction product.
17. The purified reaction product of claim 15, comprising
pentachlorodisilane in an amount of at least 98 wt. % based on the
total weight of the purified reaction product.
18. The purified reaction product of claim 15, comprising aluminum
in an amount of less than 50 ppb.
19. The purified reaction product of claim 15, wherein the metal
hydride compound comprises diisobutylaluminum hydride (DIBAH).
20. The purified reaction product of claim 15, wherein purifying
the reaction product comprises distilling the reaction product to
give the purified reaction product.
21. The purified reaction product of claim 20, wherein distilling
the reaction product prepares a crude reaction product comprising
the pentachlorodisilane, wherein the pentachlorodisilane is further
formed by purifying the crude reaction product to give the purified
reaction product.
22. The purified reaction product of claim 21, wherein purifying
the crude reaction product comprises fractionally distilling the
crude reaction product to give the purified reaction product.
23. The purified reaction product of claim 20, wherein distilling
the reaction product is carried out at a reduced pressure and an
elevated temperature.
24. The purified reaction product of claim 23, wherein: (i) the
reduced pressure is from greater than 0 to 50 Torr; (ii) the
elevated temperature is from 70 to 90.degree. C.; or (iii) both (i)
and (ii).
25. The purified reaction product of claim 15, wherein: (i) the
hexachlorodisilane and metal hydride compound are utilized in a
molar ratio of from 1:0.01 to 1:3; (ii) the forming of the
pentachlorodisilane is carried out in the absence of any solvent;
(iii) partially reducing the hexachlorodisilane is carried out at
an elevated temperature; (iv) purifying the reaction product
comprises a plurality of purification steps; or (v) any combination
of (i) to (iv).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and all advantages of
U.S. Provisional Application No. 62/538,858, filed on 31 Jul. 2017,
the content of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a method of
preparing pentachlorodisilane and, more specifically, to a method
of preparing a purified reaction product comprising
pentachlorodisilane with excellent yield and conversion and to the
purified reaction produced formed thereby.
DESCRIPTION OF THE RELATED ART
[0003] Silane compounds are known in the art and utilized in
diverse end use applications. For example, silane compounds may be
utilized to prepare organopolysiloxanes, e.g. silicone polymers or
resins. Alternatively, silane compounds are ubiquitously utilized
in the electronics industry. For example, silane compounds are
utilized to form thin films via deposition (e.g. chemical vapor
deposition, atomic layer deposition, etc.). The thin films may
comprise crystalline silicon, or silica (SiO.sub.2), depending on a
selection of the silane compound utilized. Typically, such silane
compounds include silicon-bonded hydrogen atoms (silicon hydride)
and/or silicon-bonded halogen atoms.
[0004] One such example of a silane compound is
pentachlorodisilane. However, pentachlorodisilane is difficult to
synthesize and expensive to otherwise obtain. For example, one
technique for synthesizing pentachlorodisilane involves
oligomerizing a monosilane (e.g. SiCl.sub.4) in the presence of
hydrogen (H.sub.2). Another technique involves cleaving
silicon-silicon bonds in higher order silane compounds (e.g. tri-
or higher order silane compounds). However, such techniques require
significant energy and/or expensive starting reagents.
SUMMARY OF THE INVENTION
[0005] The present invention provides a method of preparing
pentachlorodisilane. The method comprises partially reducing
hexachlorodisilane with a metal hydride compound to give a reaction
product comprising pentachlorodisilane. The method further
comprises purifying the reaction product to give a purified
reaction product comprising the pentachlorodisilane.
[0006] The purified reaction product comprising pentachlorodisilane
formed in accordance with the method is also provided.
DETAILED DESCRIPTION OF THE INVENTION
[0007] A method of preparing pentachlorodisilane is disclosed. The
pentachlorodisilane is prepared in a purified reaction product and
may be utilized in diverse end use applications. For example, the
pentachlorodisilane may be utilized as a starting component when
preparing organopolysiloxanes, e.g. via cohydrolysis and
co-condensation. Alternatively or in addition, the
pentachlorodisilane may be utilized for deposition, e.g. of a
silicon (including polysilicon or monosilicon) or silica film.
[0008] The method comprises partially reducing hexachlorodisilane
with a metal hydride compound to give a reaction product comprising
pentachlorodisilane. Partially reducing hexachlorodisilane with the
metal hydride compound generally comprises combining the
hexachlorodisilane and the metal hydride compound. Combining the
hexachlorodisilane and the metal hydride compound may also be
referred to as contacting the hexachlorodisilane and the metal
hydride compound. Said differently, there is no proactive step
required for partial reduction beyond combining the
hexachlorodisilane and the metal hydride compound.
[0009] By "partially reducing," it is meant that hexachlorodisilane
is partially reduced by the metal hydride compound to give
pentachlorodisilane, as compared to fully reducing
hexachlorodisilane to disilane. More specifically, partial
reduction refers to but one of the six silicon-bonded chlorine
atoms being replaced by or otherwise substituted with a
silicon-bonded hydrogen atom, thereby reducing the parent disilane
(i.e., hexachlorodisilane) once to give the pentachlorodisilane.
Partial reduction in the inventive method is limited to but one of
the six silicon-bonded chlorine atoms to give the
pentachlorodisilane. Any of the six silicon-bonded chlorine atoms
may be replaced with silicon-bonded hydrogen via the inventive
method; for example, the pentachlorodisilane may be represented by
HCl.sub.2Si*SiCl.sub.3 and/or Cl.sub.3Si*SiCl.sub.2H. As described
below, partial reduction of the hexachlorodisilane may result in
byproducts in the reaction product other than pentachlorodisilane.
For example, the reaction product may also include
tetrachlorodisilanes, trichlorodisilanes, etc. As is also described
below, the reaction product is purified in the inventive method so
as to minimize and/or eliminate such byproducts from the reaction
product, thereby giving the purified reaction product comprising
the pentachlorodisilane.
[0010] The invention has technical and non-technical advantages.
One of the problems solved by the processes is providing, relative
to conventional processes, improved processes of making the
pentachlorodisilane. For example, the inventive method typically
prepares pentachlorodisilane in higher purity, higher yield,
greater selectivity, or a combination of any two or more thereof,
than conventional processes. Moreover, the inventive method can be
scaled up for high volume production of pentachlorodisilane at low
cost, particularly as compared to conventional processes.
[0011] As understood in the art, hexachlorodisilane has the formula
Cl.sub.3SiSiCl.sub.3. Hexachlorodisilane may be synthesized,
prepared, or otherwise obtained. For example, hexachlorodisilane
may be synthesized via chlorination of calcium silicide
(CaSi.sub.2). Hexachlorodisilane is also commercially available
from numerous suppliers.
[0012] The metal hydride compound may comprise any metal hydride
compound capable of partially reducing the hexachlorodisilane to
give pentachlorodisilane. Metal hydride compounds suitable for the
purposes of the present invention include, but are not limited to,
hydrides of sodium, magnesium, potassium, lithium, boron, calcium,
titanium, zirconium, and aluminum, metal hydride compounds
including at least one of these same metals, and any combinations
thereof. The metal hydride compound can be a simple (binary) metal
hydride compound or a complex metal hydride compound. The metal
hydride compound may also include elements, atoms, or substituents
other than metal and hydrogen. For example, the metal hydride
compound may include substituted or unsubstituted hydrocarbyl
groups, heteroelements, etc.
[0013] In certain embodiments, the metal hydride compound is
selected from diisobutylaluminum hydride (DIBAH), dimethylaluminum
hydride, diethylaluminum hydride, di(n-propyl)aluminum hydride,
diisopropylaluminum hydride, di(n-butyl)aluminum hydride,
di(sec-butyl)aluminum hydride, di(tert-butyl)aluminum hydride,
di(n-pentyl)aluminum hydride, di(iso-pentyl)aluminum hydride,
di(sec-pentyl)aluminum hydride, di(3-pentyl)aluminum hydride,
di(tert-pentyl)aluminum hydride, di(neo-pentyl)aluminum hydride,
isomers of dihexylaluminum hydrides, isomers of diheptylaluminum
hydrides, isomers of dioctylaluminum hydrides, isomers of
dinonylaluminum hydrides, isomers of didecylalumminum hydrides,
alkylaluminum dihydrides, sodium
bis(2-methoxyethoxy)aluminumhydride (e.g. Vitride, Red-Al, etc.),
aluminum hydride, lithium hydride, sodium hydride, sodium
borohydride, lithium aluminum hydrides (including, for example,
LiAl(OtBu).sub.3H or LiAl(iBu).sub.2(OtBu)H, where tBu is
tert-butyl and iBu is isobutyl), sodium aluminum hydride, lithium
borohydride, magnesium hydride, magnesium borohydride, calcium
hydride, titanium hydride, zirconium hydride, tetramethylammonium
borohydride, potassium borohydride, etc. Combinations of different
metal hydride compounds or combinations of metal hydride compounds
with trialkylaluminum compounds may be utilized in concert. Any
alkyl groups may be independently selected from, for example,
methyl, ethyl and isomeric propyl, butyl, pentyl, hexyl, heptyl,
octyl, nonyl and/or decyl,
[0014] In specific embodiments, the metal hydride compound
comprises, alternatively consists essentially of, alternatively
consists of, diisobutylaluminum hydride (DIBAH).
[0015] It certain embodiments, the metal hydride compound is
disposed in a carrier vehicle, such as a solvent or dispersant. The
carrier vehicle, if present, may comprise an organic solvent. The
organic solvent can be an aromatic hydrocarbon such as benzene,
toluene, or xylene; an aliphatic hydrocarbon such as heptane,
hexane, or octane; a glycol ether such as propylene glycol methyl
ether, dipropylene glycol methyl ether, propylene glycol n-butyl
ether, propylene glycol n-propyl ether, or ethylene glycol n-butyl
ether, a halogenated hydrocarbon such as dichloromethane,
1,1,1-trichloroethane or methylene chloride; chloroform; dimethyl
sulfoxide; dimethyl formamide, acetonitrile; tetrahydrofuran; white
spirits; mineral spirits; naphtha; n-methyl pyrrolidone; or a
combination thereof.
[0016] When disposed in the carrier vehicle, the metal hydride
compound is typically present in the carrier vehicle in an amount
to provide from 1 to 99, alternatively from 10 to 80, alternatively
from 40 to 60, weight percent based on the combined weight of the
metal hydride compound and the carrier vehicle.
[0017] Methods of preparing metal hydride compounds are well known
in the art and many of these compounds are commercially available
from various suppliers.
[0018] The relative amount of the metal hydride compound utilized
may vary dependent upon the particular metal hydride compound
selected, the reduction parameters employed, etc. The molar ratio
of the metal hydride compound to the hexachlorodisilane utilized in
the partial reduction influences rates and/or amounts of conversion
to, and/or selectivity for, the pentachlorodisilane (i.e., as
compared to byproducts). Thus, the relative amounts of the metal
hydride compound and hexachlorodisilane, as well as the molar ratio
thereof, may vary. Typically, these relative amounts and the molar
ratio are selected to maximize a conversion rate and/or a
selectivity of partial reduction of the hexachlorodisilane to
pentachlorodisilane. For example, using a significant molar excess
of the metal hydride compound to the hexachlorodisilane may result
in an over reduction of the hexachlorodisilane to byproducts other
than pentachlorodisilane (e.g. tetrachlorodisilanes,
trichlorodisilanes, dichlorodisilanes, etc.), formation of other
byproducts, and/or decomposition of the hexachlorodisilane,
pentachlorodisilane, etc.
[0019] In certain embodiments, the molar ratio of the
hexachlorodisilane to the metal hydride compound is from 1:0.01 to
1:3, alternatively from 1:0.05 to 1:1.25, alternatively from 1:0.1
to 1:1.2, alternatively from 1:0.2 to 1:1.1, alternatively from
1:0.3 to 1:1, alternatively from 1:0.4 to 1:0.9, alternatively from
1:0.5 to 1:0.8.
[0020] Typically, partial reduction of the hexachlorodisilane to
prepare the reaction product comprising pentachlorodisilane is
carried out in a vessel or reactor. The hexachlorodisilane and the
metal hydride compound may be fed together or separately to the
vessel, or may be disposed in the vessel in any order of addition.
When partial reduction is carried out at an elevated temperature,
as described below, the vessel or reactor may be heated in any
suitable manner, e.g. via a jacket.
[0021] The hexachlorodisilane and the metal hydride compound may be
fed to the vessel sequentially over time or at once.
[0022] Parameters may be modified during partial reduction of the
hexachlorodisilane to prepare the reaction product comprising
pentachlorodisilane. For example, temperature, pressure, and other
parameters may be independently selected or modified during partial
reduction of the hexachlorodisilane to prepare the reaction product
comprising pentachlorodisilane. Any of these parameters may
independently be an ambient parameter (e.g. room temperature and/or
atmospheric pressure) and/or a non-ambient parameter (e.g. reduced
or elevated temperature and/or reduced or elevated pressure). Any
parameter may also be dynamic, modified in real time, i.e., during
the inventive method, or may be static.
[0023] In certain embodiments, partial reduction of the
hexachlorodisilane to prepare the reaction product comprising
pentachlorodisilane is carried out at an elevated temperature.
[0024] The elevated temperature is typically from greater than
ambient temperature (e.g. 22-25.degree. C.) to 150, alternatively
from 30 to 140, alternatively from 40 to 130, alternatively from 50
to 120, alternatively from 60 to 110, alternatively from 70 to 100,
alternatively from 75 to 95, alternatively from 80 to 90, .degree.
C.
[0025] The hexachlorodisilane and/or the metal hydride compound may
be independently heated and combined, combined and heated (prior
to, during, and/or after such combination), etc. In certain
embodiments, the hexachlorodisilane is heated to the elevated
temperature, and the metal hydride compound is combined with the
hexachlorodisilane at the elevated temperature. The
hexachlorodisilane and the metal hydride compound may be combined
simultaneously, incrementally, etc. The metal hydride compound may
be incrementally combined with the hexachlorodisilane compound over
time.
[0026] The hexachlorodisilane and the metal hydride compound
independently may be stored under an anhydrous condition (i.e.,
lacking water), under an inert atmosphere, or, typically, both,
i.e., an anhydrous inert atmosphere. The inert atmosphere is
typically a gas comprising molecular nitrogen, helium, argon, or a
mixture of any two or more thereof. Similarly, partial reduction of
the hexachlorodisilane to prepare the reaction product comprising
pentachlorodisilane may be carried out under an anhydrous condition
and/or under an inert atmosphere.
[0027] The method may further comprise agitating the
hexachlorodisilane and the metal hydride compound. The agitating
may enhance mixing and contacting together of the
hexachlorodisilane and the metal hydride compound when combined,
including in a reaction mixture thereof. Such contacting
independently may use other conditions, with (e.g. concurrently or
sequentially) or without (i.e., independent from, alternatively in
place of) the agitating. The other conditions may be tailored to
enhance the contacting, and thus reaction (i.e., partial
reduction), of the hexachlorodisilane so as to form the
pentachlorodisilane in a particular contacting step. Other
conditions may be result-effective conditions for enhancing
reaction yield or minimizing amount of a particular reaction
by-product included within the reaction product along with the
pentachlorodisilane.
[0028] The time during which partial reduction of the
hexachlorodisilane to prepare the reaction product comprising
pentachlorodisilane is carried out is a function of scale, reaction
parameters and conditions, selection of the metal hydride compound,
etc. In certain embodiments, the time during which partial
reduction of the hexachlorodisilane to prepare the reaction product
comprising pentachlorodisilane is carried out is from greater than
0 to 24 hours, alternatively from greater than 0 to 12 hours,
alternatively from greater than 0 to 6 hours, alternatively from
greater than 0 to 2 hours, after combining the hexachlorodisilane
and the metal hydride compound.
[0029] In certain embodiments, partial reduction of the
hexachlorodisilane to prepare the reaction product comprising
pentachlorodisilane is carried out in the absence of any carrier
vehicle or solvent. For example, no carrier vehicle or solvent may
be combined discretely with the hexachlorodisilane and/or the metal
hydride compound. In these or other embodiments, neither the
hexachlorodisilane nor the metal hydride compound is disposed in
any carrier vehicle or solvent such that no carrier vehicle or
solvent is present during partial reduction attributable to the
hexachlorodisilane and/or the metal hydride compound.
[0030] Alternatively, partial reduction may be carried out in the
presence of a carrier vehicle or solvent. Specific examples thereof
are introduced above with regard to potential carrier vehicles for
the metal hydride compound.
[0031] As introduced above, the reaction product may include
various byproducts from partially reducing the hexachlorodisilane.
These may include other reduced forms of hexachlorodisilane, e.g.
tetrachlorodisilanes, trichlorodisilanes, dichlorodisilanes, etc.,
residual and/or unreacted amounts of hexachlorodisilane and/or the
metal hydride compound, or degradation products thereof. The
reaction product typically also includes a metal chloride formed
from the metal hydride compound upon partial reduction of the
hexachlorodisilane. The metal chloride present in the reaction
product is generally a function of the metal hydride compound
utilized. For example, when the metal hydride compound comprises
diisobutylaluminum hydride, the metal chloride compound may
comprise diisobutylaluminum chloride. If partial reduction of
hexachlorodisilane is carried out in any carrier vehicle or
solvent, the reaction product typically also includes such carrier
vehicle or solvent. However, because the method is typically
carried out neat, i.e., in the absence of solvent, this is
typically not the case. The metal chloride is typically a liquid in
the reaction product.
[0032] The method further comprises purifying the reaction product
to give a purified reaction product comprising the
pentachlorodisilane. Any suitable technique for purification may be
utilized. Examples of suitable techniques include distilling,
evaporating, extracting, freeze drying, gas chromatography, ion
exchange chromatography, reverse phase liquid chromatography,
stripping, and/or volatilizing.
[0033] In certain embodiments, purifying the reaction product
comprises distilling the reaction product to give the purified
reaction product. In specific embodiments, distilling the reaction
product prepares a crude reaction product comprising the
pentachlorodisilane, and the method further comprises purifying the
crude reaction product to give the purified reaction product.
[0034] For example, the reaction product may be distilled upon
formation such that the crude reaction product is condensed and
collected. The crude reaction product has a higher content of the
pentachlorodisilane than does the reaction product. In certain
embodiments, the crude reaction product comprises the
pentachlorodisilane in an amount of from 5 to 70, alternatively
from 6 to 47, alternatively from 7 to 44, alternatively from 8 to
41, alternatively from 9 to 38, alternatively from 10 to 35,
alternatively from 11 to 32, alternatively from 12 to 29,
alternatively from 13 to 26, alternatively from 14 to 23,
alternatively from 15 to 20, weight percent based on the total
weight of the crude reaction product. The concentration of the
pentachlorodisilane in the crude reaction product may vary from the
ranges set forth herein. The concentration of the
pentachlorodisilane in the crude reaction product may be determined
via known methods, e.g. gas chromatography, optionally via a gas
chromatography-thermal conductivity detector.
[0035] Distilling the reaction product to prepare the crude
reaction product comprising the pentachlorodisilane is typically
carried out at (i) an elevated temperature; (ii) a reduced
pressure; or (iii) both an elevated temperature and reduced
pressure. By elevated or reduced, it is meant as compared to room
temperature and atmospheric pressure. As understood in the art, the
number of trays utilized in distillation may be optimized and may
influence a concentration or yield of the pentachlorodisilane. For
example, use of a greater number of trays via distillation may
increase the concentration or yield of the pentachlorodisilane in
the crude reaction product.
[0036] The elevated temperature is typically from greater than
ambient temperature to 150, alternatively from 30 to 140,
alternatively from 40 to 130, alternatively from 50 to 120,
alternatively from 60 to 110, alternatively from 70 to 100,
alternatively from 75 to 95, alternatively from 80 to 90, .degree.
C. The reduced pressure it typically operated as a vacuum, although
any reduced pressure between vacuum and atmospheric pressure may be
utilized. For example, the reduced pressure may be from greater
than 0 to 200, alternatively from greater than 0 to 100,
alternatively from greater than 0 to 90, alternatively from greater
than 0 to 80, alternatively from greater than 0 to 70,
alternatively from greater than 0 to 60, alternatively from greater
than 0 to 50, alternatively from greater than 0 to 40,
alternatively from greater than 0 to 30, alternatively from greater
than 0 to 20, alternatively from 5 to 15, Torr. The elevated
temperature may also differ from the ranges set forth above, e.g.
in the event the reaction product includes any carrier vehicle or
solvent.
[0037] The crude reaction product may be condensed and collected at
any suitable temperature. In certain embodiments, the crude
reaction product is condensed at a temperature of from 0 to 25,
alternatively from 0 to 20, alternatively from 0 to 15,
alternatively from 0 to 10, alternatively from 4 to 6. .degree.
C.
[0038] When the method further comprises purifying the crude
reaction product to give the purified reaction product, the crude
reaction product may be purified via any suitable technique. The
purification technique may be the same as or different from the
purification technique utilized to prepare the crude reaction
product from the reaction product. In certain embodiments,
purifying the crude reaction product to give the purified reaction
product comprises distilling the crude reaction product. In
specific embodiments, purifying the crude reaction product
comprises fractionally distilling the crude reaction product. The
description below associated with parameters of purifying the crude
reaction product apply whether distillation or fractional
distillation is utilized.
[0039] Like distilling the reaction product, distilling the crude
reaction product is typically carried out at (i) an elevated
temperature; (ii) a reduced pressure; or (iii) both an elevated
temperature and reduced pressure. By elevated or reduced, it is
meant as compared to room temperature and atmospheric pressure. As
introduced above and as understood in the art, the number of trays
utilized in distillation may be optimized and may influence a
concentration or yield of the pentachlorodisilane. For example, use
of a greater number of trays via distillation may increase the
concentration or yield of the pentachlorodisilane.
[0040] The elevated temperature is typically from greater than
ambient temperature to 150, alternatively from 30 to 140,
alternatively from 40 to 130, alternatively from 50 to 120,
alternatively from 60 to 110, alternatively from 70 to 100,
alternatively from 75 to 95, alternatively from 80 to 90, .degree.
C. The reduced pressure it typically operated as a vacuum, although
any reduced pressure between vacuum and atmospheric pressure may be
utilized. For example, the reduced pressure may be from greater
than 0 to 200, alternatively from greater than 0 to 100,
alternatively from greater than 0 to 90, alternatively from greater
than 0 to 80, alternatively from greater than 0 to 70,
alternatively from greater than 0 to 60, alternatively from greater
than 0 to 50, alternatively from greater than 0 to 40,
alternatively from greater than 0 to 30, alternatively from greater
than 0 to 20, alternatively from 5 to 15, Torr.
[0041] In certain embodiments, distillation of the crude reaction
product utilizes more trays or plates than distillation of the
reaction product. However, as understood in the art, the number of
trays or plates may be modified, and a feed location may also be
optimized or modified.
[0042] Typically, distillation of the crude reaction product
comprises a plurality of purification steps. For example,
distillation and/or fractional distillation may be repeated any
number of times to further concentrate the pentachlorodisilane in
the purified reaction product. The purified reaction product refers
to the final form of a composition resulting from any number of
purification steps to which the reaction product is subjected.
[0043] For example, distillation of the crude reaction product may
prepare a first concentrated reaction product. Distillation of the
first concentrated reaction product may then prepare a second
concentrated reaction product. Distillation of the second
concentrated reaction product may then prepare a third concentrated
reaction product. Each iteration of the reaction product is
distinguished from the prior iteration (i.e., the third
concentrated reaction product is distinguished from the second
concentrated reaction product, and the second concentrated reaction
product is distinguished from the first concentrated reaction
product) by virtue of a relative concentration of the
pentachlorodisilane in a particular concentrated reaction product,
as compared to other components (e.g. byproducts, starting
materials, etc.) therein. Specifically, the relative concentration
of the pentachlorodisilane (i.e., the purity) increases via each
iterative purification step. Each iterative purification step may
be independently selected.
[0044] Thus, to increase the concentration of the
pentachlorodisilane in the purified reaction product, purification
of the crude reaction product typically prepares the first
concentrated reaction product, and the first concentrated reaction
product is then further purified. In certain embodiments, the first
concentrated reaction product comprises the pentachlorodisilane in
an amount of from 20 to 83, alternatively from 22 to 80,
alternatively from 24 to 77, alternatively from 26 to 74,
alternatively from 28 to 71, alternatively from 30 to 68,
alternatively from 32 to 65, alternatively from 34 to 62,
alternatively from 36 to 59, alternatively from 38 to 56,
alternatively from 40 to 53, alternatively from 42 to 50, weight
percent based on the total weight of the first concentrated
reaction product. The concentration of the pentachlorodisilane in
the first concentrated reaction product may vary from the ranges
set forth herein. For example, distillation of the crude reaction
product could involve additional trays or plates could be utilized
in an effort to provide further purification in a single
purification step.
[0045] The concentration of the pentachlorodisilane in the first
concentrated reaction product may be determined via known methods,
e.g. gas chromatography, optionally via a gas
chromatography-thermal conductivity detector.
[0046] While each iterative purification step may be independently
selected, in certain embodiments, each iterative purification step
comprises distillation. Even in this embodiments, parameters
associated with distillation (e.g. the elevated temperature and/or
the reduced pressure) may be independently selected via each
iterative distillation step. Typically, however, each iterative
distillation step utilizes the parameters identified above relative
to the elevated temperature and the reduced pressure.
[0047] In certain embodiments, the method comprises at least 1,
alternatively at least 2, alternatively 3, iterative distillation
steps subsequent to preparing the crude reaction product comprising
the pentachlorodisilane to give the purified reaction product
comprising the pentachlorodisilane. However, the method is not so
limited, any number of iterative distillation steps, or iterative
purification steps, may be utilized. The number of iterative
distillation steps, or iterative purification steps, is typically
contingent on a desired concentration of the pentachlorodisilane in
the purified reaction product.
[0048] Any number of individual reaction products, crude reaction
products, or concentrated reaction products may be combined to form
a batch. In certain embodiments, a number of independently prepared
crude reaction products are combined to form a batch of crude
reaction product. The batch of crude reaction product is then
purified according to the present method to give the
pentachlorodisilane.
[0049] In certain embodiments, the purified reaction product
comprises the pentachlorodisilane in an amount of at least 50,
alternatively at least 55, alternatively at least 60, alternatively
at least 65, alternatively at least 70, alternatively at least 75,
alternatively at least 80, alternatively at least 81, alternatively
at least 82, alternatively at least 83, alternatively at least 84,
alternatively at least 85, alternatively at least 86, alternatively
at least 87, alternatively at least 88, alternatively at least 89,
alternatively at least 90, alternatively at least 91, alternatively
at least 92, alternatively at least 93, alternatively at least 94,
alternatively at least 95, alternatively at least 96, alternatively
at least 97, alternatively at least 97.5, alternatively at least
98, wt. % based on the total weight of the purified reaction
product. Dependent on a number of iterative purification steps, the
concentration of the pentachlorodisilane in the purified reaction
product may be 100, alternatively 99.9999999, alternatively
99.999999, alternatively 99.99999, alternatively 99.9999,
alternatively 99.999, alternatively 99.99, alternatively 99.9,
alternatively 99.0, wt. %.
[0050] In addition to the byproducts that may be present in the
reaction product, crude reaction product, and/or purified reaction
product, various trace metals may also be present in any of these
reaction products, including the purified reaction product. Such
trace metals may be attributable to the metal hydride compound
utilized or other sources, e.g. trace metals from preparing the
hexachlorodisilane (for example if made via the Direct Process). By
way of example, in certain embodiments, the purified reaction
product comprises aluminum in an amount of less than 50 parts per
billion (ppb).
[0051] It is to be understood that the appended claims are not
limited to express and particular compounds, compositions, or
methods described in the detailed description, which may vary
between particular embodiments which fall within the scope of the
appended claims. With respect to any Markush groups relied upon
herein for describing particular features or aspects of various
embodiments, different, special, and/or unexpected results may be
obtained from each member of the respective Markush group
independent from all other Markush members. Each member of a
Markush group may be relied upon individually and or in combination
and provides adequate support for specific embodiments within the
scope of the appended claims.
[0052] Further, any ranges and subranges relied upon in describing
various embodiments of the present invention independently and
collectively fall within the scope of the appended claims, and are
understood to describe and contemplate all ranges including whole
and/or fractional values therein, even if such values are not
expressly written herein. One of skill in the art readily
recognizes that the enumerated ranges and subranges sufficiently
describe and enable various embodiments of the present invention,
and such ranges and subranges may be further delineated into
relevant halves, thirds, quarters, fifths, and so on. As just one
example, a range "of from 0.1 to 0.9" may be further delineated
into a lower third, i.e., from 0.1 to 0.3, a middle third, i.e.,
from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which
individually and collectively are within the scope of the appended
claims, and may be relied upon individually and/or collectively and
provide adequate support for specific embodiments within the scope
of the appended claims. In addition, with respect to the language
which defines or modifies a range, such as "at least," "greater
than," "less than," "no more than," and the like, it is to be
understood that such language includes subranges and/or an upper or
lower limit. As another example, a range of "at least 10"
inherently includes a subrange of from at least 10 to 35, a
subrange of from at least 10 to 25, a subrange of from 25 to 35,
and so on, and each subrange may be relied upon individually and/or
collectively and provides adequate support for specific embodiments
within the scope of the appended claims. Finally, an individual
number within a disclosed range may be relied upon and provides
adequate support for specific embodiments within the scope of the
appended claims. For example, a range "of from 1 to 9" includes
various individual integers, such as 3, as well as individual
numbers including a decimal point (or fraction), such as 4.1, which
may be relied upon and provide adequate support for specific
embodiments within the scope of the appended claims.
[0053] The following examples are intended to illustrate the
invention and are not to be viewed in any way as limiting to the
scope of the invention.
EXAMPLES
Example 1: Preparation of Pentachlorodisilane
[0054] Partial Reduction of Hexachlorodisilane: Hexachlorodisilane
(3.48 kg; 12.9 mol) is loaded into a 12 L jacketed reactor and then
heated to and held at a temperature of 80.degree. C. The contents
of the reactor is then maintained at a temperature between
80-90.degree. C. and agitated while a metal hydride compound
(DIBAH; 1.48 kg; 10.4 mol) is added over a period of 2 hours to
give a reaction mixture. The reaction mixture is agitated for 30
minutes in the reactor and then distilled through a 5-tray column
under vacuum to give a reaction product comprising
pentachlorodisilane (PCDS) (.about.3.2 kg; 16% PCDS via GC-TCD
integrations), which is then condensed through a cooled condenser
(5.degree. C.) and collected in a 3 L receiving flask. The reaction
product is then fractionally distilled under vacuum (down to 10
Torr) at 80.degree. C. pot temperature through a 20-tray column to
give a crude reaction product comprising pentachlorodisilane (PCDS)
(494 g; 46% PCDS via GC-TCD integrations).
[0055] Purification of the Crude Reaction Product Comprising
Pentachlorodisilane: The partial reduction of hexachlorodisilane
and subsequent distillation is repeated 18 times, and the resulting
crude reaction products are then combined together to give a
combined crude reaction product comprising pentachlorodisilane
(13.6 kg). The combined crude reaction product is then fractionally
distilled three times under vacuum (down to 10 Torr) at 80.degree.
C. pot temperature to give a purified reaction product comprising
pentachlorodisilane (PCDS) (2.8 kg; 98+% PCDS via GC-TCD). The
purified reaction product is then analyzed via ICP-MS at 10 ppb
detection limit for 23 metals to give a total trace metal content
of 89 ppb, including 10 ppb of Al.
[0056] The invention has been described in an illustrative manner,
and it is to be understood that the terminology which has been used
is intended to be in the nature of words of description rather than
of limitation. Obviously, many modifications and variations of the
present invention are possible in light of the above teachings. The
invention may be practiced otherwise than as specifically
described.
* * * * *