WO2019060475A2 - Synthèse d'organo-chlorosilanes à partir d'organosilanes - Google Patents

Synthèse d'organo-chlorosilanes à partir d'organosilanes Download PDF

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WO2019060475A2
WO2019060475A2 PCT/US2018/051845 US2018051845W WO2019060475A2 WO 2019060475 A2 WO2019060475 A2 WO 2019060475A2 US 2018051845 W US2018051845 W US 2018051845W WO 2019060475 A2 WO2019060475 A2 WO 2019060475A2
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general formula
reaction
process according
ether
chlorosilanes
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WO2019060475A3 (fr
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Norbert Auner
Tobias SANTOWSKI
Alexander G. STURM
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Momentive Performance Materials Inc.
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/0896—Compounds with a Si-H linkage
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/12—Organo silicon halides
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/12—Organo silicon halides
    • C07F7/121—Preparation or treatment not provided for in C07F7/14, C07F7/16 or C07F7/20
    • C07F7/123—Preparation or treatment not provided for in C07F7/14, C07F7/16 or C07F7/20 by reactions involving the formation of Si-halogen linkages

Definitions

  • the present invention relates to the production of chlorosilanes, in particular to the production of mono- and dichlorosilanes. More specifically, the invention relates to a process for the production of mono- and dichlorosilanes starting from hydridosilanes, and a process for the provision of such starting materials by hydrogenation of chlorosilanes.
  • Chlorosilanes are useful starting materials in synthetic organosilicon chemistry. They can be utilized in the synthesis of defined polysiloxanes, which generally find a wide range of applications, for instance for the manufacture of adhesives, sealants, mouldings, composites and resins for example in the fields of electronics, automotive, construction etc.
  • chlorosilanes having both Si-CI and Si-H bonds are highly valuable due to their bifunctional nature, which means they have functional groups of different reactivities.
  • the chloride ligand is a better leaving group than the hydride group and allows, for instance, the controlled addition of further monomeric or oligomeric siloxane units with retention of the Si-H bond under mild conditions, thereby rendering said chlorohydridosilanes useful as blocking and coupling agents in oligo- and polysiloxane synthesis.
  • Si-H moieties present in such chlorosilanes can be utilized for post-synthesis modifications and functionalisations, for instance for the introduction of organic residues to polyorganosiloxanes or for cross-linking by hydrosilylation reactions, which is desirable in various kinds of compositions containing polyorganosiloxanes.
  • Synthesis of functionalized polysiloxanes starting with transformations via the Si-H bond(s) followed by hydrolysis or alcoholysis of the Si-CI bond(s) and optionally condensation for the formation of polysiloxanes is also viable.
  • a common route for the production of chlorosilanes is the reaction of hydridosilanes with chlorinating agents, which are able to transform Si-H bonds to Si-CI bonds, such as e.g. chlorine, acyl chlorides, alkyl halides, phosphorous pentachloride, trichloroisocyanuric acid, transition metal complexes and organosilicon radicals.
  • chlorinating agents which are able to transform Si-H bonds to Si-CI bonds, such as e.g. chlorine, acyl chlorides, alkyl halides, phosphorous pentachloride, trichloroisocyanuric acid, transition metal complexes and organosilicon radicals.
  • JP 2004182681 A relates to a process for producing a triorganomonochlorosilane from a triorganomonohydrosilane by reacting the triorganomonohydrosilane with hydrochloric acid in the presence of a catalyst composed of a transition metal, its salt, its oxide or its complex. JP 2004 182681 does not teach to carry out the reaction with hydrogen chloride, which is different from hydrochloric acid, or in the absence of a metal catalyst.
  • WO 00/64909 A1 relates to a method for the preparation of organylchlorosilanes by reaction of hydrogen halide with silanes in the presence of a Lewis acid catalyst.
  • WO 00/64909 A1 states that solvents that reduce the Lewis acidity of the catalyst, such as ethers or alcohols, or lead to side reactions, such as benzene, are unsuitable for the halogenation reaction according to the invention. Therefore WO 00/64909 A1 does not teach the production of organochlorosilanes by subjecting hydridosilanes to the reaction with hydrogen chloride in an ether compound.
  • US 5312949 relates to a method for preparation of tnorganochlorosilane by the reaction of hydrogen chloride with triorganohydrosilane in the presence of a Group 8 transition metal or complex thereof.
  • the reaction is generally run without the use of a solvent.
  • organochlorosilanes by subjecting hydridosilanes to the reaction with hydrogen chloride in an ether compound, leaving alone in the absence of a metal catalyst.
  • TOEGEL D ET AL "Formation of organosilicon compounds 1 15: the applicability as precursors for beta-SiC of carbosilanes resulting from the gas phase pyrolysis of methylsilanes", JOURNAL OF ORGANOMETALLIC CHEMISTRY, ELSEVIER-SEQUOL LAUSANNE, CH, vol. 521 , no. 1 , 23 August 1996 (1996-08-23), pages 125-131 ;
  • STANLEY TANNENBAUM ET AL "Synthesis and Properties of Some Alkylsilanes", JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 75, no.
  • KALLANE ET AL "Activation of Si-Si and Si-H Bonds at a Platinum Bis(diphenylphosphanyl)ferrocene (dppf) Complex: Key Steps for the Catalytic Hydrogenolysis of Disilanes" relate to the manufacture of hydridosilanes.
  • PhSiH 2 CI can be obtained from PhSiH 3 by reaction with Et 2 0/HCI using AICI 3 as chlorination catalyst (Chem. Ber. 123 (1990) 2087-2091). It should be noted that AICI 3 is considered to have detrimental effects in organosilicon chemistry, as it is difficult to separate from product mixtures and catalyzes redistribution reactions of silanes.
  • organosilicon hydrides and organosilicon compounds containing both Si- H and Si-CI bonds from organosilicon halides, in particular, organosilicon chlorides, is also known in the art:
  • US 5,455,367 discloses a method for the synthesis of hydrido organosilanes by the reduction of organosilicon chlorides with MgH 2 in an ether solvent and the parallel use of ultrasound or mechanical energy (e. g. ball milling) to remove the magnesium halide from the MgH 2 particles.
  • Synthesis of dimethylsilane is illustrated in Example 1 of the document.
  • the mono-, di- and trihydrogenation of organochlorosilanes with LiH in ethers, e.g. tetrahydrofurane (THF), dimethoxyethane (DME) and bis(2-methoxyethyl) ether (diglyme), in high yields was reported by Kornev and Semenov (Metallorg. Khim 4 (1991) 4, 860-863).
  • LiH can be prepared by the reaction of sodium hydride and lithium chloride following the reaction equation
  • Metal hydrides such as LiH, MgH2 and NaBH4 are expensive materials. Disposal of the corresponding metal chlorides (e.g. LiCI and MgCI 2 ) after one use is costly, wasteful and unsustainable.
  • Prior art processes for the synthesis of hydridosilanes via reduction with metal hydrides provide no teaching about recovery of the metal chlorides and recycle to the metal hydrides for use in future synthesis of hydridosilanes. The instant application recognizes this as a problem to be solved.
  • the problem to be solved by the present invention is the provision of a process for the production of mono- and dichloroorganosilanes from hydridosilanes.
  • the invention also addresses the provision of an improved process for the production of hydridosilanes serving as starting materials in the above-stated process by hydrogenation of appropriate chlorosilanes.
  • this invention addresses the recovery and purification of the metal chlorides generated during the hydrogenation, use of the purified salts for production of the metals, conversion of the metals to metal hydrides and their reuse in future hydrogenation of organosilicon chlorides.
  • the present invention relates to a process for the production of mono- and dichloroorganosilanes starting from hydridoorganosilanes, and a process for the provision of such hydridoorganosilanes.
  • the present invention provides a process for the production of chlorosilanes of the general formula (I)
  • R is an organyl group, which can be the same or different, and the organyl group is selected from linear or branched alkyl, aryl, linear or branched alkenyl, linear or branched alkynyl, aralkyl, aralkenyl, aralkynyl, alkaryl, alkenylaryl, alkynylaryl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, cycloaralkynyl, cycloalkaryl, cycloalkenylaryl, cycloalkynylaryl, linear or branched alkoxy, aryloxy and organosiloxy (cyclic and acyclic) groups, preferably alkyl, alkenyl and aryl, x is 0, 1 , 2 or 3, preferably 1 or 2,
  • y is 0, 1 , 2 or 3, preferably 1 or 2,
  • R is as defined above
  • n 1 , 2, 3, or 4
  • x 0, 1 , 2 or 3
  • m + x is 4, to the reaction with hydrogen chloride in the presence of at least one ether compound in the absence of Lewis acid compounds containing a metal atom from group 13 of the periodic table (boron group, including the metals B, Al, Ga, In, and Tl), such as B(C 6 F 5 )3 and AICI 3 , and preferably in the absence of a metal-containing catalyst and
  • the optional step of separating the resulting chlorosilanes of formula (I) refers to any technical means applied to raise the content of one or several chlorosilanes according to the general formula (I) in a product mixture, or which results in the separation of single compounds of the formula (I) from a product mixture obtained in step A) of the process according to the invention.
  • Lewis acid compounds containing a metal atom from group 13 relates to a Lewis acid compound containing an element of group 13 of the periodic table (boron group).
  • a Lewis acid is generally a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct.
  • the term "in the absence of Lewis acid compounds containing a metal atom from group 13 of the periodic table” intends to mean that any of those Lewis acid compounds or mixtures thereof are essentially absent in step A).
  • the absence of Lewis acid compounds containing a metal atom from group 13 also excludes the presence of any adducts with Lewis bases thereof, in particular the etherates thereof.
  • Essentially absent shall mean that non-functional contents of Lewis acid compounds containing a metal atom from group 13 such as impurities e.g. in a range of less than 100 ppm or less than 10 ppm based on the silane educts preferably are not excluded.
  • B(C6F 5 )3 and AICI3 are not detectable analytically in the reaction mixture of step A). It was surprising that the chlorination of the hydridosilanes was possible without such Lewis acid compounds containing a metal atom from group 13, acting as a metal containing catalyst.
  • step A) is carried out in the absence of any metal-containing catalyst, such as Lewis acid compounds, such as the Lewis acid compounds containing a metal atom from group 13.
  • the absence of any metal-containing catalyst shall intend to mean the essential absence of any metal containing compound that acts as a catalyst in the chlorination reaction, such as of Lewis acid compounds containing a metal atom from group 13, e.g. aluminum-containing catalysts, such as AICI 3 , boron-containing catalysts such as boron halides, organic boron compound, such as triorganyl boron, such as triaryl boron, e.g. B(C 6 H 5 )3 or B(C 6 F 5 )3 and ether adducts thereof.
  • the process of the invention is carried out in the essential absence of any metal-containing compound (except silicon of course).
  • Essential means that non-functional contents of metal-containing catalysts or metal containing compounds, such as impurities e.g. in a range of less than 100 ppm or less than 10 ppm based on the silane educts preferably are not excluded. Preferably any metal- containing catalysts or metal containing compounds are not detectable analytically.
  • organic group shall mean any monovalent organic group, which is bonded to silicon via a carbon atom, selected from linear or branched alkyl, aryl, linear or branched alkenyl, linear or branched alkynyl, aralkyl, aralkenyl, aralkynyl, alkaryl, alkenylaryl, alkynylaryl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, cycloaralkynyl, cycloalkaryl, cycloalkenylaryl, cycloalkynylaryl, linear or branched alkoxy, aryloxy and organosiloxy (cyclic and acyclic) groups, preferably alkyl, alkenyl and aryl.
  • the groups R are independently selected from above mentioned organyl groups, which means they can be the same or different.
  • the number of carbon atoms of an R group substituent is preferably in the range of up to about 30, preferably in the range of up to about 20, more preferably in the range of up to about 15, and most preferably in the range of up to about 6, specifically in the range of about 1 to about 30, preferably in the range of about 1 to about 20, more preferably in the range of about 1 to about 15 and most preferably in the range of about 1 to about 6.
  • ether compound shall mean any organic compound containing an ether group -0-, in particular of formula R 1 -O-R 2 , wherein Ri and R 2 are independently selected from an organyl group as defined herein above.
  • Ri and R 2 are substituted or unsubstituted linear or branched alkyl groups or aryl groups, which may have further heteroatoms such as oxygen, nitrogen, or sulfur.
  • Ri and R 2 can constitute together an optionally substituted alkylene or arylene group, which may have further heteroatoms such as oxygen, nitrogen, or sulfur.
  • the ether compounds can be symmetrical or asymmetrical with respect to the substituents at the ether group -0-.
  • the organyl group or group R of the chlorosilanes of the general formula (I) is selected from linear or branched alkyl, aryl, linear or branched alkenyl, linear or branched alkynyl, aralkyl, aralkenyl, aralkynyl, alkaryl, alkenylaryl, alkynylaryl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, cycloaralkynyl, cycloalkaryl, cycloalkenylaryl, cycloalkynylaryl, linear or branched alkoxy, aryloxy and organosiloxy (cyclic and acyclic) groups, preferably alkyl, alkenyl and aryl groups.
  • R is selected from methyl, vinyl and phenyl.
  • the ether compound is selected from ether compounds that absorb or dissolve hydrogen chloride.
  • HCI hydrogen chloride
  • hydrochloric acid is an aqueous solution of hydrogen chloride, and which accordingly is not covered by the term hydrogen chloride.
  • the term of absorbing or absorption refers to the process of one material (absorbate), in this case hydrogen chloride, being retained by another (absorbent), in this case the ether compound.
  • the term of dissolving or dissolution refers to the mixing of two phases with the formation of one new homogeneous phase, which in this case is a solution of hydrogen chloride in the ether compound.
  • the ether compound is selected from the group consisting of linear and cyclic ether compounds.
  • a cyclic ether compound according to the invention is a compound in which one or more ether groups are included in a ring formed by a series of atoms, such as for instance tetrahydrofurane, tetrahydropyrane or 1 ,4-dioxane, which can be substituted e.g. by alkyl groups.
  • the ether compound selected from the group consisting of linear and cyclic ether compounds is an aliphatic compound.
  • the ether compound is selected from the group consisting of diethyl ether, di-n-butyl ether, diethylene glycol dimethyl ether (diglyme), tetraethylene glycol dimethyl ether (tetraglyme), and dioxane, preferably 1 ,4-dioxane, 2-methyltetrahydrofurane, tetrahydrofurane, tetrahydropyrane and dimethoxy ethane.
  • the ether compound is selected from the group consisting of diethyl ether, di-n-butyl ether, 1 ,4-dioxane, tetraethylene glycol dimethyl ether (tetraglyme) and diethylene glycol dimethyl ether (diglyme), preferably the ether compound is 1 ,4-dioxane or diethylene glycol dimethyl ether.
  • the hydrogen chloride / diglyme reagent shows a higher chlorination activity compared to the hydrogen chloride / diethyl ether reagent, while the combination hydrogen chloride / di-n- butyl ether decelerates the speed of chlorination.
  • the reaction step A) is conducted at a temperature of about -50 °C to about 140 °C, preferably about 0 to about 100 °C, more preferably about 20 °C to about 80 °C.
  • the reaction temperature according to the invention is the temperature of the reaction mixture, i.e. the temperature measured inside the reaction vessel in which the reaction is conducted.
  • the monochlorination of organodi- and trihydridosilanes of formula (II) with hydrogen chloride/ether reagents already occurs at low temperature, e.g. at about -40 °C under H2 release, but the reaction times are long.
  • Increasing the reaction temperatures to about 20 °C and higher accelerates chlorination.
  • double chlorination at the silicon center takes place to yield dichlorosilanes RSiHC or
  • reaction temperatures in some cases also supports formation of side products, such as siloxanes R2(H)Si-0-Si(H)R2, or ether cleavage to give alkoxysilanes.
  • the optimal reaction temperature therefore is dependent on the solvent used and further process parameters, such as concentration of reagents and reaction pressure.
  • the reaction vessel can be an ampoule, a sealed tube, a flask or any kind of chemical reactor, without being limited thereto.
  • the chlorination reaction is carried out in a suitably sized reactor made of materials, such as glass or Hastelloy C, which are resistant to corrosion by chlorides.
  • the molar concentration of hydrogen chloride in the ether compound applied in reaction step A) is at least about 0.1 mol/l, preferably at least about 0.5 mol/l, more preferably at least about 1.0 mol/l, even more preferably at least about 3 mol/l, but most preferably about 5 to about 12 mol/l.
  • the solutions of hydrogen chloride in ether compounds can be prepared by passing gaseous HCI into the respective ether compound, the molarity of the solution can be determined by measuring the increase in mass following the dissolution or absorption of hydrogen chloride, or by titration of the HCI with a base, e.g. sodium hydroxide (NaOH).
  • step A) is carried out with an ether compound saturated with hydrogen chloride.
  • saturated refers to a saturated solution of hydrogen chloride in the ether compound applied, and is defined as a solution which has the same concentration of a solute as one that is in equilibrium with undissolved solute at specified values of the temperature and pressure.
  • a solution being close to the state of saturation is also comprised by the term "saturated”.
  • saturated solution can be prepared by passing gaseous hydrogen chloride into the corresponding ether compound (e.g. diethyl ether, di-n-butyl ether, 1 ,4-dioxane, diglyme, tetraglyme) at about 5 to about 10 °C.
  • step A) is carried out with diglyme saturated with hydrogen chloride, diethyl ether saturated with hydrogen chloride, di-n-butyl ether saturated with hydrogen chloride or 1 ,4-dioxane saturated with hydrogen chloride.
  • the saturation of the ether compounds with hydrogen chloride is performed as described above, by passing gaseous hydrogen chloride into the respective ether compound.
  • step A) is carried out at a pressure of about 1 bar to about 30 bar, more preferably at about 1 bar to about 20 bar, and most preferably at about 1 bar to about 10 bar.
  • the indicated pressure ranges refer to the pressure measured inside the reaction vessel used when conducting reaction step A).
  • step A) the molar ratio of hydrogen chloride to hydridosilanes of the general formula (II) is at least about 1 : 1 , more preferably in the range of about 1 : 1 to about 10: 1 .
  • n HCI added to the mixture of reaction step A
  • n hydroidosilanes of the general formula (II)
  • step A) the weight ratio of hydridosilanes of the general formula (I I) to the ether compound used is less than about 1 :2, preferably in the range of about 1 :2 to 1 :20.
  • the weight ratio is defined as m (hydridosilanes of the general formula (II)) / m (ether compound).
  • step A) all compounds being hydridosilanes of the general formula (II) submitted to the reaction step (A) are considered, regardless if they are submitted as a part of a mixture comprising other compounds, in particular silanes, which do not fall under the general formula (II). Furthermore, the mass of any ether compound according to above definition of the term "ether compound" present in the reaction mixture submitted to reaction step (A) is considered in the determination of the weight ratio.
  • the weight ratio of hydrogen chloride to the ether compound used is less than about 1 :2, preferably in the range of about 1 :2 to about 1 :30.
  • the weight ratio is defined as m (hydrogen chloride) / m (ether compound).
  • the chlorosilanes of the general formula (I) have at least one group R, that is x is 1 , 2 or 3, preferably x is 1 or 2, more preferably x is 2.
  • R is an organyl group as defined above.
  • the residues may be the same or different from each other.
  • one compound of formula (I), or a mixture of more than one compound of formula (I) can be formed.
  • mixtures of more than one compound of the formula (I) are formed.
  • chlorosilanes of the general formula (I) are selected in particular from the compounds:
  • the chlorosilanes of the general formula (I) are selected from the compounds Me2SiHCI, MeSiH 2 CI, and MeSiHCb, and mixtures thereof.
  • Particular preferred starting materials of the general formula (II) comprise one or more of the compounds selected from Me 2 SiH 2 , MeSiH 3 , Ph 2 SiH 2 , PhSiH 3 , MeViSiH 2 , and MePhSiH 2 , preferably Me 2 SiH 2 , MeSiH 3 and mixtures thereof.
  • the present invention includes also the process where a substrate is reacted which comprises one or more hydridosilanes of the general formula (II), e.g. in admixture with other silanes not covered by general formula (II).
  • step A) is carried out in the presence of at least one alcohol.
  • alcohol is formed by ether cleavage, which apparently acts as a catalyst for the chlorination reaction.
  • This could be subsequently confirmed in experiments adding alcohols to the reaction mixture of step A), which leads to an acceleration of the chlorination reaction. It was surprising to observe no substantial formation of alkoxysilanes and siloxanes and to see the catalytic effect of the alcohol on the chlorination reaction.
  • Preferred alcohols include aliphatic or aromatic, monohydric or polyhydric, optionally substituted alcohols having up to preferably about 20 carbon atoms, more preferred are saturated, optionally substituted, mono- or polyhydric alcohols, such as optionally substituted (C1 -C6) linear, branched or cyclic alkanols, which optionally may have one to three substituent groups, such as halogen atoms, alkoxy groups (leading to ether linkage again).
  • optionally substituted (C1 -C6) linear, branched or cyclic alkanols which optionally may have one to three substituent groups, such as halogen atoms, alkoxy groups (leading to ether linkage again).
  • Preferred alcohols include: monohydric alcohols, such as methanol, ethanol, propan-2-ol, propan- 1 -ol, butan- 1 -ol, pentan- 1 -ol, hexan-1 -ol, 2-(2-chloroethoxy)ethanol etc., polyhydric alcohols such as ethane- 1 ,2-diol, propane- 1 ,2-diol, propane-1 ,2,3-triol, unsaturated aliphatic alcohols such as prop-2-ene-1 -ol, alicyclic alcohols, such as cyclohexanol etc. Most preferred are sterically hindered alcohols such as 2-(2- chloroethoxy)ethanol.
  • the preferred amounts of alcohols are in the range of about 0.01 to about 5 mol, preferably about 0.05 to about 2 mol of the alcohol based on one mol of the hydridosilanes of the general formula (I I) .
  • step A) is carried out in a reactor resistant to chloride-induced corrosion by injection of one or several separated hydridosilanes of the general formula (I I) in gaseous or liquid state into an agitated solution of HCI dissolved in an ether solvent. Provision can be made to add HCI continuously or intermittently into the reaction mixture to effect the desired conversion of Si-H bonds to Si-CI bonds.
  • the reactor used is optionally baffled.
  • step A) is carried out in a reactor resistant to chloride-induced corrosion by injection of one or several of the hydridosilanes of the general formula (I I) at the base of a column containing HCI dissolved in an ether solvent so that reaction can occur as the bubbles rise up the column.
  • the column is optionally packed to improve gas liquid mass transfer and facilitate the desired conversion of Si-H bonds to Si-CI bonds.
  • step A) is performed by bringing into contact a solution of hydridosilanes of the general formula (I I) in ether solvent with one of HCI in ether solvent by impingement or rapid mixing in an agitated vessel or static mixer, wherein the reactor used is resistant to chloride-induced corrosion.
  • the step B) of separating the resulting chlorosilanes of the formula (I) is carried out by distillation.
  • distillation in the sense of the present invention relates to any process for separating components or substances from a liquid mixture by selective evaporation and condensation. Therein, distillation may result in practically complete separation, leading to the isolation of nearly pure components, or it may be a partial separation that increases the concentration of selected components of the mixture.
  • the distillation processes which may constitute separation step B), can be simple distillation, fractional distillation, vacuum distillation, short path distillation or any other kind of distillation known to the skilled person.
  • the step B) of separating the chlorosilanes of the formula (I) according to the invention can comprise one or more batch distillation steps, or can comprise a continuous distillation process.
  • the process is performed under inert conditions.
  • the term "performed under inert conditions" means that the process is partially or completely carried out under the exclusion of surrounding air, in particular of moisture and oxygen.
  • surrounding air in particular of moisture and oxygen.
  • closed reaction vessels, reduced pressure and/or inert gases, in particular nitrogen or argon, or combinations of such means may be used.
  • the process of the invention is carried out in the presence of a Lewis base such as phosphanes R 1 3 P, amines R 1 3N , wherein R 1 is hydrogen or an organyl group R as defined above, and salts thereof with preferably coordinating anions, such as halogenides (e.g. CI " , Br), hydroxide (OH ), alkoxide (OR ), etc. such as HR3PCI, R 4 PCI, R 4 NCI, wherein R is preferably phenyl, alkyl, such as n-butyl.
  • a Lewis base such as phosphanes R 1 3 P, amines R 1 3N , wherein R 1 is hydrogen or an organyl group R as defined above, and salts thereof with preferably coordinating anions, such as halogenides (e.g. CI " , Br), hydroxide (OH ), alkoxide (OR ), etc.
  • a Lewis base such as phosphanes R 1 3 P,
  • R 1 3 P Phosphanes R 1 3 P, wherein R 1 is hydrogen or an organyl group and can be the same or different, preferably R 3 P, wherein R is as defined above and can be the same or different, such as PPh 3 , n-Bu 3 P and
  • R 1 3 N wherein R 1 is hydrogen or an organyl group and can be the same or different, preferably R 3 N, wherein R is as defined above and can be the same or different, such as n-Bu 3 N or NPh 3 and
  • the salts thereof with preferably coordinating anions are preferably coordinating anions.
  • the salts with preferably coordinating anions can be conveniently prepared in situ by the reaction of the phosphanes or amines e.g. with HCI in the presence of the ether compound. It has been found that the addition of such compounds (e.g. n-Bu 3 P) allows in particular the formation of dichlorinated silanes (such as MeSiHC ) and even trichlorinated silanes (such as MeSiC ) from organosilanes (MeSihh) in high yields under moderate conditions. Further it has been found that the addition of such compounds in general accelerates the chlorination, that is, also the formation of monochlorinated silanes.
  • dichlorinated silanes such as MeSiHC
  • MeSiC trichlorinated silanes
  • MeSihh organosilanes
  • the invention further relates to the process described above in which the hydndosilanes of the general formula (II) are prepared by the hydrogenation of the corresponding chlorosilanes.
  • RxSiHm (II), wherein x and m are as defined above, are prepared from the corresponding chlorosilanes of the general formula (III) RxSiClm (III) wherein x and m are as defined above, by hydrogenation of said chlorosilanes of the general formula (III).
  • hydrogenation is understood as substitution of one or more chloro substituents at the silicon atom of the chlorosilanes of the general formula (III) by one or more hydrogen atoms.
  • hydrogenation refers to the transformation of one or more Si-CI bonds to one or more Si-H bonds.
  • the hydrogenation is conducted by reacting the chlorosilanes of the general formula (III) with a hydride donor in the presence of an organic solvent.
  • a hydride donor is any compound being capable of providing hydride anions for the transformation of chlorosilanes of the formula (III) to hydndosilanes of the formula (II).
  • An organic solvent may be any organic compound which is in liquid state under reaction conditions and which is suitable as a medium for conducting the hydrogenation therein. Accordingly, the organic solvent is preferably inert to the hydride donors according to present invention under reaction conditions.
  • the hydride donor is selected from the group of metal hydrides.
  • metal hydride refers to any hydride donor containing at least one metal atom or metal ion.
  • the hydride donor is selected from the group of alkali metal hydrides, such as LiH, NaH, KH, alkaline earth metal hydrides, such as calcium hydride, or complex metal hydrides, such as LiAIH 4 and NaBH 4 .
  • complex metal hydrides refers to metal salts wherein the anions contain hydrides.
  • complex metal hydrides contain more than one type of metal or metalloid.
  • metalloid comprises the elements boron, silicon, germanium, arsenic, antimony, tellurium , carbon, aluminum, selenium, polonium , and astatine.
  • the organic solvent applied in the hydrogenation reaction can be any suitable organic solvent, and is preferably an ether compound or a mixture of solvents containing at least one ether compound.
  • ether compound is defined as stated above.
  • the organic solvent applied in the hydrogenation reaction is an ether compound selected from the group of diethyl ether, di-n- butyl ether, tetrahydropyrane, 1 ,4-dioxane, 1 ,2-dimethoxyethane, tetrahydrofurane, tetraethylene glycol dimethyl ether (tetraglyme) or diethylene glycol dimethyl ether (diglyme) , or mixtures thereof, without being limited thereto.
  • the hydride donor for the hydrogenation reaction is selected from LiAIH 4 , LiH, CaH 2 or LiH which is formed in situ by admixture of LiCI and NaH and subsequent heating of said mixture to a temperature in the range of about 60 °C to about 200 °C, preferably in the range from about 80 to about 160 °C, more preferably in the range from about 100 to about 160 °C, and most preferably in the range from about 120 to about 160 °C.
  • an amount of one or more hydride donors providing about 100 to about 120 mol- % of hydride anions in relation to the chloro substituents in the chlorosilanes of general formula (I I I) is applied in the hydrogenation step.
  • LiH for the application as hydride donor in the hydrogenation reaction is formed in situ, up to about 1000 % excess of NaH in relation to LiCI, more preferably about 5 to about 400 mol-% excess of NaH, and most preferably about 10 to about 200 mol-% excess of NaH are mixed and heated with LiCI in order to form LiH in situ.
  • LiCI serves as a hydride acceptor, as it is able to accept hydride ions from NaH, forming LiH. At the same time, the LiH formed in situ donates hydride ions for the reduction of Si-CI bonds, whereby LiCI is regenerated. Accordingly, LiCI acts as a catalyst in the hydrogenation reaction with a stoichiometric amount of NaH. This implies that LiCI can be applied in stoichiometric amounts, substoichiometric amounts or catalytic amounts in the process.
  • the reaction temperature in the hydrogenation step is about -70 °C to about 160 °C, preferably about -50°C to 100 °C, more preferably about -30°C to about 50 °C, and most preferably about 0°C to about 25 °C.
  • the reaction temperature according to the invention is the temperature of the reaction mixture, i.e. the temperature measured inside the reaction vessel in which the reaction is conducted.
  • Such measurement can be performed by any means common in the art, for instance by various kinds of temperature sensors, or thermometers including infrared thermometers.
  • the reaction temperature is set by immersion of the reaction vessel into a heating or cooling medium, e.g. an ice bath, a water bath or an oil bath
  • a heating or cooling medium e.g. an ice bath, a water bath or an oil bath
  • the reaction vessel can be an ampoule, a sealed tube, a flask or any kind of chemical reactor, without being limited thereto.
  • the hydrogenation reaction is carried out in a suitably sized reactor made of materials, such as glass or Hastelloy C, which are resistant to corrosion by chlorides.
  • a means of vigorous agitation is provided to disperse the metal hydride in the solvent and to enhance mass transfer of the chlorosilane (I II) to the metal hydride surface, while simultaneously renewing the metal hydride surface for effective contact with the chlorosilane.
  • the chlorosilanes of the general formula (III) are hydrogenated with the mixture of LiCI and NaH, and the chlorosilanes of the general formula (III) are added to the reaction mixture before or during the heating of the mixture of LiCI and NaH.
  • the hydridosilanes of the general formula (II) RxSiHm are isolated or purified by distillation.
  • term "distillation" in the sense of the present invention relates to any process for separating components or substances from a liquid mixture by selective evaporation and condensation. Therein, distillation may result in essentially complete separation, leading to the isolation of nearly pure components, or it may be a partial separation that increases the concentration of selected components of the mixture.
  • distillation processes utilized for the isolation or purification of the hydridosilanes of the formula (I I) can be simple distillation, fractional distillation, vacuum distillation, short path distillation or any other kind of distillation known to the skilled person.
  • the step of separating or purifying the hydridosilanes of the formula (I I) according to the invention may comprise one or more batch distillation steps, or may comprise a continuous distillation process.
  • Isolation or purification by collecting the hydridosilanes of general formula (I I) in a cooling trap at a temperature between their boiling point and -196 °C is also comprised by the definition of the term "distillation" according to the invention.
  • distillation step for the isolation or purification of the hydridosilanes of the general formula (I I) can be performed at the same time as the hydrogenation step is performed.
  • the direct removal of the hydridosilanes of the general formula (I I) formed in the hydrogenation step can be achieved.
  • the hydridosilane products of the general formula (I I) can be volatilized from the hydrogenation reactor and condensed as a liquid and/or solid in a refrigerated vessel from which it can be subsequently recovered by distillation, or by solution in an ether solvent, for use.
  • the hydridosilanes of the general formula (I I) can be absorbed in an ether solvent contained in a refrigerated vessel.
  • the chlorosilane Me 2 SiHCI is obtained by subjecting hydridosilane Me 2 SiH 2 to the reaction of step A) with hydrogen chloride in the presence of at least one ether compound, wherein the hydridosilane Me 2 SiH 2 is previously prepared from the corresponding chlorosilane Me 2 SiCI 2 by hydrogenation as defined above.
  • Me 2 SiCI 2 may be submitted to the hydrogenation reaction as a pure compound, as a constituent of a mixture with further chlorosilanes of the general formula (I I I) , or as a constituent of a mixture with any other compounds.
  • the chlorination step A) may be performed with Me 2 SiH 2 as a pure substrate, with Me 2 SiH 2 as a part of a mixture of several compounds of the general formula (I I) , or with a mixture of Me 2 SiH 2 and any other compounds.
  • the chlorosilane MeSiHC is obtained by subjecting hydridosilane MeSiH 3 to the reaction of step) A with hydrogen chloride in the presence of at least one ether compound, wherein the hydridosilane MeSih is previously prepared from the corresponding chlorosilane MeSiC by hydrogenation as defined above.
  • MeSiC may be submitted to the hydrogenation reaction as a pure compound, as a constituent of a mixture with further chlorosilanes of the general formula (III), or as a constituent of a mixture with any other compounds.
  • the chlorination step A) may be performed with MeSiH 3 as a pure substrate, with Me 2 SiH 2 as a part of a mixture of several compounds of the general formula (II), or with a mixture of Me 2 SiH 2 and any other compounds.
  • the hydridosilanes of the general formula (II) which are submitted to chlorination in step A) are obtained in a previous step by a Si-Si bond cleavage reaction.
  • Si-Si bond cleavage reaction refers to any reaction in which a covalent bond between two silicon atoms is cleaved homolytically or heterolytically.
  • the hydridosilanes of the general formula (I I) which are submitted to chlorination in step A) are obtained in a previous step by a Si-Si bond cleavage reaction, wherein the substrate in the Si-Si bond cleavage reaction is a disilane or a mixture of two or more disilanes, which can also be part of a mixture with any other compounds.
  • the term "disilane” refers to any compound in which there is a Si- Si moiety, i.e. a functional group in which two silicon atoms are connected by a single bond.
  • the disilanes submitted to the cleavage reaction are substituted by organyl substituents, chloro substituents and hydrido substituents, more preferably by organyl substituents and hydrido substituents.
  • the Si-Si bond cleavage and hydrogenation reaction is effected by reaction of the substrate with hydrogen chloride in etheral solvents, phosphonium chloride or 2-methylimidazole or an alkali metal salt, an alkaline earth metal salt, or a combination of hydrogen chloride and an alkaline earth metal salt or an alkali metal salt, or a combination of phosphonium chloride and/or 2- methylimidazole and an alkaline earth metal salt or an alkali metal salt.
  • the hydrogenation of the chlorosilanes of the general formula (I II) to the hydridosilanes of the general formula (II) is conducted with LiH as a hydride donor
  • the resulting LiCI is at least partially recovered from the reaction mixture and subjected to electrolysis to obtain Li, which is then reacted to LiH.
  • lithium chloride along with unreacted lithium hydride, is present in the organic solvent of the reduction step, which is preferably an ether solvent. It is desirable to recover the lithium chloride safely and recycle it.
  • HCI gas is injected into the suspension to convert residual LiH to LiCI, and thereafter, the LiCI solid is separated from the organic solvent by filtration, sedimentation or centrifugation and optionally dried to remove adherent solvent.
  • the electrolysis of LiCI is preferably performed with an eutectic mixture of LiCI and a metal salt, more preferably with an eutectic mixture of LiCI and KCI.
  • the reaction of the lithium obtained from the electrolysis to form LiH is preferably performed with H 2 .
  • a further subject of the invention is a process for the production of hydridosilanes of the general formula (IV)
  • R is as defined above
  • p 0, 1 , 2 or 3,
  • q 1 , 2, 3, or 4
  • r is 0, 1 , 2, or 3
  • the reaction vessel for mixing LiCI and NaH and for the hydrogenation reaction can be an ampoule, a sealed tube, a flask or any kind of chemical reactor, without being limited thereto.
  • the hydrogenation reaction is carried out in a suitably sized reactor made of materials, such as glass or Hastelloy C, which are resistant to corrosion by chlorides.
  • a means of vigorous agitation is provided to disperse the metal hydride in the solvent and to enhance mass transfer of the chlorosilane (V) to the metal hydride surface, while simultaneously renewing the metal hydride surface for effective contact with the chlorosilane.
  • LiH formed in situ as hydride donor in the hydrogenation reaction up to 1000 mol-% excess of NaH in relation to LiCI, more preferably 5 to 400 mol-% excess of NaH, and most preferably 10 to 200 mol-% excess of NaH are mixed and heated with LiCI.
  • the reaction temperature in the hydrogenation is 60 °C to 200 °C, more preferably 80 to 160 °C, even more preferably 100 to 160 °C, and most preferably 120 to 160 °C.
  • the chlorosilanes of the general formula (V) are added to the reaction mixture before or during the heating of the mixture of LiCI and NaH for the in situ preparation of LiH.
  • the products of the general formula (IV) are isolated or purified by distillation.
  • distillation As defined above for the isolation or purification of the hydridosilanes of the general formula (II), the term "distillation" with regards to the process according to the present invention relates to any process for separating components or substances from a liquid mixture by selective evaporation and condensation. Therein, distillation may result in a complete separation, leading to the isolation of nearly pure components (having purities of e.g. > 95 wt-%, preferably > 97 wt-% and more preferably > 99 wt-%), or it may be a partial separation that increases the concentration of selected components of the mixture.
  • distillation processes utilized for the isolation or purification of the hydridosilanes of the formula (IV) can be simple distillation, fractional distillation, vacuum distillation, short path distillation or any other kind of distillation known to the skilled person.
  • the step of separating or purifying the hydridosilanes of the formula (IV) according to the invention may comprise one or more batch distillation steps, or may comprise a continuous distillation process. Isolation or purification by collecting the hydridosilanes of general formula (IV) in a cooling trap at a temperature between their boiling point and about -196 °C is also comprised by the definition of the term "distillation" according to the invention.
  • distillation step for the isolation or purification of the hydridosilanes of the general formula (IV) can be performed at the same time as the hydrogenation step is performed.
  • the direct removal of the hydridosilanes of the general formula (IV) formed in the hydrogenation step can be achieved.
  • the hydridosilane products of the general formula (IV) can be volatilized from the hydrogenation reactor and condensed as a liquid and/or solid in a refrigerated vessel from which it can be subsequently recovered by distillation, or by solution in an ether solvent, for use.
  • the hydridosilanes of the general formula (IV) can be absorbed in an ether solvent contained in a refrigerated vessel.
  • R is an organyl group, which can be the same or different, and the organyl group is selected from linear or branched alkyl, aryl, linear or branched alkenyl, linear or branched alkynyl, aralkyl, aralkenyl, aralkynyl, alkaryl, alkenylaryl, alkynylaryl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, cycloaralkynyl, cycloalkaryl, cycloalkenylaryl, cycloalkynylaryl, linear or branched alkoxy, aryloxy and organosiloxy (cyclic and acyclic) groups, preferably alkyl, alkenyl and aryl,
  • x is 0, 1 , 2 or 3, preferably 1 or 2,
  • y is 0, 1 , 2 or 3, preferably 1 or 2,
  • R is as defined above
  • n 1 , 2, 3, or 4
  • x 0, 1 , 2 or 3
  • m + x is 4, to the reaction with hydrogen chloride in the presence of at least one ether compound in the absence of Lewis acid compounds containing a metal atom from group 13 of the periodic table (boron group), such as B(C6F 5 )3 and AlC ,
  • ether compound is selected from ether solvents, such as cyclopentyl methyl ether, di-n-butyl ether, di-te/f-butyl ether, diethyl ether, diisopropyl ether, dimethoxyethane, dimethoxymethane, dioxane such as 1 ,4-dioxane, ethyl fe/f-butyl ether, methoxyethane, 2-(2- methoxyethoxy)ethanol, methyl fe/f-butyl ether, 2-methyltetrahydrofurane, morpholine, polyethylene glycol, tetrahydrofurane, tetrahydropyrane, 2,2,5,5-tetramethyltetrahydrofurane, tetraethylene glycol dimethyl ether (tetraglyme) , and diethylene glycol dimethyl ether (diglyme) , and diethylene glycol dimethyl ether (dig
  • ether compound is selected from ether solvents such as those of the group consisting of diethyl ether, di-n-butyl ether, diethylene glycol dimethyl ether (diglyme) , tetraethylene glycol dimethyl ether (tetraglyme) and dioxane, preferably 1 ,4-dioxane, 2-methyltetrahydrofurane, tetrahydrofurane, tetrahydropyrane, dimethoxy ethane.
  • ether solvents such as those of the group consisting of diethyl ether, di-n-butyl ether, diethylene glycol dimethyl ether (diglyme) , tetraethylene glycol dimethyl ether (tetraglyme) and dioxane, preferably 1 ,4-dioxane, 2-methyltetrahydrofurane, tetrahydrofurane, tetrahydropyrane, dimethoxy ethan
  • the ether compound is selected from the group consisting of diethyl ether, di-n-butyl ether, 1 ,4- dioxane, tetraethylene glycol dimethyl ether (tetraglyme) and diethylene glycol dimethyl ether (diglyme), preferably the ether compound is 1 ,4-dioxane or diethylene glycol dimethyl ether.
  • reaction step A) is conducted at a temperature of about - 50 °C to about 140 °C, preferably about 0 °C to about 100 °C, more preferably about 20 °C to about 80 °C.
  • step A) is carried out with an ether compound saturated with hydrogen chloride.
  • step A) is carried out with diglyme saturated with hydrogen chloride, diethyl ether saturated with hydrogen chloride, di-n-dibutyl ether saturated with hydrogen chloride or 1 ,4-dioxane saturated with hydrogen chloride.
  • step A) is carried out in the presence of at least one alcohol.
  • step A) is carried out at a pressure of about 1 bar to about 30 bar, preferably about 1 bar to about 20 bar, most preferably about 1 bar to about 10 bar.
  • step A) the molar ratio of hydrogen chloride to hydridosilanes of the general formula (II) is at least about
  • step A) the weight ratio of hydridosilanes of the general formula (I I) to the ether compound used is less than about 1 :2, preferably in the range about 1 :2 to about 1 :20.
  • step A) the weight ratio of hydrogen chloride to the ether compound used is less than about 1 :2, preferably in the range of about 1 :2 to about 1 :30.
  • chlorosilanes of the general formula (I) are selected from: Me 2 SiHCI, MeSiH 2 CI, MeSiHCb, Ph 2 SiHCI, PhSiH 2 CI, PhSiHC , MeViSiHCI, and MePhSiHCI, wherein Vi is vinyl and Ph is phenyl.
  • step A) is carried out in a reactor resistant to chloride-induced corrosion by injection of one or several separated hydridosilanes of the general formula (II) in gaseous or liquid state into an agitated solution of HCI dissolved in an ether solvent. Provision can be made to add HCI continuously or intermittently into the reaction mixture to effect the desired conversion of Si-H bonds to Si- CI bonds, and the reactor used is optionally baffled.
  • step A) is carried out in a reactor resistant to chloride-induced corrosion by injection of one or several of the hydridosilanes of the general formula (II) at the base of a column containing HCI dissolved in an ether solvent and the column is optionally packed.
  • step A) is performed by bringing into contact a solution of hydridosilanes of the general formula (II) in ether solvent with one of HCI in ether solvent by impingement or rapid mixing in an agitated vessel or static mixer, wherein the reactor used is resistant to chloride-induced corrosion.
  • step B) of separating the resulting chlorosilanes of the formula (I) is carried out by distillation.
  • hydride donor is selected from the group of alkali metal hydrides, such as LiH, NaH, KH, alkaline earth metal hydrides, such as calcium hydride, or complex metal hydrides, such as L1AIH4 and NaBhU.
  • alkali metal hydrides such as LiH, NaH, KH
  • alkaline earth metal hydrides such as calcium hydride
  • complex metal hydrides such as L1AIH4 and NaBhU.
  • R is as defined above
  • p is 0, 1 , 2 or 3, p is preferably 1 , 2 or 3,
  • q 1 , 2, 3, or 4
  • r is 0, 1 , 2, or 3, r is preferably 0, and
  • reaction temperature in the hydrogenation is about 20 °C to about 160 °C.
  • R is an organyl group, which can be the same or different,
  • x is 0, 1 , 2 or 3, preferably 1 or 2,
  • y is 0, 1 , 2 or 3, preferably 1 or 2,
  • compositions comprising at least one of the chlorosilanes of the general formula (I)
  • R is an organyl group, which can be the same or different
  • x is 0, 1 , 2 or 3, preferably 1 or 2,
  • y is 0, 1 , 2 or 3, preferably 1 or 2,
  • LiH is preferably in situ synthesized from a LiCI/NaH mixture and directly reacted with the chlorosilanes to give hydridosilanes in a one step process in good yields.
  • the organosilanes of formula (I I) were reacted with the HCI/ether reagents (ether: diethyl ether, di-n-butyl ether, diglyme, 1 ,4-dioxane etc. ; molarity of HCI in ethers: 5 molar in Et 2 0, 4.8 molar in n-Bu 2 0, 8- 12 molar in diglyme, 8-12 molar in 1 ,4-dioxane) .
  • the reactions were performed mixing the reaction partners, such as organosilanes (0.1 ml) and HCI/ether solution (0.4 ml) in an NMR tube.
  • the tube was evacuated under vacuum (about 0.1 mbar), and sealed. NMR spectra were recorded depending on reaction time and temperature. The molar ratios of products formed were determined by integration of relevant NMR signals that were assigned to specific products within the mixture.
  • the HCI/diglyme reagent showed the highest chlorination activity compared to the HCI/diethyl ether reagent, while the combination HCI/di-n-butyl ether decelerated the speed of chlorination. Furthermore, the use of a specific HCI/ether reagent is mostly determined by the boiling points of products formed. For simplification of product isolation, for high boiling products the use of the HCI/Et 2 0 reagent is favored, while for low boiling organochlorosilanes high boiling ethers (e.g. diglyme) are preferred.
  • Table 4 describes the synthesis of organochlorosilanes from organohydridosilanes with the HCI/Et 2 0 reagent
  • Table 5 deals with the use of the HCI/diglyme chlorination reagent
  • Table 6 with the use of the HCI/n-Bu20 chlorination reagent
  • Table 7 with the use of the HCI/1 ,4-dioxane chlorination reagent.
  • the organosilanes indicated in Table 4 as starting compounds were reacted with the HCI/diethyl ether reagent (molarity of HCI in diethyl ether: 5 mol/l).
  • the reactions were performed by mixing the reaction partners, i.e. the respective organosilane (0.1 ml) and the HCI/diethyl ether solution (0.4 ml) in an NMR tube. After cooling the sample with liquid nitrogen (-196 °C), the tube was evacuated under vacuum (-0.1 mbar), and sealed. NMR spectra were recorded depending on reaction time and temperature. The molar ratios of products formed were determined by integration of relevant NMR signals that were assigned to specific products within the mixture. After optimization and completion of the chlorination reaction SiH + HCI - SiCI + H 2 the NMR tube was opened to analyze the product mixture by GC-MS. Product identification was verified in all cases for the main products.
  • Table 4 shows the results obtained in the synthesis of organochlorosilanes from organohydridosilanes with the HCI/Et 2 0 reagent in Examples 1a to 1 u.
  • Table 5 shows the results obtained in the synthesis of organochlorosilanes from organohydridosilanes with the HCI/diglyme chlorination reagent in Examples 2a to 2s.
  • Table 6 shows the results obtained in the synthesis of organochlorosilanes from organohydridosilanes with the HCI/n-Bu 2 0 chlorination reagent.
  • Table 6 Synthesis of methylchlorosilanes from methylhydridosilanes and the
  • Table 7 shows the results obtained in the synthesis of organochlorosilanes from organohydridosilanes with the HCI/1 ,4-dioxane chlorination reagent. Table 7: Syntheses of organochlorosilanes from organohydridosilanes and the
  • Dimethylsilane (Me2SiH2, b.p.: -20 °C) formed continuously evaporated and was frozen in a cooling trap (about -196 °C) which was connected with the top of the reflux condenser. After dimethyldichlorosilane addition was completed the mixture was subsequently heated to about 130 °C for an additional hour and cooled down to r.t.. To collect the complete amount of Me 2 SiH 2 formed in the cooling trap, the reaction flask was applied to vacuum and the product was pumped off to yield 54 g (0.90 mol, 90 %) of pure Me 2 SiH 2 . About 10 % of the hydridosilane remained in the diglyme residue.
  • the HCI/diglyme flask was connected with a cooling trap (-78 °C) and after the overall reaction time of 12 hours a mixture of 16.85 g (0.28 mol) Me 2 SiH 2 , 0.83 g (9 mmol) Me2SiHCI and 0.13 g (3 mmol) of methyl chloride were collected. Volatile compounds of the HCI/diglyme solution were condensed under vacuum in a cooling trap (about -196 °C) that was connected to another trap cooled to about -78 °C. The condensed mixture (about -196 °C) was allowed to warm to r.t.
  • Me 2 SiHCI was collected in the -78 °C cooling trap while excess HCI was directly recycled by evaporation into a 1 L flask filled with diglyme used for the chlorination reaction at the beginning.
  • the Me 2 SiHCI collected in the -78 °C trap was condensed into an ampoule with Young-valve to give 59 g (0.62 mol) of Me2SiHCI besides traces of methyl chloride and Me2SiC , obviously formed by double chlorination of Me 2 SiH 2 .
  • Me 2 SiH 2 collected in the -78 °C cooling trap after chlorination reaction (16.85 g, see above), was additionally evaporated into the (recycled) HCI/diglyme mixture and reacted and worked up as described before, giving 25 g (0.27 mol) Me 2 SiHCI, contaminated with traces of methyl chloride. Combining both Me 2 SiHCI fractions and final distillation over a 50 cm Vigreux column at normal pressure gave 74 g (0.89 mol) of Me 2 SiHCI (b.p. : 35 °C), in a yield of 99 % for the chlorination step.
  • Me2SiC 25 ml, 0.21 mmol was admixed with a suspension of 4.65 g LiH (97%, 0.57 mol) in 1 10 ml of 1 ,4-dioxane. Upon warming the mixture to 60 °C the reduction started virgorously. Thus, it is preferably recommended to warm the LiH/1 ,4- dioxane suspension to 60 °C and then to add the chlorosilane slowly by a dropping funnel. Me 2 SiH 2 , formed by the chlorosilane reduction, evaporated into the cooling trap (-196 °C) that was connected with the reflux condenser.
  • reaction mixture was subsequently warmed to about 150 °C (oil bath) under normal pressure with reflux of the solvent. Then the reaction mixture was cooled to r.t. and the remaining dimethylsilane (Me 2 SiH 2 ) was pumped off and condensed in the cooling trap (about -196 °C) under reduced pressure.
  • the HCI/1 ,4-dioxane solution (12.04 mol/l) was cooled to about -15 °C and upon warming the cooling trap to r.t., Me 2 SiH 2 was slowly evaporated into the HCI/1 ,4-dioxane reagent. The reaction mixture was stirred at about -15 °C for about 12 hours, but didn't show any visible reaction.
  • the trap (about -196 °C), containing all condensed volatile components, was connected to another trap cooled to about -78 °C, which was attached to the 1 ,4-dioxane containing flask, just separated from the system.
  • the condensed mixture (about -196 °C) was allowed to warm to about 5 °C at normal pressure separating dimethylchlorosilane from Me 2 SiH 2 and gaseous hydrogen chloride: Me 2 SiHCI mainly remained in the first trap at about 5 °C and condensed in traces into the about -78 °C cooled trap while excess HCI was directly recycled by evaporation into the 1 ,4-dioxane containing flask.
  • Me 2 SiH 2 collected at -78 °C, has to be reintroduced into the HCI/1 ,4-dioxane reagent.
  • this process has to be repeated several times and limits product yield because of the low boiling point of the silane.
  • Me 2 SiH 2 condensed at about -78 °C, was therefore reintroduced into the HCI/1 ,4-dioxane reagent by warming to r.t..
  • Me 2 SiHCI collected in both traps was then condensed into an ampoule to give 9.14 g (0.10 mol, 46% yield) of Me 2 SiHCI. After a second reintroduction the yield was increased to 71 % (14.08 g, 0.15 mol) with 24% of Me 2 SiH 2 (3.03 g, 0.05 mmol) still isolated in a cooling trap.
  • MeSiC (5.00 g, 33.5 mmol) was reacted with LiH (0.93 g, 1 17.0 mmol) to give 1 .54 g (33.5 mmol) MeSiH 3 that was directly evaporated into the HCI/1 ,4-dioxane reagent (7 ml, 12 mol/l HCI/1 ,4-dioxane) that was placed in a glass ampoule. After completion the reaction mixture was cooled to about -196 °C, evacuated in vacuo and sealed. After warming to r.t. the mixture was heated to about 100 °C for about 240 hours. After cooling to r.t. the ampoule was opened and MeSiHC was condensed off. Yield: 3.27 g, 28.4 mmol, 85%.
  • Me2SiHCI dimethylchlorosilane
  • Me2SiH2 (1.12 g, 19 mmol) formed in 75 % besides Me 2 SiHCI (0.12 g, 1 mmol, 5 %); 20 % of Me 2 SiCI 2 (0.64 g, 5 mmol) remained unreacted; purity of products formed was checked by NMR-spectroscopy. Then the Me2SiH2/Me 2 SiHCI mixture was slowly evaporated into the HCI/diglyme solution and worked up as described in Example 8 to give Me 2 SiHCI quantitatively.
  • LiCI/NaH mixture LiCI: 25.4 g, 0.6 mol; NaH: 24.1 g, 0.6 mol, 60 % in mineral oil
  • a LiCI/NaH mixture LiCI: 25.4 g, 0.6 mol; NaH: 24.1 g, 0.6 mol, 60 % in mineral oil
  • Me2SiCl2 21.2 g, 0.16 mol
  • Reduction of the dimethyldichlorosilane started immediately by self-heating of the mixture to about 84 °C. Dimethylsilane formed was condensed in a cooling trap (-196 °C) that was connected with the top of the reflux condenser.
  • LiCI works as a catalyst.
  • a mixture of LiCI/NaH (in mineral oil) in a molar ratio of 1 :18 gave Me 2 SiH 2 and Me 2 SiHCI in acceptable yields besides siloxanes, obviously resulting from reactions with the mineral oil and NaOH impurities (reaction conditions: closed ampoule, about 160 °C, 91 h).
  • reaction conditions: closed ampoule, about 160 °C, 91 h the LiCI/NaH/LiH/diglyme suspension changed color upon chlorosilane addition and became orange/brown instead of white/colorless, especially at higher temperatures (>140 °C). Finely dispersed LiH in diglyme did not change color of the suspension.
  • the NaH/mineral oil dispersion should be washed with an unpolar solvent, such as hexane or pentane, to avoid product losses.
  • an unpolar solvent e.g. pentane or hexane
  • the reduction of the chlorosilane started with self-heating of the solution but also changing its color to brown.
  • the Me 2 SiHCI yield in this experiment was 38 %.
  • PhSiH 2 CI phenylchlorosilane
  • PhSihh (56.70 g, 0.52 mol) was added to a 5mol/l HCI/Et 2 0 solution (220 ml) and stirred for 98 hours at r.t. and normal pressure (1013 mbar). Due to hydrogen evolution the flask was connected to an overpressure valve. After removal of Et 2 0 by distillation at about 60-100 °C, the residue (59.53 g) was analyzed by NMR spectroscopy, which revealed a product distribution of 63 % PhSihhCI (0.29 mol, 41 .42 g) and 37 % PhSihh (0.17 mol, 18.19 g).
  • Ph 2 SiH 2 was separated from diglyme by fractional distillation at about 1 10-178 °C under reduced pressure (about 0.1-32 mbar) to give 30.59 g Ph 2 SiH 2 (0.17 mol, 75 %).
  • Ph2SiH2 (29.00 g, 0.16 mol) was added to a 10 mol/l HCI/diglyme solution (1 15 ml) and stirred for 72 hours at r.t. and normal pressure (1013 mbar). Due to hydrogen evolution the flask was connected to an overpressure valve. NMR spectroscopic measurements confirmed a quantitative conversion of Ph 2 SiH 2 into Ph 2 SiHCI without the formation of byproducts. Fractional distillation of the crude product at 1 10-178 °C under reduced pressure (0.1 mbar) gave 26.58 g Ph 2 SiHCI (0.12 mmol, 77 %). Additionally, byproducts were formed upon distillation at high temperatures.
  • PhSiH 3 phenylsilane
  • PhSiH 2 CI phenylchlorosilane
  • PhSiHC phenyldichlorosilane
  • Examples 14a-c) clearly demonstrate that the chlorination reaction can be drastically accelerated by the addition of an alcohol showing a catalytic effect of the alcohol with surprisingly no formation of alkoxysilanes and/or siloxanes.
  • trihydridosilanes here exemplarily MeSihh
  • n-Bu3P/HCI/1 ,4-dioxane reagent at r.t. and at 60 °C
  • concentration of HCI 13M.
  • MeSiH 2 CI was formed after 4 h (r.t.) in 99.2%, besides 0.5% of the double chlorinated species MeSiHCI 2 . 0.3% of the starting hydridosilane remained (Fig 2a).
  • MeSiH 2 CI After 160 h, the amount of MeSiH 2 CI decreased to 92.6%, while the double chlorinated MeSiHCb was formed in only 7.4%. The addition of catalytical amounts of n-Bu 3 P drastically enhanced the formation of MeSiHCI 2 .
  • MeSihh was quantitatively chlorinated to give MeSiH 2 CI and MeSiHCb in 92% and 8%, respectively.
  • the amount of MeSiH 2 CI continuously decreased with prolonged reaction times due to dichlorination.
  • the targeted product MeSiHCb was formed in 92.2%, while MeSiH 2 CI remained in only 2.0%. The higher chlorination reactivity also gave the fully chlorinated species MeSiC in 5.8%.
  • n-Bu 3 P was reacted with an excess of the 5M HCI/Et 2 0 reagent to quantitatively give n- Bu 3 P(H)CI as a viscous liquid ( ⁇ 31 ⁇ 12.2 ppm, d, 1 J P _ H 490 Hz; ⁇ 1 ⁇ 7.12 ppm, d, 1 J P _ H 491 Hz) after removal of HCI and Et 2 0 in vacuo.
  • This compound was reacted with an equimolar amount of Et 2 SiH 2 in benzene to give Et 2 SiHCI in 87% and Et 2 SiCI 2 in 4% yield, 6% of Et 2 SiH 2 remained unreacted (Table 1 1 , entry 1).
  • Table 1 1 covers the chlorination reactions of Et 2 SiH 2 and of HexSiH 3 with n-Bu 3 P(H)CI as chlorination reagent
  • Table 12 the chlorination of HexSiH 3 (0.6 mmol) with n-Bu 3 P (0.02 mmol) and HCI/Et 2 0 (0.4 ml, 5M) as chlorination reagent.
  • Table 11 Chlorination reactions of Et 2 SiH 2 and HexSiH 3 with n-Bu 3 P(H)CI as chlorination reagent.
  • any numerical range recited herein includes all sub-ranges within that range and any combination of the various endpoints of such ranges or sub-ranges, be it described in the examples or anywhere else in the specification. It will also be understood herein that any of the components of the invention herein as they are described by any specific genus or species detailed in the examples section of the specification, can be used in one embodiment to define an alternative respective definition of any endpoint of a range elsewhere described in the specification with regard to that component, and can thus, in one non-limiting embodiment, be used to supplant such a range endpoint, elsewhere described.
  • any compound, material or substance which is expressly or implicitly disclosed in the specification and/or recited in a claim as belonging to a group of structurally, compositionally and/or functionally related compounds, materials or substances includes individual representatives of the group and all combinations thereof.

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Abstract

L'invention concerne un procédé de production de chlorosilanes consistant à soumettre au moins un hydridosilane à la réaction avec du chlorure d'hydrogène en présence d'au moins un composé éther, ainsi qu'un procédé de production de tels hydridosilanes servant de matériaux de départ.
PCT/US2018/051845 2017-09-20 2018-09-20 Synthèse d'organo-chlorosilanes à partir d'organosilanes WO2019060475A2 (fr)

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CN116102018A (zh) * 2022-11-11 2023-05-12 石河子大学 一种多晶硅副产低聚氯硅烷中六氯二硅烷的分离方法
US11851450B2 (en) 2021-11-17 2023-12-26 Honeywell Federal Manufacturing & Technologies, Llc Monosubstituted diphenylsilanes and synthesis thereof

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CN116102018A (zh) * 2022-11-11 2023-05-12 石河子大学 一种多晶硅副产低聚氯硅烷中六氯二硅烷的分离方法
CN116102018B (zh) * 2022-11-11 2024-06-04 石河子大学 一种多晶硅副产低聚氯硅烷中六氯二硅烷的分离方法

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