WO2015116281A1

WO2015116281A1 - Halogenation method

Info

Publication number: WO2015116281A1
Application number: PCT/US2014/064463
Authority: WO
Inventors: Dimitris Katsoulis; John Roberts
Original assignee: Dow Corning Corporation
Priority date: 2014-01-30
Filing date: 2014-11-07
Publication date: 2015-08-06

Abstract

A method for preparing a reaction product includes 1 ) reacting a composition including a) a hydrogen halide of formula i): HX, where X is a halogen atom, and b) a compound of average formula ii): M(OR¹ )_x, or an oligomer thereof, where M is an element selected from Sn, Ge, or Si, and each R¹is independently a monovalent hydrocarbon group, and subscript x has a value from 1 to maximum valence of the element selected for M; in the presence of c) a scavenging agent of formula iii) or formula iv), where formula iii) is R²-CEN, where R² is an organic group, and formula iv) is 0=C=N-R³, where R³ is an organic group, and d) a catalyst. The reaction product includes a halogenated compound and a side product.

Description

HALOGENATION METHOD

[0001] Various halosilanes find use in different industries. Diorganodihalosilanes, such as dimethyldichlorosilane, are hydrolyzed to produce a wide range of polyorganosiloxanes, such as polydiorganosiloxanes.

[0002] Methods of preparing halosilanes are known in the art. Typically, halosilanes are produced commercially by the Mueller-Rochow Direct Process, which comprises passing a halide compound over zero-valent silicon (Si⁰) in the presence of a copper catalyst and various optional promoters. Mixtures of halosilanes are produced by the Direct Process. When an organohalide is used, a mixture of organohalosilanes is produced by the Direct Process.

[0003] The typical process for making the Si⁰ used in the Direct Process consists of the carbothermic reduction of S1O2 in an electric arc furnace. Extremely high temperatures are required to reduce the S1O2, so the process is energy intensive. Consequently, production of Si⁰ adds costs to the Direct Process for producing halosilanes. Therefore, there is a need for a more economical method of producing halosilanes that avoids or reduces the need of using Si⁰.

[0004] In addition to the Direct Process, diorganodihalosilanes have been produced by the alkylation of silicon tetrachloride and various methylchlorosilanes by passing the vapors of these chlorosilanes together with an alkyl halide over finely divided aluminum or zinc at elevated temperatures. However, this process results in the production of a large amount of aluminum chloride or zinc chloride, which is costly to dispose of on a commercial scale.

[0005] Recently, Dow Corning developed an alternative process for producing halosilanes, such as diorganodihalosilanes, from a silicon tetrahalide starting material. However, current industrial processes that produce silicon tetrahalide as a side product, such as the manufacture of polycrystalline silicon, may not produce enough silicon tetrahalide to support such alternative process on a commercial scale.

[0006] Therefore, there is an industry need for new methods for synthesizing

tetrahalides, such as SiCl4.

BRIEF SUMMARY OF THE INVENTION

[0007] A method for preparing a reaction product comprises:

1 ) reacting a composition comprising

a) a hydrogen halide of formula i): HX, where X is a halogen atom, and b) a compound of average formula ii): M(OR¹ )_x, or an oligomer thereof, where M is an element selected from Sn, Ge, or Si, and each R¹ is independently a monovalent hydrocarbon group, and subscript x has a value from 1 to maximum valence of the element selected for M;

c) a scavenging agent of formula iii) or formula iv), where

formula iii) is R²-C≡N, where R² is an organic group, and

formula iv) is 0=C=N-R³, where R³ is an organic group, and d) a catalyst; thereby preparing the reaction product, where the reaction product comprises a halogenated compound and a side product.

DETAILED DESCRPTION OF THE INVENTION

[0008] The method for preparing a reaction product comprises:

1 ) reacting

a) a hydrogen halide of formula i): HX, where X is a halogen atom, and

b) a compound of formula ii): M(OR¹ )_x, or an oligomer thereof, where M is an element selected from the group consisting of Sn, Ge, and Si, each R¹ is independently a monovalent hydrocarbon group, and subscript x has a value from 1 to maximum value of the element selected for M;

in the presence of

c) a scavenging agent, and

d) a catalyst;

thereby preparing the reaction product, where the reaction product comprises a halogenated compound and a side product. The method may optionally further comprise

2) recovering the halogenated compound. The method may optionally further comprise 3) recovering the scavenging agent. The method may optionally further comprise 4) recycling the recovered scavenging agent in step 1 ).

[0009] Ingredient a) used in the method is a hydrogen halide of formula i): HX, where X is a halogen atom. X may be fluorine (F), chlorine (CI), bromine (Br), or iodine (I);

alternatively F, CI, or Br; alternatively CI or Br; alternatively F or CI; alternatively CI or I; alternatively F; alternatively CI; alternatively Br; and alternatively I. Ingredient a) is exemplified by HBr and HCI; alternatively HCI. Hydrogen halides are known in the art and are commercially available, for example, from Sigma-Aldrich, Inc., of St. Louis, MO, U.S.A. (Aldrich). The amount of hydrogen halide depends on various factors including the type of reactor used and the compound selected for ingredient b), however the amount of hydrogen halide may be sufficient to provide a mole ratio of ingredient a) to ingredient b) (a:b ratio) of >1 :1 , alternatively 1 :1 to 50:1 , alternatively 2:1 to 25:1 , and alternatively 4:1 to 16:1 .

[0010] Ingredient b) used in the method is a compound of formula ii): M(OR¹ )_x, or an oligomer thereof, where M is tin (Sn), germanium (Ge), or silicon (Si); each R¹ is independently a monovalent hydrocarbon group; and subscript x has a value from 1 to the maximum valence of the element selected for M. For example, when M is Si, x can be 1 to 4. Alternatively, x = 4. When M is Ge, x can be 1 to 4. And, when M is Sn, x can be 2 or 4. Alternatively, M is Sn. Alternatively, M is Ge or Si. Alternatively, M is Si. The monovalent hydrocarbon group for R¹ may be an alkyl group, an alkenyl group, or an alkynyl group. Alternatively, R¹ may be an alkyl group. Alternatively, R¹ may be an alkyl group of 1 to 6 carbon atoms, alternatively 1 to 4 carbon atoms. Alternatively, R¹ may be

Me or Et. Alternatively, M is Si, x is 4, and R¹ is alkyl of 1 to 4 carbon atoms. Compounds of formula ii) and oligomers thereof are known in the art and may be prepared, for example, as described in U.S. Patent 5,183,914 to Yeh, et al. Examples of compounds of formula ii) include Sn(OMe)2, Ge(OMe)4, Si(OMe)4, and Si(OEt)4. Alternatively, the compound of formula ii) may be an orthosilicate such as tetramethoxysilane or tetraethoxysilane.

Compounds of formula ii) are known in the art and are commercially available from Aldrich, Alfa Aesar, and Fisher Scientific. Examples of oligomers include silicone oligomers of formula: R¹0)3Si-0-Si(OR¹ )3, and/or formula:

, where R¹ is alkyl, such as Me or

Et and subscript n is 0 or 1 , alternatively n = 0.

[0011] Ingredient c) used in the method is a scavenging agent that can remove R¹ OH, which is produced as a side product of the reaction of ingredients a) and b), from the reaction mixture. Ingredient c) may be a nitrile-functional compound of formula iii): R²-C≡N, where R² is an organic group. R² may be a hydrocarbon group, such as an alkyl group or an alkenyl group of 1 to 10 carbon atoms, alternatively 1 to 6 carbon atoms, and alternatively 1 to 4 carbon atoms. Examples of nitrile-functional compounds suitable for ingredient c) include acetonitrile, propionitrile, trimethyl acetonitrile, hexanenitrile, 5- hexynenitrile. Suitable nitrile-functional compounds are known in the art and are commercially available from Aldrich. Alternatively, the scavenging agent may be an isocyanate-functional compound of formula iv): 0=C=N-R³, where R³ is an organic group.

R³ may be a hydrocarbon group, such as an alkyl group or an alkenyl group, of 1 to 10 carbon atoms, alternatively 1 to 6 carbon atoms, and alternatively 1 to 4 carbon atoms. Examples of isocyanate functional compounds suitable for ingredient c) include methyl isocyanate, ethyl isocyanate, butyl isocyanate, 3-methyl-2-butyl isocyanate, hexyl isocyanate, 2-heptyl isocyanate, 2-octyl isocyanate, and allyl isocyanate. Suitable isocyanate functional compounds are known in the art and are commercially available from Aldrich. Alternatively, ingredient c) may be selected from acetonitrile and ethyl isocyanate. The amount of ingredient c) depends on various factors including the reactivity of the scavenger selected as ingredient c) and the compound selected for ingredient b), however the amount of ingredient c) may be sufficient to provide a mole ratio of ingredient c) to ingredient b) (c:b ratio) of >1 :1 , alternatively 1 :1 to 50:1 , alternatively 2:1 to 25:1 , and alternatively 4:1 to 16:1 .

[0012] Ingredient d) used in the method is a catalyst that catalyzes the reaction of ingredients a) and b). Ingredient d) may be a Lewis acid or a Lewis base. Suitable Lewis acids for ingredient d) may be metal halides, such as metal chlorides and metal bromides, or metal triflates. Alternatively, the Lewis acid may be a metal chloride selected from FeCl3, ZnCl2 and LiCI; alternatively the Lewis acid may be FeC^. Suitable Lewis bases for ingredient d) include pyridines, tertiary amines, phosphines, phosphine oxides, sulfoxides, or combinations thereof. An exemplary Lewis base includes hexamethyl phosphoramide (HMPA). The amount of ingredient d) depends on various factors including the type of catalyst selected for ingredient d) and the reactivity of ingredients a) and b), however the amount of ingredient d) may be 10 mol% to 1 mol% based on the amount of ingredient b).

[0013] In the method, ingredients a) and b) react to form the halogenated compound of average formula M(OR¹ )(4_-y)Xy. In this formula, M, R¹ and X are as described above, and subscript y is 1 to 4. The reaction of ingredients a) and b) also produces a side product. The side product includes R¹ OH. Ingredient c) is a scavenging agent that reacts with R¹ OH. Without wishing to be bound by theory, it is thought that scavenging the R¹ OH with ingredient c) will allow the reaction of ingredients a) and b) to proceed faster and/or to a higher conversion (i.e., maximizing the amount of more halogenated species, such MX_y in the reaction product, where X and subscript y are as described above). One skilled in the art would recognize that the reaction product may have a mixture of compounds, e.g., when the maximum valence of M is 4, the reaction product includes one or more of

M(OR¹ )₃X, M(OR¹ )₂X2, M(OR¹ )X₃, and/or MX₄. The method is preferably performed under conditions so as to maximize the amount of MX_y. Examples of the halogenated compound include SiCI₃(OMe), SiCI₃(OMe)₂, SiCI₃(OMe)₃, and SiCI₄. One object of the present invention is to produce a reaction product comprising S1CI4, when M is Si. It is a further object of the invention to produce a reaction product that maximizes the amount of the fully halogenated compound (e.g., S1CI4, when M is Si and X is CI), as compared to amounts of partially chlorinated compounds (e.g., SiCI(OMe)₃, SiCl2(OMe)2, and/or

SiCI₃(OMe)) in the reaction product.

[0014] Step 1 ) of the method is performed under conditions that form the reaction product comprising the halogenated compound and the side product. Step 1 ) may be performed at a temperature less than room temperature (RT) of 25 to the freezing temperature of the compound selected for c). Alternatively, step 1 ) may be performed at 20 °C to -40 °C, alternatively 15 °C to -30 °C, alternatively 10 °C to -15 °C alternatively 0 °C.

[0015] Step 1 ) may be performed at ambient pressure, or above ambient pressure. The pressure may range from 0 kPag to 413.8 kPag, alternatively 0 kPag to 206.7 kPag.

[0016] Without wishing to be bound by theory, it is thought that conditions selected for step 1 ) may be selected so as to optimize solubility of ingredient a) in the reaction mixture with ingredients b), c) and d). It is thought that temperatures lower than RT and pressures above atmospheric pressure may optimize solubility of ingredient a). It was surprisingly found that solvents, both polar and nonpolar, may negatively impact conversion in step 1 ). Therefore, step 1 ) may be performed neat; in the absence of polar solvents and in the absence of nonpolar solvents.

[0017] The method may optionally further comprise 2) recovering the halogenated compound. After step 1 ), solid and liquid components in the reaction mixture may be separated by any convenient means, such as filtration. The halogenated compound may be removed from the liquid components of the reaction mixture by conventional techniques such as stripping and/or distillation. [0018] The method may optionally further comprise 3) recovering the scavenging agent. The scavenging agent may be recovered by precipitating the salt thereof from solution using conventional techniques, such as adding an acid, concentrating the reaction mixture via stripping and/or distillation, or dropping the temperature of the reaction mixture.

Alternatively, a non-polar solvent may used to cause the scavenging agent to precipitate from solution. The salt may then be converted to re-form the scavenging agent (e.g., to MeCN) and by-products (e.g., MeOH and HCI) in the following sequence. For example, when an imidate salt is present, it can be removed from the reaction mixture by conventional techniques, such as filtration. Once removed from the reaction mixture, the imidate salt can be hydrolyzed to MeOH, HCI, and acetamide by addition of water to the imidate salt. The HCI and MeOH can be removed and separated by stripping and/or distillation, and the acetamide can be recycled to MeCN by conventional techniques, such as dehydration over metal oxide catalysts.

[0019] The method may optionally further comprise 4) recycling the recovered scavenging agent in step 1 ). The recovered scavenging agent from step 3) may be recycled in step 1 ).

EXAMPLES

[0020] These examples are intended to illustrate some embodiments of the invention and should not be interpreted as limiting the scope of the invention set forth in the claims. Reference examples should not be deemed to be prior art unless so indicated. The following materials were used in the examples herein. Si(OMe)4 was ACS reagent, > 99% tetramethoxysilane from Aldrich, Si(OEt)4 was anhydrous, > 99.5% tetraethoxysilane from

Fisher, FeCl3 was anhydrous, > 99% iron trichloride from Aldrich, HMPA was 99% hexamethyl phosphoramide from Aldrich, CH3CN was 95% acetonitrile from Aldrich, 95%, SiEt4 was 99% tetraethylsilane from Gelest, Sn(OMe)2 was 99% tin dimethoxide from Alfa

Aesar, Ge(OMe)4 was 99% germanium tetramethoxide from Aldrich, CDCI3 was deuterated chloroform, and HCI was 99% Hydrogen Chloride from Aldrich. All materials were used as received.

Reference Example 1 - General Procedure

[0021] To a stirred solution of a compound of formula ii) and acetonitrile was added a catalyst (if desired) in a reactor. The resulting reaction mixture was adjusted to the desired temperature and then HCI gas was introduced via a sparger, and gas and vapor was removed through a cold trap. The reaction stirred in this manner for a period of time. After a period of time the contents of the trap were re-introduced to the reactor and an internal standard (SiEt.4) was added. An aliquot of the reactor contents was removed, diluted with

CDCI3, and ²⁹Si and ^{1 3}C NMR were immediately taken.

Comparative Example 1 - FeCl3-catalyzed TMOS chlorination (No MeCN):

[0022] FeCl3 (1 .37g, 8.45 mmol) was added to a stirred solution of Si(OMe)4 (25 ml, 169 mmol) and toluene (75 ml). The solution was warmed to 130°C and then a stream of HCI (40 seem) was sparged through the solution and through a Dean-Stark trap. The resulting reaction mixture was stirred for three hours. A biphasic mixture began to form in the Dean- Stark trap. The more dense layer was shown to be a mixture of methanol and Si(OMe)4.

After three hours numerous condensed orthosilicate species were observed in the reaction mixture via GCMS.

Example 2 HMPA-catalyzed TMOS chlorination (with MeCN):

[0023] HMPA (0.48 ml, 2.73 mmol) was added to a stirred solution of Si(OMe)4 (4 ml,

27.35 mmol) and acetonitrile (23.4 ml, 437.6 mmol). The reaction mixture was cooled to 0 °C and then HCI gas (25 seem) was sparged through the reaction mixture. The reaction mixture was stirred in this manner for 6 hours. After 6 hours the contents of the cold trap were re-introduced to the reactor and an internal standard (SiEt.4, 1 ml, 5.29 mmol) was added. An aliquot was taken, diluted with CDCI3, and ²⁹Si and ³C NMR were immediately taken. The reaction product contained 85 mole % of S1CI4, along with a trace amount of SiCI₃(OMe).

Example 3 HMPA-catalyzed TMOS chlorination (pressurized):

[0024] HMPA (0.48 ml, 2.73 mmol) was added to a stirred solution of Si(OMe)4 (4 ml,

27.35 mmol) and acetonitrile (23.4 ml, 437.6 mmol). The reaction mixture was pressurized and purged with argon. After purging, the reactor was pressurized with HCI gas (30 psi, flowed at 25 seem). The reaction mixture was stirred in this manner for 6 hours. After 6 hours an internal standard (SiEt.4, 1 ml, 5.29 mmol) was added. An aliquot was taken, diluted with CDCI3, and ²⁹Si and ^{1 3}c NMR were immediately taken. The reaction product contained 36 mole % of S1CI4, along with 58 mole % of SiCl3(OMe).

Example 4 HMPA-catalyzed Tin(ll) Methoxide Chlorination

[0025] HMPA (0.48 ml, 2.73 mmol) was added to a stirred solution of Sn(OMe)2 (5 g, 27.35 mmol) and acetonitrile (23.4 ml, 437.6 mmol). The reaction mixture was cooled to 0°C and then HCI gas (25 seem) was sparged through the reaction mixture. The reaction mixture was stirred in this manner for 6 hours. After 3 hours SnCl4 was the only observed

Sn product in the reaction mixture by GCMS. Example 5 HMPA-catalyzed Germanium Tetramethoxide Chlorination

[0026] HMPA (0.48 ml, 2.73 mmol) was added to a stirred solution of Ge(OMe)4 (4.06,

27.35 mmol) and acetonitrile (23.4 ml, 437.6 mmol). The reaction mixture was cooled to 0 °C and then HCI gas (25 seem) was sparged through the reaction mixture. The reaction mixture was stirred in this manner for 6 hours. After 2 hours GeCl4 was the only observed

Ge product in the reaction mixture by GCMS.

Example 6 HMPA-catalyzed Silicon Tetramethoxide Chlorination

[0027] HMPA (0.38 ml, 2.2mmol) was added to a stirred solution of Si(OMe)4 (22 ml, 22 mmol) and ethyl isocyanate (25g ml, 351 .7 mmol). The reaction mixture was cooled to 0 °C and then HCI gas (25 seem) was sparged through the reaction mixture. The reaction mixture was stirred in this manner for 6 hours. After 6 hours the contents of the cold trap were re-introduced to the reactor and an internal standard (SiEt.4, 1 ml, 5.29 mmol) was added. An aliquot was taken, diluted with CDCI3, and ²⁹Si and ³C NMR were immediately taken. The reaction product contained 14 mole % of S1CI4, along with 57 mole % of SiCl3(OMe) and 14 mole % of SiCl2(OMe)2.

[0028] The Brief Summary of the Invention and the Abstract are hereby incorporated by reference. All ratios, percentages, and other amounts are by weight, unless otherwise indicated. The articles 'a', 'an', and 'the' each refer to one or more, unless otherwise indicated by the context of the specification. For purposes of this application, the term 'oligomer' means a polymer having an average of two to six monomer units; and alternatively, two to five monomer units, and alternatively two to four monomer units. Abbreviations used herein are defined in Table A, below.

Table A - Abbreviations

[0029] The disclosure of ranges includes the range itself and also anything subsumed therein, as well as endpoints. For example, disclosure of a range of 2.0 to 4.0 includes not only the range of 2.0 to 4.0, but also 2.1 , 2.3, 3.4, 3.5, and 4.0 individually, as well as any other number subsumed in the range. Furthermore, disclosure of a range of, for example, 2.0 to 4.0 includes the subsets of, for example, 2.1 to 3.5, 2.3 to 3.4, 2.6 to 3.7, and 3.8 to 4.0, as well as any other subset subsumed in the range.

[0030] With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, it is to be appreciated that 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 with any other member or members of the group, and each member provides adequate support for specific embodiments within the scope of the appended claims. For example, disclosure of the Markush group: alkyl, aryl, and carbocyclic includes the member alkyl individually; the subgroup alkyl and aryl; and any other individual member and subgroup subsumed therein.

[0031] It is also to be understood that any ranges and subranges relied upon in describing various embodiments of the present disclosure 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. The enumerated ranges and subranges sufficiently describe and enable various embodiments of the present disclosure, 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 20 to -40" may be further delineated into a lower third, i.e., from -20 to 0, a middle third, i.e., from 0 to +20, and an upper third, i.e., from +20 to +40, 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 0.1 %" inherently includes a subrange from 0.1 % to 35%, a subrange from 10% to 25%, a subrange from 23% to 30%, 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 "1 to 6" 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.

[0032] The subject matter of all embodiments of the invention and combinations of independent and dependent claims, both singly and multiply dependent, is expressly contemplated but is not described in detail for the sake of brevity. The disclosure 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. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.

Embodiments of the Invention

[0033] In a first embodiment, a method for preparing a reaction product comprises: 1 ) reacting a composition comprising

a) a hydrogen halide of formula i): HX, where X is a halogen atom, and

b) a compound of average formula ii): M(OR¹ )_x, or an oligomer thereof, where M is an element selected from Sn, Ge, or Si, and each R¹ is independently a monovalent hydrocarbon group, and subscript x has a value from 1 to maximum valence of the element selected for M;

in the presence of

c) a scavenging agent of formula iii) or formula vi), where

formula iii) is R²-C≡N, where R² is an organic group, and

formula iv) is 0=C=N-R³, where R³ is an organic group, and

d) a catalyst;

thereby preparing the reaction product, where the reaction product comprises a halogenated compound and a side product.

[0034] In a second embodiment, step 1 ) is performed neat.

[0035] In a third embodiment, ingredient a) used in the first embodiment comprises HCI.

[0036] In a fourth embodiment, M is Si and x = 4

[0037] In a fifth embodiment, ingredient b) used in the fourth embodiment comprises an orthosilicate.

[0038] In a sixth embodiment, ingredient c) used in the first embodiment comprises acetonitrile or ethyl isocyanate.

[0039] In a seventh embodiment, ingredient d) used in the first embodiment comprises a Lewis acid. [0040] In an eighth embodiment, the Lewis acid of the seventh embodiment is selected from selected from FeCkj, ZnCl2 and LiCI.

[0041] In the ninth embodiment, ingredient d) used in the first embodiment comprises a Lewis base.

[0042] In the tenth embodiment, the Lewis base used in the ninth embodiment comprises hexamethyl phosphoramide.

[0043] In the eleventh embodiment, step 1 ) in the first embodiment is performed at a temperature from 20 °C to -40 °C.

[0044] In the twelfth embodiment, step 1 ) in the first embodiment is performed at a pressure from 0 kPag to 206.7 kPag.

[0045] In the thirteenth embodiment, the method of the first embodiment further comprises step 2), recovering the halogenated compound.

[0046] In the fourteenth embodiment, the halogenated compound produced in the first embodiment comprises a halosilane.

[0047] In the fifteenth embodiment, the halosilane of the fourteenth embodiment comprises S1CI4.

[0048] In the sixteenth embodiment, the method of the first embodiment further comprises 3) recovering the scavenging agent.

[0049] In the seventeenth embodiment, the method of the first embodiment further comprises 4) recycling the scavenging agent recovered in step 3) in step 1 ).

Claims

1. A method for preparing a reaction product comprises:

1 ) reacting a composition comprising

a) a hydrogen halide of formula i): HX, where X is a halogen atom, and

in the presence of

c) a scavenging agent of formula iii) or formula iv), where

formula iii) is R²-C≡N, where R² is an organic group, and

formula iv) is 0=C=N-R³, where R³ is an organic group, and

d) a catalyst;

2. The method of claim 1 , where step 1 ) is performed neat.

3. The method of claim 1 or claim 2, where ingredient a) is HCI.

4. The method of any one of claims 1 to 3, where M is Si, x = 4, and R¹ is alkyl of 1 to 4 carbon atoms.

5. The method of any one of claims 1 to 4, where ingredient c) is acetonitrile or ethyl isocyanate.

6. The method of any one of claims 1 to 5, where ingredient d) is a Lewis acid.

7. The method of claim 6, where the Lewis acid is selected from selected from FeCk;, ZnCI₂ and LiCI.

8. The method of any one of claims 1 to 5, where ingredient d) is a Lewis base.

9. The method of claim 8, where the Lewis base is hexamethyl phosphoramide.

10. The method of any one of claims 1 to 9, where step 1 ) is performed at a temperature from 20 °C to -40 °C and/or a pressure from 0 kPag to 206.7 kPag.

11 . The method of any one of claims 1 to 10, further comprising step 2), recovering the halogenated compound.

12. The method of any one of claims 1 to 1 1 , where the halogenated compound is a halosilane.

13. The method of claim 12, where the halosilane comprises SiCl4.

14. The method of any one of claims 1 to 13, further comprising 3) recovering the scavenging agent.

15. The method of claim 14, further comprising 4) recycling the scavenging agent recovered in step 3) in step 1 ).