An improved direct synthesis of alkenylhalosilanes.

Abstract

A process for the Direct Synthesis of alkenylhalosilane monomers is provided, comprising forming a slurry in a heat-stable solvent from a liquid and copper-activated silicon from virgin silicon, cyclone fines and / or fine dust from silicon grinding, ultrafine particles and / or spent contact mass from the Direct Synthesis of alkylhalosilanes and arylhalosilanes. The slurry is reacted with at least one of the compounds of formula R 1 X together with an unsaturated aliphatic or cycloaliphatic organic halide, and optionally an organohalosilane and / or hydrogen halide, in the presence of a polymerization-inhibiting Lewis base additive, 1 SiHX2, R 1 2SiHX, R 1 3SiX, R 1 SiX3, and R 1 The silanes are reacted with stirring for a reaction time, temperature, and pressure effective to produce an alkenylhalosilane having 2SiX2 or mixtures thereof.

Description

[Technical Field]

[0001] This application claims the benefit of and priority to Provisional Application No. 63 / 452,038, filed March 14, 2023, the entire contents of which are incorporated herein by reference. This invention relates to the synthesis, particularly slurry-phase Direct Synthesis, of alkenylhalosilanes from silicon powders, particularly copper-activated silicon reaction residues and by-products. Such silicon sources include the silicon-containing solid residues produced during the Direct Synthesis of organohalosilanes from organic halides. [Background technology]

[0002] Allylhalosilanes are useful intermediates for the synthesis of specialty organic chemicals and sulfur silanes useful in tire and rubber applications (see U.S. Pat. Nos. 3,890,213; 8,003,724; 8,349,940; and 8,536,261). A particularly valuable intermediate is allyltrichlorosilane, which can be converted to allyltriethoxysilane for the synthesis of sulfur silanes. The use of diallyldiethoxysilane for the preparation of polyester-glass fiber laminates is disclosed in U.S. Pat. Nos. 2,563,288 and 2,649,396. Polymerization of this product can be carried out in the direct synthesis of allylchlorosilane and other alkenylhalosilanes. Therefore, these reactions are typically unstable, and typical monomer yields are low.

[0003] Conventional methods for the synthesis of allylsilanes include the Grignard reaction (see, for example, TK Sarkar, Science of Synthesis, vol. 4 (2002) pp. 837-922) and the dehydrohalogenation reaction of halopropylsilanes (see, for example, Bailey, DL; Pines, AN, Ind. Eng. Chem. 1954, 46, pp. 2363).

[0004] Hurd (J. Amer. Chem. Soc., 67 (1945) p. 1813; U.S. Pat. No. 2,420,912) reported a fixed-bed direct synthesis of allyl chloride with a copper-silicon alloy at 200-400°C, optionally 230-300°C. The product mixture contained allyldichlorosilane (ADCS, C3H5SiHCl2), diallyldichlorosilane (DADCS, (C3H5)2SiCl2), and allyltrichlorosilane (ATCS, C3H5SiCl3), the latter being predominant.

[0005] U.S. Patent No. 2,904,574 discloses the direct synthesis of allylchlorosilanes via a fixed-bed reaction of allyl chloride with CuS (copper(I) sulfide)-coated silicon at 150-220°C. The examples show a product mixture containing 1-5 wt% allyldichlorosilane (ADCS, C3H5SiHCl2), 13-16 wt% allyltrichlorosilane (ATCS, C3H5SiCl3), and 11-24 wt% diallyldichlorosilane (DADCS, (C3H5)2SiCl2), in addition to unconverted allyl chloride and 30-50 wt% undistillable high-boiling residue.

[0006] U.S. Patent No. 5,338,876 discloses the direct synthesis of allylchlorosilanes in stirred-bed and fluidized-bed reactors at 220-350°C and 1-5 atmospheres, preferably 300-330°C and 1-3 atmospheres. This disclosure is particularly directed to the direct synthesis of allyldichlorosilanes (ADCS) by reacting freshly obtained silicon metal with a mixture of allyl chloride (AC) and hydrogen chloride, where the hydrogen chloride is in molar excess. The corresponding journal publication containing this information is Yeon et al. (Organometallics, vol. 12 (1993) pp. 4887-4891). Other references for the direct synthesis of allylhalosilanes, as well as other alkenylhalosilanes, using freshly obtained silicon metal in fixed-bed, stirred-bed, or fluidized-bed reactors are as follows: RJH Voorhoeve, Organohalosilanes: Precursors to Silicones, pp. 203-204; Petrov et al., Synthesis of Organosilicon Monomers, pp. 44-46 and Table 5, p. 55.

[0007] Hurd (supra) describes that diallyldichlorosilane rapidly polymerizes in the absence of a polymerization inhibitor when heated above 150°C. However, there is no teaching on how to control or avoid polymerization during the Direct Synthesis to achieve reaction stability. Polymerization of diallyl substrates such as diallyldimethylsilane has been reported in: Forbes et al., J. Amer. Chem. Soc., vol. 114 (1992) pp. 10978-10980; Marvel et al., J. Org. Chem., vol. 25 (1960) pp. 1641-1642; Butler et al., J. Org. Chem., vol. 25 (1960) pp. 1643-1644.

[0008] Alkyl and aryl halosilanes are valuable precursors to silicones and organofunctional silanes, used in a wide range of industries. Methyl and phenyl chlorosilanes are particularly valuable and are the most commonly produced products of their class. Production is typically carried out using the Rocho-Muller direct process (also known as direct synthesis or direct reaction), in which copper-activated silicon is reacted with the corresponding organohalide in a gas-solid or slurry-phase reactor at temperatures and pressures sufficient to achieve the desired reaction rate and stability, as well as product selectivity and yield. Fluidized-bed reactors are the most commonly used gas-solid reactors.

[0009] Organohalosilanes have the general formula R 1 a Six b wherein R 1 is a saturated or unsaturated aromatic group, a saturated or unsaturated aliphatic group, an alkaryl group, or an alicyclic hydrocarbyl group, such as methyl, ethyl, or phenyl; X is a halogen atom, such as chlorine or bromine; and a and b are positive integers provided that the sum (a+b)=4.

[0010] Organohalohydrosilanes have the general formula R 1 c SiH d X e wherein R 1 and X have the same meaning as above. The subscripts c, d, and e are positive integers that satisfy the sum (c+d+e=4).

[0011] Halosilane (H f Six g ), where f≧0 and g is an integer such that (f+g=4), and X is a halogen atom as defined above.

[0012] Organohalodisilanes are represented by the general formula (R 1 h X j SiSiX k R 1 l) has one Si-Si bond. 1 and X have the same meaning as defined above. The subscripts h, j, k, and l are independently ≧0 and sum to (h+j=3) and (k+l=3). By extension, trisilanes have Si-Si-Si units, while polysilanes have more than three connected Si atoms.

[0013] Typically, the silicon used in the direct process (Rochow-Muller direct process) is a chemical grade containing 98.5-99.5% pure silicon metal by weight. (All percentages in this application are by weight unless otherwise specified.) This silicon can be produced by any currently practiced method, such as casting, water granulation, atomization, and acid leaching. These methods are described in more detail in Silicon for the Chemical Industry (edited by H. Oye et al.), Vol. I (pp. 39-52), Vol. II (pp. 55-80), Vol. III (pp. 33-56, pp. 87-94), Tapir Publishers, Norwegian Institute of Technology, and U.S. Patent Nos. 5,258,053; 5,015,751; 5,094,832; 5,128,116; and 4,539,194.

[0014] The hot effluent discharged from the fluidized-bed reactor, in which copper-activated silicon reacts with organic halides, typically contains a mixture of copper, metal halides, metal silicon, silicides, carbon, gaseous organic halides, organohalosilanes, organohalodisilanes, carbosilanes, and hydrocarbons. This mixture generally first undergoes gas-solid separation in cyclones and filters (see U.S. Pat. No. 4,328,353). The gaseous mixture and fine solids are concentrated in a settler or sludge tank, from which the organic halides, organohalosilanes, hydrocarbons, and a portion of the organohalodisilanes and carbosilanes are vaporized and sent to a fractionator. The fine solids generally accumulate in the settler along with less volatile silicon-containing compounds, and this mixture (sludge) is typically periodically discharged and sent to waste treatment or secondary treatment for monomer recovery from the liquid fraction.

[0015] Generally, three silicon-containing solid residues are produced from the fluidized bed: (1) the elutriated solids captured in the cyclone or filter are called cyclone fines or cyclone solids; (2) the particles that leave the cyclone and are collected in the settler are called ultrafine particles, settler solids, or re-evaporator solids; and (3) the solids remaining in the fluidized bed unreacted at the end of the run, called spent material or spent contact mass. The spent material typically has a larger average particle size and a broader particle size distribution than the cyclone solids, which are typically larger than the ultrafine particles. The spent material and cyclone fines are dry solids and can be pyrophoric. The ultrafine particles are typically wet and agglomerated to form sludge. For this reason, the ultrafine particles are sometimes called sludge.

[0016] A world-class methylchlorosilane plant typically generates thousands of tons of ultrafine particles, cyclone solids, and spent materials annually, which must be disposed of at considerable cost and result in loss of raw material value. The waste disposal methods employed also have environmental impacts. Therefore, it is desirable to recover value from these waste solids. Patents and journals have disclosed methods for reusing the solids to recover copper and to produce chlorosilanes, alkoxysilanes, methylchlorosilanes, and phenylchlorosilanes. However, the reactions tend to be unstable, and monomer yields are typically low.

[0017] Passivation of cyclone solids for safe landfill disposal or later recovery of copper is disclosed in US Pat. No. 5,342,430.

[0018] U.S. Patent No. 2,803,521 discloses a method for separating and recovering silicon and copper from spent reaction mass. Soucek et al. (Chem.Abstr. vol. 64 (1966) 17638c) and Kopylov et al. (Chem.Abstr. vol. 75 (1971) 14421g) disclose a metallurgical process for recovering copper from calcined spent materials.

[0019] (Chem.Abstr.vol.81(1974)78008) reported the direct synthesis of phenylchlorosilanes using spent material from the direct synthesis of methylchlorosilanes. Takami et al. (Chem.Abstr.vol.89(1978)509946) disclosed a similar direct synthesis of phenylchlorosilanes from spent material from methylchlorosilanes, which is first heated to 500-900°C.

[0020] Ritzer et al. (U.S. Pat. No. 4,390,510) and others have shown that reaction of cyclone fines with HCl produces trichlorosilane and tetrachlorosilane. Reaction of cyclone fines with alcohol produces alkoxysilanes. Such uses of cyclone solids are shown in Catalyzed Direct Reactions of Silicon, KM Lewis and DG Rethwisch (eds.), Elsevier, NY 1993, pp. 28-29, and references cited therein.

[0021] U.S. Pat. No. 5,712,405 discloses collecting the cyclone fines and filtered fines and recycling them to the bottom of a fluidized bed reactor for further reaction with an organic halide to produce organohalosilanes.

[0022] US Patent No. 6,465,674 discloses the direct synthesis of chlorosilanes or organochlorosilanes by introducing cyclone fines into liquid silane and reinjecting the suspension into a fluidized bed.

[0023] U.S. Patent No. 4,224,297 discloses a method for recycling spent material having a maximum particle size of 50 micrometers, which involves heating the spent material at 100-350°C in air or nitrogen for at least 15 hours, followed by reaction with methyl chloride to produce methylchlorosilane monomers. This particle size distribution is too small for most conventional Rocho-Muller fluidized bed reactors.

[0024] The above references describing the synthesis of organohalosilanes from cyclone fines and spent materials involve gas-solid phase reactions in two-phase reactors. The references cited below use three-phase reactors, such as mechanically agitated slurry reactors and bubble columns that utilize all three phases of material.

[0025] British Patent No. 1,131,477 describes a process for preparing alkylhalosilanes, which involves suspending a contact mass composition in an inert liquid, such as a halogenated aromatic hydrocarbon, at a temperature above 175°C and reacting with an alkyl halide to produce the alkylhalosilane.

[0026] U.S. Pat. No. 7,153,991 discloses a slurry-phase direct synthesis of organohalosilanes, which involves preparing a slurry of a nanosized copper catalyst and 90 percent silicon, about 1 to about 300 micrometers, in a heat-stable organic solvent, followed by reaction with an organic halide at temperatures above 250° C.

[0027] U.S. Patent No. 9,249,165 discloses catalytic slurry-phase direct synthesis of organohalosilanes from cyclone fines, in which special additives are used to prevent solvent decomposition. The drawing shows the conversion to produce dimethyldichlorosilane. These additives include the addition of solvent-protecting terpenes, hexamethyldisiloxane, diphenylamine, and alpha-omega dialkyl polyethers.

[0028] All references cited herein (both above and below) are incorporated by reference in their entirety.

[0029] Numerous attempts have been made to recover valuable materials, particularly methylchlorosilane monomers, from spent materials and cyclone solids produced during the Direct Synthesis of organohalosilanes, such as methylchlorosilanes, but none of these attempts has resulted in a reliable process for producing sufficient quantities of the highly valuable alkenylhalosilane compositions.

[0030] It would be desirable to develop an improved method for synthesizing alkenylhalosilanes that avoids the drawbacks of conventional methods. Summary of the Invention

[0031] The present invention provides a stable and efficient slurry-phase Direct Synthesis of alkenylhalosilanes, particularly allylhalosilanes, from copper-activated fresh silicon, cyclone fines, spent materials, ultrafine particles, silicon dust from grinding, and other materials, as well as mixtures thereof, resulting in improved product yields and efficiency. This includes the synthesis of alkenylhalosilanes from silicon-containing solid residues produced during the Direct Synthesis of organohalosilanes (the Rocho-Muller Direct Process) and suitable organic halides. According to the present invention, certain additives exhibiting Lewis base properties are effective in preventing or inhibiting undesirable side reactions, such as the polymerization of allylhalosilanes.

[0032] One embodiment of the present invention provides a process for the synthesis of alkenylhalosilanes, which comprises forming a slurry of copper-activated silicon from virgin silicon, cyclone fines, fine dust from silicon grinding, ultrafine particles, and / or spent contact mass from the Direct Synthesis of organohalosilanes in a heat-stable solvent. The slurry is stirred and reacted with a compound of formula R 1 X is reacted with at least one unsaturated aliphatic or unsaturated alicyclic organic halide, and optionally an organohalosilane and / or hydrogen halide.

[0033] In accordance with the present invention, selected additives are added to prevent or control undesired side reactions or polymerization of the desired monomers. These additives typically exhibit Lewis base properties, which in particular have the ability to coordinate or react with Lewis acids or to adsorb to unoxidized copper surfaces.

[0034] The reaction time, temperature and pressure are calculated according to the formula R 1 SiHX2, R 1 2SiHX, R 1 3SiX, R 1 SiX3, and R 1 It is controlled to produce alkenylhalosilanes with 2SiX2 or mixtures thereof. 1is an unsaturated aliphatic or cyclic alkenyl group, and X is a halogen. The alkenylhalosilane or mixture thereof can then be recovered from the solvent, or more reactants can be added.

[0035] In accordance with the present invention, additives exhibiting Lewis base properties include selected sulfur-containing compounds, preferably including aliphatic and / or aromatic mercaptans (thiols), aliphatic and aromatic thioethers, thioureas, and aliphatic and aromatic thioureas, phenothiazines, and thioesters.

[0036] In another embodiment of the invention, the additive can be a mixture of tetramethylurea and hexamethyldisiloxane, and mixtures of these with one or more sulfur-containing additives.

[0037] Yet another aspect of the present invention is directed to the selective slurry-phase direct synthesis of allyltrihalosilanes, or mixtures of allyltrihalosilanes and allyldihalosilanes, from copper-activated silicon containing allyl halides, including virgin (fresh) silicon, grinding dust, cyclone fines, ultrafine particles, and / or spent materials, in the presence of hydrogen halides and an additive capable of inhibiting the Lewis acid-catalyzed polymerization of the allylhalosilanes.

[0038] Thus, the present invention improves the stability of slurry-phase Direct Synthesis. The present invention also enables stable slurry-phase Direct Synthesis of allylchlorosilanes in sufficient yield from cyclone fines and / or virgin silicon. DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention relates to the production of monomers, such as alkenylhalosilanes. A catalytic reaction process is provided for converting virgin copper-activated silicon, as well as process by-products such as spent material, cyclone fines, and / or ultrafine particles from the Direct Synthesis of organohalosilanes, into more useful and potentially valuable products, such as alkenylhalosilanes. Preferred products include monomers of the general formula: R 1 SiHX2, R 1 2SiHX, R 1 2SiX2, R 1 3SiX and R 1 SiX3 (and mixtures thereof). Particularly preferred monomers have the general formula: 1 SiHX2 and R 1 SiX3.R 1 is preferably an unsaturated aliphatic or cyclic alkenyl group, and X is a halogen atom.

[0040] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the terms used in this application and in the experimental procedures described are well known and commonly used in the art. Where a term is used in the singular, the inventors also contemplate that the plural form of that term is also applicable.

[0041] The expressions "virgin (fresh) silicon and virgin (fresh) copper-activated silicon" refer to silicon and copper-activated silicon that have not previously been reacted with an organic halide or alcohol, but may have already been reacted with a hydrogen halide.

[0042] "Direct process," "direct synthesis," and "direct reaction" refer to the Rochow-Muller (Eugene Rochow and Richard Muller) process, the most common technique for preparing organosilicon compounds on an industrial scale. It involves the copper-catalyzed reaction of alkyl halides with silicon, typically carried out in a chemical reactor, particularly a fluidized-bed reactor.

[0043] "Alkyl," as used herein, is intended to include straight-chain, branched-chain, and cyclic alkyl groups. Specific non-limiting examples of alkyl include, but are not limited to, methyl, ethyl, propyl, and isobutyl.

[0044] "Substituted alkyl," as used herein, refers to an alkyl group that contains one or more substituents that are inert under the process conditions to which the compound containing them is subjected, and that do not substantially or detrimentally interfere with the process.

[0045] "Aryl," as used herein, refers to any non-limiting example of an aromatic hydrocarbon from which one hydrogen atom has been removed. An aryl may have one or more aromatic rings, which may be fused or connected by a single bond or other group. Specific non-limiting examples of aryl include, but are not limited to, tolyl, xylyl, phenyl, and naphthalenyl.

[0046] "Substituted aryl," as used herein, refers to an aromatic group substituted as described above in the definition of "substituted alkyl." Like aryl, substituted aryl can have one or more aromatic rings, which can be fused or connected by a single bond or other group; however, when the substituted aryl has a heteroaromatic ring, the free valence of the substituted aryl group can be to a heteroatom (e.g., nitrogen) of the heteroaromatic ring instead of to a carbon. Unless otherwise specified, substituted aryl groups in this application preferably have from 1 to about 30 carbon atoms.

[0047] The present invention can involve a three-phase catalytic reaction process. Copper-activated silicon, spent material, cyclone fines, and / or ultrafine particles are suspended in a thermally stable liquid. They are then reacted with a gaseous alkenyl halide in the presence of an additive that exhibits Lewis base properties and inhibits side reactions and polymerization. Hydrogen halide can optionally be included. The desired organohalosilane is then recovered. Temperature, pressure, solvent / solids ratio, catalyst concentration, and reaction time can be adjusted to selected levels to achieve the desired conversion to alkenylhalosilane monomer. This type of three-phase catalytic reaction process can also be referred to as a slurry-phase process.

[0048] The preferred slurry-phase process according to the present invention for the direct synthesis of alkenylhalosilane monomers from virgin copper-activated silicon, spent material, cyclone solids, and ultrafine particles can result in silicon conversions of at least 40% by weight and greater. The total (ATCS + ADCS) can be 40%, 60%, and even higher by weight of the crude product. Allyl chloride is the preferred reagent, with gaseous HCl preferably injected therewith.

[0049] The process according to the present invention can be characterized by additives, such as selected sulfur-containing compounds, that suppress side reactions. These additives can reduce or eliminate polymerization of alkenylhalosilanes, allowing for a lower solvent / solids ratio and increased silicon conversion, resulting in the production of higher value alkenylhalosilane monomers.

[0050] The organic halide is an alkenyl halide (R 1 X), the reaction product is typically R 1 2SiX2, R 1 2SiHX, R 1 SiHX 2、 R 1 3SiX and R 1 SiX3, where R 1is an alkenyl radical having 2 to 8 carbon atoms, such as vinyl, allyl, methallyl, or cyclohexenyl, and X is a halogen. When the organic halide is an allyl halide, both allyltrihalosilanes and allyldihalosilanes are highly desirable.

[0051] Thus, the present invention provides a method for the preparation of virgin copper-activated silicon, spent material, cyclone fines and ultrafine particles (e.g., from the fluidized bed direct synthesis of organohalosilanes), and mixtures thereof with organic halides R 1 X in a three-phase reactor to form a compound of general formula R 1 SiHX2, R 1 2SiHX, R 1 3SiX, R 1 SiX3 and R 1 A process for the synthesis of organohalosilane monomers of 2SiX2 or mixtures thereof is provided. 1 is preferably an alkenyl radical having 2 to 8 carbon atoms, and X is preferably a halogen atom, such as fluorine, chlorine, bromine, or iodine. 1 Examples include allyl, vinyl, methallyl, and cyclohexenyl.

[0052] A preferred process according to the present invention comprises the following steps: (1) forming a slurry of copper-activated silicon from virgin silicon, cyclone fines, cyclone fine dust, silicon ultrafine particles, and / or spent contact mass from the Direct Synthesis of organohalosilanes in a heat-stable organic solvent; (2) stirring the slurry; (3) The stirred slurry is reacted with a solution of alkenylhalosilane of formula R in the presence of an additive effective to inhibit polymerization of alkenylhalosilanes exhibiting Lewis base properties. 1 and optionally at least one organohalosilane or hydrogen halide, the reaction being carried out for a reaction time, reaction temperature, and reaction pressure effective to produce an alkenylhalosilane having the formula R 1 SiHX2, R1 2SiHX, R 1 3SiX, R 1 SiX3, and R 1 2SiX2 or mixtures thereof, where R 1 is an unsaturated aliphatic or cyclic alkenyl group, and X is a halogen; and (4) Recovering the alkenylhalosilane from the slurry. In another embodiment, the process of the present invention may also comprise the additional step of: (5) separating the solid reaction residue from the liquid and reusing the recovered liquid in step (1); and / or (6) Passivating the solids and treating or recovering the copper. General formula R 1 SiX3 and R 1 The preference of SiHX2 over alkenylhalosilanes can be expressed as the following weight ratio: (R 1 SiX3 / R 1 2SiX2), (R 1 SiHX2+R 1 SiX3) / R 1 2SiX2, R 1 SiX3 / (R 1 2SiX2+R 1 3SiX+R 1 SiHX2+R 1 2SiHX) and (R 1 SiHX2+R 1 SiX3) / (R 1 2SiX2+R 1 3SiX+R 1 2SiHX).

[0053] Each of these ratios is preferably greater than 1, and more preferably greater than 5. 1 SiX3 and R 1 One reason SiHX2 are desirable is that they can be readily converted to alkenylalkoxysilanes, such as allyltriethoxysilane, which have utility as organofunctional silane coupling agents.

[0054] Reaction rates can be reported either as the transient consumption of silicon or alkenyl halide, or as the transient formation of alkenylhalosilane. Typical rate units include weight percent silicon conversion per hour, weight of crude alkenylhalosilane produced per hour, or kilograms of alkenylhalosilane per kilogram of silicon per hour. Stability can be considered the maintenance of the desired rate and selectivity until the raw materials are consumed, or until a predetermined silicon conversion limit is exceeded.

[0055] The alkenyl halide is introduced into the slurry as a gas, vapor, and / or liquid. The liquid can be fed under conditions where the flow rate is controlled to avoid a large reduction in reaction temperature and / or rapid expansion of bubbles formed upon evaporation. Mixtures of alkenyl halides and mixtures of alkenyl halide and hydrogen halide can also be used. Mixtures of allyl halide and hydrogen halide can be used in the R process when the cyclone fines are the source of copper-activated silicon. 1 According to a preferred embodiment of the present invention, it is advantageous that the molar ratio of the allylic halide to the hydrogen halide fed is greater than or equal to 0.8 to 1, and preferably in the range of 1 to 100. This ratio determines the R 1 SiHX2 and R 1 It is one of the variables that influences the relative amount of SiX3. The value that results in the desired product composition can be established by experimentation.

[0056] As noted above, allylalkoxysilanes are important intermediates for the preparation of sulfur organofunctional silanes. The alkenylhalosilanes R produced by the process of the present invention are 1 SiHX2 and R 1SiX3 can be converted to alkenylalkoxysilanes via reaction with an appropriate alcohol. For example, as disclosed in U.S. Patent No. 6,878,839, allyldichlorosilane (ADCS) and allyltrichlorosilane (ATCS), either individually or as a mixture, can be reacted with ethanol to form allyltriethoxysilane (Equations 1 and 2). To produce allyltriethoxysilane in high yield, efficient removal of hydrogen chloride or the presence of a hydrogen chloride acceptor is important. In the absence of a hydrogen chloride acceptor, hydrogen chloride readily adds to the double bond of allyltriethoxysilane (Equation 3), resulting in cleavage of the C-Si bond, the formation of by-products, and a reduced yield of allyltriethoxysilane. [ka] [ka] [ka]

[0057] When sodium ethoxide was used as the HCl acceptor, tetraethoxysilane was generally the major product. The hydrochloride salt formed a concentrated ionic liquid with 1-methylimidazole (see U.S. Pat. No. 7,351,339), which facilitated the isolation of allyltriethoxysilane. The yield was 87%. When poly(vinylpyridine) was used as the HCl acceptor, allyldichlorosilane was quantitatively converted to allyldiethoxysilane and allyltrichlorosilane, as well as allyltriethoxysilane. The insolubility of poly(vinylpyridine) allowed for easy recovery of the reaction products. Thus, the crude allyltrichlorosilane product, containing ADCS, ATCS, and DADCS, could be ethoxylated in the presence of 1-methylimidazole to produce allyltriethoxysilane (boiling point 147°C) and diallyldiethoxysilane (boiling point 189.5°C). The same crude product, when ethoxylated in the presence of poly(vinylpyridine) as an HCl acceptor, produces allyldiethoxysilane (boiling point 108°C), allyltriethoxysilane (boiling point 147°C), and diallyldiethoxysilane (boiling point 189.5°C), which can be recovered individually by distillation.

[0058] Silicon, spent contact mass, cyclone fines, and ultrafine particles The silicon metal reactant used in preferred embodiments of the process of the present invention can be any commercially available grade of particulate silicon. It may be produced by any currently practiced method, such as casting, water granulation, spraying, and acid leaching. These methods are described in more detail in Silicon for the Chemical Industry (edited by H. Oye et al.), Vol. I (pp. 39-52), Vol. II (pp. 55-80), Vol. III (pp. 33-56, pp. 87-94), Tapir Publishers, Norwegian Institute of Technology, and U.S. Patent Nos. 5,258,053; 5,015,751; 5,094,832; 5,128,116; and 4,539,194.

[0059] A special type of chemical-grade silicon containing controlled levels of promoters and alloying elements is also suitable, provided that copper is not one of the alloying elements. This type of special silicon is described in U.S. Patent Nos. 5,059,43; 5,714,131; 5,334,738; 5,605,583; 5,973,177; 6,057,467 and European Patent Nos. 0,494,837 and 0,893,448. A typical composition, expressed by weight, of commercially available chemical-grade silicon metal useful in the present invention is: Si - 98.5%, Fe - 0.1 to 0.7%, Al - 0.05 to 0.7%, Ca - 0.001 to 0.3%, Pb < 0.001%, and Water < 0.1%. Generally, smaller particle sizes are preferred for ease of dispersion in the slurry, faster reaction, and minimal corrosion in the reactor. Preferably, no particles are larger than 500 micrometers, minimizing reactor corrosion. The particle size distribution is preferably such that at least 90% by weight of the silicon is between 1 and 300 micrometers. A particularly preferred distribution is one in which at least 90% by weight of the silicon particles are between 1 and 100 micrometers. This includes dust from the silicon granulation operation.

[0060] During the Direct Synthesis of methylchlorosilanes and phenylchlorosilanes, particularly fluidized-bed Direct Synthesis, silicon is typically steadily consumed from the contact mass and converted to volatile organochlorosilane products. Whether batchwise or with continuous addition of additional silicon, copper catalyst, and promoter, a point is reached where the desired product yield and selectivity cannot be economically maintained. At the end of the process, a solid residue is typically left behind. This residue is referred to as spent contact mass or spent material. It generally contains unreacted silicon, unreacted copper-activated silicon, copper, copper chloride, chlorides of metals originally present in the silicon (e.g., AlCl3, TiCl4, FeCl3), chlorides of promoter elements (e.g., Zn, Sn, P, Bi), and carbon. Compared to the unused contact mass, the particle size distribution is eliminated in particles less than about 75 micrometers.

[0061] The elutriated solids captured in the cyclone or filter are called cyclone fines or cyclone solids. Cyclone solids are typically less than about 50 micrometers in size, with 90 percent of the particles between 1.0 and 20 micrometers. The silicon content should be approximately 40-80% by weight, and the content of Cu, Al, Fe, Sn, Zn, P, C, and other elements is enriched compared to the virgin or spent contact mass. For example, copper is typically 2% by weight in the spent material and 10% by weight in the cyclone solids. Aluminum is typically about 1% by weight in the spent material and about 2% by weight in the cyclone solids. Iron is typically about 1.5% by weight in the spent material and about 3% by weight in the cyclone solids. Tin, zinc, and phosphorus may be 5 to 50 times more concentrated in the cyclone solids than in the spent material.

[0062] The particles that exit the cyclone and are collected in the settler are called ultrafine particles, settler solids, or reevaporator solids. Their particle size is generally about 0.1 to 5 micrometers. The silicon content should be about 40-60% by weight, copper about 10-20% by weight, and Al, Fe, Sn, Zn, C, and P are usually more concentrated than in the cyclone fines and spent material. While the spent material and cyclone fines are dry solids and potentially pyrophoric, the ultrafine particles are wetted with organohalosilanes and agglomerated into sludge. For this reason, the ultrafine particles are sometimes referred to as sludge.

[0063] The sludge can be filtered, centrifuged, or dried to separate the solids from the liquid. The liquid typically contains organohalosilane monomers, organohalodisilanes, organosiloxanes, and hydrocarbons. Fractional distillation of the liquid can recover the individual monomer and disilane fractions, which can be cleaved into monomers by conventional means and by the improved methods disclosed in U.S. Patents 8,637,895 and 8,697,901. The solids content of the sludge is advantageously less than 65% by weight, preferably 20-60% by weight to facilitate stirring and flow. The sludge can be thermally dried, with or without vacuum, to produce a free-flowing powder for use in the present invention. Alternatively, the sludge is added to a reaction solvent in an amount that facilitates stirring of the resulting slurry, and the organohalosilane monomer, organohalodisilane, organosiloxane, and hydrocarbon are evaporated by heat and inert gas stripping prior to introducing the organohalide reactant.

[0064] The process according to an embodiment of the present invention can perform the Direct Synthesis of alkenylhalosilanes using virgin silicon, grinding dust, spent contact mass, cyclone fines, ultrafine particles, and mixtures thereof. It has been found that the composition of the product can be advantageously controlled by the selection of the silicon source. Thus, the composition of the product can be controlled by combining the virgin silicon and cyclone fines in the appropriate ratio.

[0065] Halogenated alkenyl-R 1 X General formula R 1 X represents the alkenyl halide used to react with the copper-activated silicon of the present invention. 1 is an unsaturated aliphatic or cyclic alkenyl hydrocarbon radical, and X is a halogen atom. 1Examples of alkenyl halides are groups such as vinyl, allyl, methallyl, and cyclohexenyl. Suitable examples of alkenyl halides are vinyl chloride, allyl chloride, allyl bromide, methallyl chloride, and cyclohexenyl chloride. Allyl chloride and cyclohexenyl chloride are preferred organic halides.

[0066] The allyl chloride preferably has a purity greater than 98 percent. It preferably vaporizes below the temperature at which thermal decomposition and polymerization begin. Allyl chloride can be mixed with hydrogen chloride, methyltrichlorosilane, or dimethyldichlorosilane, vaporized at 80-100°C, and injected into the reaction slurry.

[0067] Reaction Solvent Solvents for Direct Synthesis according to embodiments of the present invention must maintain the particulate solids well dispersed and facilitate mass transfer of the alkenyl halide to the active catalytic sites of the copper-activated silicon. Ideal solvents useful in the process of this invention are thermally stable compounds or mixtures that do not degrade under activation and reaction conditions. Structurally, the solvents are advantageously straight- and branched-chain paraffins and naphthenes. One class of preferred paraffinic solvents are organic solvents stable at high temperatures that are typically used as heat transfer media. Examples include aliphatic heat transfer fluids available from Petro Canada, such as Calflo. TM A.F., Calflo TM LT and Calflo TM There is HTF.

[0068] Naphthenes are cycloparaffins. They are components of white mineral oils, petroleum fractions, and certain fuels. White mineral oils and petroleum fractions also contain normal and branched paraffins (see A. Debska-Chwaja et al., Soap, Cosmetics and Chemical Specialties (November 1994), pp. 48-52; ibid. (March 1995), pp. 64-70). Suitable examples of commercially available naphthenes and paraffins useful as reaction solvents in the present invention include white mineral oils CARNATION 70, KAYDOL, and petroleum fractions sold by Sonneborn. Other examples of naphthenes useful as reaction solvents include decahydronaphthalene, perhydroanthracene, perhydrophenanthrene, perhydrofluorene and their alkyl derivatives, perhydroterphenyl, and perhydrobinaphthyl and their alkyl derivatives.

[0069] CALFLO sold by Petro-Canada TM The heat transfer fluid is a paraffin-based material that is thermally stable up to about 250-330°C. A suitable example is CALFLO TM L.T., CALFLO TM AF and CALFLO TM HTF. Squalane is another paraffinic solvent suitable for the slurry-phase Direct Synthesis process of the present invention. Its unsaturated derivative, squalene, is also an effective solvent. Direct Synthesis in paraffinic and olefinic solvents is desirably carried out at temperatures below 330°C. Mixtures of naphthenes with normal and branched paraffins are also useful as reaction solvents in the present invention.

[0070] It is desirable that all solvents be free of components with normal boiling points below 200°C, and in particular free of compounds with normal boiling points that overlap with the boiling point of the resulting alkenylhalosilane. It is also desirable for the practice of this invention that the solvent does not decompose into low molecular weight compounds when heated alone or when contacted with silicon, copper-activated silicon, cyclone fines, ultrafine particles, and sludge at temperatures up to about 350°C and pressures up to about 10 bar. Product analysis, distillation, and purification can be complicated by low molecular weight hydrocarbons and other compounds with normal boiling points that overlap with the boiling point of the alkenylhalosilane. It is desirable to avoid or prevent the formation of these impurities.

[0071] The used solvent can be treated to remove solids, metal salts, polymer by-products, and other accumulated impurities prior to recycling and reuse in the slurry reactor. Such recovery involves filtering the solids and stripping the filtrate at temperatures up to about 250°C (atmospheric pressure) to remove low-boiling hydrocarbons and distillable silicon-containing by-products. Alternatively, the solvent can be recovered by distillation under reduced pressure and separated from the copper-bearing solids from which copper is recovered.

[0072] Silicon, copper-activated silicon, cyclone fines, ultrafine particles, spent material, and mixtures thereof can be added to the reactor in any order along with the solvent. The solvent must be present in an amount sufficient to uniformly disperse the solid and gaseous reactants. Generally, the reaction is initiated at a solids to solvent weight ratio of about 1:2 to about 6:1, preferably about 2:1 to about 5:1. However, as silicon is consumed during batch Direct Synthesis, the solvent to solids ratio increases. To allow the reaction to continue, this ratio can be maintained within the narrow limits of a preferred range.

[0073] additives It has been found that the presence of Lewis acids, such as AlCl3, TiCl4, and FeCl3, in the cyclone fines, ultrafine particles, and spent materials, as well as the presence of oxygen-free copper, can undesirably contribute to the decomposition and / or polymerization of alkenyl halides, solvent degradation, and other side reactions, either preventing the formation of the desired alkenylhalosilane or promoting its polymerization once the alkenylhalosilane is formed. These undesirable reactions can be prevented or controlled by the use of selected additives. Specifically, these additives can coordinate or react with Lewis acids or can be adsorbed onto oxygen-free copper. These additives have been found to exhibit Lewis base properties.

[0074] Bases such as amines that bind to copper residues are generally not the most desirable polymerization inhibitor additives. In general, "hard" Lewis acids tend to contain smaller molecules, such as various chlorides. Thus, "soft" Lewis bases tend to be the most effective polymerization inhibitors according to the present invention. Those skilled in the art will be able to determine, without undue trial and error, which additives exhibiting Lewis base properties, in addition to those listed below, can effectively inhibit undesired polymerization.

[0075] Lewis acids and the oxygen-free copper mentioned above include both those present in the initial cyclone fines, ultrafine particles, and spent material feedstocks, and those produced as a result of the Direct Synthesis of alkenyl halides in the reaction slurry. Additives must be selected so as not to inhibit the Direct Synthesis and / or cause undesirable chemical reactions in the alkenylhalosilanes being produced. However, as demonstrated by the following examples, not all additives are equally effective at inhibiting the synthesis of alkenylhalosilanes. For example, dibutyl sulfate, thiourea, and tetramethylurea are more effective at inhibiting the polymerization of allyltrichlorosilane than allyldichlorosilane.

[0076] Sulfur-containing additives with -SH functionality (thiols or mercaptans), -CH2-S-CH2- (thioethers), -SS- (disulfides), >C=S (thioketones), and (>N)2C=S (thioamides and thioimidazoles) have been shown to effectively inhibit the polymerization of alkenylhalosilanes both experimentally and during the Direct Synthesis. Cyclic sulfur-containing compounds, such as thiophenes, phenothiazines, thiomorpholines, and 1,4-thioxanes, have also been found to be effective inhibitors of the polymerization of alkenylhalosilanes and polymerization occurring during the Direct Synthesis of alkenylhalosilanes. These additives are advantageous in that they are resistant to decomposition during the Direct Synthesis and have boiling or sublimation points higher than the temperatures at which the Direct Synthesis is carried out.

[0077] The mercaptan additives of the present invention have the general formula RSH and HS(Q)SH, where R is a straight or branched chain aliphatic group, an aryl group, an alkaryl group, or a cycloaliphatic group. Q is a group that bridges between sulfur atoms in a thiol having more than one sulfur atom. Thus, Q can be a straight or branched chain alkylene group having 2 to 20 carbon atoms. Q can also be an oxyalkylene group, a phenylene group, or a cycloaliphatic group. Examples of Q include -CH2. n -, (n = 1 to 8) and -(CH2) n -O(CH2CH2O) x —CH2CH2—, n=1 to 4, x=1 to 8.

[0078] Aliphatic examples of R include C8 to C20 alkyl radicals, such as octyl, dodecyl, and octadecyl. Suitable mercaptan additives include C 10 H 21 SH, C6H 13Examples of HS(Q)SH include C(CH3)2SH (tert-nonyl mercaptan), p-heptylbenzyl mercaptan, furfuryl mercaptan, and grapefruit mercaptan (1-p-menthen-8-thiol). 1,5-Pentanedithiol, HS(CH2)5SH, 1,9-nonanedithiol, HS(CH2)9SH, and 2,2'-(ethylenedioxy)diethanethiol, HSCH2CH2OCH2CH2OCH2CH2SH.

[0079] The effective amount of mercaptan or mixture of mercaptans used must be at least stoichiometrically sufficient to bind and inactivate the Lewis acids initially present and / or generated during Direct Synthesis. An amount can be added at the beginning of the reaction, with additional amounts introduced periodically or continuously. When cyclone fines and / or spent materials are the silicon source for Direct Synthesis, the initial level of mercaptan used can be determined from the aluminum content of the cyclone fines and spent materials. At the beginning of the reaction or at any time during the reaction, the stoichiometric ratio (SH / Al) can be 0.05 to 15, preferably 2 to 5. For virgin, chemical-grade silicon, a lower ratio can be used initially, and the ratio can be increased for subsequent silicon charges. Higher ratios result in inhibition of polymerization caused by Lewis acids other than AlX3.

[0080] Thiophene, phenothiazine, thiomorpholine, and 1,4-thioxane are examples of heterocyclic sulfur-containing additives that are effective inhibitors of the polymerization of alkenylhalosilanes.

[0081] Dodecyl methyl sulfide, CH3(CH2) 11 SCH3 and ethyldithioacetate, CH3CSSCH2CH3, are examples of thioether and thioester additives, respectively, which are effective inhibitors of the polymerization of alkenylhalosilanes.

[0082] Urea, tetraalkylureas, thioureas, and tetraalkylthioureas are another class of additives that are effective in inhibiting the polymerization of alkenylhalosilanes, including the polymerization of alkenylhalosilanes produced during the Direct Synthesis. These additives can be used alone or in combination with the sulfur-containing additives described above.

[0083] Advantageously, the effective use level of all additives is greater than or equal to the molar concentration of the Lewis acid in the reaction mixture. Nevertheless, their inhibitory effect on the polymerization of alkenylhalosilanes can be observed even at low concentrations. In all cases, the additives must be charged initially and then preferably added continuously or intermittently according to the course of the reaction. The initial charge and subsequent additions must be effective to provide stable selectivity for the desired silane (allyltrichlorosilane and allyldichlorosilane when the organic halide is allyl chloride) and to prevent solvent decomposition.

[0084] Reaction conditions Design, description, and operational considerations for three-phase reactors (e.g., stirred slurry reactors, bubble columns, trickle beds) are contained in the following books, articles, and patents, all of which are incorporated herein by reference: A. Ramachandran and RV Chaudhari, Three Phase Catalytic Reactors, Gordon and Breach Science Publishers, NY, 1983 N. Gartsman et al., International Chemical Engineering, vol. 17 (1977) pp. 697-702 H. Ying et al., Industrial & Engineering Chemistry, Process Design & Development, vol.19(1980) pp.635-638 N. Satterfield et al., Chemical Engineering Science, vol. 35 (1980) pp. 195-202 M. Boxall et al., Journal of Metals (August 1984) pp. 58-61 W. Roeckel, C. Scaccia and J. Conti, U.S. Patent No. 4,328,175 (May 4, 1982) LMLitz U.S. Patent No. 4,454,077 (June 12, 1984)

[0085] The reactor may be operated in batch or continuous mode. In batch operation, a single addition of silicon and copper catalyst precursor, optionally containing cyclone fines, ultrafine particles, or spent material, either individually or mixed with each other, must be made to the reactor initially, and alkenyl halide vapor is added continuously or intermittently until the silicon is completely reacted or reacted to the desired conversion level. In continuous operation, the cyclone fines, ultrafine particles, and / or spent material, and optional additives, are added to the reactor initially, and then the solids content and slurry composition are maintained within desired limits.

[0086] In a preferred form, the present invention involves the Direct Synthesis of Alkenylhalosilanes from Copper-Activated Silicon by contacting a gaseous alkenyl halide with a solvent, silicon, and a copper catalyst precursor, optionally containing cyclone fines, ultrafine particles, or spent materials, either individually or mixed together, tetramethylurea and / or a sulfur-containing additive, and a foam control agent in a continuously stirred slurry reactor. The reactor may have a single nozzle or multiple nozzles for gas introduction. Means for continuous or intermittent addition of silicon, copper catalyst precursor, cyclone fines, ultrafine particles, or spent materials, and a polymerization inhibitor additive may also be provided. Means for continuous removal and recovery of volatile alkenylhalosilane reaction products and unreacted alkenyl halide are also desirably provided. Separation and purification of the alkenylhalosilane product are ideally accomplished by continuous fractional distillation.

[0087] The reaction is generally carried out at a temperature above about 180°C, but below a temperature that would degrade or decompose the reactants, solvent, or desired product. Preferably, the reaction of allyl chloride with copper-activated silicon is carried out at a temperature below about 300°C, more preferably within the range of about 200°C to about 280°C. The pressure at which the reaction is carried out can vary from subatmospheric to superatmospheric. Generally, pressures between atmospheric and about 10 atmospheres are used. A preferred range is 1 to 5 atmospheres. The reaction time ranges from 0.1 to 100 hours.

[0088] Preferably, the contents of the reaction mixture are stirred to maintain a well-mixed slurry of the copper-activated silicon, polymerization inhibitor additive, foam control agent, and gaseous alkenyl halide in the solvent. The stirring speed and input power must be sufficient to allow effective mass transfer of the reactants to the copper-activated silicon surface and to keep the largest particles suspended in the solvent and prevent them from settling to the bottom of the reactor. Input power is usually calculated as a power-to-volume ratio. Those skilled in the art will be familiar with the relevant equations.

[0089] The exit line carrying the reaction mixture from the reactor is preferably well insulated to ensure that the alkenylhalosilane remains gaseous. Solvent vapors and droplets present in the gas stream can be removed by cooling to a temperature that allows condensation, and the alkenylhalosilane can be returned to the reactor as evaporated and / or removed by passing the reaction mixture through a demister. Volatile metal salts, such as AlCl, FeCl, SnCl, TiCl, ZnCl, and mixed metal salts (e.g., CuAlCl) that escape from the slurry can also be removed thereby.

[0090] The presence of gaseous alkenyl halides, alkenylhalosilanes, and other gases in the reactor can lead to foaming, which is undesirable because it results in the loss of solvent and solids from the reactor. U.S. Patent No. 5,783,720 (1998) describes the use of foam control agents, preferably silicon-containing foam control agents, such as Momentive's SAG foam control agent. 登録商標 1000, SAG 登録商標 100, SAG 登録商標 The addition of SAG 47, FF170, and Dow Corning's FS1265 has been shown to eliminate or control foaming in the slurry-phase Direct Synthesis of trialkoxysilanes. These are also effective foam control agents in the process of the present invention. 登録商標 1000, SAG 登録商標 100 and SAG 登録商標 47 is a composition containing polydimethylsilicone and silica. FS1265 and FF170 contain fluorinated silicones, such as poly(dimethylsiloxane-co-trifluoropropyl-methylsiloxane). The foam control agent is preferably long-lasting; a single addition at the beginning of a batch reaction is sufficient to prevent or mitigate foam formation until all the silicone is consumed. Effective use levels of foam control agents range from 0.000001 to 5 wt.%, based on the initial total weight of the reaction slurry. Higher levels may result in a slower reaction rate. Physical and mechanical methods to prevent or control foam formation can also be used. These include rakes, ultrasonic devices, and foam traps.

[0091] Example

[0092] The following examples are presented to illustrate preferred embodiments of the present invention. They are not intended to limit the scope of the invention. Rather, they are presented to illustrate the scope and content of the invention. TIFF2026508653000004.tif97163

[0093] When the alkenyl halide was allyl chloride, the reaction products and unreacted alkenyl halide were discharged from the reactor via a bubble trap and a 40 cm long x 2.5 cm diameter Vigreux column controlled at 140-160 °C. This acted as an entrainment separator for solvent droplets and metal salts. The gaseous reaction mixture was then introduced into a condenser, cooled to ~0 °C with chilled silicone oil, and collected in a sampling flask fitted with a dry ice-isopropanol cold finger (-65 °C). The gases emerging from the collection flask were cooled by a second dry ice-isopropanol cold finger (-65 °C) before being vented to a fume hood through a vapor-fixed bubbler. The liquid collected in this second, final trap was recovered at the end of the experiment, weighed, and analyzed; the data were used to calculate the total amount of silicon conversion. The bubbler contained silicone oil and had a separate opening for releasing excess pressure.

[0094] Samples were collected in weighed flat-bottom flasks and analyzed by gas chromatography. Gas chromatographic analysis of reaction products was performed using an HP 5890E chromatograph. The column was 10 feet x 1 / 4 inch ID and packed with acid-washed Chromosorb P coated with 30 wt% OV-210. The program, flow rate, and other conditions were appropriate for the sample being analyzed.

[0095] The response factors of a gas chromatographic thermal conductivity detector for allyl chloride and allylchlorosilane were experimentally determined using mixtures in dodecane. These values ​​showed good agreement with those calculated from chemometric parameters (see A.E. Smith (ed.), The Analytical Chemistry of Silicones, pp. 282-284). The quantitative analysis error was ±2%.

[0096] Gas chromatography / mass spectrometry (GC / MS) analysis was performed using an Agilent 6890GC / 5973MSD instrument equipped with a 30-meter-long ZB5 (5% phenyl, 95% methylpolysiloxane) capillary column. The column inner diameter was 0.25 mm and the film thickness was 2.5 mm. The carrier gas was helium, and the injection split ratio was 200:1. The injection port and GC / MS interface temperatures were 250°C and 270°C, respectively. The injection volume was 1 μl. The oven temperature was held at 50°C for 2 min, then increased to 340°C at a rate of 8°C / min and held for 16 min. The mass analyzer was operated in full scan (m / z 10–800) mode with EI (70 eV electron impact ionization).

[0097] For NMR characterization, samples were analyzed using a Bruker AVANCE600 spectrometer operating at a field strength of 14.1 T. Proton ( 1 H) resonates at 600 MHz at this field strength. 29 Samples for Si NMR were prepared as 25% to 30% (v / v) solutions in Cr(AcAc)3 / CDCl3, with a final Cr salt concentration of ~0.05 M Cr(AcAc)3. The solutions were placed in 10 mm NMR tubes. Chemical shifts were referenced to tetramethylsilane (TMS) as an external standard. 29 For the Si measurements, an inverse gated decoupling pulse sequence with a pulse width of 45° was used. A 10-second delay (AQ = 1.4 seconds) was added between each scan. Line broadening (LB) of 2 Hz was applied for data processing.

[0098] Materials used in the illustrative examples Cyclone fines and ultrafine particles (sludge) were obtained from a commercial production of methylchlorosilane. The cyclone fines ranged in size from 1 to 10 micrometers, with an average of 5 micrometers. Their composition is summarized in Table 1. Virgin silicon used in some experiments had an average particle size of 30 mm and an elemental composition of Fe = 0.31%, Al = 0.27%, Ti = 0.033%, Ca = 0.021%, and P = 0.0045%.

[0099] The solvent used was Calflo TM AF and Calflo TM It contained LT. [Table 1]

[0100] The allyl chloride used was a commercially available product with a purity of 98.5-99.5%. Major impurities included 2-chloropropene, 2-chloropropane, 1-chloro-1-propene, and 1,5-hexadiene. In some experiments, allyl chloride was delivered by syringe to the top of the reaction slurry. In others, allyl chloride was vaporized at 80 °C and introduced into the bottom of the reactor. Mixtures of allyl chloride with methylchlorosilane or HCl were also used in some experiments.

[0101] Examples 1A-1C (Comparative Examples) The desired monomer is volatile and evaporates from the reaction slurry. The undesired polymer is heavy and accumulates in the vessel. Thus, weight gain indicates that undesired polymerization is occurring. The three experiments in this example were performed by Calflo. TM Figure 1 illustrates the weight and volume increase of the reaction mixture during the slurry-phase Direct Synthesis of allyltrichlorosilane and allyldichlorosilane from an allyl chloride-HCl mixture in AF and cyclone fines. This weight increase is due to polymerization and side reactions, primarily the formation of diallyldichlorosilane (DADCS), as explained below. The amounts of materials used and reaction conditions are outlined in Table 2.

[0102] In each experiment, Calflo TM AF and cyclone fines (~70 wt% Si) were charged to the reactor along with FF-170. The reaction mixture was sparged with nitrogen at 100 mL / min, stirred at 500 rpm, and heated to 235°C. HCl gas was then introduced into the reactor at 420 mL / min. Allyl chloride was delivered from a reservoir to an evaporator heated to 80°C and then fed as a vapor to the reactor. Due to the exotherm, the actual average reaction temperature (Table 3) was higher than the setpoint.

[0103] [Table 2]

[0104] The gaseous reaction products were condensed, and the liquid was collected every half hour and then analyzed by gas chromatography. The experiment was terminated after the reaction times shown in Table 2. Table 3 shows the total weight of the crude product collected, the weight and composition of the recovered product, and the percent silicon conversion calculated based on the weight of silicon obtained in the cyclone fines. Table 3 also outlines the composition of the major silicon-containing products in the crude product.

[0105] [Table 3]

[0106] An increase in the weight of the slurry was observed during the reaction. This indicates that a reaction product was formed that was not discharged from the reactor at the above reaction temperature due to polymerization and other side reactions. Polymer formation (300.4 g) was greatest in Example 1A, which was carried out with the highest allyl chloride / HCl molar ratio and for the shortest time. This example also had the highest DADCS and the highest ATCS / ADCS weight ratio (1.44). Based on the data and observations in the above-mentioned references and Examples 2-5, it was assumed that the weight increase was due to polymerization of allylchlorosilane. The adjusted silicon conversions shown in Table 3 were calculated based on the assumption that diallyldichlorosilane (DADCS), with 15.50 wt% Si, was the primary driver of polymer formation.

[0107] The basis for the calculation is as follows: Normally, silicon evaporates from the reactor as allylchlorosilane, causing the reactor to lose weight. If polymerization occurs, the mass produced must first offset this loss due to the reaction of silicon before any gain appears. Thus, the total weight of the polymer is the sum of the reacted silicon and the increased weight of the reactor.

[0108] Examples 2A-2C: Polymerization of Allyl Chloride Under Different Conditions (Comparative Examples) These examples demonstrate that it is the reaction product of allyl chloride and cyclone fines that undergoes polymerization, not the allyl chloride itself.

[0109] Polymerization of allyl groups via peroxide and metal complex catalysts is well known in the literature (Forbes et al., Marvel et al., and Butler et al., supra). Therefore, a set of experiments under different conditions was carried out in the apparatus described in Example 1 to determine whether the mass increases observed in Examples 1A-1C were due to polymerization of allyl chloride. Table 4 lists these different conditions and the corresponding changes in residue weight.

[0110] [Table 4]

[0111] At 235°C (Example 2A), 52 g (0.68 mol) of allyl chloride and 7.44 ml / min of HCl (3.32 x 10 -4 (mol / min) to Calflo TM Feed during AF for 30 minutes resulted in no weight gain in the reactor. 52 g (0.68 mol) of allyl chloride was added over 30 minutes, and 7.44 ml / min of HCl (3.32 x 10 -4 (mol / min) to Calflo TM Adding 4.9 g of AlCl to AF (Example 2B), i.e., in the presence of a Lewis acid present in the cyclone fines, also resulted in no weight gain. However, adding 52 g of allyl chloride (0.68 mol) and 7.44 ml / min of HCl (3.32 x 10 -4 When 1000 mol / min was fed over 30 minutes to a reactor containing cyclone fines (154.7 g) and 4.9 g of AlCl (Example 2C), 20 g of non-distillable material was formed. These results indicate that the material produced in the reactor was most likely due to further reactivity of the allylchlorosilanes formed from the reaction of allyl chloride / HCl and silicon in the cyclone fines, rather than polymerization of allyl chloride itself. Examples 3A~3C (comparative examples)

[0112] Examples 3A-3C describe the Friedel-Crafts reaction of allylchlorosilanes with toluene (Example 3A) and the undesired polymerization of allylchlorosilanes when heated at 70°C in toluene or dodecane in the presence of AlCl (Examples 3B-3C). These experiments were conducted in a 50 ml, three-necked, round-bottom flask equipped with a reflux condenser, magnetic stirrer, and thermocouple. The amounts of materials used in these experiments are listed in Table 5.

[0113] In Example 3A, a violent exothermic reaction occurred when the DADCS in toluene mixture was added to AlCl in the reaction flask. The product was a brown, viscous solution. GC / MS of the reaction mixture showed a component with mass 272, which corresponds to the isomers of the Friedel-Crafts reaction of DADCS with toluene, as shown in the reaction below. [ka]

[0114] In Example 3B, no reaction was observed when DADCS and dodecane were refluxed at 70°C for 2 hours or stirred with 6.5 wt% AlCl at room temperature for 1 hour. However, when DADCS was heated with 6.5 wt% AlCl in dodecane at 70°C for 1.5 hours, a brown, insoluble solid was produced. GC analysis of this solution indicated that 93 percent of the DADCS had been consumed.

[0115] [Table 5]

[0116] In Example 3C, 0.213 g of AlCl3 was added to 3.73 g of a mixture of 65 wt % ATCS and 35 wt % ADCS dissolved in 6.0 g of dodecane. After stirring at room temperature for 1 hour, no observable reaction occurred. Heating at 70°C for 1.5 hours produced an insoluble polymer. GC analysis of the liquid indicated that all of the ADCS and ATCS had been consumed.

[0117] The results of these experiments demonstrate that Lewis acids such as AlCl are capable of catalyzing the undesired polymerization of allylchlorosilanes at temperatures lower than those used in the Direct Synthesis reaction. Example 3A demonstrates that aromatic solvents (heat transfer fluids) are not recommended for the practice of this invention.

[0118] Examples 4A-4E: Controlled Polymerization of Allylchlorosilane with Thiol and Disiloxane Additives Examples 4A-4E illustrate the effective use of mercaptan and disiloxane additives to inhibit Lewis acid-catalyzed polymerization of allylchlorosilanes at temperatures below the direct synthesis temperature of allylchlorosilanes. The additives used were octadecyl mercaptan (C 18 H 37 The solvents used were methylsiloxane (SH) and hexamethyldisiloxane (see Table 6). The reaction was carried out at 70° C. for 1.5 hours. The reaction mixture was then cooled to room temperature and analyzed by gas chromatography.

[0119] Example 4A: The experiment in Example 4A was carried out in a manner similar to that of Example 3B. -2 mol) of DADCS, 0.72 g (2.5 × 10 -3 (mol) C 18 H 37 SH, 0.227g (1.70 x 10 -3 mol) AlCl3, and 5.07 g dodecane were mixed and heated to 70°C and held for 1.5 hours.

[0120] Example 4B: The experiment in Example 4B was carried out using 5.17 g of a mixture of 35 wt% ADCS and 65 wt% ATCS, 0.317 g (2.4 × 10 -3 mol) of AlCl, 0.85 g (3.0 × 10 -3 (mol) C 18 H 37 SH, and 6.18 g of dodecane at 70° C. for 1.5 hours.

[0121] Example 4C: In this experiment, 5.18 g of a mixture of 35 wt% ADCS and 65 wt% ATCS, 0.317 g (2.4 × 10 -3 mol) of AlCl, 3.1 g (1.91 × 10 -2 mol) of hexamethyldisiloxane and 2.7 g of dodecane were heated at 70° C. for 1.5 hours.

[0122] Gas chromatographic analyses of the reaction mixtures of Examples 4A-4C are shown in Table 6 as the area ratio of allyl substrate to dodecane. Thus, in Example 4A, the ratio of diallyldichlorosilane (DADCS) area to dodecane area was 0.266 at the start and 0.192 at the end of the experiment. This means that 72.2 percent of the original DADCS was still present in the final reaction mixture. In contrast, 93 percent of the DADCS was consumed in the experiment of Example 3B, and only 27.8 percent was consumed in Example 4A. This demonstrates the inhibitory effect of octadecyl mercaptan on the AlCl3-catalyzed polymerization of DADCS.

[0123] [Table 6]

[0124] Table 6 shows the individual area ratios of allyldichlorosilane (ADCS) and allyltrichlorosilane (ATCS) obtained in Example 4B. It is clear that the polymerization of ATCS was completely inhibited by octadecyl mercaptan, and 85.6 percent of the original ADCS was still present. Thus, compared to Example 3C, in which both allyl substrates were completely polymerized, only 14.4 percent was consumed, which was mostly ADCS.

[0125] The area ratios in Example 4C were equal within the ±2% error range mentioned above for quantitative gas chromatography analysis. Thus, the AlCl3-catalyzed polymerization of ATCS and ADCS was completely inhibited by hexamethyldisiloxane. Complete inhibition of ADCS polymerization was also observed in a separate experiment using AlCl3 and hexamethyldisiloxane (Example 4D), as well as in the combination of a mixture of ATCS and ADCS with octadecyl mercaptan and hexamethyldisiloxane (Example 4E). Polymerization was inhibited as shown in the following equation: [ka]

[0126] AlCl3-induced inhibition of polymerization of allylchlorosilanes in the presence of hexamethyldisiloxane (MM) Examples 5A-5E: Controlled Polymerization of Allylchlorosilane with Urea and Thio Additives These examples demonstrate the effective inhibition of the polymerization of allylchlorosilanes by tetramethylthiourea [(CH)NCSN(CH)], thiourea (HNCSNH), tetramethylurea [(CH)NCON(CH)], and dibutyl sulfide [(CH(CH)]S].

[0127] All experiments were carried out simultaneously in a 75 ml reactor in an MRS-5000 combined reactor. The starting material (stock solution) for Examples 5A-5D was prepared from 18.54 g of dodecane and 32.86 g of a mixture of 35 wt% ADCS and 65 wt% ATCS. ​​An aliquot of this stock solution was charged to a 75 ml reactor along with AlCl3 and the appropriate additives listed in Table 7. The molar ratio of additive to AlCl3 was approximately 2. The starting material for Example 5E was prepared in nonane because dibutyl sulfide and dodecane co-elute under the gas chromatography conditions used. After charging, the reactor was sealed under 1 bar of nitrogen pressure. The reaction mixture was stirred at room temperature (23 °C) for 1 hour and then heated to 70 °C for an additional hour. After the reactor cooled to room temperature, the reactor was opened and the liquid reaction mixture was collected for gas chromatography analysis.

[0128] In the control, Example 5A, where no additive was used, complete polymerization of ADCS and ATCS occurred. The sulfur-containing additives used in Examples 5B, 5C, and 5E inhibited the polymerization of ATCS. ​​The loss of ADCS due to polymerization was 14-16% at the molar ratio of additive to AlCl used (~2). This represents a recovery of 84-86 percent. When tetramethylurea was used (Example 5D), 79 percent of ADCS and all of the ATCS were recovered.

[0129] [Table 7]

[0130] Examples 6A and 6B Examples 6A and 6B are Calflo TM This study demonstrates the use of hexamethyldisiloxane to improve the reaction stability of the slurry-phase Direct Synthesis of allyltrichlorosilane and allyldichlorosilane from an allyl chloride-HCl mixture in AF and cyclone fines. A 2-liter glass reactor was used.

[0131] Example 6A 641.5g of Calflo TM AF and 212.3 g of cyclone fines (70 wt% Si) were charged to a reactor along with 2.0 g of FS1265 and 25.7 g of hexamethyldisiloxane. The fines contained ~2 wt% Al, so the amount of hexamethyldisiloxane was equimolar to the aluminum. The reaction mixture was sparged with nitrogen at 100 mL / min, stirred at 500 rpm, heated to 80°C, and held for 1 hour. 9.8 g of distillate was collected.

[0132] The reactor temperature was then increased to 235°C, and hydrogen chloride was introduced at a rate of 7.44 mL / min. Allyl chloride was delivered from a reservoir to an evaporator heated to 80°C and then to the reactor as a vapor. The experiment was discontinued after 4 hours, during which time a total of 355 mL of allyl chloride had been delivered to the reactor.

[0133] The reservoir was again charged with a mixture of 8.8 g of hexamethyldisiloxane and 350 g of allyl chloride. The flow of HCl and allyl chloride was then resumed and the reaction continued at 235° C. for 3 hours.

[0134] In total, 2.45 liters of HCl (0.11 moles) and 582.8 g of allyl chloride (7.62 moles) were introduced into the reactor. The molar ratio [allyl chloride / HCl] was 69.3. The product was collected and analyzed by GC every hour. 603.3 g of crude product was collected, and a silicon conversion of 59.98% was obtained from the silicon available in the cyclone fines. The average reaction rate was 8.57 percent of silicon converted per hour based on the collected crude product. The weight gain of the reactor was 120 g. Thus, the adjusted silicon conversion was 82 percent.

[0135] Table 8 summarizes the composition of the major silicon-containing products in the crude product. It can be seen that the sum of ATCS and ADCS remains fairly stable until approximately 48 percent silicon conversion is reached. The steady-state average was 83.69 ± 2.46 wt%.

[0136] [Table 8]

[0137] [Table 9]

[0138] Example 6B was run without the addition of hexamethyldisiloxane and is therefore the control reaction to which Example 6A and the other reactions with additives are compared.

[0139] In this experiment, 638.6 g of CALFLO AF, 212.70 g of cyclone fines, and 2 g of FS1265 were used. The reaction was carried out at 235°C and 500 rpm using allyl chloride and HCl as described above for Example 6A. Overall, the reaction continued for 7 hours, during which 545.2 g of allyl chloride and 2.54 L of HCl were fed, and 566.6 g of crude allylchlorosilane was recovered. The AC / HCl molar ratio was 63.4. The silicon conversion was 55.2 percent, with an average reaction rate of 7.88 percent silicon conversion per hour. The reactor weight increased by 110 g. The adjusted silicon conversion was 75.1 percent.

[0140] As shown, the use of hexamethyldisiloxane resulted in increased silicon conversion to the desired allylchlorosilane (82% vs. 75.1%), although additional amounts were required to achieve higher reaction rates and stability.

[0141] In Example 6B (control), the sum of the ADCS and ATCS concentrations remained nearly constant (81.95 ± 1.63) from the start of the reaction until approximately 43 percent of the silicon had been converted. Thus, the use of hexamethyldisiloxane in Example 6A expanded the steady-state region by 5 percent, thereby improving the stability of the reaction. To determine whether the difference in the steady-state values ​​for (ADCS + ATCS) in Examples 6A and 6B was statistically significant, a z-test (see R. Langley, "Practical Statistics Explained," Dover Publications, Inc., NY, pp. 152-154) was performed. As shown in the following formula, the z-value was 2.61, which is greater than the threshold of 2.58 for chance variation at P = 1%. Therefore, the sum in Example 6A is statistically different from the sum in Example 6B.

number

[0142] Examples 7A, 7B and 7C Examples 7A, 7B, and 7C illustrate the use of phenothiazine to inhibit the polymerization of allylchlorosilane during the direct reaction of cyclone fines with allyl chloride. Example 6B serves as a comparative control for these experiments. The amounts of raw materials used and reaction conditions are shown in Table 10, and the results are summarized in Table 11.

[0143] [Table 10]

[0144] These data indicate that the use of >0.37 wt% phenothiazine allows for greater conversion of silicon to the desired allylchlorosilanes than was achieved in the control experiment (Example 6B). The reactor weight gain decreased from 110 g in the control to 52 g and 32 g in Examples 7B and 7C, respectively. These decreases are attributed to the inhibition of polymerization of allylchlorosilanes by phenothiazine. Additionally, the average reaction rate increased from 7.88% Si / h in Example 6B to 8.82% Si / h in Example 7B and 9.33% Si / h in Example 7C. Thus, a trend toward improved reactivity and stability with increased use of phenothiazine is established. Additionally, the data in Example 7B demonstrate the advantage of adding phenothiazine intermittently (or continuously) rather than as a single shot at the beginning of the reaction.

[0145] [Table 11]

[0146] Example 8: Direct synthesis of allylchlorosilanes with CuCl, Zn, Sn, and ~30 micrometer virgin silicon Example 8 describes the slurry-phase Direct Synthesis of allylchlorosilanes via the CuCl-catalyzed, zinc- and tin-promoted reaction of allyl chloride with virgin silicon. 157.5 g of silicon (mean particle size ~30 micrometers) was added to 599 g of Calflo AF along with 7.63 g of CuCl, 0.96 g of anhydrous zinc formate, 0.02 g of anhydrous tin formate, and 1.8 g of FS1265. This fine silicon powder is similar to waste silicon powder that can be generated during silicon processing. The reaction was run with HCl (7.44 ml / min) and allyl chloride (1.44 ml / min) for 6 hours at 235 °C, stirring at 500 rpm. A total of 520 ml (488.8 g, 6.39 mol) of allyl chloride was used, and a total of 2.68 L (0.119 mol) of HCl was used. The molar ratio of allyl chloride to HCl was 53.67.

[0147] [Table 12]

[0148] A total of 617 g of crude allylchlorosilane was collected. The reactor weight decreased by 73 g. Using the hourly product composition and sample weights, it was calculated that 74.68 g of silicon was converted to allylchlorosilane. The average reaction rate was 7.90% Si conversion / h during the reaction, and 84.19 ± 4.30% (ADCS + ATCS). Further data summary is shown in Table 12.

[0149] Examples 9A and 9B: Virgin silicon initially with or without inhibitor (phenothiazine) then charged with cyclone fines These examples demonstrate the effect of phenothiazine on the slurry-phase Direct Synthesis of allylchlorosilanes from virgin silicon with and without added cyclone fines. Example 9A was carried out similarly to Example 8, but with the addition of 1 wt. % phenothiazine. Example 9B is a continuation of Example 9A, with the addition of cyclone fines and phenothiazine. Besides the reagents allyl chloride and HCl, no other substances were added to the experiment in Example 9B.

[0150] The average reaction rates for Examples 8, 9A, and 9B were 7.90% Si conversion / h, 8.17% Si conversion / h, and 9.05% Si conversion / h, respectively. Thus, when cyclone solids were added to a reaction initiated with virgin silicon, there was an approximately 11 percent increase in reactivity. Reactions with virgin silicon alone (Examples 8 and 9A) showed weight losses: 73 g for Example 8 and 82 g for Example 9A. In contrast, Example 9B with added cyclone solids gained 20 g. Using the hourly product compositions and sample weights, it was calculated that 77 g of silicon was converted to allylchlorosilane in Example 9A and 62.8 g in Example 9B. Therefore, a total of 82.8 g of polymer was formed in Example 9B, resulting in an adjusted silicon conversion of 49 percent.

[0151] Thus, in Example 9B, further addition of phenothiazine was necessary to completely obviate polymer formation and increase the conversion of silicon to allylchlorosilane.

[0152] [Table 13]

[0153] [Table 14]

[0154] Table 15

Claims

1. 1. A process for synthesizing alkenylhalosilanes, comprising: (1) forming a slurry of copper-activated silicon derived from at least one of virgin silicon, cyclone fines, cyclone fine dust, silicon ultrafine particles, spent contact mass from the Direct Synthesis of organohalosilanes, or mixtures thereof, in a heat stable solvent; (2) stirring the slurry; (3) The stirred slurry is mixed with the mixture of the formula R １ and optionally at least one organohalosilane or hydrogen halide in the presence of an additive exhibiting Lewis base properties, which additive is effective to inhibit polymerization of the alkenylhalosilane, said reaction being conducted for a reaction time, reaction temperature, and reaction pressure effective to produce an alkenylhalosilane having the formula R １ SiHX ２ , R １ ２ SiHX,R １ ３ SiX, R １ Six ３ , and R １ ２ Six ２ or mixtures thereof, wherein R １ is an unsaturated aliphatic or cyclic alkenyl group and X is a halogen; and (4) recovering the alkenylhalosilane from the slurry.

2. R １ 2. The process of claim 1, wherein is allyl, vinyl, methallyl, or cyclohexenyl, and X is fluorine, chlorine, bromine, or iodine.

3. 10. The process of claim 1, wherein the additive is a sulfur-containing additive selected from the group consisting of polymerization inhibiting thiols and mercaptans, thioethers, thioesters, disulfides, thioketones, thioamides, thioimidazoles, and mixtures thereof.

4. 10. The process of claim 1, wherein the additive is a cyclic sulfur-containing compound selected from the group consisting of polymerization inhibitors thiophenes, phenothiazines, thiomorpholines, 1,4-thioxanes, and mixtures thereof.

5. 10. The process of claim 1, wherein the additive is selected from the group consisting of urea, tetraalkylurea, thiourea, tetraalkylthiourea, and mixtures thereof.

6. 10. The process of claim 1, wherein the additive comprises hexamethyldisiloxane.

7. 10. The process of claim 1, wherein the additive comprises hexamethyldisiloxane and an additive selected from the group consisting of polymerization inhibiting thiols, mercaptans, thioethers, thioesters, disulfides, thioketones, thioamides, thioimidazoles, tetramethylureas, and mixtures thereof.

8. 10. The process of claim 1, wherein the solvent is selected from the group consisting of normal or branched chain paraffins, naphthenes, and mixtures thereof, and has a boiling point above 200°C at standard conditions.

9. 10. The process of claim 1, wherein the solvent is a paraffinic heat transfer fluid.

10. R １ is allyl or methallyl, and the organohalosilane is R １ Six ３ and R １ SiHX ２ and optional hydrogen halide is present, wherein the molar ratio of allylic halide to hydrogen halide in the reagent mixture in step (1) is about 0.8:1 or greater.

11. 6. The process of claim 5, wherein the molar ratio of alkenyl halide to hydrogen halide is from about 1 to about 100 or greater.

12. 10. The process of claim 1, wherein an additional amount of additive is added to the slurry during the reaction.

13. 10. The process of claim 1, wherein the molar ratio of the amount of additive added to the slurry during the reaction is based on the molar ratio of additive to total Lewis acid formed in the slurry during the reaction, said ratio being from about 0.05:1 to about 15:

1.

14. 10. The process of claim 1, wherein the ratio of the amount of additive added to the slurry during the reaction is based on a molar ratio of additive to total Lewis acid formed in the slurry during the reaction, said ratio being from about 2:1 to about 5:

1.

15. The additive is C ８ H １７ S.H., C. １２ H ２５ S.H., C. １８ H ３７ S.H., C. ６ H １３ C(CH ３ ) ２ SH (tert-nonyl mercaptan), p-heptylbenzyl mercaptan, furfuryl mercaptan, grapefruit mercaptan (1-p-menthen-8-thiol), 1,5-pentanedithiol, HS (CH ２ ) ５ SH, 2,2'-(ethylenedioxy)-diethanethiol, HSCH ２ CH ２ OCH ２ CH ２ OCH ２ CH ２ and the thioether is selected from the group consisting of dibutyl sulfide, (C ４ H ９ ) ２ S or dodecyl methyl sulfide, CH ３ (CH ２ ) １１ SCH ３ 10. The process of claim 1, wherein the hydroxybenzoate is selected from the group consisting of: and mixtures thereof.

16. 10. The process of claim 1, wherein the reaction temperature is greater than 180°C.

17. 10. The process of claim 1, wherein the alkenyl halide is allyl chloride and the reaction temperature ranges from about 220°C to about 300°C.

18. 10. The process of claim 1, wherein the reaction pressure ranges from atmospheric to about 10 atmospheres.

19. 10. The process of claim 1, wherein the reaction time ranges from 0.1 to 100 hours.

20. 10. The process of claim 1, further comprising recovering the solvent from the slurry and reusing the solvent in a new step (1).

21. 10. The process of claim 1, further comprising, after the initial charge has been partially or completely converted, introducing additional virgin silicon, fine dust from silicon grinding, cyclone fines, ultrafine particles, and / or spent material into the reaction slurry in a new step (1), and continuing the reaction with the alkenyl halide to produce additional alkenylhalosilanes without first recovering or restoring the solvent.

22. 10. The process of claim 1, wherein a foam control agent is added to the reaction step.

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