JP5915493B2 - Process for producing alkoxytrihalosilane - Google Patents

Description

  The present invention relates to a production method capable of selectively obtaining alkoxytrihalosilane in high yield using halosilane and alcohol as raw materials, and the obtained alkoxytrihalosilane serves as an intermediate raw material for chemical products such as silane coupling agents. It is also used as a semiconductor process material such as an insulating film raw material.

  Conventionally, various alkoxysilanes are used as silicon chemical materials such as silane coupling agents and intermediate raw materials, and various production methods for industrially efficient production have been studied. Among alkoxysilanes, alkoxytrihalosilanes have been studied. Since the use thereof is relatively limited, production methods aimed at obtaining alkoxytrihalosilanes have not been sufficiently studied so far. However, in recent years, alkoxytrihalosilane has attracted attention as a silicon source material for CVD and sol-gel methods used in semiconductor manufacturing, and the need for alkoxytrihalosilane has increased, and high-purity alkoxytrihalosilane can be produced efficiently. A method has come to be sought.

  As a method for producing an alkoxytrihalosilane, a method for producing an alkoxyhalosilane by reacting a polyhalosilane with an alcohol has long been known as an alcoholysis reaction. In Non-Patent Document 1, silicon tetrachloride and methanol are used. When reacted in the liquid phase state, four types of methoxytrichlorosilane, dimethoxydichlorosilane, trimethoxychlorosilane, and tetramethoxysilane are produced. By changing the charged molar ratio of raw material silicon tetrachloride and methanol, Although there is a description that the production ratio can be changed, in order to selectively obtain methoxytrichlorosilane, it is necessary to select a condition in which methanol is insufficient, in which case a large amount of unreacted silicon tetrachloride remains. Therefore, the yield of methoxytrichlorosilane is low. Can not be achieved to, it was not efficient. In Non-Patent Document 1, there was a description that the reaction between silicon tetrachloride and methanol was performed in a liquid state in a temperature range of ice-cooling to 40 ° C. There was no description or suggestion.

  In Non-Patent Document 2, the same thing occurs in the liquid phase reaction of silicon tetrachloride and ethanol. Such a reaction is called sequential competitive ethanolysis, and is obtained as in Non-Patent Document 1. Although it is described that it is a mixture of each component, as in Non-Patent Document 1, in order to selectively obtain ethoxytrichlorosilane, there is no choice but to select ethanol-deficient conditions. Since a large amount of silicon chloride remains, only a low value of the yield of ethoxytrichlorosilane can be achieved. The reaction conditions shown in the experimental part were to perform a liquid phase reaction by cooling with ice using an airtight stirrer and a dropping funnel, and there was no description or suggestion about the reaction at a high temperature or in the gas phase. That is, Non-Patent Documents 1 and 2 described a production method for obtaining alkoxyhalosilanes by reacting liquid alcohol and tetrahalosilane at a low temperature, but the composition ratio of alkoxytrihalosilane is sufficiently high. It can be said that no conditions for high yield of alkoxytrihalosilane based on the amount of raw material silicon tetrachloride were found.

  On the other hand, in the patent document as a prior art document, there is no document on a production method using alkoxytrihalosilane as a target product. For example, in the example of Patent Document 1, a solution of silicon tetrachloride diluted with dry ether and methanol There is a description that methoxytrichlorosilane was obtained as an intermediate raw material by reacting in phase. Although there is no description of temperature, yield, etc. for this reaction, it is common knowledge that the reaction is carried out below the boiling point of diethyl ether (35 ° C.), assuming that dry ether means diethyl ether. Moreover, since the yield is 66.7% when the amount of silicon tetrachloride charged is 255 g and the amount of methoxytrichlorosilane used in the next step is 165.5 g, the yield is 66.7%. It can be considered that it was known that methoxytrichlorosilane can be obtained in a yield of 66.7% by weight based on the raw material when diluted and subjected to a liquid phase reaction between silicon tetrachloride and methanol at 35 ° C. or lower. . However, it is an indispensable production method to make the reaction using highly flammable ether, and to distill off the ether after the reaction, which is difficult to say efficient.

  Patent Document 2 discloses a production method in which an alkoxytrichlorosilane is obtained by reacting a mixture of silicon tetrachloride and trimethylmonochlorosilane with an alcohol, and 1 for each mixture of silicon tetrachloride and trimethylmonochlorosilane. Although there is a description of dripping 3 to 3 moles of alcohol under cooling, Example 1 discloses a method of reacting a raw material diluted with benzene, and alkoxy based on a silicon tetrachloride raw material. Since the yield of trichlorosilane is only 46.7% by weight and the selectivity of alkoxytrichlorosilane in the product is estimated to be 52.1% by weight, it can be said that alkoxytrihalosilane can also be obtained efficiently. It was a difficult method.

  Patent Document 3 discloses a method of reacting organochlorosilane with alcohol in the presence of a catalyst system, and Example 16 reacts silicon tetrachloride with methanol at a molar ratio of 1: 1 at room temperature. The results are described. It is understood that this reaction was carried out in the liquid phase in a 250 ml three-necked flask without solvent dilution, and the selectivity of methoxytrichlorosilane in the product was calculated to be 51.5% from the gas chromatographic analysis value of the product. can do. Therefore, it can be considered that the selectivity in the liquid phase reaction is not so high. Example 16 also describes the results when 0.05 moles of triethylamine per mole of silicon tetrachloride is added as a co-catalyst, and the selectivity for methoxytrichlorosilane in that case can be calculated as 71.8%. From this, it can be seen that a method for improving the selectivity of methoxytrichlorosilane in the liquid phase reaction is suggested, but the added triethylamine may be mixed as an impurity, and the alkoxytrihalosilane can be efficiently used. It was still inadequate for how to get it.

Japanese Patent Publication No. 52-109207 Japanese Patent Publication No. 28-5421 JP 62-283981 A

Published in 1951, The Japan Chemical Journal, Vol. 77, No. 6, p. 893 Published in 1951, Journal of Industrial Chemistry, Volume 54, Volume 3, Page 213

  There has been known a production method for obtaining alkoxyhalosilanes by reacting silicon tetrachloride and alcohol in a liquid phase at a temperature of approximately 40 ° C. or lower. However, a single product cannot be obtained, and various alkoxyhalosilanes are obtained. Since it becomes a mixture of silanes, there is a problem that when only the alkoxytrihalosilane is used as a target product, the yield is low and the selectivity in the product is low, so that energy for separation and purification is required. The subject of this invention is providing the manufacturing method of alkoxy trihalosilane which can obtain an alkoxy trihalosilane with a high yield with a simple method, and has high selectivity in a product.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that when tetrahalosilane and alcohol are reacted in a gas phase, the yield of alkoxytrihalosilane relative to the raw material is higher than that of conventionally known methods. In addition, the inventors have found that the selectivity of alkoxytrihalosilane in the reaction product is high, and have completed the invention as a method for producing alkoxytrihalosilane.

  According to the present invention, since the yield of alkoxytrihalosilane with respect to the raw material is high and the selectivity of alkoxytrihalosilane in the reaction product is high, alkoxytrihalosilane can be obtained efficiently with good yield. Compared to the above, high-purity alkoxytrihalosilane can be produced at low cost.

Conceptual diagram of the synthesis apparatus used in Example 1 Conceptual diagram of the synthesis apparatus used in Example 11

The present invention will be described below. In addition,% is weight%.
One of the raw materials used in the method for producing alkoxytrihalosilane of the present invention is represented by the formula [1].
SiX ₄ [1]
(However, X is a halogen.)
X may be the same or different, and a plurality of raw materials represented by the formula [1] may be used in combination. Specific examples of the compound represented by the formula [1] include tetrafluorosilane, tetrachlorosilane, tetrabromosilane, tetraiodosilane, monofluorotrichlorosilane, difluorodichlorosilane, monochlorotrifluorosilane, monobromotrichlorosilane, dibromo. Examples include dichlorosilane. Of these, tetrafluorosilane and tetrachlorosilane which have a low boiling point and are easily vaporized are preferable, and tetrachlorosilane which can be obtained industrially at low cost is more preferable.

Another material used in the present invention is represented by the formula [2].
R ¹ OH [2]
(R ¹ is a hydrocarbon group having 1 to 6 carbon atoms.)
R ¹ may be linear or branched, and any of primary alcohol, secondary alcohol, and tertiary alcohol can be used as the structure. Specific examples of the compound represented by the formula [2] include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol. 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 2,2 dimethyl-1-propanol, 1 -A hexanol, 2-hexanol, 3-hexanol etc. are mentioned, A several raw material can also be used together. Among these, preferred are highly reactive primary alcohols or secondary alcohols, and specific examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and 2-methyl. -1-propanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2,2 dimethyl-1-propanol, 1-hexanol, 2 -Hexanol, 3-hexanol, etc. can be mentioned. More preferably, it is a primary alcohol or secondary alcohol having 1 to 4 carbon atoms which is easily vaporized at a low boiling point and can be obtained industrially at low cost. Specific examples include methanol, ethanol, 1-propanol, 2- Examples include propanol, 2-methyl-1-propanol, 1-butanol, and 2-butanol. More preferably, it is a secondary alcohol that increases the selectivity of the resulting monoalkoxytrihalosilane, and examples thereof include 2-propanol and 2-butanol.

  In the present invention, when the tetrahalosilane represented by the formula [1] and the alcohol represented by the formula [2] are reacted, the charging ratio of the alcohol represented by the formula [2] to the tetrahalosilane represented by the formula [1], that is, the formula The numerical value of alcohol (mole) represented by [2] / tetrahalosilane (mole) represented by formula [1] may be called the OH / Si ratio, and the numerical value is preferably in the range of 0.1 to 10. More preferably, it is 0.3-4, More preferably, it is 0.5-1.5, Most preferably, it is the range of 0.8-1.2. A preferred embodiment is a continuous method in which the tetrahalosilane represented by the formula [1] and the alcohol represented by the formula [2] are supplied into the reaction vessel at the same time within the range of this ratio. You can also.

By the production method of the present invention, a compound having the structure of the formula [3] can be obtained. It is essential that the reaction product contains a compound having the structure of the formula [3]. Preferably, the compound having the structure of the formula [3] in the reaction product is 50% by weight or more, more preferably Is 60% by weight or more. As other components, the unreacted compound represented by the formula [1], the compound represented by the formula [2], and the higher-order reaction products, the formula [4], the formula [5], the formula [6]. ] The compound represented by this may be contained.
X ₃ Si (OR ¹ ) [3]
(However, X may be the same or different from each other.)
X ₂ Si (OR ¹ ) ₂ [4]
(However, X may be the same or different from each other.)
X Si (OR ¹ ) ₃ [5]
Si (OR ¹ ) ₄ [6]

Specific examples of the compound represented by the formula [3] include methoxytrichlorosilane, ethoxytrichlorosilane, 1-propoxytrichlorosilane, 2-propoxytrichlorosilane,
Examples include methoxytrifluorosilane, ethoxytrifluorosilane, 1-propoxytrifluorosilane, 2-propoxytrifluorosilane, methoxytribromosilane, ethoxytribromosilane, methoxymonofluorodichlorosilane, ethoxymonofluorodichlorosilane, and the like. Of these, preferred are methoxytrichlorosilane, ethoxytrichlorosilane, 1-propoxytrichlorosilane, and 2-propoxytrichlorosilane, and more preferred are methoxytrichlorosilane, ethoxytrichlorosilane, and 2-propoxytrichlorosilane.

  The production method of the present invention is characterized in that the tetrahalosilane represented by the formula [1] and the alcohol represented by the formula [2] are reacted in the gas phase. A reaction vessel is required to carry out the reaction. The shape of the reaction vessel is not limited, but when controlling the reaction temperature, a method of controlling the reactor internal temperature using a heat exchange means such as a heat medium jacket or a mantle heater is simple and preferable, and the heat exchange means May be provided inside or outside the reaction vessel, but so-called external temperature control provided on the outside can be simplified in the shape of the apparatus and is suitable for preventing corrosion.

  When tetrahalosilane and alcohol are reacted in a liquid phase, many known literatures disclose a reaction temperature of ice cooling or 40 ° C. or less, and a method of reacting at a high temperature has not been known. When reacting in a phase, the reaction temperature is preferably 50 ° C. or higher in order to prevent condensation of raw materials and products and to increase the reaction rate. In addition, if the reaction temperature is too high, decomposition of raw materials and products is likely to occur, and according to Boyle-Charles's law, if the pressure is kept constant at a high temperature, the gas density decreases and volumetric efficiency of the reactor deteriorates. Therefore, the reaction temperature is preferably 300 ° C. or lower. A more preferable lower limit of the reaction temperature is 70 ° C. or higher, more preferably 90 ° C. or higher, particularly preferably 120 ° C. or higher, and a more preferable upper limit of the reaction temperature is 250 ° C. or lower, more preferably 200 ° C. or lower, particularly preferably. 180 ° C. or lower.

  In order to control the temperature inside the reaction vessel, heat exchange means such as an inner jacket method, an outer jacket method, or a reactor immersed in a heat medium bath can be used. The shape preferably has a large surface area relative to the internal volume, and more preferably is a cylindrical shape. The thickness of the cylindrical shape does not have to be constant, and a so-called coiled shape in which the cylindrical shape is continuously curved is also preferable. The length of the long side with respect to the diameter of the cylindrical shape can be referred to as an aspect ratio, and is preferably 3 to 1000, more preferably 5 to 500, and more preferably 10 to 100 as a reaction vessel used in the present invention.

  In order to detect the temperature of the reaction performed in the gas phase, a temperature detection means such as a thermocouple can be provided inside the reaction vessel, and the reaction temperature is changed by changing the temperature of the heat exchange means based on the detected temperature. Can be controlled. A plurality of temperature detection means may be provided, and a feedback method such as PID control may be used when setting the temperature of the heat exchange means based on the detected temperature.

  The pressure inside the reaction vessel is preferably higher because the reaction efficiency per reaction vessel volume is higher, but the pressure around the atmospheric pressure is preferred because it is easy to handle and has high safety. A preferable pressure range is 0.08 to 0.14 MPa in absolute pressure, and more preferably 0.09 to 0.12 MPa.

  When the reaction vessel is used in a batch system, the raw material can be charged and the product can be recovered by providing at least one inlet / outlet port. Preferably, at least two of the raw material supply port and the product outlet port are provided. It is preferable to have it, and it can be used also for a continuous reaction. When the reactor has a raw material supply port and a product discharge port, it is preferable to dispose these at positions far from each other. Also, providing at least two of the raw material supply ports, the compound supply port of the formula [1] and the compound supply port of the formula [2], prevents the reaction from occurring before being supplied to the reactor. It is preferable in that it can be performed. For the same reason, it is also preferable to make a difference in the penetration length of the compound feed port of the formula [1] and the feed port of the compound of the formula [2] into the reactor or to make a double pipe. In addition to this, it is also preferable to circulate an inert gas in the reactor. The inert gas is circulated for drying in the reactor before the reaction is performed, or products and unreacted raw materials are discharged after the reaction is completed. For this purpose, it is also preferable to circulate an inert gas, a supply port for supplying the inert gas can be provided, or an inert gas can be introduced from at least one of the reaction raw material supply ports.

  In order to reliably react the compound of formula [1] and the compound of formula [2] in the reaction vessel in the gas phase in the reaction vessel, each compound is vaporized before being introduced into the reactor. For example, using an apparatus generally called a bubbler, an inert gas is circulated in a container containing raw materials, and the amount of the compound supplied to the reaction container is determined by the temperature of the container and the flow rate of the inert gas. A control method can be used, and a vaporized compound can be introduced into the reaction vessel by directly adjusting the temperature of the reaction raw material vessel without using an inert gas.

  Any inert gas may be used in the present invention as long as it does not react with the compounds of the formula [1], formula [2], and formula [3]. In this sense, dry air is also used. In the category of inert gas, from the viewpoint of safety such as explosion prevention, preferred are rare gases such as helium and argon, and inert gases in a narrow sense such as nitrogen and carbon dioxide. Nitrogen is more preferable in that it can be obtained and a low-moisture product is easily available. The water content of the inert gas is preferably 50 ppm by volume or less, more preferably 10 ppm by volume or less, and even more preferably 1 ppm by volume or less. It is also preferable to include a step of bringing the inert gas supply line into contact with the desiccant.

  The method in which the reaction raw material is vaporized in advance and then fed into the reactor is excellent in that impurities having different vapor pressures that can be contained in the raw material can be reduced in the raw material vaporization step. When the alkyl alcohol No. 4 is used as a raw material, the alcohol has a higher vapor pressure than water, and is therefore effective in reducing the water content in the vaporized raw material to be supplied. As for tetrahalosilane, if it contains moisture, it is hydrolyzed and condensed into a high boiling point compound such as disiloxane, so that moisture in the vaporized raw material to be supplied can also be reduced. In addition, for the purpose of further reducing moisture, a step of bringing a liquid raw material or a vaporized raw material into contact with a dehydrating agent can be added.

  In the method in which the reaction raw material is vaporized in advance and then sent to the reactor, the supply amount of the raw material can be known by a measuring method such as a mass flow controller. In this method, the weight of the raw material supplied to the reactor is calculated from the weight reduction of the raw material container. It is also possible to measure the amount of water by installing a dew point meter in the path, and the amount of water in the gas containing the supplied raw material is preferably 50 ppm by volume or less, more preferably 10 ppm by volume or less, more preferably 1 Volume ppm or less.

  On the other hand, the reaction raw material can be sent in liquid without being vaporized in advance, and can be introduced by evaporating by raising the temperature or reducing the pressure at the supply port to the reaction vessel. The reaction raw material is supplied to the reaction vessel in a liquid state, and the reaction vessel It can also be vaporized in the gas phase reaction. This method has the effect that the heat of vaporization absorbed when the raw material is vaporized in the vicinity of the raw material supply port reduces the reaction heat generated in the reactor, so that the reactor can be easily cooled. ,Are better.

  When at least one of the reaction raw materials is supplied to the reaction vessel in a liquid state, it is preferable to supply from a position not in contact with the other reaction raw material supply port in order to avoid a reaction in the liquid state. In order to assist, it is preferable to mix and supply an inert gas to the reaction raw material supplied with a liquid. In this case, the preferable mixing amount of the inert gas is preferably 0.01 to 100 mol, more preferably 0.1 to 30 mol, relative to 1 mol of the supply molar amount of the reaction raw material.

  The reaction product produced in the reaction vessel can be taken out from the outlet of the reaction vessel and can be used after being stored in the product receiving tank. In an industrial continuous apparatus, a discharge port and a receiving tank are not necessarily required, and they can be purified by distillation while maintaining the temperature of the product, or can be used in other processes. In the case of using a product receiving tank, the product can be efficiently collected by maintaining a low temperature at which the product is condensed, and a device such as a cooling trap can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this. The synthesis experiment of the example was performed by the synthesis apparatus shown in FIG. 1 and FIG. 2, but the dimensions of the reaction vessel were the same diameter 20 mm and a length of 300 mm quartz tube, one end was provided with a raw material supply port, and the other 1 A product discharge port is provided at the end, and the entire quartz tube can be heated by a mantle heater. A common point is that the temperature in the reaction chamber is detected by a temperature sensor protruding from the center of the quartz tube, fed back to the mantle heater, and the internal temperature is controlled to a predetermined temperature.

  The component ratio of the product recovered in the product recovery device D1 is determined by integrating the area of the peak that the signal detected by the TCD detector draws on the chart by gas chromatography, The component ratio was determined by normalization so as to be 100%. Identification of each component separated by the gas chromatograph method was performed by combining mass detectors.

<Example 1>
In Example 1, using the reaction apparatus shown in FIG. 1, silicon tetrachloride (SiCl ₄ ) was used as the compound represented by the formula [1], and methanol was used as the compound represented by the formula [2]. Using. The dimensions of the reaction vessel used in Example 1 are a synthetic quartz tube having a diameter of 20 mm, a length of 300 mm, and a thickness of 2 mm. At one end, a supply tube for SiCl ₄ and methanol vaporized by a bubbling device is provided in parallel. It is.
The other end of the reaction vessel was connected to a discharge pipe, and the other end was introduced into a product recovery vessel D1 cooled to -78 ° C with a dry ice methanol mixed cryogen. D2 is a backflow-preventing empty container, and D3 was filled with water to prevent the exhaust gas from leaking into the atmosphere. Nitrogen gas having a dew point of −70 ° C. (water content of 2.6 volume ppm or less) was used as the inert gas.

  In Example 1, first, 100 ml / min of nitrogen gas was circulated through the reaction vessel for 30 minutes while maintaining the reactor internal temperature at 220 ° C. using the temperature control of the mantle heater, and then silicon tetrachloride vapor and methanol vapor. Nitrogen containing was simultaneously supplied to the reaction vessel. The feed rates of silicon tetrachloride and methanol were controlled by the temperature control of the bubbling device. That is, nitrogen is circulated in silicon tetrachloride or methanol placed in a bubbling device, the temperature of the bubbling device is adjusted to 20 to 25 ° C. in a water bath, the nitrogen flow rate flowing to silicon tetrachloride is 80 ml / min, and the nitrogen flow rate flowing to methanol Was 200 ml / min, and the molar supply amount of methanol and silicon tetrachloride supplied to the reactor was maintained at the OH / Si ratio = 1.02 plus or minus 0.05 shown in Table 2. In addition, OH / Si ratio means the numerical value of (molar amount of alcohol subjected to reaction) / (molar amount of silicon tetrachloride subjected to reaction). As soon as the supply of raw materials was started, condensation of liquid started at D1. As a precaution, when the dew point was measured by collecting the reaction vessel outlet gas before entering D1, it showed -80 ° C. or less, and it was found that the water content was 0.53 volume ppm or less.

The reaction was continued for 3 hours. After the supply of nitrogen containing raw material vapor was stopped, only 100 ml / min of nitrogen was passed through the reaction vessel for 30 minutes, and the product accumulated in D1 was analyzed with a gas chromatography TCD detector. The results are shown in Table 1 with the results assigned so that the total is 100% according to the peak area ratio of each component. Not limited to Table 1, tetraalkoxysilane was not detected in all examples reacted in the gas phase. The selectivity of alkoxytrihalosilane in the product was calculated according to the definition of formula [7].

Selectivity (wt%) = alkoxytrihalosilane peak area / (peak area of tetrahalosilane + alkoxytrihalosilane + dialkoxydihalosilane + trialkoxyhalosilane) × 100 [7]

In addition, the weight of silicon tetrachloride and methanol remaining in the raw material container of the raw material supply apparatus and the weight of the product accumulated in D1 were weighed, and the yield was analyzed and listed in Table 2. The yield was determined according to the definition of the formula [8] so that the total amount of the raw material tetrahalosilane was changed to alkoxytrihalosilane was 100%.

Yield (wt%) = Product yield × Alkoxytrihalosilane selectivity / (Consumption of tetrahalosilane × M1 / M2) × 100 [8]

(The consumption of tetrahalosilane means the weight obtained by subtracting the weight of unreacted tetrahalosilane in the product from the decrease in the weight of tetrahalosilane in the feeder. M1 is the molecular weight of alkoxytrihalosilane, M2 is the molecular weight of tetrahalosilane.)

<Example 2>
A synthesis experiment was conducted in the same manner as in Example 1 except that the reaction temperature was 150 ° C. The results are shown in Tables 1 and 2.

<Example 3>
A synthesis experiment was conducted in the same manner as in Example 1 except that the reaction temperature was 100 ° C., and the results are shown in Tables 1 and 2.

<Example 4>
A synthesis experiment was conducted in the same manner as in Example 1 except that the reaction temperature was set to 70 ° C. The results are shown in Tables 1 and 2.

<Example 5>
A synthesis experiment was conducted in the same manner as in Example 1 except that the reaction temperature was 20 ° C. The results are shown in Tables 1 and 2.

<Example 6>
A synthesis experiment was conducted at a reactor internal temperature of 150 ° C. in the same manner as in Example 2 except that the flow rate of bubbling nitrogen in the methanol supply apparatus was changed to 60 ml / min. After the reaction was completed, the amount of residual liquid in the raw material container of the raw material supply apparatus was measured. As a result, the molar ratio of methanol / silicon tetrachloride supplied to the reaction was 0.88. The results of the reaction were analyzed and listed in Tables 1 and 2.

<Example 7>
A synthesis experiment was performed at a reactor internal temperature of 150 ° C. in the same manner as in Example 2 except that the flow rate of bubbling nitrogen in the methanol supply apparatus was changed to 100 ml / min. After the reaction was completed, the amount of residual liquid in the raw material container of the raw material supply apparatus was measured. As a result, the molar ratio of methanol / silicon tetrachloride supplied to the reaction was 1.13. The results of the reaction were analyzed and listed in Tables 1 and 2.

<Example 8>
A synthesis experiment was conducted at a reactor internal temperature of 150 ° C. in the same manner as in Example 2 except that the temperature of the water bath of the bubbling device of the methanol supply device was raised to 50 ° C. and the flow rate of nitrogen was changed to 100 ml / min. After the reaction was completed, the amount of residual liquid in the raw material container of the raw material supply apparatus was measured. As a result, the molar ratio of methanol / silicon tetrachloride supplied to the reaction was 3.12. The results of the reaction were analyzed and listed in Tables 1 and 2.

<Example 9>
Synthesis experiment at a reactor internal temperature of 150 ° C. in the same manner as in Example 2 except that ethanol was used instead of methanol as the compound represented by the formula [2] and the water bath of the raw material container of the raw material supply apparatus was set to 40 ° C. Went. After the reaction was completed, the amount of residual liquid in the raw material container of the raw material supply apparatus was measured, and as a result, the ethanol / silicon tetrachloride molar ratio supplied to the reaction was 1.02. The results of the reaction were analyzed and listed in Tables 1 and 2.

<Example 10>
A synthesis experiment was conducted in the same manner as in Example 1 except that the reaction temperature was 350 ° C. The results are shown in Tables 1 and 2.

<Example 11>
In Example 11, using the reactor shown in FIG. 2, SiCl ₄ was used as the compound represented by the formula [1], and ethanol was used as the compound represented by the formula [2]. The dimensions of the reaction vessel are a synthetic quartz tube having a diameter of 20 mm, a length of 300 mm, and a thickness of 2 mm. At one end, a supply tube of SiCl ₄ vaporized by a raw material supply device, a supply tube of methanol in a liquid state, and A double pipe with an enclosed nitrogen blowing pipe is provided in parallel, but the ethanol supply pipe has a structure in which the nitrogen blowing pipe surrounding the ethanol supply pipe protrudes into the reaction vessel longer. The other end of the reaction vessel was connected to a discharge pipe in the same manner as in Example 1, and the other end was introduced into a product recovery vessel D1 cooled to -78 ° C with a dry ice methanol mixed cryogen. D2 is a backflow-preventing empty container, and D3 was filled with water to prevent the exhaust gas from leaking into the atmosphere.

  Silicon tetrachloride was supplied by a supply device using nitrogen bubbling in the same manner as in Example 1, but ethanol was supplied as a liquid using a gear-driven quantitative supply syringe, and surrounded by a nitrogen stream with a double tube at 100 ml / min. Was diffused into the reactor. In addition, when a test was conducted in advance to send ethanol and nitrogen into the reactor at 150 ° C., the supplied ethanol was not dripped, and it was seen that it was rapidly vaporized at the tip of the blowing tube. The reaction is considered to have occurred in the gas phase. However, when only ethanol was supplied to the reaction vessel and the dew point of the reaction vessel outlet gas was measured, it was −55 ° C., so the water content of the supply gas on the ethanol side was considered to be about 11 ppm by volume.

After the reaction was completed, the amount of residual ethanol solution in the quantitative supply syringe container was measured. As a result, the molar ratio of ethanol / silicon tetrachloride supplied to the reaction was 1.02. The results of the reaction were analyzed and listed in Tables 1 and 2.

<Example 12>
Example 12 was carried out in the same manner as Example 11 except that 2-propanol was used as the compound represented by the formula [2], and the results are shown in Tables 1 and 2.
<Comparative Example 1>
The glass-sealed two-necked flask with a volume of 2 L sealed with nitrogen was ice-cooled, charged with 320 g of methanol, and 580 g of silicon tetrachloride was added dropwise over 3 hours while stirring the flask. Thereafter, the liquid temperature was raised to 40 ° C. and stirring was continued for 4 hours to complete the reaction. When the liquid in the flask was analyzed, it was as shown in Table 1. The results were analyzed in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

  When the measurement results of Examples 1 to 5 and 10 having the same conditions except that the reaction temperature was changed to 20 ° C. to 350 ° C. in the analysis results of the product liquid in Table 1, the reaction was between 20 ° C. and 150 ° C. The higher the temperature, the less unreacted silicon tetrachloride residue tends to increase, and the proportion of alkoxytrihalosilane produced tends to increase. However, at 220 ° C or higher, the proportion of alkoxytrihalosilane decreases, and at 350 ° C silicon tetrachloride is reduced. There was a tendency to increase. When the reaction temperature of Example 2 was 150 ° C., the proportion of alkoxytrihalosilane produced was the highest. The above results show that the higher the reaction temperature, the higher the reaction rate and the lower the residual rate of silicon tetrachloride, and the production reaction of alkoxytrihalosilane proceeds to improve the yield. It is considered that higher-order reactions and decomposition reactions of silane are likely to occur, and the yield of alkoxytrihalosilane tends to decrease.

  In the analysis results of the product liquid in Table 1, when the conditions were the same except that the raw material alcohol / tetrahalosilane ratio was changed and the reaction temperature was 150 ° C., Example 2 and Examples 6-8 were compared, the OH / Si ratio As compared with Example 2 in which 1 is about 1 (equimolar), Example 6 with insufficient alcohol has more residual silicon tetrachloride, and Examples 7 and 8 with excess alcohol have dialkoxyhalohalosilanes and trialkoxyhalogens. There was a tendency for the proportion of silane to be increased. As a result, the alkoxytrihalosilane selectivity and yield shown in Table 2 are the highest and excellent in Example 2 where the OH / Si ratio is close to 1, and the OH / Si ratio is 0.8 to 1.2. A value comparable to that of Example 2 was obtained, but in Example 8 in which the silicon tetrachloride was excessively large, the result was slightly inferior.

  In the analysis results of the product solution in Table 1, when Example 9 using ethanol as an alcohol was compared with Example 2 using methanol, Example 9 using ethanol had a slightly lower reaction rate and the remaining silicon tetrachloride. Although the yield shown in Table 2 was low, the production rate of dialkoxy halo silane and trialkoxy halo silane was suppressed in Example 11 where the reactor was changed with an ethanol raw material. As a result, the selectivity and yield were improved. In addition, Example 12 using 2-propanol which is a secondary alcohol as an alcohol has a higher reaction rate despite the large number of carbons than Example 11 using ethanol, and the residual silicon tetrachloride is higher. The result was surprising. As a result, the yield of the alkoxytrihalosilane was the best, and an unexpected effect was obtained. This is because the boiling point of 2-propanol is almost the same as that of ethanol and is easily vaporized. This is because the production of dialkoxydihalosisilanes and trialkoxyhalosilanes was suppressed because secondary alcohols have a large steric hindrance when bonded to tetrahalosilanes. It was considered that the secondary alcohol had less residual tetrahalosilane because the alcohol charged in the vicinity of an equimolar amount and the tetrahalosilane reacted efficiently due to the suppression of.

  According to the production method of the present invention, alkoxytrihalosilane can be obtained with high selectivity, so that high-purity alkoxytrihalosilane can be produced industrially at low cost. The obtained alkoxytrihalosilane can be used as a raw material for silicon compounds such as silane coupling agents, and can also be used in semiconductor processes such as CVD and sol-gel methods.

1 and 2 (C) show a reaction vessel, and FIGS. 1 and 2 (A1) show a halosilane supply apparatus.
FIG. 1 (B1) shows an alcohol supply apparatus.
FIG. 2 (B2) shows an alcohol supply apparatus.
(A0) in FIG. 2 shows an inert gas supply pipe.
1 and 2 (D1) shows a product recovery apparatus.
1 and 2 (D2, D3) show an exhaust gas abatement apparatus.

Claims (8)

A tetrahalosilane represented by the formula [1] and an alcohol represented by the formula [2] are reacted in a gas phase at a reaction temperature in the range of 20 ° C. or higher and 350 ° C. or lower , and expressed by the formula [3]. A process for producing an alkoxytrihalosilane to obtain a product comprising an alkoxytrihalosilane.
SiX ₄ [1]
(However, X is a halogen.)
R ¹ OH [2]
(R ¹ is a hydrocarbon group having 1 to 6 carbon atoms.)
(R ¹ O) SiX ₃ [3]
(However, X may be the same or different from each other.) The method for producing an alkoxytrihalosilane according to claim 1, wherein the reaction temperature is in the range of 50 ° C to 300 ° C. The tetrahalosilane represented by the formula [1] and the alcohol represented by the formula [2] are reacted in a molar ratio of alcohol / tetrahalosilane in the range of 0.1 to 10. A method for producing an alkoxytrihalosilane as described in 1. above. The tetrahalosilane represented by the formula [1] and the alcohol represented by the formula [2] are reacted in a molar ratio of alcohol / tetrahalosilane within a range of 0.1 to 1.5. The manufacturing method of the alkoxy trihalosilane in any one of -3. The method for producing an alkoxytrihalosilane according to any one of claims 1 to 4 , wherein the alcohol represented by the formula [2] is a primary alcohol or a secondary alcohol. The method for producing an alkoxytrihalosilane according to any one of claims 1 to 5 , wherein the reaction is carried out by using an inert gas having a water content of 10 volume ppm or less and keeping the reaction atmosphere at a water content of 10 volume ppm or less. Raw material by bubbling the inside of a supply apparatus filled with at least one of tetrahalosilane represented by the formula [1] and alcohol represented by the formula [2] with an inert gas having a water content of 10 volume ppm or less The method for producing alkoxytrihalosilane according to any one of claims 1 to 6 , wherein: The alkoxytrihalo according to any one of claims 1 to 7, wherein a raw material is supplied from one end of the reaction vessel and a product is discharged from the other end using a tubular reaction vessel having an aspect ratio of 3 or more and 1000 or less. A method for producing silane.

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