Method for producing fluoromethane from chloromethane and fluoromethane composition

Abstract

A method is provided for synthesizing fluoromethane from chloromethane and at least 150% stoichiometric excess hydrogen fluoride into a fluoromethane product composition. The above synthesis method is, A step of contacting the reactants in a gaseous phase in a reactor in the substantial absence of chromium, optionally in the presence of solid support particles; A control step of controlling the conditions within the reactor to promote the reaction conversion rate of the reactants to 3 to 30% to form a reactor effluent stream; A separation step of separating unreacted chloromethane and hydrogen fluoride from the reactor effluent stream to form a recirculation stream, wherein at least some of the remaining components of the reactor effluent stream form a crude intermediate stream comprising a fluoromethane product and a hydrogen chloride byproduct; A step of recirculating at least a portion of the above recirculation stream to the reactor; A removal step for removing hydrogen chloride byproducts from the above intermediate stream to form a fluoromethane product stream, and Optionally, the step of purifying the fluoromethane product stream is included.

Description

Technology Field

[0001] The present invention relates to a method useful for producing fluoromethane from chloromethane and a relatively pure fluoromethane composition produced by said method. Background Technology

[0002] Various literature widely teaches the catalytic fluorination of reactants to form fluoromethane. Some representative examples are as follows.

[0003] U.S. Patent No. 3,258,500 discloses a fluorination substitution reaction on a C1-C8 halogenated aliphatic hydrocarbon in the presence of an activated anhydrous chromium-containing fluorination catalyst.

[0004] U.S. Patent No. 4,139,568 discloses fluoromethane synthesized from methanol and hydrogen fluoride in the presence of steam and a catalyst.

[0005] PCT Publication No. WO 2006 / 030677 discloses a method of reacting a chloromethane reactant with hydrogen fluoride after contacting it with a zeolite in the presence of a fluorination catalyst.

[0006] Japanese published patent application No. JP 2017036227 discloses the synthesis of fluoromethane from monohalomethanes (bifluorohalomethanes) and hydrogen fluoride in the presence of a chromium fluoride catalyst. Similar publications include Japanese published patents No. 60-013726, No. 60-008234, No. 60-008235 and No. 60-016943.

[0007] Chinese Patent No. CN 106542959 initiates a gaseous reaction of chloromethane and hydrogen fluoride in the presence of a highly active (chromium and heavy metal) fluorination catalyst.

[0008] Chinese Patent No. CN 110283041 discloses the synthesis of fluoromethane from chloromethane and hydrogen fluoride in the presence of a chromium-containing catalyst.

[0009] Chinese published patent application No. CN 110606797 discloses the synthesis of monofluoromethane with a high conversion rate from highly dehydrated reactants, chloromethane and hydrogen fluoride, and highly dehydrated oxygen-containing gas in the presence of a chromium-containing catalyst.

[0010] In addition, Chinese published patent application No. CN 103910600 discloses activated carbon as a mechanism for adsorbing and removing impurities in crude fluoromethane production to obtain a high-purity fluoromethane composition.

[0011] It is extremely rare for a fluoromethane synthesis reaction not to be catalyzed. For example, U.S. Patent Publication No. 2023 / 159415 discloses the synthesis of fluoromethane from various gaseous reactants (including chloromethane from one list and hydrogen fluoride from another list) without a catalyst, for example, by inducing an electric discharge through the use of an externally applied voltage. Other similar publications include PCT Publication WO 2022 / 255120, Japanese Patent Publication No. JP 2022184047, and PCT Publication WO 2021 / 241372.

[0012] However, no published literature has been found that initiates the synthesis of fluoromethane without the presence of chromium and / or other catalytic metals, nor has any literature been found that discloses uncatalytic yields / selectivity approaching the yield / selectivity of the catalytic system.

[0013] The method for synthesizing fluoromethane disclosed herein includes a description of method conditions / modes in which the conversion rate is significantly improved in the substantial absence of chromium and / or other catalytic metals (e.g., iron). In practice, one or more of the following benefits can be obtained by not using conventional (chromium-containing) metal catalysts.

[0014] · Catalysts generally have a limited lifespan and must be regenerated or replaced after their lifespan is over.

[0015] · Catalysts (precursors) require activation, and the activation procedure can be quite complex to achieve and maintain high catalytic activity.

[0016] · Since catalysts undergo kinetic aging during use, the reaction effluent profile may change over time, sometimes rapidly inducing downstream purification and causing the recirculation stream to change over time, which can adversely affect product quality and process operation.

[0017] · It does not require a stable supply of catalyst, and purchasing or manufacturing costs are not added to the total cost of the finished product.

[0018] Since most fluorination catalysts are based on transition metals, various byproducts are formed, particularly at high temperatures, which can directly affect the purity of the final product and increase manufacturing costs by requiring more sophisticated purification schemes.

[0019] · Non-catalytic methods can obtain more consistent and reliable reaction effluents and final products.

[0020] Surprisingly, it has been found that commercially acceptable fluoromethane conversion rates can be achieved from chloromethane and hydrogen fluoride reactants in the absence of chromium and / or other catalytic metals, regardless of the presence or absence of solid particles (generally used as catalyst supports or porous and thought to function as reaction promoters instead of chemical catalysts). Specific details for implementing the invention

[0021] As used herein, the term "comprising" may also include the phrases "consisting of" and "essentially consisting of."

[0022] method

[0023] The initial step of the method for synthesizing fluoromethane includes the step of contacting the reactants in a reactor. In this case, the reactants include chloromethane (also known as methyl chloride, HCC-40 and / or R-40) and hydrogen fluoride (also known as HF, generally anhydrous or "aHF") (or essentially composed of these). Advantageously, both reactants may be introduced into the reactor in a gaseous phase, or, even if introduced in other forms, e.g., liquid, they may be converted to at least a gas under reaction conditions or near-reaction conditions.

[0024] It was found that a stoichiometric (molar) excess of hydrogen fluoride reactant may be required to carry out the reaction compared to the chloromethane reactant. In various forms, HF may be present in an amount of at least 100% stoichiometric excess with respect to CH3Cl, for example, at least 150% stoichiometric excess, at least 200% stoichiometric excess, at least 250% stoichiometric excess, at least 300% stoichiometric excess, at least 350% stoichiometric excess, at least 400% stoichiometric excess, at least 450% stoichiometric excess, at least 500% stoichiometric excess, at least 550% stoichiometric excess, at least 600% stoichiometric excess, at least 700% stoichiometric excess, at least 800% stoichiometric excess, at least 900% stoichiometric excess, or at least 1,000% stoichiometric excess. Since a 1:1 molar ratio of HF:CH3Cl is considered stoichiometric in the fluoromethane formation reaction, a 50% stoichiometric excess of HF corresponds to a 1.5:1 molar ratio of HF:CH3Cl, and a 100% stoichiometric excess of HF corresponds to a 2:1 molar ratio of HF:CH3Cl. Exemplary ranges of stoichiometric (molar) excess of hydrogen fluoride reactant to chloromethane reactant include 100 to 4,900%, 100 to 3,900%, 100 to 3,400%, 100 to 2,900%, 100 to 2,400%, 100 to 2,150%, 100 to 1,900%, 100 to 1,650%, 100 to 1,400%, 100 to 1,200%, 100 to 1,000%, 100 to 800%, 100 to 600%, 100 to 400%, 150 to 4,900%, 150 to 3,900%, 150 to 3,400%, 150 To 2,900%, 150 to 2,400%, 150 to 2,150%, 150 to 1,900%, 150 to 1,650%, 150 to 1,400%, 150 to 1,200%, 150 to 1,000%, 150 to 800%, 150 to 600%,150 to 400%, 200 to 4,900%, 200 to 3,900%, 200 to 3,400%, 200 to 2,900%, 200 to 2,400%, 200 to 2,150%, 200 to 1,900%, 200 to 1,650%, 200 to 1,400%, 200 to 1,200%, 200 to 1,000%, 200 to 800%, 200 to 600%, 200 to 400%, 300 to 4,900%, 300 to 3,900%, 300 to 3,400%, 300 to 2,900%, 300 to 2,400%, 300 to 2,150%, 300 to 1,900%, from 300 to 1,650%, 300 to 1,400%, 300 to 1,200%, 300 to 1,000%, 300 to 800%, 300 to 600%, 300 to 400%, 400 to 4,900%, 400 to 3,900%, 400 to 3,400%, 400 to 2,900%, 400 to 2,400%, 400 to 2,150%, 400 to 1,900%, 400 to 1,650%, 400 to 1,400%, 400 to 1,200%, 400 to 1,000%, 400 to 800%, 400 to 600%, 500 to 4,900%, 500 to 3,900%, 500 to 3,400%, 500 to 2,900%, 500 to 2,400%, 500 to 2,150%, 500 to 1,900%, 500 to 1,650%, 500 to 1,400%, 500 to 1,200%, 500 to 1,000%, 500 to 800%, 500 to 600%, 600 to 4,900%, 600 to 3,900%, from 600 to 3,400%, 600 to 2,900%, 600 to 2,400%, 600 to 2,150%, 600 to 1,900%, 600 to 1,650%, 600 to 1,400%, 600 to 1,200%, 600 to 1,000%, 600 to 800%, 700 to 4,900%, 700 to 3,900%, 700 to 3,400%, 700 to 2,900%, 700 to 2,400%, 700 to 2,150%, 700 to 1,900%, 700 to 1,650%, 700 to 1,400%, 700 to 1,200%, 700 to 1,000%, 700 to 800%, 800 to 4,900%, 800 to 3,900%, 800 to 3,400%, 800 to 2,900%, 800 to 2,400%, 800 to 2,150%, 800 to 1,900%, 800 to 1,650%, 800 to 1,400%, 800 to 1,200%, 800 to 1,000%, 900 to 4,900%, 900 to 3,900%, from 900 to 3,400%, 900 to 2,900%, 900 to 2,400%, 900 to 2,150%, 900 to 1,900%, 900 to 1,650%, 900 to 1,400%, 900 to 1,200% or 900 to 1,000%; In particular, 150 to 3,400%, 200 to 2,900%, 300 to 2,400%, 400 to 1,900%, or 500 to 1,400% may be included.

[0025] In many embodiments, it may be advantageous not to include single-functional CH3R reactants other than chloromethane (R = Cl), e.g., bromomethane (R = Br), iodomethane (R = I), methanol (R = OH), alkyl ethers (R = oxyalkyl moiety), and combinations thereof, but not necessarily limited thereto.

[0026] The step of contacting the reactants in the reactor may be carried out in the substantial absence of chromium and / or other metals (in particular, metals known to have catalytic activity in the chemical reaction of chloromethane to fluoromethane), non-limiting examples of other metals include iron, zinc, nickel, cobalt, molybdenum, tungsten, osmium, indium, antimony, gallium, arsenic, tin, and combinations thereof, in particular chromium, iron, or both. With respect to chromium and / or other metals, "substantial absence" may mean that chromium and / or other metals were not intentionally added. Additionally or otherwise, with respect to chromium and / or other metals, "substantial absence" may indicate less than 500 wppm, less than 300 wppm, less than 200 wppm, less than 100 wppm, less than 75 wppm, less than 50 wppm, less than 40 wppm, less than 30 wppm, less than 20 wppm, less than 10 wppm, or immeasurable amounts of chromium and / or other metals, in particular less than 100 wppm, less than 50 wppm, or less than 10 wppm. Accordingly, in certain embodiments, the contact step may be performed in the substantial absence of chromium (e.g., less than 100 wppm, less than 50 wppm, or less than 10 wppm), in the substantial absence of iron (e.g., less than 500 wppm, less than 100 wppm, less than 50 wppm, or less than 10 wppm), or in the substantial absence of chromium and iron (e.g., combined less than 500 wppm, combined less than 100 wppm, combined less than 50 wppm, or combined less than 20 wppm).

[0027] The chromium and / or other metal content can be measured by various methods, for example, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectroscopy (performed, for example, in an electron microscope and / or X-ray fluorescence (XRF) spectrometer), Auger electron spectroscopy (AES), or UV-Vis spectrophotometry, particularly by XPS spectroscopy.

[0028] Therefore, although not intended to be theoretical, the fluoromethane reaction disclosed herein can be considered (chemically) non-catalyzed reaction in the substantial absence of a catalytic metal (therefore, the method(s) according to the present invention can be considered (chemically) non-catalyzed method(s)).

[0029] The step of contacting the reactants in the reactor can be carried out in an empty reactor or in the presence of solid particles, and the reaction can take place.

[0030] Advantageously, these solid particles may be porous where present, and in some cases, highly porous. Although not intended to be linked to theory, the porosity of the solid particles may act as a promoter for the halogen exchange reaction to form fluoromethane (in a different way than metal catalysts, e.g., chromium-based metal catalysts). In this porous mode, depending on the specific physicochemical properties of the porous particles, the solid particles may have a BET surface area of ​​at least 5 m² / g, at least 10 m² / g, at least 25 m² / g, at least 50 m² / g, at least 75 m² / g, at least 100 m² / g, at least 200 m² / g, at least 300 m² / g, at least 400 m² / g, at least 500 m² / g, at least 600 m² / g, at least 700 m² / g, at least 800 m² / g, at least 900 m² / g, or at least 1,000 m² / g, and (if necessary) up to 10,000 m² / g, 5,000 m² / g, or 3,500 m² / g.

[0031] Additionally or otherwise, and advantageously, the solid particles may be made of a support material on which a catalytic metal can be deposited / associated on the surface, where present (however, since the catalytic metal is generally not deposited / associated on the surface, it is suggested herein that such reaction be considered non-catalytic). Non-limiting examples of such solid support particles include, but are not limited to, alumina, activated alumina, silica, activated carbon, aluminosilicate, borosilicate, aluminoborate, aluminophosphate, silicophosphate, silicoaluminophosphate, zeolite, alkali (e.g., sodium, potassium, lithium or combinations thereof; particularly sodium and / or potassium) oxide, alkaline earth metal (e.g., magnesium, calcium, barium, beryllium or combinations thereof; particularly magnesium, calcium and / or barium) oxide, carbonate, or combinations thereof. These solid (support) particles may include extruders and other configurations / shapes known in the field of fine particles. As mentioned above, the surface of these solid particles may not contain a significant amount of a specific metal (e.g., a metal known as a catalyst for the reaction, namely chromium and optionally other metals).

[0032] Alternatively, due to the presence of solid particles within the gas phase reaction system, where particles are present, the reactor may be a fixed-bed reactor, and one or more (porous) particle layers in the reactor may be pre-packed over and / or through the region where the gas phase reactants flow (e.g., to promote the reaction). In other particle-containing embodiments, other reactor designs may include, but are not limited to, fluid-bed reactors, bubble-bed reactors, trickle-bed reactors, etc., and each of said reactors may include a single layer or multiple layers of solid particles (or said reactors may include a combination of different layers operating as individual types of reactors). In a particle-free embodiment, a simple gas phase reactor design may be used.

[0033] To create a fluidized reaction zone, an additional diluent gas may be included during the addition of (gaseous) reactants, whether in a particle-containing environment or not, if desirable and / or necessary. Such diluent gas may include, if present, nitrogen, air, carbon dioxide, carbon monoxide, helium, neon, argon, krypton, xenon, or a combination thereof, or may be said gas, particularly including nitrogen and optionally including an inert gas. However, in some embodiments, it may be particularly desirable not to include a diluent gas.

[0034] Additionally, the method may advantageously include a control step of controlling conditions within the reactor to promote the reaction of the reactants (particularly, regardless of the presence of solid support particles) to form a reactor effluent stream. For example, the conditions within the reactor may advantageously include substantially no electrical discharge and / or no intentional application of an external voltage. Thus, unlike the initiation of a non-catalytic chloromethane-to-fluoromethane reaction of U.S. Patent Application No. 2023 / 0159415, the method(s) according to the present invention may include controlling reactor conditions without electrical discharge and / or intentionally applied external voltage, and generally in the absence of plasma. It should be understood that the phrase “not intentionally applied external voltage” as used herein means, for example, the intentional application of external voltage to the reaction zone of a reactor (which can electrically discharge a gas to promote a reaction, as disclosed in U.S. Patent Application No. 2023 / 0159415), and does not mean the application of external voltage that enables the use of electrically driven equipment to control flow rate, temperature, pressure, etc. in the reaction zone of the reactor.

[0035] Other controlled conditions include a reactant (molar) conversion rate, and the reactant (molar) conversion rate is 3% or more and 30% or less (e.g., 3% or more and 25% or less, 3% or more and 23% or less, 3% or more and 20% or less, 3% or more and 18% or less, 3% or more and 16% or less, 3% or more and 14% or less, 3% or more and 12% or less, 3% or more and 10% or less, 5% or more and 30% or less, 5% or more and 25% or less, 5% or more and 23% or less, 5% or more and 20% or less, 5% or more and 18% or less, 5% or more and 16% or less, 5% or more and 14% or less, 5% or more and 12% or less, 5% or more and 10% or less, 7% or more and 30% or less, 7% or more and 23% or less, 7% or more and 25% or less, 7% or more and 20% or less, 7% or more and 18% or less, 7% or more and 16% or less, 7% or more and 14% or less, 7% or more and 12% or less, 7% or more and 10% or less, 8% or more and 30% or less, 8% or more and 25% or less, 8% or more and 23% or less, 8% or more and 20% or less, 8% or more and 18% or less, 8% or more and 16% or less, 8% or more and 14% or less, 8% or more and 12% or less, 8% or more and 10% or less, 9% or more and 30% or less, 9% or more and 25% or less, 9% or more and 23% or less, 9% or more and 20% or less, 9% or more and 18% or less, 9% or more and 16% or less, 9% or more and 14% or less, 9% or more and 12% or less, 9% or more and 10% or less, 10% or more and 30% or less, 10% or more It may be 25% or less, 10% or more and 23% or less, 10% or more and 20% or less, 10% or more and 18% or less, 10% or more and 16% or less, 10% or more and 14% or less, or 10% or more and 12% or less; in particular, 3% or more and 30% or less, 5% or more and 25% or less, 7% or more and 23% or less, or 9% or more and 20% or less).

[0036] Considering incomplete conversion, the reactor effluent stream may contain or be essentially composed of unreacted reactants, namely chloromethane and hydrogen fluoride, and fluoromethane products and hydrogen chloride byproducts, and optionally all impurities contained in reactants that cannot be converted under reaction conditions to form fluoromethane products and / or hydrogen chloride byproducts (and / or optionally additionally said reacted impurities if they can be converted into some other impurities under reaction conditions).

[0037] In various embodiments, conditions within the reactor may be controlled to include one, some or all of the following conditions: about 200 to about 550°C (e.g., about 200 to about 500°C, about 200 to about 450°C, about 200 to about 400°C, about 200 to about 350°C, about 200 to about 300°C, about 250 to about 550°C, about 250 to about 500°C, about 250 to about 450°C, about 250 to about 400°C, about 250 to about 350°C, about 250 to about 300°C, about 280 to about 550°C, about 280 to about 500°C, about 280 to about 450°C, about 280 to about 400°C, about 280 to about 400°C, about 280 to about 280°C Reactor temperature of 350°C, about 280 to about 300°C, about 300 to about 550°C, about 300 to about 500°C, about 300 to about 450°C, about 300 to about 400°C, about 300 to about 350°C; particularly about 200 to about 550°C, about 250 to about 400°C or about 280 to about 450°C; About 10 to about 300 psia (e.g., about 10 to about 270 psia, about 10 to about 240 psia, about 10 to about 200 psia, about 10 to about 180 psia, about 10 to about 160 psia, about 10 to about 140 psia, about 10 to about 120 psia, about 10 to about 100 psia, about 10 to about 80 psia, about 10 to about 60 psia, about 10 to about 50 psia, about 10 to about 40 psia, about 15 to about 300 psia, about 15 to about 270 psia, about 15 to about 240 psia, about 15 to about 200 psia, about 15 to about 180 psia, about 15 to about 160 psia, About 15 to about 140 psia, about 15 to about 120 psia, about 15 to about 100 psia, about 15 to about 80 psia, about 15 to about 60 psia, about 15 to about 50 psia,About 15 to about 40 psia, about 20 to about 300 psia, about 20 to about 270 psia, about 20 to about 240 psia, about 20 to about 200 psia, about 20 to about 180 psia, about 20 to about 160 psia, about 20 to about 140 psia, about 20 to about 120 psia, about 20 to about 100 psia, about 20 to about 80 psia, about 20 to about 60 psia, about 20 to about 50 psia, about 20 to about 40 psia, about 25 to about 300 psia, about 25 to about 270 psia, about 25 to about 240 psia, about 25 to about 200 psia, about 25 to about 180 psia, about 25 to about 160 psia, about 25 to about 140 psia, about 25 to about 120 psia, about 25 to about 250 psia, about 25 to about 80 psia, about 25 to about 60 psia, about 25 to about 50 psia, about 25 to about 40 psia, about 30 to about 300 psia, about 30 to about 270 psia, about 30 to about 240 psia, about 30 to about 200 psia, about 30 to about 180 psia, about 30 to about 160 psia, about 30 to about 140 psia, about 30 to about 120 psia, about 30 to about 300 psia, about 30 to about 80 psia, about 30 to about 60 psia, about 30 to about Reactor pressure of 50 psia or about 30 to about 40 psia; particularly about 10 to about 300 psia, about 15 to about 270 psia, about 20 to about 240 psia, or about 30 to about 300 psia); 150 seconds or less (e.g., 120 seconds or less, 105 seconds or less, 90 seconds or less, 75 seconds or less, 60 seconds or less, 45 seconds or less, 30 seconds or less, 20 seconds or less, 15 seconds or less, or 10 seconds or less) and (if necessary) at least 0.5 seconds or 1 second; particularly 150 seconds or less,120 seconds or less or 30 seconds or less and (if necessary) a minimum residence time of 1 second; and about 1:4 to about 24:1 (e.g., about 1:4 to about 19:1, about 1:4 to about 16:1, about 1:4 to about 13:1, about 1:4 to about 10:1, about 1:4 to about 9:1, about 1:4 to about 8:1, about 1:4 to about 7:1, about 1:4 to about 6:1, about 1:4 to about 5:1, about 1:4 to about 4:1, about 1:2 to about 24:1, about 1:2 to about 19:1, about 1:2 to about 16:1, about 1:2 to about 13:1, about 1:2 to about 10:1, about 1:2 to about 9:1, about 1:2 to about 8:1, about 1:2 to about 7:1, about 1:2 to about 6:1, about 1:2 to about 5:1, about 1:2 to about 4:1, about 1:1 to about 24:1, about 1:1 to about 19:1, about 1:1 to about 16:1, about 1:1 to about 13:1, about 1:1 to about 10:1, about 1:1 to about 9:1, about 1:1 to about 8:1, about 1:1 to about 7:1, about 1:1 to about 6:1, about 1:1 to about 5:1, about 1:1 to about 4:1, about 2:1 to about 24:1, about 2:1 to about 19:1, about 2:1 to about 16:1, about 2:1 to about 13:1, about 2:1 to about 10:1, about 2:1 to about 9:1, about 2:1 to about 8:1, about 2:1 to about 7:1, about 2:1 to about 6:1, about 2:1 to about 5:1, about 2:1 to about 4:1, about 3:1 to about 24:1, about 3:1 to about 19:1, about 3:1 to about 16:1, about 3:1 to about 13:1, about 3:1 to about 10:1, about 3:1 to about 9:1, about 3:1 to about 8:1, about 3:1 to about 7:1, about 3:1 to about 6:1, about 3:1 to about 5:1, about 3:1 to about 4:1, about 4:1 to about 24:1, about 4:1 to about 19:1,The ratio of recycled (unreacted) chloromethane to new chloromethane and / or the ratio of recycled (unreacted) hydrogen fluoride to new hydrogen fluoride of about 4:1 to about 16:1, about 4:1 to about 13:1, about 4:1 to about 10:1, about 4:1 to about 9:1, about 4:1 to about 8:1, about 4:1 to about 7:1, about 4:1 to about 6:1, about 4:1 to about 5:1; particularly about 1:4 to about 24:1, about 1:1 to about 19:1 or about 4:1 to about 16:1).

[0038] As mentioned above, due to incomplete reaction conversion, it may often be advantageous to separate unreacted reactants, particularly chloromethane and hydrogen fluoride, from the reactor effluent stream to form a recirculation stream, at least a portion (substantially all in a preferred embodiment) of said recirculation stream is recirculated to the reactor, and at least a portion (substantially all in a preferred embodiment) of the remaining components of said reactor effluent stream forms a crude intermediate stream comprising fluoromethane products and hydrogen chloride byproducts. If necessary, the entire remainder of the recirculation stream may be used in one or more other reactions and / or separated for various other purposes. Separation to form the recirculation stream may advantageously be carried out via distillation (said distillation may be represented as a single distillation step or multiple distillation steps; in the case of multiple distillation steps, the final distillation product should be understood as the crude intermediate stream, and the multiple distillation / fractionated stream should be understood collectively as the recirculation stream).

[0039] In some cases, separation (distillation) conditions must be selected so that unreacted chloromethane and unreacted hydrogen fluoride remain in the crude intermediate stream (which again contains the fluoromethane product and hydrogen chloride byproduct) in no or extremely small amounts (particularly unreacted chloromethane at 100 wppm or less, 50 wppm or less, or 10 wppm or less; and particularly unreacted hydrogen fluoride at 300 wppm or less, 100 wppm or less, 50 wppm or less, or 10 wppm or less). According to PCT Publication WO 2005 / 009933, part or all of the crude intermediate product may consist of an azeotropic mixture of the fluoromethane product and the hydrogen chloride byproduct. Additionally or otherwise, part or all of the crude intermediate product stream may consist of a semi-azeotropic mixture of the fluoromethane product and the hydrogen chloride byproduct.

[0040] The step of recirculating (part or all of) the separated unreacted reactants (in the recirculation stream) may include a heating step before reintroducing the unreacted reactants (in the recirculation stream) into the reactor, for example, to prevent low-temperature components (generally resulting from temperature(s) of separation(s) lower than the reaction temperature in the reactor) from having a negative effect on the temperature stability of the reaction by "cold" reintroduction. In this case, heating the unreacted reactants may result in a temperature that is at least 10°C lower than the average temperature of the reactor and / or the inlet temperature of the reactor, particularly at least 5°C lower than the average temperature of the reactor and / or the inlet temperature of the reactor, and (if necessary) at most a temperature that is at least 10°C higher than the average temperature of the reactor and / or the inlet temperature of the reactor or at least 5°C higher than the average temperature of the reactor and / or the inlet temperature of the reactor.

[0041] The step of recirculating some or all of the separated unreacted reactants (in the recirculation stream) may optionally include a step of adjusting the pressure of the unreacted reactants (in the recirculation stream) before reintroducing them into the reactor, for example, so that the low-pressure component (generally resulting from the pressure(s) of the separation(s) being lower than the reaction pressure in the reactor) does not have a negative effect on the pressure stability of the reaction upon reintroduction. In such cases, the pressure of the unreacted reactants may be adjusted to a pressure at least 15 psi lower than the average pressure of the reactor and / or the inlet pressure of the reactor, particularly at least 7 psi lower than the average pressure of the reactor and / or the inlet pressure of the reactor, and (if necessary) to a maximum of 15 psi higher than the average pressure of the reactor and / or the inlet pressure of the reactor or 7 psi higher than the average pressure of the reactor and / or the inlet pressure of the reactor.

[0042] To better isolate the desired fluoromethane, the method may advantageously include the step of removing hydrogen chloride byproducts from a crude intermediate product stream to form a fluoromethane product stream. There may be various methods for isolating hydrogen chloride from fluoromethane (e.g., present together in the crude intermediate stream), but one method is to first treat the fluoromethane / hydrogen chloride mixture (crude intermediate stream) with a caustic substance (e.g., hydroxy moiety and alkali metal or alkaline earth metal, e.g., Na, Li, K, Rb, Cs, Be, Ba, Mg, Sr, Ca, etc.; in particular, containing Na, K, Li, Ca, Mg or a mixture thereof, or containing Na and / or K, and such caustic substance may optionally additionally contain water), possibly in a scrubber, to neutralize the acidic hydrogen chloride, e.g., with a salt, said salt can be removed by precipitation and easily separated from the fluoromethane (said fluoromethane is present in the crude intermediate stream; said separation may occur naturally, e.g., by gravity and / or phase separation, or, for example, by an auxiliary to physical separation and / or natural separation by filtration, e.g., (This may include centrifugation). Secondly, the caustic-treated mixture (i.e., crude intermediate) is dried to limit the water content that may generally be formed due to the reaction between the acid and the neutralizing agent (and / or the use of an aqueous caustic substance during the neutralization treatment). In various embodiments, drying may be performed by changing the temperature / pressure and / or by introducing (and subsequently separating) a heterogeneous moisture trap (a solid hygroscopic agent, e.g., a molecular sieve, or a liquid capable of selectively attracting moisture in a heterogeneous phase).

[0043] If these steps do not sufficiently isolate the desired fluoromethane, the method may optionally include a step of (further) purifying the fluoromethane product stream to form a purified fluoromethane product stream. In various embodiments, further purification of the fluoromethane product stream may include further distillation. In some of these embodiments, distillation for purifying the fluoromethane product stream may be performed at a pressure at least 15 psi higher than the pressure at which unreacted reactants are separated (distilled) from the reactor effluent stream (e.g., at least 30 psi higher, at least 40 psi higher, at least 50 psi higher, at least 60 psi higher, at least 70 psi higher, at least 80 psi higher, at least 90 psi higher, or at least 100 psi higher; particularly at least 30 psi higher, at least 50 psi higher, or at least 70 psi higher).

[0044] The product specifications from the above method(s) may vary depending, for example, the desired end use of the fluoromethane product (and optionally other products or by-products), whether the product stream is further processed / purified, and / or various other factors, but the fluoromethane product stream and / or purified fluoromethane product stream from the disclosed method are individually at least 98.5 wt% (e.g., at least 98.8 wt%, at least 99.0 wt%, at least 99.2 wt%, at least 99.4 wt%, at least 99.6 wt%, at least 99.8 wt%, at least 99.9 wt% or at least 99.95 wt%, (if necessary) up to 99.99 wt%, up to 99.999 wt% or up to 99.9999 wt%; in particular, at least 98.5 wt%, at least 99 wt% or at least 99.9 wt%, optionally up to 99.999 wt% of fluoromethane, up to 1.4 wt% (e.g., up to 1.1 wt%, up to 1.0 wt%, up to 0.8 wt%, up to 0.6 wt%, up to 0.5 wt%, up to 0.4 wt%, up to 0.2 wt%, up to 0.1 wt% or up to 0.05 wt%, (if necessary) at least 0.01 wt%, 0.005 wt%, 0.001 wt% or unmeasurable; in particular, up to 1.1 wt%, up to 1.0 wt%, up to 0.5 wt% or up to 0.1 wt% (optionally extendable to immeasurable), methane of 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or immeasurable amount; particularly, 200 wppm or less, 100 wppm or less, 20 wppm or less, or immeasurable amount), difluoromethane of 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or immeasurable amount; particularly, 200 wppm or less, It may include all by-products with more than 1 carbon atom (100 wppm or less, 50 wppm or less, or 10 wppm or less).

[0045] In addition to characterizing the reaction effluent stream, the reaction may be further or otherwise characterized by product selectivity(s). As used herein, “selectivity” or “raw selectivity” refers to a product or byproduct in a given stream (preferably in a method for producing fluoromethane according to the present invention) as a weight percentage content of the specific product / byproduct in the given stream relative to the weight of other products and byproducts measured in the stream, and generally ignores unreacted reactants (e.g., from incomplete conversion), solid particles (where present, e.g., support particles / porous promoters included in the method disclosed herein), already reacted products / byproducts (e.g., from a recirculation step / stream), and all other materials converted into reactants under reaction conditions. (In the method for producing fluoromethane disclosed herein, preferably) the “reaction-specific selectivity” used herein for a product or byproduct in a given stream may be further adjusted to ignore a (non-reactive) diluent in a given stream (a reaction diluent that may have non-reactive functionality, e.g., a diluent introduced into the reactor as a heat transfer agent, etc., or as an impurity in the reactants).Accordingly, the “reaction-specific selectivity” for a product or byproduct in a given stream can be defined as the sum of the “raw selectivity” and the total weight percentage of impurities in other streams added to the reactor (e.g., inert substances in chloromethane, e.g., methane, etc.; reactive species that are chloromethane, such as dichloromethane, which can only be a byproduct of difluoromethane or chlorofluoromethane and can never be a fluoromethane product; inert substances that are fluorinated, e.g., water; and reactive species that are fluorinated, which cannot react with chloromethane reactants to form fluoromethane, e.g., carbon tetrachloride, hydrogen bromide, etc.) based on the weight of other products and byproducts in the stream. This results in the additional exclusion of inert substances and unproductive reactive impurities among the reactants that were overlooked in the definition of "selectivity" or "low selectivity" (assumed to be non-existent or to have a very negligible impact on reaction kinetics and / or product / by-product formation).

[0046] In fact, in the method(s) according to the present invention, in particular, the chloromethane reactant may contain a small, measurable amount of methane and / or other impurities (which cannot be converted into a fluoromethane product under reactor conditions). If present, the chloromethane reactant is 10 wppm to 1.4 wt% (e.g., 10 wppm to 1.2 wt%, 10 wppm to 1.0 wt%, 10 wppm to 0.8 wt%, 10 wppm to 0.6 wt%, 10 wppm to 0.4 wt%, 10 wppm to 0.2 wt%, 10 wppm to 0.1 wt%, 20 wppm to 1.4 wt%, 20 wppm to 1.2 wt%, 20 wppm to 1.0 wt%, 20 wppm to 0.8 wt%, 20 wppm to 0.6 wt%, 20 wppm to 0.4 wt%, 20 wppm to 0.2 wt%, 20 wppm to 0.1wt%, 30wppm to 1.4wt%, 30wppm to 1.2wt%, 30wppm to 1.0wt%, 30wppm to 0.8wt%, 30wppm to 0.6wt%, 30wppm to 0.4wt%, 30wppm to 0.2wt%, 30wppm to 0.1wt%, 50wppm to 1.4wt%, 50wppm to 1.2wt%, 50wppm to 1.0wt%, 50wppm to 0.8wt%, 50wppm to 0.6wt%, 50wppm to 0.4wt%, 50wppm to 0.2wt%, 50wppm to 0.1wt%, 70wppm to 1.4wt%, 70wppm to 1.2wt%, 70wppm to 1.0wt%, 70wppm to 0.8wt%, 70wppm to 0.6wt%, 70wppm to 0.4wt%, 70wppm to 0.2wt%, 70wppm to 0.1wt%, 100wppm to 1.4wt%, 100wppm to 1.2wt%, 100wppm to 1.0wt%, 100wppm to 0.8wt%, 100wppm to 0.6wt%, 100wppm to 0.4wt%, 100wppm to 0.2wt%, 100wppm to 0.1wt%; In particular, 10 wppm to 1.4 wt%, 100 wppm to 1.0 wt%, 20 wppm to 0.8 wt%, or 30 wppm to 0.6 wt% of methane and optionally up to 2.0 wt% (e.g., up to 1.9 wt%, up to 1.8 wt%, up to 1.7 wt%, up to 1.6 wt%, up to 1.5 wt%, up to 1.4 wt%, up to 1.3 wt%, up to 1.2 wt%, up to 1.1 wt%, up to 1.0 wt%, up to 0.9 wt%, up to 0.8 wt%, up to 0.7 wt%, up to 0.6 wt%, up to 0.5 wt%, up to 0.4 wt%, up to 0.3 wt%, up to 0.2 wt%, or up It may contain 0.1 wt%, and (if necessary) at least 100 wppm, 10 wppm, or an immeasurable amount; in particular, up to 1.9 wt%, up to 1.0 wt%, or up to 0.3 wt%, and (if necessary) at least 0 / an immeasurable amount) other impurities (impurities that cannot be converted into fluoromethane products under reactor conditions). Under these circumstances, by controlling the conditions within the reactor, the reaction-specific selectivity of the fluoromethane product can be achieved at least 98.5 wt%, e.g., at least 98.8 wt%, at least 99.0 wt%, at least 99.2 wt%, at least 99.4 wt%, at least 99.5 wt%, at least 99.6 wt%, at least 99.8 wt%, or at least 99.9 wt% (and optionally up to 99.9999 wt% or 99.999 wt%) as needed; in particular, at least 99.0 wt% or at least 99.5 wt% (and optionally up to 99.999 wt%) as needed.

[0047] The above method may be continuous or semi-continuous, or batch or semi-batch.

[0048] Fluoromethane product composition

[0049] The fluoromethane product composition may comprise a fluoromethane product stream and / or a purified fluoromethane product stream from the synthesis method(s) disclosed herein. Regardless of the method of preparation, the fluoromethane product composition comprises at least 98.5 wt% (e.g., at least 98.8 wt%, at least 99.0 wt%, at least 99.2 wt%, at least 99.4 wt%, at least 99.5 wt%, at least 99.6 wt%, at least 99.8 wt%, at least 99.9 wt% or at least 99.95 wt%, and (if necessary) up to 99.99 wt%, up to 99.999 wt% or up to 99.9999 wt%; in particular, at least 98.5 wt%, at least 99.0 wt%, at least 99.5 wt% or at least 99.9 wt%, optionally up to 99.999 wt%) of fluoromethane, up to 1.4 wt% (e.g., up to 1.1 wt%, up to 1.0 wt%, max. 0.8 wt%, max. 0.6 wt%, max. 0.5 wt%, max. 0.4 wt%, max. 0.2 wt%, max. 0.1 wt% or max. 0.05 wt%, and (if necessary) at least 0.01 wt%, 0.005 wt%, 0.001 wt% or an unmeasurable amount; in particular, at least 1.1 wt%, max. 1.0 wt%, max. 0.5 wt% or max. 0.1 wt%, and optionally an unmeasurable amount) methane of 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less or measured Difluoromethane of an unmeasurable amount (in particular, 200 wppm or less, 100 wppm or less, 20 wppm or less, or an immeasurable amount), 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or an immeasurable amount;In particular, all by-products having more than 1 carbon number other than methane (200 wppm or less, 100 wppm or less, 50 wppm or less, or 10 wppm or less); optionally, a water / moisture content of 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or an immeasurable amount; in particular, 200 wppm or less, 100 wppm or less, 50 wppm or less, or 10 wppm or less); optionally, 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm It may include a hydrogen chloride content of 200 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or an immeasurable amount; in particular, 200 wppm or less, 100 wppm or less, 50 wppm or less, or 10 wppm or less, optionally a hydrogen fluoride content of 200 wppm or less (e.g., 100 wppm or less, 80 wppm or less, 60 wppm or less, 50 wppm or less, 40 wppm or less, 20 wppm or less, 10 wppm or less, 5 wppm or less, 1 wppm or less, or an immeasurable amount; in particular, 200 wppm or less, 100 wppm or less, 50 wppm or less, or 10 wppm or less). In some embodiments, the fluoromethane product composition may be used, for example, as an etching gas composition for use in semiconductor etching or as a component of an etching gas composition.;

[0050] Various forms

[0051] Additionally or otherwise, the present invention may include the following non-limiting embodiments, but is not necessarily limited thereto.

[0052] Embodiment 1. As a method for synthesizing fluoromethane,

[0053] A step of contacting reactants comprising chloromethane and at least 150% stoichiometric excess of hydrogen fluoride with respect to chloromethane in the gaseous phase in a reactor in the substantial absence of chromium and optionally in the presence of solid support particles;

[0054] A control step of controlling the conditions within the reactor to optionally promote the reaction of the reactants in the presence of the solid support particles to form a reactor effluent stream containing fluoromethane at a reactant conversion rate of 3% or more and 30% or less, wherein the conditions within the reactor include substantially no electrical discharge and / or no external voltage being intentionally applied;

[0055] A separation step of separating unreacted chloromethane and hydrogen fluoride from the reactor effluent stream to form a recirculation stream, wherein at least some of the remaining components of the reactor effluent stream form a crude intermediate stream comprising a fluoromethane product and a hydrogen chloride byproduct;

[0056] A step of recirculating at least a portion of the recirculation stream containing the unreacted chloromethane and hydrogen fluoride to the reactor;

[0057] A removal step for removing hydrogen chloride byproducts from the above intermediate stream to form a fluoromethane product stream, and

[0058] Optionally, the method includes the step of purifying the fluoromethane product stream to form a purified fluoromethane product stream,

[0059] A method for synthesizing fluoromethane, wherein the fluoromethane product stream and / or the purified fluoromethane product stream comprises at least 98.5 wt% fluoromethane, up to 1.1 wt% methane, 200 wppm or less difluoromethane, and 200 wppm or less all by-products having more than 1 carbon atom.

[0060] Embodiment 2. A method for synthesizing fluoromethane of Embodiment 1, wherein the stoichiometric excess of hydrogen fluoride to chloromethane is 200 to 2,900%, particularly 300 to 1,900% or 400 to 1,400%.

[0061] Embodiment 3. A method for synthesizing fluoromethane according to Embodiment 1 or Embodiment 2, wherein the solid support particles are present and the solid support particles are porous.

[0062] Embodiment 4. A method for synthesizing fluoromethane of any one of Embodiments 1 to 3, wherein the solid support particles are present, and the solid support particles comprise alumina, activated alumina, silica, activated carbon, aluminosilicate, borosilicate, aluminoborate, zeolite, alkali oxide, alkaline earth metal oxide, carbonate, or a combination thereof.

[0063] Aspect 5. A method for synthesizing fluoromethane of any one of Aspects 1 to 4, wherein the step of contacting reactants in the reactor is further performed in the substantial absence of iron.

[0064] Aspect 6. The above conditions in the reactor,

[0065] A reactor temperature of about 200 to about 550°C, particularly about 250 to about 400°C, or about 280 to about 450°C;

[0066] A reactor pressure of about 10 to about 300 psia, particularly about 15 to about 270 psia, and

[0067] A method for synthesizing fluoromethane of any one of embodiments 1 to 5, controlled to include a residence time of 150 seconds or less, particularly 120 seconds or less.

[0068] Embodiment 7. A method for synthesizing fluoromethane of any one of Embodiments 1 to 6, wherein the reactant conversion rate is 5% or more and 25% or less.

[0069] Embodiment 8. A method for synthesizing fluoromethane of any one of Embodiments 1 to 7, wherein the step of separating unreacted reactants includes distillation.

[0070] Embodiment 9. A method for synthesizing fluoromethane of any one of Embodiments 1 to 8, wherein the step of recirculating unreacted reactants comprises, after separation, heating the unreacted reactants to a temperature at least 10°C lower than the inlet temperature of the reactor, particularly at least 5°C lower than the inlet temperature of the reactor.

[0071] A method for synthesizing fluoromethane of any one of embodiments 1 to 9, wherein the removal step for removing hydrogen chloride from the crude intermediate stream comprises the step of treating the crude intermediate stream with a caustic substance and then drying it.

[0072] Embodiment 11. A method for synthesizing fluoromethane of any one of Embodiments 1 to 10, wherein the fluoromethane product stream is purified using distillation.

[0073] Aspect 12. A method for synthesizing fluoromethane of Aspect 11, wherein the distillation for purifying the fluoromethane product stream is performed at a pressure at least 30 psi higher than the pressure at which unreacted reactants are separated from the reactor effluent stream, particularly at least 50 psi higher or at least 70 psi higher.

[0074] Embodiment 13. A method for synthesizing fluoromethane of any one of Embodiments 1 to 12, wherein the fluoromethane product stream and / or the purified fluoromethane product stream comprises at least 99.0 wt% fluoromethane, up to 1.0 wt% methane, 20 wppm or less difluoromethane, and 50 wppm or less all by-products other than methane having more than 1 carbon atom.

[0075] Embodiment 14. A method for synthesizing fluoromethane of any one of Embodiments 1 to 13, wherein the chloromethane reactant comprises 100 wppm to 1.0 wt% of methane and optionally comprises up to 1.9 wt% of other impurities that cannot be converted into a fluoromethane product under the conditions in the reactor, and the conditions in the reactor are controlled to have a reaction-specific selectivity of at least 99.0 wt%, particularly at least 99.5 wt% of the fluoromethane product.

[0076] Embodiment 15. As a fluoromethane product composition,

[0077] Optionally manufactured according to any one of the methods of embodiments 1 to 13, and

[0078] At least 99 wt%, particularly at least 99.9 wt% of fluoromethane;

[0079] Up to 0.5 wt%, particularly up to 0.1 wt% methane;

[0080] 20 wppm or less, particularly immeasurable amounts of difluoromethane;

[0081] All by-products other than methane with more than 1 carbon atom, at 50 wppm or less;

[0082] Optionally, water content of 10 wppm or less;

[0083] Optionally, a hydrogen chloride content of 10 wppm or less and

[0084] A fluoromethane product composition optionally comprising a hydrogen fluoride content of 10 wppm or less.

[0085] Examples

[0086] Comparative Examples 1 to 9

[0087] In ~16" length ~1" diameter Hastelloy® (C-276) reactors, ~80 mL (Comparative Examples 1 and 2) or ~30 mL (Comparative Examples 3 to 9) of bulk chromium oxide catalyst (E 410 T 1 / 8", purchased from BASF) was activated at ~300°C under a flow of aHF and nitrogen. After each catalyst activation, the reactor was maintained at ~300°C and a pressure of ~25 psig. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at varying flow rates ranging from ~4 to ~32 g / h. Commercially available chloromethane was introduced at varying flow rates ranging from ~1.2 to ~17 g / h and at various HF / CH3Cl molar ratios ranging from ~4:1 to ~17:1. After passing the gas from each reactor outlet through a caustic scrubber and a drying column, the cut of the outlet gas was subjected to online gas chromatography (GC). The conversion rate of chloromethane to fluoromethane, the selectivity of the fluoromethane, the approximate residence time of each reaction, and the other variables mentioned above are shown in Table 1 below.

[0088]

[0089] Comparative Examples 10 to 12

[0090] In a ~16" long ~1" diameter Hastelloy® (C-276) reactor, ~30 mL of bulk chromium oxide catalyst (Pricat™ 62-3M, purchased from Johnson Matthey) was activated at ~300°C under a flow of aHF and nitrogen. After each catalyst activation, the reactor was maintained at ~300°C and a pressure of ~25 psig. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~30 g / h. Commercially available chloromethane was introduced at varying flow rates ranging from ~9.8 to ~17 g / h and at various HF / CH3Cl molar ratios ranging from ~4:1 to ~8:1. After passing the gas from each reactor outlet through a caustic scrubber and a drying column, the cut of the outlet gas was introduced into an online GC. The conversion rate of chloromethane to fluoromethane, the selectivity of the fluoromethane, the approximate residence time of each reaction, and the other variables are shown in Table 2 below.

[0091]

[0092] Comparative Examples 13 to 20

[0093] In a ~16" long ~1" diameter Hastelloy® (C-276) reactor, ~10 mL of alumina-supported chromium oxide catalyst (PBN1, purchased from Arkema) was activated at ~300°C under a flow of aHF and nitrogen. After each catalyst activation, the reactor was maintained at ~300°C and a pressure of ~25 psig. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at varying flow rates ranging from ~5 to ~50 g / h. Commercially available chloromethane was introduced at varying flow rates ranging from ~1.6 to ~17 g / h and at various HF / CH3Cl molar ratios ranging from ~4:1 to ~8:1. After passing the gas from each reactor outlet through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online gas chromatograph (GC). The conversion rate of chloromethane to fluoromethane, the selectivity of the fluoromethane, the approximate residence time of each reaction, and the other variables are shown in Table 3 below.

[0094]

[0095] Examples 21 to 25

[0096] In a ~16" long ~1" diameter Hastelloy® (C-276) reactor, ~10 mL of ~5% FeCl3 catalyst supported on activated carbon was activated at ~300°C under a flow of aHF and nitrogen. After each catalyst activation, the reactor was maintained at ~300°C (Examples 21 and 22) or ~335°C (Examples 23 to 25) at a pressure of ~25 psig. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C or ~335°C, respectively, aHF was introduced at varying flow rates ranging from ~2.4 to ~30 g / h. Commercially available chloromethane was introduced at varying flow rates ranging from ~1.5 to ~8 g / h and at varying HF / CH3Cl molar ratios ranging from ~4:1 to ~9:1. After passing the gas from each reactor outlet through a caustic scrubber and a drying column, the cut of the outlet gas was introduced into online gas chromatography (GC). The conversion rate of chloromethane to fluoromethane, the selectivity of the fluoromethane, the approximate residence time of each reaction, and the other variables are shown in Table 4 below.

[0097]

[0098] Examples 26 to 28

[0099] In Example 26, a ~3 / 8" diameter Hastelloy® (C-276) reactor with a length of ~16" was heated to ~450°C for ~24 hours under a nitrogen flow at a pressure of ~150 psig. The nitrogen supply was stopped, and while maintaining the temperature at ~450°C, aHF was introduced at a flow rate of ~40 g / h. Commercially available chloromethane was introduced at a flow rate of ~20 g / h with an HF / CH3Cl molar ratio of ~5:1. The residence time was ~5.4 seconds. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was ~5.4 seconds, and the conversion rate of chloromethane to fluoromethane was ~3%.

[0100] In Example 27, Example 26 was repeated with an aHF flow rate of ~19 g / h, a chloromethane flow rate of ~1.9 g / h, and an HF / CH3Cl molar ratio of ~25:1. The retention time was ~17 seconds, and the conversion rate was ~3.8%.

[0101] In Example 28, Example 26 was repeated in a ~1" diameter Hastelloy® (C-276) reactor at a pressure of ~100 psig (temperature of ~450°C), an aHF flow rate of ~30 g / h, a chloromethane flow rate of ~17 g / h, and an HF / CH3Cl molar ratio of ~5:1. The residence time was ~156 seconds, the conversion rate was ~1%, and the raw selectivity for fluoromethane was >99%.

[0102] In Example 29, Example 28 was repeated with a temperature of ~300°C (pressure of ~100 psig), an aHF flow rate of ~67 g / h, and chloromethane of ~32 g / h (HF:CH3Cl molar ratio of ~5:1). The residence time was ~89 seconds, and the conversion rate was <1%, but the selectivity for fluoromethane was >99%.

[0103] Examples 30 to 33

[0104] In a ~1" diameter Hastelloy® (C-276) reactor with a length of ~16", ~80 mL of low surface area alumina (corundum, ~5 m² / g, purchased from Panadyne) was heated to ~300°C (Examples 30 and 31) or ~335°C (Examples 32 and 33) for ~24 hours under a nitrogen flow at a pressure of ~25 psig. The nitrogen supply was stopped, and aHF was introduced at a flow rate of ~10 g / h while maintaining the temperature at ~300°C or ~335°C, respectively. Commercially available chloromethane was introduced at a flow rate of ~3.3 g / h (Examples 30 and 33) or ~1.6 g / h (Examples 31 and 32) with an HF / CH3Cl molar ratio of ~8:1 (Examples 30 and 33) or ~16:1 (Examples 31 and 32). After passing the gas from each reactor outlet through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The conversion rate of chloromethane to fluoromethane, the selectivity of the fluoromethane, the approximate residence time of each reaction, and the other variables are shown in Table 5 below.

[0105]

[0106] Examples 34 to 36

[0107] In Example 34, ~13 mL of porous alumina (Alum-SAS200™-sphere-l / 8", ~350 m² / g, purchased from BASF) was heated to ~300°C for ~24 hours under a nitrogen flow at a pressure of ~150 psig in a ~16" length ~1 / 2" diameter Hastelloy® (C-276) reactor. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~30 g / h. Although an exothermic reaction was observed, when the temperature stabilized at ~300°C, commercially available chloromethane was introduced at a flow rate of ~10 g / h with an HF / CH3Cl molar ratio of ~7.6:1. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was 6 to 7 seconds. The conversion rate of chloromethane to fluoromethane It was ~2%, and the selectivity for fluoromethane was >99%.

[0108] In Example 35, Example 34 was repeated at a temperature of ~325°C. The conversion rate was ~6%, and the residence time and row selectivity were the same.

[0109] In Example 36, Example 34 was repeated at a temperature of ~350°C. The conversion rate was ~10%, and the residence time and row selectivity were the same.

[0110] Examples 37 to 48

[0111] In Example 37, ~13 mL of coal-based activated carbon granules (purchased from Calgon Carbon) were heated to ~300°C for ~24 hours under a nitrogen flow at a pressure of ~150 psig in a ~16" length Hastelloy® (C-276) reactor. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~30 g / h. Commercially available chloromethane was introduced at a flow rate of ~10 g / h with an HF / CH3Cl molar ratio of ~7.6:1. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was ~6.7 seconds. The conversion rate of chloromethane to fluoromethane was ~9.7%, and the selectivity of the fluoromethane was >99%.

[0112] In Examples 38 to 47, Example 37 was repeated at temperatures of ~100°C, ~125°C, ~150°C, ~175°C, ~200°C, ~225°C, ~250°C, ~275°C, ~325°C, and ~350°C, respectively.

[0113] The conversion rates at or below ~200°C were all ≤0.5%. The conversion rate at ~225°C was ~1%, and the raw selectivity for fluoromethane was >99%. The conversion rate at ~250°C was ~3.5%, and the raw selectivity for fluoromethane was >99%. The conversion rate at ~275°C was ~7.6%, and the raw selectivity for fluoromethane was >99%. The conversion rate at ~325°C was ~10%, and the raw selectivity for fluoromethane was >99%. The conversion rate at ~350°C was ~11%, and the raw selectivity for fluoromethane was >99%.

[0114] In Example 48, ~120 mL of coal-based activated carbon granules (purchased from Calgon Carbon) were heated to ~300°C for ~24 hours under a nitrogen flow at a pressure of ~100 psig in a ~1" diameter Hastelloy® (C-276) reactor. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~50 g / h. Commercially available chloromethane was introduced at a flow rate of ~17 g / h with an HF / CH3Cl molar ratio of ~7.4:1. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was ~11 seconds, the conversion rate was ~10%, and the raw selectivity for fluoromethane was >99%.

[0115] Examples 49 to 51

[0116] In Example 49, ~13 mL of activated carbon extruder (coconut-based, ~1,000 m² / g, purchased from Johnson Matthey) was heated to ~300°C for ~24 hours under a nitrogen flow at a pressure of ~150 psig in a ~16" length ~1 / 2" diameter Hastelloy® (C-276) reactor. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~30 g / h. Commercially available chloromethane was introduced at a flow rate of ~10 g / h with an HF / CH3Cl molar ratio of ~7.6:1. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was 6 to 7 seconds. The conversion rate of chloromethane to fluoromethane was ~8%, and the selectivity of the low for fluoromethane was >99%.

[0117] In Example 50, Example 49 was repeated at a temperature of ~325°C. The conversion rate was ~10%, and the retention time and row selectivity were maintained at the same level.

[0118] In Example 51, Example 49 was repeated at a temperature of ~350°C. The conversion rate was ~11%, and the residence time and row selectivity were maintained at the same level.

[0119] Examples 52 to 54

[0120] In Example 52, ~13 mL of activated carbon extruder (coal-based, 4 mm, 1,050 to 1,200 m² / g, purchased from Carbon Activated Corporation) was heated to ~300°C for ~24 hours under a nitrogen flow at a pressure of ~150 psig in a ~16" length, ~1 / 2" diameter Hastelloy® (C-276) reactor. The nitrogen supply was stopped, and while maintaining the temperature at ~300°C, aHF was introduced at a flow rate of ~30 g / h. Commercially available chloromethane was introduced at a flow rate of ~10 g / h with an HF / CH3Cl molar ratio of ~7.6:1. After passing the reactor outlet gas through a caustic scrubber and a drying column, a cut of the outlet gas was introduced into an online GC. The residence time was 6 to 7 seconds. The conversion rate of chloromethane to fluoromethane was ~5%.

[0121] In Example 53, Example 52 was repeated at a temperature of ~325°C. The conversion rate was ~6%, and the residence time was kept the same.

[0122] In Example 51, Example 49 was repeated at a temperature of ~350°C. The conversion rate was ~7%, and the residence time was kept the same.

[0123] In this specification, aspects and / or embodiments have been described to ensure a clear and concise specification, and it should be understood that the aspects may be combined or separated in various ways without departing from the invention. For example, it should be understood that all preferred characteristic configurations disclosed herein may be applicable to all aspects of the invention.

[0124] In some embodiments, this specification may be interpreted as excluding all elements of a method step that do not substantially affect the fundamental and novel features of the composition, material, product and manufactured article, and thus methods of using said composition, material, product and article. Additionally, in some embodiments, this specification may be interpreted as excluding all elements or method steps not specified herein.

[0125] Although this specification is described with reference to specific embodiments and / or examples, the invention should not be interpreted as being limited to the details presented. Rather, variations in the details and the scope of the claims and equivalents may be made without departing from the scope of the invention.

Claims

Claim 1 A method for synthesizing fluoromethane, comprising: a step of contacting reactants comprising chloromethane and at least 150% stoichiometric excess of hydrogen fluoride relative to chloromethane in the gaseous phase in a reactor, optionally in the presence of solid support particles in the substantial absence of chromium; a control step of controlling conditions within the reactor to promote the reaction of said reactants, optionally in the presence of said solid support particles, to form a reactor effluent stream comprising fluoromethane at a reactant conversion rate of 3% or more and 30% or less, wherein said conditions within the reactor comprise substantially no electrical discharge and / or no external voltage intentionally applied; a separation step of separating unreacted chloromethane and hydrogen fluoride from said reactor effluent stream to form a recirculation stream, wherein at least a portion of the remaining components of said reactor effluent stream form a crude intermediate stream comprising a fluoromethane product and a hydrogen chloride byproduct; and at least a portion of said recirculation stream comprising unreacted chloromethane and hydrogen fluoride to said reactor A method for synthesizing fluoromethane comprising: a step of recirculating; a removal step of removing a hydrogen chloride byproduct from the crude intermediate stream to form a fluoromethane product stream; and optionally, a step of purifying the fluoromethane product stream to form a purified fluoromethane product stream, wherein the fluoromethane product stream and / or the purified fluoromethane product stream comprise at least 98.5 wt% fluoromethane, up to 1.1 wt% methane, 200 wppm or less difluoromethane, and 200 wppm or less all byproducts having more than 1 carbon atom. Claim 2 A method for synthesizing fluoromethane according to claim 1, wherein the stoichiometric excess of hydrogen fluoride to chloromethane is 200 to 2,900%, particularly 300 to 1,900% or 400 to 1,400%. Claim 3 A method for synthesizing fluoromethane according to claim 1 or 2, wherein the solid support particles are present and the solid support particles are porous. Claim 4 A method for synthesizing fluoromethane according to any one of claims 1 to 3, wherein the solid support particles are present, and the solid support particles comprise alumina, activated alumina, silica, activated carbon, aluminosilicate, borosilicate, aluminoborate, zeolite, alkali oxide, alkaline earth metal oxide, carbonate, or a combination thereof. Claim 5 A method for synthesizing fluoromethane according to any one of claims 1 to 4, wherein the step of contacting reactants in the reactor is further performed in the substantial absence of iron. Claim 6 A method for synthesizing fluoromethane according to any one of claims 1 to 5, wherein the conditions within the reactor are controlled to include a reactor temperature of about 200 to about 550°C, particularly about 250 to about 400°C, or about 280 to about 450°C; a reactor pressure of about 10 to about 300 psia, particularly about 15 to about 270 psia; and a residence time of 150 seconds or less, particularly 120 seconds or less. Claim 7 A method for synthesizing fluoromethane according to any one of claims 1 to 6, wherein the reactant conversion rate is 5% or more and 25% or less. Claim 8 A method for synthesizing fluoromethane according to any one of claims 1 to 7, wherein the step of separating unreacted reactants includes distillation. Claim 9 A method for synthesizing fluoromethane, wherein, in any one of claims 1 to 8, the step of recirculating unreacted reactants comprises, after separation, heating the unreacted reactants to a temperature at least 10°C lower than the inlet temperature of the reactor, particularly at least 5°C lower than the inlet temperature of the reactor. Claim 10 A method for synthesizing fluoromethane according to any one of claims 1 to 9, wherein the removal step of removing hydrogen chloride from the crude intermediate stream comprises the step of treating the crude intermediate stream with a caustic substance and then drying it. Claim 11 A method for synthesizing fluoromethane according to any one of claims 1 to 10, wherein the fluoromethane product stream is purified using distillation. Claim 12 A method for synthesizing fluoromethane according to claim 11, wherein the distillation for purifying the fluoromethane product stream is performed at a pressure at least 30 psi higher than the pressure at which unreacted reactants are separated from the reactor effluent stream, particularly at least 50 psi higher or at least 70 psi higher. Claim 13 A method for synthesizing fluoromethane according to any one of claims 1 to 12, wherein the fluoromethane product stream and / or the purified fluoromethane product stream comprises at least 99.0 wt% fluoromethane, up to 1.0 wt% methane, 20 wppm or less difluoromethane, and 50 wppm or less all by-products other than methane having more than 1 carbon atom. Claim 14 A method for synthesizing fluoromethane according to any one of claims 1 to 13, wherein the chloromethane reactant comprises 100 wppm to 1.0 wt% of methane and optionally comprises up to 1.9 wt% of other impurities that cannot be converted into a fluoromethane product under the conditions in the reactor, and wherein the conditions in the reactor are controlled to have a reaction-specific selectivity of at least 99.0 wt%, particularly at least 99.5 wt% of the fluoromethane product. Claim 15 A fluoromethane product composition comprising: at least 99 wt%, particularly at least 99.9 wt%, of fluoromethane; up to 0.5 wt%, particularly up to 0.1 wt%, of methane; 20 wppm or less, particularly an immeasurable amount of difluoromethane; 50 wppm or less, of all by-products other than methane having more than 1 carbon atom; optionally, a water content of 10 wppm or less; optionally, a hydrogen chloride content of 10 wppm or less; and optionally, a hydrogen fluoride content of 10 wppm or less.

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