MXPA96003730A - Methods to destroy substances that decrease the oz - Google Patents

Abstract

Ozone depleting flurocarbon compounds are dehalogenated through more economical partial reduction reactions, with solvated electrons that are formed from smaller equivalents of reactive metals than previously employed. The partially reduced products are further dehalogenated with bases containing non-aqueous liquid nitrogen, such as ammonia in the same reaction mixture or alternatively in an independent reaction when treating with ammonia or another base alone. In other embodiments, blends of fluorocarbon refrigerants include dichlorodifluoromethane-difficult to separate dichlorodifluoromethane-contaminated azeotropes, are recycled by treating only weak nonaqueous nitrogen-containing bases to provide the dichlorodifluoromethane refrigerant which is essentially chemically pure suitable for recycling / reuse.

Description

METHODS FOR DESTROYING SUBSTANCES THAT DECREASE THE TECHNICAL FIELD The present invention relates in general to methods for treating ozone-depleting substances and more specifically to methods for decomposing and purifying chlorofluorocarbon (CFC) refrigerants. BACKGROUND OF THE INVENTION Chlorofluorocarbons (CFCs) are synthetic chemical compounds widely used in air conditioning and refrigeration; as aerosol propellants and solvents; to form foams, including those used in fast food packaging; and a rigid isolation. Scientists now see synthetic chemicals as the main threat to Earth's protective ozone layer. Because CFCs are immune to destruction in the troposphere and because they eventually float upward, their manufacture and release have led to the accumulation of large amounts in the stratiferous. In the stratosphere, CFCs are broken by sunlight in chlorine, which has a catalytic and destructive effect on ozone. The result has been a significant decrease in the screen or global ozone protector and an increase in the amount of harmful ultraviolet radiation reaching the earth's surface. According to a study by the United Nations, each reduction of 1% in ozone will lead to a 3% increase in non-elanomic cancer in the skin, in people with fair skin, as well as dramatic increases in "~: spiders, cancers of lethal melanoma and damage to the human immune system Higher levels of ultraviolet light can also worsen pollution at ground level and injure plants, animals and especially light-sensitive aquatic organisms, resulting in the destruction of CFCs and in some In some cases, the recycling of CFC refrigerants is a vital component of national and global strategies to protect the ozone layer in the land in a manner consistent with minimal economic disruptions associated with the disposal of this class of chemicals. dimensional size of available CFCs, which must be treated and converted to environmentally benign substances, until they are replaced or replaced. Adapt serial production of existing air conditioning and refrigeration equipment with devices that are capable of operating with more environmentally friendly refrigerants, as CFC production is shortened and eventually eliminated, the industry and consumers must support each more time on the availability of recycled refrigerants. Various methods have been proposed for the destruction of unwanted CFCs, such as thermal oxidation, catalytic decomposition, supercritical water oxidation, plasma destruction methods, biological processes, UV photolysis, to name a few. Many are either in the experimental stages of development, are not economically "" "* - ractive, or are unable to selectively decompose only specifically targeted compounds.Other method for the destruction of CFCs is described in U.S. Patent No. 5,110,364 by Mazur et al, which provides chemical degradation of unwanted CFCs by dehalogenation reactions through solvated electron chemistry Mazur et al. describes the formation of solvated electrons through metal dissolution reactions with nitrogen-containing bases, such as ammonia. , wherein at least one chlorine atom of the CFC compound is removed during the reaction to give products having reduced environmental impact.A somewhat related process is also described in Japanese Application No. 59-10329 (1984) issued to Showa Den or KK Contrary to the descriptions of the previous Showa Denko process, Mazur and collaborators discover The reduction of CFCs or other chlorinated organic compounds, for example PCBs with solvated electrons, can be carried out successfully in the presence of substances previously considered to interfere with the stability of the solvated electrons or the selectivity of the reaction. Mazur et al. Discovered the need to remove substances that were previously considered competent, such as oxygen., carbon dioxide, water, etc. of the reaction mixture, not only was required and this expensive pre-treatment stage or steps could be omitted. While solvated electrons provide a practical solution for disposing fluorocarbon compounds, including CFCs, in practice, solvent and metal consumption requirements, for example sodium and ammonia, are significant cost elements. Together, the two can consume as much as 70% of total operating costs. Of the two main reagents, ammonia is the least expensive and processes for ammonia recovery are available. However, metals such as calcium, sodium and potassium are not recoverable and are more expensive consumable reagents, which can deteriorate the economy of the process. Accordingly, it would be highly desirable to have an improved economic process for the dehalogenation and destruction of fluorocarbons and particularly CFCs, this process also allows the purification of contaminated refrigerant compositions. It would also be convenient to have as an improvement in the recycling of these compounds, a significant reduction compared to the usual stoichiometric equivalents of metal to refrigerant reagent normally used to dehalogenate target compounds, and in some cases, to completely eliminate the metal requirements from the process. .

BRIEF DESCRIPTION OF THE INVENTION The term "refrigerant" as used throughout the specification and claims, is a generic term intended to denote fluorocarbon compounds as a class of chemicals that are suitable for use in refrigeration and air conditioning equipment, but they may have other applications. The term thus encompasses halofluorocarbons and halofluorohydrocarbons, such as chlorofluorocarbons (CFCs), bromofluorocarbons, chlorofluorohydrocarbons, and forward. Likewise, the term "refrigerant" is also intended to include fluorocarbons that are useful as solvents, aerosol propellants, for making synthetic foams, packaging, insulation, retardant compounds for fire extinguishers, and the like. In this way, it will be understood that the term "refrigerant" is intended to encompass a broader range of compounds than simply those that are suitable for air conditioning and refrigeration applications. They include products commercially available under brands such as Freon, Halon, Frigen, Arcton, Genetron and Isotron. According to the invention, there is provided an improved method for dehalogenating refrigerants, and more particularly fluorshydrocarbon refrigerants, wherein instead of pouring the solution of a reactive metal to the liquid ammonia or other nitrogen-containing base in the formation of solvated electrons, the improved method is based on the steps of: (a) providing a fluoroalkane refrigerant having at least one hydrogen atom and at least one other halogen atom in addition to fluorine, and (b) in the absence of a dissolved lethal reagent , react the fluoroalkane refrigerant with only the base containing nitrogen containing to dehalogenate and decompose the refrigerant. The base that contains nitrogen is not watery. The fluoroaicane as described herein is intended to include halofluorohydrocarbons having in addition at least one hydrogen atom, at least one other halogen atom, in addition to fluorine, ie chlorine, bromine and / or iodine. Fluoroalkane refrigerants are preferably intended to encompass halofluorohydrocarbons with < 4 carbon atoms, and more preferably compounds having 1 or 2 carbon atoms. Unlike the previous method, the Patent of the E.U.A. No. 2,738,371 (Par elee) allows treatment of perfluorocarbons, ie compounds composed exclusively of 5 to 25 carbon atoms, which are completely substituted with fluorine. Parmelee found that in the synthesis of perfluorocarbons, the impurities developed consist of incompletely fluorinated compounds, which contain up to 0.1% hydrogen. Upon reaction of the impure perfluorocarbon composition with ammonia or an amine according to the Parmelee methods, the fluorohydrocarbon is converted to fluorocarbon amine compounds.

In contrast, experimentation by the present inventors has shown that weak non-aqueous nitrogen-containing bases, such as ammonia, are capable of fully reacting with ozone-depleting halofluorohydrocarbons, and particularly chlorofluorohydrocarbons having 1 or 2 carbon atoms, such as chlorodifluoromethane. , to dehalogenate it selectively and decompose it. Advantageously, it was also found that environmentally harmful halofluorohydrocarbons can be removed without introducing metal into the reaction. In addition to a more attractive economy of the process, any potential risks associated with the handling, transport and storage of highly reactive alkali metals are avoided. A still further object of the invention is to selectively dehalogenate compositions that have a plurality of refrigerant compounds. Accordingly, the invention also contemplates recycling methods, wherein the halofluorocarbon refrigerant which is contaminated with : omitted of halofluorohydrocarbon is purified faithfully. The method is carried out by the steps of: (a) providing a composition with at least two refrigerants, (i) a primary perhalogenated compound and (ii) a contaminated fluoroalkane compound, having at least one hydrogen atom and at least one another halogen atom in addition to fluorine; (b) reacting the refrigerant composition of step \) with a weak base, i.e. a non-aqueous hydrogen-containing compound such as ammonia, to selectively decompose the contaminating fluoroalkane refrigerant compound (ii) and (c) recover a refrigerant composition of the reaction mixture of step (b), the composition comprises the primary perhalogenated cooling compound (i). The recovered composition is sufficiently free of the contaminated fluoroalkane refrigerant (ii) to allow recycling / reuse. More preferably, the process comprises the steps of: (a) providing a composition with at least two refrigerants, (i) a primary perhalogenated compound, usually a halofluorocarbon, eg, chlorofluorocarbon, bromofluorocarbon, etc., and (ii) a contaminated fluoroalkane refrigerant compound having 1 or 2 carbon atoms, at xylene a hydrogen atom and at least one other halogen atom in addition to fluorine, for example chlorine, bromine or iodine; (b) reacting the refrigerant composition of step (a) with a base containing non-aqueous nitrogen to selectively decompose the contaminating fluoroalkane refrigerant compound (ii) and (c) recover a refrigerant composition from the reaction mixture of the step (b), the composition comprises the primary perhalogenated cooling compound (i). The recovered composition is sufficiently free of the contaminated fluoroalkane refrigerant compound (ii) to allow recycling / reuse. This aspect of the invention is particularly unique in view of the discovery that weak nitrogen-containing bases are capable of selectively dehalogenate / decompose halofluorohydrocarbons (ii) without also reacting with the primary fluorocarbon Compounds (i). The selectivity of the process is also significant in allowing the recovery of refrigerants from mixtures that otherwise can not be easily purified by distillation methods because they form azeotropes with other refrigerants. To date, these azeotropes were discarded by decomposing the entire mixture since there was no practical and economical means of separating and recovering the still useful refrigerant compounds. Still a further object of the invention is to provide an improved method for dehalogenating fluorocarbon refrigerants by a reduction mechanism through a dissolution reaction of metal in a nitrogen-containing base, such as ammonia. Unlike previous methods for the destruction of ozone-depleting perhalogenated refrigerants undesired with solvated electrons which typically employ 8 tactile metal equivalents per mole of refrigerant, the present inventors discovered that dehalogenation of these refrigerants can be effectively performed with only a fraction of the metal previously used, making the process economically more attractive. The improved method includes the steps of: (a) providing a perhalogenated fluorocarbon refrigerant having at least one other halogen atom in addition to fluorine, for example chlorine, bromine and iodine. (b) forming a solution of solvated electrons by dissolving in ammonia or other weak nitrogen containing base a substoichiometric padlocks of the reactive metal in an amount approximately sufficient to partially reduce the perhalogenated refrigerant of step (a) by removing a halogen atom from there. (c) reacting the refrigerant in step (a) in the solvated electron solution of step (b), the reaction is conducted at temperatures sufficiently low to retard the reactions of the solvated electrons and liquid ammonia or other base containing nitrogen with by-products of the reduction reaction, and (d) raising the temperature of the reaction mixture of ** stage (c) to initiate further dehalogenation by reaction with ammonia or other nitrogen-containing base, to form non-depleting compounds the ozone The above preferred method is performed by the steps of: (a) providing a perhalogenated fluorocarbon refrigerant; (b) forming a solution of solvated electrons by dissolving in liquid ammonia or other nitrogen-containing base the reactive metal in an amount approximately sufficient to partially reduce the perhalogenated fluorocarbon refrigerant from step a; (c) reacting the refrigerant in step (a) in the solvated electron solution of step (b), the reaction is conducted at temperatures sufficiently low to retard reactions of solvated electrons and liquid ammonia or other nitrogen-containing base with byproducts of this reduction reaction; and (c) raising the temperature of the reaction mixture of step (c) to initiate further dehalogenation by reaction with the liquid ammonia or other nitrogen-containing base. DESCRIPTION PE THE PREFERRED MOPAUPAPES Methods of the invention includes the dehalogenation and destruction of "fluoroalkane" refrigerants, this term for purposes of the present invention is intended to mean, in particular, fluoromethane type coolants, and also flouroethane types. The fluoroalkane refrigerants have at least one hydrogen atom and another halogen atom in addition to fluorine, ie chlorine, bromine and / or iodine. Representative fluoroalkane types include refrigerants available under the E.I. duPont Freoniß such as 22 (chlorodifluoromethane), Freon 21 (fluorodichloromethane), Freon 31 (chlorofluoromethane), Freon 31B1 (bromine luoromethane), Freon 22B1 (bromodifluoromethane), and mixtures thereof, other fluoroalkane refrigerants include for example l, l , 2,2-tetrachloro-2-fluoroethane (FC-121); 1,1,1-trifluoro-2, -dichloroethane (FC-123). A preferred embodiment of the invention includes reacting the above fluoroalkane refrigerants with a base containing non-aqueous nitrogen. The term "non-aqueous nitrogen containing base" or similar variations thereof as it appears in the specification and claims, is intended to mean substantially free of water. That is, the pressure is intended to denote anhydrous bases that are free of any water, but also bases containing nitrogen having small or small amounts of water in the range of 3% less, which may be present for example as an impurity. Representative examples of non-aqueous nitrogen-containing bases include mainly ammonia, i.e., anhydrous liquid ammonia and liquid ammonia, have minor amounts of water, ie 3% or less. Other non-aqueous containing bases, besides ammonia, that can be used in the dehalogenation of fluoroalkane refrigerant, include primary amines, secondary amines, tertiary amines, cyclic amines, heterocyclic alkyl and polyabs and mixtures thereof. Representative examples of these bases include methyl amine, ethyl amine, dimethyl amine, diethyl amine, triethyl amine, n-propyl amine, piperidine, morpholine and ethylenediamine. The above nitrogen-containing bases are weak bases. For purposes of this invention, the term "weak base" is generally intended to encompass primarily nitrogen-containing bases, which have a pK ^ in the range of 2 to 5. Bases containing nonaqueous nitrogen are suitable for use as such. , or can be mixed with other organic solvents, provided that the solvents are substantially soluble in the refrigerant and do not react with the base. Representative examples of suitable organic solvents include primary alcohols, such as methanol, "ethanol, propanol, butanol; secondary alcohols such as 2-propanol; ethers such as diethyl ether and 1,4-dioxane; glycol monoethers such as methoxyethanol and butoxypropanol; nitriles, such as acetonitrile and acids such as N, N-dimethylformamide or N, N-dimethylacetamide.

The dehalogenation of fluoroalkanes with nonaqueous nitrogen-containing bases is easily performed in a pressure vessel under ambient temperature conditions, including temperatures generally in the range of about 10 to about 70 ° C. The concentration of the nitrogen-containing base employed in general is in the range of about 10% to about 100%. The reactions of preference are carried out under anaerobic conditions. A means is provided for removing insoluble reaction products (salts) by filtration. As a further preferred embodiment, the invention includes methods to selectively dehalogenate refrigerant compositions containing 2 or more refrigerants. More particularly, the invention includes methods for purifying refrigerant compositions containing useful primary coolants, which have been contaminated with other refrigerants. Expressions such as "primary coolant" and "primary perhalogenated refrigerant" as they appear here, are used to make the specific refrigerant (s) desired to recover from the contaminated refrigerant mixtures in the dehalogenation process. Primary coolants primarily include refrigerants that are perhalogenated or in other words, fluorocarbon refrigerants in which all carbons are fully substituted with halogen atoms. they include representative examples such as Freon, "" 11 (fluorotrichloromethane), Freon 12 (dichlorodifluoromethane), Freon '' (chlorotrifluoromethane), Freon 14 (tetrafluoromethane), Freon 13B1 (bromotrifluoromethane), and so on. The term "other refrigerant" is used herein to denote the contamination or portion of undesired refrigerant that has been removed from refrigerant compositions containing the primary refrigerant. Other refrigerants correspond to the "fluoroalkane refrigerants" previously discussed in connection with the first embodiment of the invention, and include halofluorohydrocarbon compounds having less than 4 carbon atoms, and more preferably 1 to 2 carbon atoms, at least one hydrogen atom and at least one other halogen atom in addition to fluorine, for example chlorine, bromine and / or iodine. Representative examples include chlorodifluoromethane, fluorodichloromethane, chlorofluoromethane, bromofluoromethane, bromodifluoromethane and mixtures thereof. This second embodiment of the invention is useful for recycling refrigerant compositions. In order to qualify for reuse, recycled refrigerants are required to meet the "700" specifications of the American Refrigeration Institute that stipulate the permissible level of contaminants. That is, strict limits are imposed on humidity, particles, acidity, oil content, non-condensable gases and other refrigerants present. Existing recycling processes are able to meet all previous criteria, except for "other" * ^ "frigerante", which is not allowed to exceed 0.5% maximum. Therefore, the second embodiment of the invention is useful for treating mixtures of fluorocarbon compounds, including those contaminated with more than 0.5% of other refrigerants. However, methods of the present invention are also effective for treating compositions containing minor amounts or even in traces, ie less than 0.5% of another refrigerant or refrigerants. A representative example of a widely encountered refrigerant mixture is dichlorodifluoromethane also known as Freon, »12 or FC-12, which is frequently contaminated with Freon 22 or chlorodifluoromethane, both hereinafter referred to as R-12 and R-22, respectively. Although the separation of unwanted contaminant R-22 from this mixture seems to be easily achieved by distillation due to differences in its boiling points (R-12 pe -29.8 ° C and R-22 pe -41 * C), it is not easily achieved. separation by distillation due to the formation of a 4e azeotrope consisting of 75% R-22, when the two refrigerants are mixed. The main objective of this embodiment of the invention is the selective chemical decomposition of other refrigerants in refrigerant mixture compositions without loss of primary refrigerant. This includes the steps of separating and recovering the composition containing the primary coolant from the reaction medium in a free refined or purified state or virtually free of other refrigerant, to meet the ARI specifications for other refrigerants. The methods of this second embodiment are especially useful for recycling discontinued refrigerant compounds or scarce power. While the methods of the invention are especially useful in the recycling of contaminated perhalomethane-type primary coolants, the invention contemplates the purification and recovery of other primary perhaloalkane refrigerants alike, such as fluoroethanes and fluorobutanes. Representative examples include fluorocarbon or FC-112 (1,1,2-tetrachloro-l, 2-difluoroethane), FC-113 (1,1,2-trichloro-1,2,2-trifluoroethane), and the like. In addition to the recycling of refrigerant compositions comprising a single primary perhalogenated refrigerant contaminated with one or more other refrigerants, the invention contemplates the purification of refrigerant mixtures having similar boiling points and particularly jzeotrope refrigerants, such as Freon 500 (dichlorofluoromethane and 2,2- difluoroethane), Freon 503 (trifluoromethane and chlorotrifluoromethane) and particularly an azeotrope of dichlorodifluoromethane in which the halofluorohydrocarbon, chlorodifluoromethane is the other refrigerant.

The reaction of the non-aqueous nitrogen-containing base "**" in the contaminated refrigerant composition is carried out in a closed pressure vessel at room temperature conditions, the process can be batch or continuous. At suitably elevated boiling points, purified refrigerant can be separated from the reaction mixture by evaporation, however, with ammonia or low-boiling amines, the separation is achieved by passing the vaporized mixture through water, dilute acid or a of the two to selectively dissolve the amine, either as the free base or as a salt.The refrigerant vapors are then compressed and cooled to bring it to the liquid state.As a third embodiment of the invention, fluorocarbon refrigerants and particularly perhalogenadps types, that do not dehalogenate easily with weak bases, such as dichlorodifluoromethane, chlorotrifluoromethane, bromotrifluoromethane, and other perhalogenated fluorocarbons are partially dehalogenated, initially through a reduction reaction with solvated electron solutions. It was found that this partial dehalogenation reaction of fluorocarbon refrigerants requires as little as a quarter of the reactive metal that is ordinarily employed in processes, such as described by US Pat. No. 5,110,364 and Japanese Application Unexamined 59-10329 (1984). These previous methods provide for the separation of all halogen atoms from perhalo ethane refrigerants, with quantitative amounts of reactive metals, such as sodium in the formation of electrons solvated with ammonia or another nitrogen-containing solvent. Unlike the previous methods, the improved process of the instant invention provides the separation of a quantity as small as a single halogen atom, for example chlorine, bromine or iodine, thus requiring only a fraction of the metal reagent, in view of the minor requirement for solvated electrons. With the separation of an amount as small as a single nitrogen atom, greater dehalogenization of the fluorocarbon is achieved with the remaining ammonia available or another nitrogen-containing base in the reaction mixture. While it is not desired to be bound by any specific mechanism of action with respect to this third embodiment, it is nevertheless considered that partial reduction or dehalogenation of a percarbon refrigerant when treated in a solvated electron solution can result in hydrogenate if starting, and possibly forming a halohydroalkane intermediate that is subjected to further dehalogenation through acid-base reaction with the residual ammonia or other remaining nitrogen containing base in the reaction mixture.

The solvated electrons are formed in a reaction of such dissolution with ammonia or other nitrogen-containing base, such as a primary amine, secondary amine or tertiary amine soluble in fluorosarbide. Specific representative examples were previously provided. The reactive metals may consist of alkali metals, such as sodium, potassium and lithium and alkaline metals such as calcium and magnesium. Mixtures of these metals can also be used. Aluminum can also be used as a dissolution metal. Compared with the stoichiometric amounts of metal per mole of perfluorocarbon refrigerant employed according to the previous methods, the present invention uses two molar equivalents of reactive metal per mole of perhalogenated fluorocarbon or in other words, one fourth of the amount previously required. The reduction of the perfluorocarbon refrigerant with solvated electrons is carried out in a closed pressure vessel at a temperature sufficiently low to retard reactions that may otherwise occur between by-products of the reduction reaction and the solvated electrons or the nitrogen-containing base. Typically, reactions will be performed at approximately 0 * c or lower. Subsequently, the reaction vessel is allowed to warm to room temperature, which in turn will initiate further dehalogenation of the partially dehalogenated fluorosarbide to completely dehalogenate it, ie remove the remaining atoms of fluorine, chlorite, bromine and / or iodine, as a reaction acid-base with ammonia or other nitrogen-containing base The following specific examples demonstrate the various embodiments of the invention, however it will be understood that they are for illustrative purposes only and are not intended to be totally definitive in terms of conditions and scope. EXAMPLE 1 In order to demonstrate that a base containing nitrogen such as ammonia was capable of effectively destroying halohydroalkane refrigerant in the absence of a dissolving metal reagent, such as sodium or calcium, an initial experiment was performed using a reactor. consisting of a thick-walled threaded glass tube from Ace Glass, In c., adapted with a Teflor plug and pressure gauge. The tube was charged with 25.0 g of anhydrous liquid ammonia (1.5 mols) and 4.1 g of pure chlorodifluoromethane refrigerant (R-22). The tube was charged while cooling dry ice / isopropyl alcohol (IPA). 3rd time the load is complete, the tube is sealed and allowed to warm to room temperature. In 80 minutes after mixing the refrigerants, salt crystals are observed at the bottom of the tube consisting of by-products of the reaction. It was observed that additional salts formed continuously. Within 140 minutes in the experiment, the reaction was judged complete and the reactor tube was again cooled in dry ice / IPA to reduce the pressure in the ammonia tube. The pressure gauge is replaced with a vented plug through a Teflon tube, and the reaction tube is allowed to warm up.When the gas evolution was interrupted, 7.5 g of solids were recovered. products was 8.1 g, indicating that at least 93% of R-22 was destroyed in the reaction EXAMPLE II In order to demonstrate the selectivity of weak nitrogen-containing bases in the absence of a dissolution metal, such as potassium or calcium, in the purification of refrigerant mixtures, an additional experiment was carried out: 90.5 g of a refrigerant mixture consisting of 87.2% dichlorodifluoromethane (R-12) and 12.8% chlorodifluoromethane (R-22) was charged to a steel tube reactor The refrigerant charge thus contained 11.6 g (0.13 moles) of R-22, 24.4 g or 1.43 moles of anhydrous liquid ammonia were added to the refrigerant mixture.The reactor tube was sealed and allowed to stand for 3 days at temp. Environmental environment The composition was analyzed and found to contain 99.154% of R-12; 0.105% of R-22 and traces of another refrigerant (0.141% of R-32). The analysis showed that the reaction is highly effective to destroy only R-22. In order to recover substantially pure R-12 from the reaction mixture, the ammonia in the reactor is converted into water-soluble salts, by the addition of diluted aqueous sulfuric acid solution. Due to the insolubility of the R-12 frigid in the aqueous salt solution, separate separate phases are formed in the reactor, which consist of a lower refrigerant phase and a higher aqueous phase. The lower refrigerant phase containing the R-12 can be removed so that it is substantially free of the water-soluble salts. EXAMPLE H To demonstrate the effectiveness of other weak nitrogen-containing bases for dehalogenating halohydroalkanes, the experiment of Example I was repeated using ethylene diamine < _ place of ammonia. Approximately 5.0 g of chlorodifluoromethane are mixed in the glass pressure tube with approximately 20 ml of ethylene diamine and allowed to warm to room temperature. A vigorous exothermic reaction arose indicating that weak nitrogen containing bases other than anhydrous liquid ammonia readily react with the halohydroalkane refrigerant. EJEHPLp IV Reactions of dissolution metal with ammonia or other weak base are useful in the destruction of most refrigerants, including the most stable perhalogenated types. Significantly reduced amounts of dissolving metals than those previously required can be effectively used to achieve complete destruction of unwanted refrigerants. This can be demonstrated by charging liquid ammonia to a reaction vessel and allowing it to cool by self-cooling. When it reaches a temperature of -10 to -33"c, two molar equivalents of calcium metal are added and stirred to give the typical solution of solvated blue electrons: 8 molar equivalents of dichlorodifluoromethane, approximately 4 times the amount of The coolant that the metal is present to fully dehalogenate the refrigerant, is allowed to react until the blue color no longer appears.The temperature of the reaction mixture is then allowed to rise.At approximately ambient temperature, greater destruction of refrigerant occurs through Reaction only of the ammonia remaining in the reactor While the invention has been described in conjunction with specific examples thereof, they are only illustrative.According to this, many alternatives, modifications and variations will be apparent to persons with skill in the art. in light of the above description, and therefore it is intended to cover all these alternatives, modifications and Aries to fall within the spirit and broad scope of the appended claims. We claim:

Claims (25)

1. CLAIMS 1.- Method for chemically dehalogenating hydrofluorocarbon refrigerants, characterized by the steps of: (a) introducing into a reactor a fluoromethane refrigerant having at least one hydrogen atom and at least one other halogen atom in addition to fluorine, and (b) in the absence of a reagent of dissolved material react the fluoromethane refrigerant with ammonia or other nitrogen-containing base to dehalogenate the refrigerant, ammonia or other nitrogen-containing base is not aqueous.
2. 2. The method according to claim 1, characterized in that the base containing non-aqueous nitrogen which is a unit with liquid or a solution containing ammonia, the solution is substantially soluble in the refrigerant.
3. 3. The method according to claim 1, characterized in that the base containing non-aqueous nitrogen is a member selected from the group consisting of primary amines, secondary amines and tertiary amines soluble in refrigerant.
4. 4. The method according to claim 1, characterized by a fluoromethane refrigerant which is a halofluorohydrocarbon.
5. 5. The method according to claim 4, characterized by a halofluorohydrocarbon refrigerant which is a member selected from the group consisting of chlorodifluoromethane, fluorodichloromethane, chlorofluoromethane, i-omofluoromethane, bromodifluoromethane and mixtures thereof.
6. 6. The method according to claim 2, characterized by a solution comprising ammonia, which is liquid ammonia and an organic solvent.
7. 7. A method for disposing fluorohydrocarbon refrigerants, characterized by the steps of introducing into a reactor a refrigerant essentially consisting of a halofluoromethane compound, having at least one hydrogen atom and another halogen atom in addition to fluorine, and reacting the compound with a base that contains nitrogen to decompose the compound, the base is not watery.
8. 8. The method according to claim 7, characterized by a halofluoromethane compound which is chlorodifluoromethane and the nitrogen-containing base is ammonia.
9. 9. Method for purifying a refrigerant composition, characterized by the steps of: (a) introducing into a reactor a composition comprising at least two refrigerants, (i) a primary perhalogenated oxide having at least one other halogen atom in addition to fluorine; and (ii) a contaminating fluoroalkane refrigerant compound having at least one hydrogen atom and at least one other halogen atom in addition to fluorine; (b) reacting the refrigerant composition of step (a) with a base containing non-aqueous nitrogen to selectively decompose the contaminating fluoro-gas constituent (ii) and (c) recover a refrigerant composition of. "reaction mixture of step (b), the composition comprises the primary perhalogenated refrigerant compound (i), the recovered composition is sufficiently free of the contaminating fluoroalkane refrigerant compound (ii) to allow recycling / reuse
10. 10.- The compliance method with claim 9, characterized by a primary perhalogenated compound (i) of step (a) which is a halofluorocarbon compound selected from the group consisting of chlorofluorocarbon and bromofluorocarbon
11. 11. The method according to claim 10, characterized by a polluting fluoroalkane refrigerant compound (ii) of step (a) which is a chlorofluorohydrocarbon
12. 12. The method according to claim 9, characterized by a hydrogen atom of the contaminating fluoroalkane refrigerant (ii) of the stage (a) located in the carbon atom that contains the other halogen atom in addition to r.lúor
13. 13.- The method of compliance c in claim 11, characterized by a hydrogen atom in the chlorofluorohydrocarbon of step (a) in the carbon atom containing the chlorine atom.
14. 14. - The method according to claim 9, / "" rasterized by a base containing non-aqueous nitrogen which is liquid ammonia or a solution comprising liquid ammonia, the solution is substantially soluble in the reflectant composition.
15. 15. The method according to claim 9, characterized by a nitrogen-containing base which is a member selected from the group consisting of primary amines, secondary amines and tertiary amines soluble in refrigerant.
16. 16. The method according to claim 9, characterized by a refrigerant composition of step (a) comprises an azeotrope.
17. 17. The method according to claim 9, characterized by a refrigerant composition of step (a) comprises a mixture of at least two refrigerants having substantially similar boiling points.
18. 18. The method according to claim 16, characterized by an azeotrope comprising dichlorofluoro ethane and chlorodifluoromethane and the refrigerant composition recovered from step (c) comprises dichlorodifluoromethane.
19. 19. The method according to claim 9, characterized in that a refrigerant composition recovered from step (c) comprises one or more compounds suitable for use in refrigeration or air conditioning equipment.
20. 20. The method according to claim 9, characterized by a step of incorporating an organic solvent into the reaction mixture of step (b)
21. 21. In a method to chemically dehalogenate fluorocarbon refrigerants by reacting with a solution of solvated electrons that is formed by dissolving a reactive metal in liquid ammonia or other base containing weak nitrogen, characterized by the steps of: (a) introducing into a reactor a refrigerant comprising a halofluorocarbon compound, (b) forming a solution of solvated electrons by dissolving in liquid ammonia, or other nitrogen-containing base, the reactive metal in less than a stoichiometric amount sufficient to only partially reduce the halofluorocarbon compound, (c) reacting the refrigerant from step (a) in the solution of the solvated electrons from stage (b), the reaction is carried out at sufficiently low temperatures to delay electron reactions solvates and liquid ammonia or other nitrogen-containing base With by-products of this reduction reaction, and (d) raising the temperature of the reaction mixture of step (c) to initiate further dehalogenation of the halofluorocarbon compound by reacting with liquid ammonia or another base that contains nitrogen.
22. 22. The method according to claim 21, characterized by a reactive metal which is a member selected from the group consisting of alkali metals, alkaline earth metals, aluminum and mixtures thereof.
23. 23. The method according to claim 22, characterized by a solution of solvated electrons that are formed with approximately two equivalents of reactive metal per mole of halofluorocarbon compound present.
24. 24. The method according to claim 22, characterized by a haloofluorocarbon refrigerant compound of step (a) comprising a perhalofluorocarbon compound.
25. 25. The method according to claim 24, characterized by a perhalofluorocarbon compound which is a member selected from the group consisting of dichlorodifluoromethane, chlorotrifluoromethane, bromotrifluoromethane and fluorotrichloromethane.