Process and Composition for Purifying Arsine, Phosphine, Ammonia and Inert Gases to Remove Lewis Acid and Oxidant Impurities Therefrom

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Europa,schesP_ MM II M M M I M Ml Mill M M I M J European Patent Office ... _. © Publication number: 0 283 961 B1 Office europeen* des.. brevets t

@ Date of filing: 18.03.88

Process and composition for purifying arsine, phosphine, ammonia and inert gases to remove Lewis acid and oxidant impurities therefrom

© Priority: 24.03.87 US 29632 © Proprietor: MILLIPORE INVESTMENT HOLD- INGS LIMITED @ Date of publication of application: 1013 Centre Road, 28.09.88 Bulletin 88/39 Suite 350 Wilmington, Delaware 19805 (US) © Publication of the grant of the patent: 20.12.95 Bulletin 95/51 @ Inventor: Tom, Glenn M. 2 Powder Horn Lane © Designated Contracting States: New Milford, Ct. 06776 (US) DE FR GB IT Inventor: Brown, Duncan W. 30 Cobblestone Place © References cited: Wilton, Ct. 06897 (US) EP-A- 0 179 969 US-A- 4 565 677 US-A- 4 659 552 © Representative: Schwan, Gerhard, Dipl.-lng. Elfenstrasse 32 PATENT ABSTRACTS OF JAPAN vol. 10, no. D-81739 Munchen (DE) 90 (C-337)(2147) 08 April 1986

CO Oi CO 00 CM Note: Within nine months from the publication of the mention of the grant of the European patent, any person ® may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition CL shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee LU has been paid (Art. 99(1) European patent convention). Rank Xerox (UK) Business Services (3. 10/3.09/3.3.3) EP 0 283 961 B1

Description

BACKG ROU N D OF THE I N VEN JION

5 Field of jhejnventiqn

This invention relates generally to a process and composition for removing Lewis acid and oxidant impurities from arsine, phosphine, ammonia, and inert gases. io Description of_the_ Related Art

Arsine, phosphine, and ammonia are widely used in the semiconductor industry for the manufacture of microcircuitry devices, as source reagents for elemental arsenic, phosphorus, and nitrogen, respectively. In such applications, it is critical that the arsine, phosphine and ammonia source reagents be essentially 75 completely free of impurities such as water and oxygen. Such impurities, when introduced onto the semiconductor chip during its manufacture, tend to produce localized defects in the crystalline structure which may then propagate to produce an undesirable epitaxy, and render the chip deficient or even useless for its intended purpose. Arsine and phosphine are particularly difficult to purify, due to their extreme toxicity and hazardous 20 character, and the fact that they react detrimentally with many otherwise potentially useful scavengers to poison to active sorption sites of such materials. In addition, arsine and phosphine have a higher affinity for water than they do for inert impurities, e.g., nitrogen, which are less objectionable in the semiconductor manufacturing process. Although ammonia does not possess the toxicity and handling disadvantages of arsine and phosphine, 25 it nonetheless is a poison to many otherwise potentially useful scavengers, such as those commonly used in redox purification systems for removal of water and oxygen contaminants from other gases. Among the methods utilized in the prior art for removing water from ammonia are the use of moisture- sorptive molecular sieves. The difficulty of employing such method for production of high-purity ammonia for semiconductor applications is that ammonia is competitive with water for the adsorption sites on the 30 molecular sieves. As a result, it is not possible to obtain the necessary low residual water values, on the order of part-per-million concentrations of water in the effluent from the molecular sieve contacting step. Ammonia has also been dehydrated by sodium metal followed by distillation, although such methods are complex, costly, and entail the use of strong reducing agents. Arsine and phosphine have also been treated by molecular sieves to remove water but such treatment 35 in order to achieve high water removal efficiency requires that the molecular sieve contacting be carried out at low temperatures, e.g., on the order of about -20 degrees Centrigrade for arsine. This and other refrigeration-based water removal techniques involve high energy expenditure and operating costs, and therefore are not fully satisfactory. In addition, trimetal eutectics comprising indium and gallium components, and liquid at room tempera- 40 tures, have been employed for purifying arsine and phosphine of water impurity, but such dehydration method suffers the disadvantage that substantial amounts of oxide particles are generated in the treatment stream. Apart from arsine, phosphine, and ammonia, a variety of inert gases are employed in semiconductor manufacturing, for which extremely high purity is also required. As used herein, the term "inert gases" is 45 intended to be broadly construed as being inclusive of gases which may be unreactive in various semiconductor manufacturing operations, and are selected from the group consisting of one or more members of the group consisting of nitrogen, hydrogen, helium, argon, neon, xenon, silane, germane, and gaseous hydrocarbons (methane, ethane, ethylene, propane, propylene, etc.). Japanese Kokai Tokkyo Koho JP 60/222127 discloses the thermal decomposition of trimethyl aluminum 50 to deposit elemental aluminum on a glass substrate, e.g., glass beads, following which the aluminum coating is reacted with arsine to form a scavenger for water and oxygen. EP-A-0 179 969 and US-A-4,603,148 disclose a macroreticulate polymer scavenger for removing Lewis acid and oxidant impurities from inert fluids such as aliphatic hydrocarbons, olefins, and gases including nitrogen, argon, helium, xenon, hydrogen, carbon tetrafluoride, ammonia and silane, and a process for 55 purifying fluids containing Lewis acid and oxidant impurities by the use of such a scavenger. The macroreticulate polymer backbone of the scavenger has bonded thereto a plurality of metallated functional groups of the formula:

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•At- ■C- I M

where: Ar is an aromatic hydrocarbon radical of 1-3 rings; Ri and R2 are each independently hydrogen, C1- C12 alkyl, methylene-bridged benzophenone, methylene-bridged fluorenone, or alkali or alkaline earth metal salts of such benzophenone or fluorenone radicals; and M is lithium, potassium, sodium, alkyl magnesium, 10 or alkyl zinc, the alkyl substituents being C1-C12 alkyl. Within the pores of the macroreticulate polymer is a metallating agent selected from the group consisting of alkyl lithium, alkyl sodium, alkyl potassium, dialkyl magnesium, alkyl magnesium halide, dialkyl zinc, wherein the alkyl moiety is C1-C12 alkyl; alkali or alkaline earth metal salts of benzophenone; and alkali or alkaline earth metal salts of fluorenone. It is an object of the present invention to provide a highly efficient composition and process for 15 removing Lewis acid and oxidant impurities from arsine, phosphine, ammonia, and inert gases. It is another object of the invention to provide a composition and process of such type, which when employed to dry arsine, phosphine, ammonia, and inert gas streams, is capable of reducing the water content of the treated stream to levels on the order of 0.01 part per million by volume and less. Other objects and advantages of the invention will be more fully apparent from the ensuing disclosure 20 and appended claims.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a process for purifying a gaseous mixture comprising (i) a 25 primary component selected from one or more members of the group consisting of arsine, phosphine, ammonia and gases selected from the group consisting of one or more members of the group consisting of nitrogen, hydrogen, helium, argon, neon, xenon, silane, germane, and gaseous hydrocarbons, and (ii) impurities selected from one or more members of the group consisting of Lewis acids and oxidants, to remove such impurities therefrom, comprising: 30 contacting the mixture with a scavenger including a support having associated therewith, but not covalently bonded thereto, a compound which in the presence of the mixture provides an anion which is reactive to effect the removal of the impurities, such compound being selected from the group consisting of one or more members of the group consisting of: (i) carbanion source compounds whose corresponding protonated carbanion compounds have a pKa 35 value of from about 22 to about 36; and (ii) anion source compounds formed by reaction of the aforementioned carbanion source compounds with the primary component of the mixture. said scavenger being devoid of metallated pendant functional groups. As used herein, "carbanion source compounds whose corresponding protonated carbanion compounds 40 have a pKa value of from about 22 to about 36" refers to compounds which in the presence of the impurity- containing mixture provide a carbanion which is directly or indirectly reactive to effect the removal of impurity constituents, i.e., the carbanion provided by such compound either itself reacts with the impurity species to remove same from the mixture, or else the carbanion provided by the compound reacts with a primary component of the mixture, viz., arsine, phosphine, or ammonia, to yield an anion source compound, 45 an arsenide, phosphenide, or amide compound, which in turn reacts with the impurity species to remove same from the mixture. It will be appreciated that when the primary component of the impurity-containing mixture is an inert gas, only the carbanion source compounds will be the impurity-removing compounds, i.e., the inert gas, since it is inert, will not react with the carbanion source compounds to form any anion source compounds. 50 The carbanion source compound thus comprises a cation and an associated carbanion moiety. This carbanion moiety when protonated, forms a corresponding protonated carbanion compound having a pKa value of from about 22 to about 36. As used herein, the pKa value of a compound refers to the pKa numerical value determined in accordance with the procedure described in A. Streitwieser and J.H. Hammons, Prog. Phys._Org._Chern., 3, 55 41 (1965), in a solvent medium in which fluorene and diphenylmethane, as reference compounds, have pKa values of about 22.6 and 34.1, repectively. Another aspect of the invention relates to a scavenger, having utility for purifying a gaseous mixture comprising (i) a primary component selected from one or more members of the group consisting of arsine,

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phosphine, ammonia, and gases selected from the group consisting of one or more members of the group consisting of nitrogen, hydrogen, helium, argon, neon, xenon, silane, germane, and gaseous hydrocarbons, and (ii) impurities selected from one or more members of the group consisting of Lewis acids and oxidants said scavenger comprising: 5 (a) a support having a surface area in the range of from about 50 to about 1000 square meters per gram of support; and (b) associated with, but not covalently bonded to, said support, an anion which is reactive to effect the removal of said impurities, said anion being selected from one or more members of the group consisting of: io (1) carbanions whose corresponding protonated compounds have a pKa value of from about 22 to about 36; and (2) anions formed by reaction of said carbanions with the primary component of said mixture; and said scavenger being devoid of metallated pendant functional groups. Other aspects and features of the invention will be more fully apparent from the ensuing disclosure and is appended claims.

BRIEF DESCRIPTION OF THE DRAWING

The single drawing is a schematic representation of a vessel containing a bed of a scavenger according 20 to one embodiment of the invention, and an associated source of an impurity-containing mixture which is purified by passage through such vessel.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED E M BO DJ M E NTS THEREOF

25 The scavengers of the present invention utilize comcompounds which in the presence of Lewis acid and/or oxidant impurities in one or more of arsine, phosphine, ammonia, and inert gases, furnish an anion which reacts either directly with the impurities to remove same from the primary component material, or (for arsine, phosphine, and/or ammonia) indirectly, by deprotonating the arsine, phosphine, and/or ammonia primary component, to form a corresponding arsenide, phosphenide, and/or amide anion which in turn 30 reacts with the impurities to remove same from the primary component. The impurities which may potentially be removed from the arsine, phosphine, and/or ammonia primary component in the broad practice of the invention, depending on the choice of the anion-providing compound employed in the scavenger, include, but are not limited to, water, oxygen, carbon oxides, alcohols, aldehydes, ketones, as well as any other Lewis acid or oxidant species which are removable by 35 reaction with anion-providing compounds which meet the criteria of the invention, i.e., anion-providing compounds selected from one or more members of the group consisting of: (i) carbanion source compounds whose corresponding protonated carbanion compounds have a pKa value of from about 22 to about 36; and (ii) anion-providing compounds formed by reaction of such carbanion source compounds with the 40 primary component of the mixture. As used herein, "Lewis acid" is a substance which can take up an electron pair to form a bond. The anion-providing compound which is employed in the scavenger of the invention is physically associated with a suitable support which is compatible with the anion-providing compound as well as the impurity-containing mixture. The anion-providing compound is not covalently bonded to the support, as are 45 the metallated functional groups in the previously described Tom patent U.S. 4,603,148. The type of non- covalently bonded association of the anion-providing compound with the support is not critical; the anion- providing compound may for example be dispersed throughout the support matrix in the form of particulates or agglomerates, as a film or plating on the support, or otherwise localized in pores of the support. 50 As indicated, the anion-providing compound may be (i) a carbanion source compound whose corresponding protonated carbanion compound has a pKa value of from about 22 to about 36, (ii) an anion source compound formed by reaction of the carbanion source compound with a primary component of the mixture to be contacted with the scavenger, or (iii) a combination of anion-providing compounds (i) and (ii). The scavenger may conveniently be formed from a suitable support material, the support being more 55 fully described hereinafter, by applying to the support the aforementioned protonated carbanion compound having a pKa value of from about 22 to about 36, so that such compound is associated with the support, followed by reaction of the associated compound with a suitable reactant serving to deprotonate the compound and yield the aforementioned carbanion source compound as a reaction product associated with

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the support. The deprotonating co-reactant may be any suitable material yielding the desired reaction product. Preferred co-reactant materials include organometallic compounds such as alkyl lithium, alkyl sodium, alkyl potassium, dialkyl magnesium, alkyl magnesium halide, and dialkyl zinc, wherein the alkyl radical contains 1 5 to 12, and preferably 1 to 8, carbon atoms. A particularly preferred organometallic compound for such purpose is butyllithium, with alkyl or dialkyl metal compounds being a most preferred co-reactant class. Accordingly, for the aforementioned most preferred co-reactant class of alkyl or dialkyl metal compounds, the resulting carbanion source compound will have the formula MA, where: M is lithium, sodium, potassium, alkyl magnesium, or alkyl zinc; and A is carbanion derived from the protonated carbanion io compound. The selection criteria for the protonated carbanion compound as a precursor of the carbanion source compound of the scavenger is now described with reference to Table I below, in which pKa values are set forth for various compounds, including anions and dianions of arsine and phosphine, as well as the corresponding log values of the equilibrium constants for arsine (A), phosphine (P), and water (H20) for is reference.

TABLE I

Compound pKa logKeq(A) logKeq(P) logKeq(H20) Diphosphide= (Hydrogen Phosphide HP=) 42 -— -— 27 Butane 42 16 14 27 Diarside= (Hydrogen Arsenide HA5=) 40 - — - — 25 Methane 40 14 12 25 Benzene 37 11 9 22 Phosphide" (Dihydrogen Phosphide H2P") 37 -— -— 22 Ethylene 36.5 10.5 8.5 21.5 Propylene 36.5 10.5 8.5 21.5 Toluene 35 9 7 20 Arsenide" (Dihydrogen Arsenide H2A5_) 35 - — - — 20 Diphenylmethane 34.1 8.1 6.1 19.1 Triphenylmethane 32.5 4.5 2.5 18.5 Phosphine 28 Xanthene 27.1 1.1 -0.9 12.1 Arsine 26 Fluorene 22.6 -3.4 -5.4 7.6 9-Phenylfluorene 18.5 -7.5 -9.5 3.5 Indene 18.2 -7.8 -9.8 3.2

The foregoing tabulation listing is not inclusive of all possible compounds in the range of pKa values given, and other compounds within the aforementioned range of pKa of from about 22 to about 36 may be suitably utilized in the practice of the invention as precursors for, or protonated analogs of, useful carbanion source compounds. With reference to permissible pKa values and the carbanion precursors shown in Table I above, the scavengers of the present invention comprise two distinct types: a first type (Type I) in which the carbanion source compound is substantially non-reactive with the primary component, arsine, phosphine, ammonia, and/or inert gases, so that the carbanion of such source compound is the active scavenging moiety which reacts with the impurities in the primary component, and a second type (Type II), applicable only to arsine, phosphine, and/or ammonia as the primary component, in which the carbanion source compound reacts with the primary component and forms an arsenide, phosphenide, and/or amide as the active scavenging moiety which reacts with the impurities in the primary component. With reference to their pKa values, the anions of the compounds shown in Table I must satisfy distinct criteria as regards their suitability for use in Type I and Type II scavengers. The pKa value is the negative logarithm of the acidity constant of a given material, so that increasing values of pKa indicate increasing basicity. At the lower end of the pKa range, the pKa value of the scavenger anion must be at least about 22, in order that the scavenger anion is sufficiently basic to react with and remove water as an impurity in the mixture being contacted with the scavenger.

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At the upper end of the pKa range, the pKa value of the scavenger anion must not be so great that it doubly deprotonates the primary component to form dianions therefrom, e.g., diarside or diphosphide anions, since undesirable side reactions are thereby promoted such as the generation of hydrogen gas. As applied to arsine, the only suitable Type I scavenger anion precursor (corresponding protonated 5 carbanion source compound) in Table I is fluorene, having a pKa value of 22.6. The fluorene anion, when present with arsine, will only deprotonate about 0.04% of proton sites of the arsine; such anion in moisture- containing arsine yields an equilibrium water vapor pressure of about 0.6 parts-per-million (ppm) on a volume basis. For phosphine, the suitable Type I scavenger anion precursors in Table I are fluorene and xanthene. In io moisture-containing phosphine, the xanthene anion will yield a residual water concentration of less than 1 .0 part-per-billion (ppb) on a volume basis. In the case of arsine and Type II scavengers derived from the anions of the Table I compounds, diphenylmethane, with a pKa value of 34.1, is the limiting anion compound, and the suitable anion compounds are xanthene, phosphine, triphenylmethane, and diphenylmethane. In the case of diphenyl- 15 methane, some deprotonation of the monoanion of arsenide will occur, and the fraction of the arsenic in the dianion state being about 11%. Residual arsine after deprotonation by the diphenylmethane anion is estimated to be 0.2 ppm by volume, and residual water concentration after scavenging by the arsenide anion will be very low at 2.4 ppb by volume. In phosphine purification applications, the Type II scavenger precursors in Table I will be limited at the 20 upper end of the pKa range by toluene, having a pKa value of 35. Useful Type II scavenger precursors from among those listed in Table I will thus include phosphine, triphenylmethane, diphenylmethane, and toluene. When the toluene anion is utilized as a reactant to form phosphenide anion as the scavenger, about 10% of the phosphorus may end up as dianion, while residual phosphine will be on the order of about 2.4 ppm by volume, and water concentration after scavenging will be expected to be less than 1 ppb by volume. 25 A basic requirement of the scavenger in the practice of the invention, consistent with the residual water concentration values given above in connection with the illustrative arsine and phosphine scavenger anions, is that the vapor pressure of the scavenger and non-primary component reaction products of the impurity- scavenging reaction(s) be very low, preferably below about 1 ppm by volume, and most preferably below about 0.1 ppm by volume, to insure that the gas stream being purified is not contaminated by the 30 scavenger or scavenging reaction products. This vapor pressure criterion is particularly important in the case of hydrocarbons, except of course in the case where gaseous hydrocarbons are the primary component of the gas mixture being purified. In instances where arsine, phosphine, or ammonia is the primary component, and such primary component is being purified by its corresponding monoanion as the active scavenging entity, the proto- 35 nation of such monoanion in the scavenging reaction will advantageously produce the primary component as a reaction product. Accordingly, it is only the non-primary component reaction products of the scavenging reaction which are of concern vis-a-vis their vapor pressure. Thus, there exists a narrow range of pKa values associated with compounds whose anions are useful to form scavengers for the purification of arsine, phosphine, ammonia, and inert gases. Although ammonia and 40 inert gases have not been illustratively addressed in the preceding discussion of exemplary scavengers and anion species, it will be apparent to those skilled in the art that similar considerations are applicable and that based on such considerations suitable scavengers and related anion species may readily be determined without undue experimentation. When a Type II scavenger is to be utilized for gas purification in accordance with the invention, it will of 45 course be permissible to utilize on the scavenger support the carbanion source compound which is reactive with the primary component gas, arsine, phosphine, and/or ammonia, to form the actual scavenging anion, i.e., arsenide, phosphenide, and/or amide, in situ during gas treatment. Such a scavenger, comprising a support and the reactant carbanion source compound, is referred to as an "unconditioned" scavenger, while if this scavenger is pre-reacted with the primary component gas to form the actual scavenging anion 50 species on the support, the resulting scavenging is referred to as a "preconditioned" scavenger. The supports useful in the scavengers of the present invention include any suitable materials which are compatible with the gas mixtures being purified, and the reaction products of the impurity removal, and any intermediates involved with conditioning or otherwise preparing the scavenger, and which are stable under the conditions of use. 55 Illustrative materials which may be potentially useful in the broad practice of the invention include materials such as macroreticulate polymers, aluminosilicates, alumina, silica, kieselguhr, and carbon. As used herein, the term "aluminosilicates" means a support composition including the elements aluminum, silicon, and oxygen, such as molecular sieves; such aluminosilicates may be natural or synthetic in

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character. Among the macroreticulate polymers which may be useful in the broad practice of the invention are those formed from monomers such as styrene, vinyltoluene, vinylisopropylbenzene, vinyl naphthalene, alpha-methylstyrene, beta-methylstyrene, and mixtures thereof. Such polymers may suitably be polymer- 5 ized in the presence of a cross-linking agent such as divinylbenzene or divinylnaphthalene. A particularly preferred macroreticulate polymer is poly (styrene-divinylbenzene), commercially avail- able as Amberlite XAD4 (50 Angstrom pore size) and Amberlite XAD2 (100 Angstrom pore size), from Rohm & Haas, Philadelphia, Pennsylvania. The preferred characteristics of supports which are useful for scavengers of the invention include (a) io high surface area, for example a surface area in the range of from about 50 to about 1000 square meters per gram of support, (b) high porosity, such as a significant porosity from pores of a diameter in the range of from about 3 to about 200 Angstroms, and (c) good thermal stability, e.g., thermally stable at temperatures up to about 250 degrees Centigrade. The scavengers of the invention may be readily formed into a bed through which the impurity- 15 containing gas mixture is flowed for purification thereof, thereby providing a highly efficient removal system for substantially eliminating water and other impurities from arsine, phosphine, ammonia, and/or inert gases. Suitable scavengers according to the invention, utilizing anions derived from the compounds of Table I herein on supports such as the aforementioned Amberlite materials, may variously provide water removal capacity of from about 0.5 to about 20 liters of gaseous water per liter of bed of the scavenger. In some 20 instances where the impurity-removing reactions are highly exothermic in character, it may be desirable to utilize a removal capacity, based on water, of from about 1 to about 5 liters gaseous water per liter of bed of the scavenger. The impurity removal capacity of the bed may of course be readily adjusted to a particular desired level by controlling the loading of the scavenger anion on the support in the impregnation or other fabrication 25 step by which the carbanion source compound is applied to the support. The single drawing hereof shows a schematic representation of an apparatus for carrying out the purification method of the invention. The vessel 10 comprises an upper cylindrically shaped block 12 joined to the cup-like receptacle 14 by means of circumferentially extending weld 16. In the lower portion of receptacle 14 is disposed a bed 18 of 30 the scavenger according to the present invention. The vessel features means for introducing impurity-containing gas mixture, comprising as a primary component one or more of arsine, phosphine, ammonia, and/or inert gases, into the interior space of the receptacle 14 for contact with the scavenger in bed 18. Such introduction means comprise the conduit 20, provided at its exterior end with an appropriate fitting 22 for joining with the supply line 32 to gas mixture 35 source 30. The conduit 20 passes through the block 12 as shown, in a generally horizontal direction toward the center of the block and then downwardly extending from the block into the bed 18. At its lower portion in contact with the bed, this conduit has a plurality of gas distribution openings 34, through which the gas mixture flows outwardly and upwardly through the scavenger in the bed. Above the bed in the receptacle 14, the impurity-depleted gas flows into the outlet conduit 24, provided 40 with a suitable fitting 26 for connection to the product gas discharge line 28, from which the purified gas may be supplied to a downstream end-use processing facility. The advantages of the invention are more fully illustrated with reference to the following examples.

EXAMPLE I 45 A suitable quantity of Amberlite XAD4 is introduced to a flask and sized by washing with tap water to remove fines. The sized polymer is then washed in sequence with deionized water, methanol, isopropanol, and hexane, each in an amount equal to twice the volume of the bed of polymer. The polymer is air dried, and then dried with nitrogen at 150-190 degrees Centigrade overnight to 50 remove solvent. Triphenylmethane is dissolved in toluene, and the polymer bed is flooded with the resulting solution to apply the carbanion precursor at a loading of 10 grams of triphenylmethane per liter of bed. Solvent then is removed from the bed with nitrogen at 120 degrees Centigrade. Next, butyllithium in hexane solvent is added to the bed to form the carbanion source compound, 55 triphenylmethyllithium, following which solvent is removed from the bed and the unconditioned scavenger is packed under inert atmosphere into a suitable vessel. If desired, the scavenger in the vessel is then conditioned for service as a moisture scavenger for arsine by blowing helium gas containing on the order of 1-2 volume percent arsine through the scavenger bed in a

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stoichiometric amount to carry out the exothermic reaction of triphenylmethyllithium with arsine to form lithium arsenide and triphenylmethane. The exit gas from this conditioning step is scrubbed with hypochlo- rite, and the scavenger bed then is swept with inert gas to remove any free arsine remaining in the bed. Lithium arsenide thus is formed as the anion source compound in the scavenger, with the arsenide 5 anion from such compound serving as the active water gettering moiety when the vessel is placed in active service to purify water-containing arsine.

EXAMPLE II io The efficacy of a scavenger bed constructed in accordance with Example I is evaluated by flowing therethrough an arsine stream containing 40 ppm water, at a flow rate providing 1000 volumes of the wet arsine gas per volume of scavenger bed per hour. The effluent from the bed is measured for moisture content by a DuPont 5700 Trace Moisture Analyzer, and yields a moisture content of less than 0.01 ppm water. 15 EXAMPLE IN

Capacity of a scavenger bed constructed in accordance with Example I is measured by flowing therethrough a stream of nitrogen containing 200 ppm of water. The effluent is measured by the same 20 moisture analyzer device as is employed in Example II. Operation is continued until breakthrough of the water front occurs, by measurement of the water concentration of the effluent gas as a function of time. The water removal capacity of the scavenger bed is between 1 and 5 liters of gaseous water per liter of bed. Corresponding measurements on oxygen-containing streams indicate an oxygen removal capacity for 25 the scavenger bed of from about 0.5 to about 3 liters of oxygen per liter of bed.

Claims

1. A process for purifying a gaseous mixture comprising (i) a primary component selected from one or 30 more members of the group consisting of arsine, phosphine, ammonia and gases selected from the group consisting of one' or more members of the group consisting of nitrogen, hydrogen, helium, argon, neon, xenon, silane, germane, and gaseous hydrocarbons, and (ii) impurities selected from one or more members of the group consisting of Lewis acids and oxidants, to remove said impurities therefrom, comprising: 35 contacting the mixture with a scavenger including a support having associated therewith, but not covalently bonded thereto, a compound which in the presence of said mixture provides an anion which is reactive to effect the removal of said impurities, said compound being selected from one or more members of the group consisting of: (i) carbanion source compounds whose corresponding protonated carbanion compounds have a pKa 40 value of from about 22 to about 36; and (ii) anion source compounds formed by reaction of said carbanion source compounds with the primary component of said mixture; said scavenger being devoid of metallated pendant functional groups.

45 2. A process according to Claim 1, wherein said anion-providing compound is a carbanion source compound whose corresponding protonated carbanion compound has a pKa value of from about 22 to about 36, and whose carbanion directly reacts with said impurities.

3. A process according to Claim 2, wherein the corresponding protonated carbanion compound is selected 50 from the group consisting of fluorene, xanthene, triphenylmethane, and diphenylmethane.

4. A process according to Claim 2, wherein the carbanion moiety of the carbanion source compound is protonated by Lewis acid impurities during contacting of the mixture with the scavenger.

55 5. A process according to Claim 2, wherein the carbanion source compound is of the formula MA, wherein: M is a metal or organometal selected from the group consisting of lithium, sodium, potassium, alkyl magnesium, and alkyl zinc; and A is a carbanion.

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6. A process according to Claim 2, wherein the primary component is substantially non-deprotonated in the contacting thereof with the scavenger.

7. A process according to Claim 2, wherein the primary component is arsine, and the carbanion source 5 compound comprises a fluorene carbanion.

8. A process according to Claim 2, wherein the primary component is phosphine, and the carbanion source compound comprises a carbanion moiety selected from the group consisting of fluorene carbanions and xanthene carbanions. 10 9. A process according to Claim 1 , wherein said anion-providing compound is an anion source compound formed by reaction of a said carbanion source compound with the primary component of said mixture, and the primary component of the mixture is selected from one or more of the group consisting of arsine, phosphine, and ammonia. 15 10. A process according to Claim 9, wherein arsine is the primary component, and the anion source compound comprises an arsenide anion.

11. A process according to Claim 9, wherein phosphine is the primary component, and the anion source 20 compound comprises a phosphenide anion.

12. A process according to Claim 1, wherein the support is a mixture-compatible material selected from the group consisting of macroreticulate polymers, aluminosilicates, alumina, silica, kieselguhr and carbon.

25 13. A process according to claim 1, wherein the support is a macroreticulate polymer formed from monomers selected from those of the group consisting of styrene, vinyltoluene, vinylisopropylbenzene, vinylnaphthalene, alpha-methylstyrene, beta-methylstyrene, and mixtures thereof.

14. A process according to claim 13, wherein the polymer has been polymerized in the presence of a 30 cross-linking agent selected from the group consisting of divinylbenzene and divinylnaphthalene.

15. A process according to claim 13, wherein the polymer is poly (styrene-divinylbenzene).

16. A scavenger, having utility for purifying a gaseous mixture comprising (i) a primary component selected 35 from one or more members of the group consisting of arsine, phosphine, ammonia, and gases selected from the group consisting of one or more members of the group consisting of nitrogen, hydrogen, helium, argon, neon, xenon, silane, germane, and gaseous hydrocarbons, and (ii) impurities selected from one or more members of the group consisting of Lewis acids and oxidants said scavenger comprising: 40 (a) a support having a surface area in the range of from about 50 to about 1000 square meters per gram of support; and (b) associated with, but not covalently bonded to, said support, an anion which is reactive to effect the removal of said impurities, said anion being selected from one or more members of the group consisting of: 45 (1) carbanions whose corresponding protonated compounds have a pKa value of from about 22 to about 36; and (2) anions formed by reaction of said carbanions with the primary component of said mixture; and said scavenger being devoid of metallated pendant functional groups.

50 17. A scavenger according to claim 16, wherein said support is a mixture-compatible material selected from the group consisting of macroreticulate polymers, aluminosilicates, alumina, silica, kieselguhr, and carbon.

18. A scavenger according to claim 16, wherein said support is a macroreticulate polymer formed from 55 monomers selected from the group consisting of styrene, vinyltoluene, vinylisopropylbenzene, vinylnaphthalene, alpha-methylstyrene, beta-methylstyrene, and mixtures thereof.

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19. A scavenger according to claim 18, wherein the polymer has been polymerized in the presence of a cross-linking agent selected from the group consisting of divinylbenzene and divinylnaphthalene.

20. A scavenger according to claim 16, wherein said support is poly (styrene-divinylbenzene). 5 21. A scavenger according to claim 16, wherein the support has a significant porosity from pores of a diameter in the range of from about 3 to about 200 Angstroms, and is thermally stable at least up to about 250 degrees Centigrade.

70 22. A scavenger according to claim 16, having a water removal capacity of from about 0.5 to about 20 liters gaseous water per liter of a bed thereof.

23. A scavenger according to claim 16, wherein said anion is a carbanion whose corresponding protonated compound has a pKa value of from about 22 to about 36, said carbanion being directly reactive with 75 said impurities.

24. A scavenger according to claim 23, wherein the corresponding protonated carbanion compound is selected from the group consisting of fluorene, xanthene, triphenylmethane, and diphenylmethane.

20 25. A scavenger according to claim 23, wherein the carbanion moiety of the carbanion source compound is protonatable by Lewis acid impurities during contacting of the mixture with said scavenger.

26. A scavenger according to claim 23, wherein the carbanion is present as an anionic moiety of a compound of the formula MA, where M is a metal or organometal and A is said carbanion. 25 27. A scavenger according to claim 23, which in contact with the mixture is substantially non-deprotonating of the primary component therein.

28. A scavenger according to claim 23, wherein the anion comprises a carbanion selected from the group 30 consisting of fluorene carbanions and xanthene carbanions.

29. A scavenger according to claim 16, wherein said anion is formed by reaction of a said carbanion with the primary component, and said primary component is selected from one or more members of the group consisting of arsine, phosphine, and ammonia. 35 30. A scavenger according to claim 29, wherein said anion is selected from the group consisting of arsenide and phosphide anions.

31. A scavenger according to claim 16, wherein said anion is selected from one or more members of the 40 group consisting of: (1) carbanions present as anionic moieties of compounds of the formula MA, where: M is a metal or organometal, and A is said carbanion; and (2) anions formed by reaction of said carbanions with said primary components.

45 32. A scavenger according to claim 31 , wherein A is a carbanion formed by deprotonation of a precursor compound selected from the group consisting of fluorene, xanthene, diphenylmethane, and triphenylmethane.

33. A scavenger according to claim 31 , wherein said anion is a carbanion of the formula MA, where M is 50 lithium and A is triphenylmethide.

34. A scavenger according to claim 31, wherein said anion is formed by reaction of said primary component with a carbanion of the formula MA, where M is lithium and A is triphenylmethide.

55 Patentanspruche

1. Verfahren zum Reinigen eines gasformigen Gemisches, das (i) eine Primarkomponente aufweist, die aus einem oder mehreren Gliedern der aus Arsin, Phospin, Ammoniak und Gasen bestehenden Gruppe

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ausgewahlt ist, die aus der aus einem oder mehreren Gliedern der aus Stickstoff, Wasserstoff, Helium, Argon, Neon, Xenon, Silan, German und gasformigen Kohlenwasserstoffen bestehenden Gruppe ausgewahlt sind, und (ii) Verunreinigungen aufweist, die aus einem oder mehreren Gliedern der aus Lewis-Sauren und Oxidationsmitteln bestehenden Gruppe ausgewahlt sind, urn diese Verunreinigungen 5 zu entfernen, bei dem: das Gemisch mit einem Sauberungsmittel in Kontakt gebracht wird, das einen Trager aufweist, mit dem eine Verbindung assoziiert, jedoch nicht kovalent verbunden ist, die in Gegenwart des Gemisches ein Anion liefert, das reaktionsfahig ist, urn die Beseitigung der Verunreinigung zu bewirken, wobei diese Verbindung aus einem oder mehreren Gliedern der aus: io (i) Carbanionquellenverbindungen, deren entsprechende protonierte Carbanionverbindungen einen pKa-Wert von etwa 22 bis etwa 36 haben; und (ii) durch die Umsetzung dieser Carbanionquellenverbindungen mit der Primarkomponente des Gemisches gebildeten Anionquellenverbindungen bestehenden Gruppe ausgewahlt ist; is wobei das Sauberungsmittel frei von metallierten funktionellen Seitengruppen ist.

2. Verfahren nach Anspruch 1, bei dem die Anionen liefernde Verbindung eine Carbanionquellenverbin- dung ist, deren entsprechende protonierte Carbanionverbindung einen pKa-Wert von etwa 22 bis etwa 36 hat und deren Carbanion mit den Verunreinigungen unmittelbar reagiert. 20 3. Verfahren nach Anspruch 2, bei dem die entsprechende protonierte Carbanionverbindung aus der aus Fluoren, Xanthen, Triphenylmethan und Diphenylmethan bestehenden Gruppe ausgewahlt ist.

4. Verfahren nach Anspruch 2, bei dem der Carbanionanteil der Carbanionquellenverbindungwahrend des 25 Inkontaktbringens des Gemisches mit dem Sauberungsmittel durch Lewis-Saure-Verunreinigungen protoniert wird.

5. Verfahren nach Anspruch 2, bei dem die Carbanionquellenverbindung die Formel MA hat, wobei M ein Metall oder Organometall ist, das aus der aus Lithium, Natrium, Kalium, Alkylmagnesium und Alkylzink 30 bestehenden Gruppe ausgewahlt ist, und wobei A ein Carbanion ist.

6. Verfahren nach Anspruch 2, bei dem die Primarkomponente bei dem Inkontaktbringen mit dem Sauberungsmittel im wesentlichen nicht deprotoniert wird.

35 7. Verfahren nach Anspruch 2, bei dem die Primarkomponente Arsin ist und die Carbanionquellenverbin- dung ein Fluorencarbanion aufweist.

8. Verfahren nach Anspruch 2, bei dem die Primarkomponente Phosphin ist und die Carbanionquellenver- bindung einen Carbanionanteil aufweist, der aus der aus Fluorencarbanionen und Xanthencarbanionen 40 bestehenden Gruppe ausgewahlt ist.

9. Verfahren nach Anspruch 1, bei dem die Anionen liefernde Verbindung eine Anionenquellenverbindung ist, die durch Umsetzung einer der Carbanionquellenverbindungen mit der Primarkomponente des Gemisches gebildet wird, und die Primarkomponente des Gemisches aus einem oder mehreren 45 Gliedern der aus Arsin, Phosphin und Ammoniak bestehenden Gruppe ausgewahlt ist.

10. Verfahren nach Anspruch 9, bei dem Arsin die Primarkomponente ist und die Anionenquellenverbin- dung ein Arsenidanion aufweist.

50 11. Verfahren nach Anspruch 9, bei dem Phosphin die Primarkomponente ist und die Anionquellenverbin- dung ein Phosphenidanion aufweist.

12. Verfahren nach Anspruch 1, bei dem der Trager ein mit dem Gemisch kompatibles Material ist, das aus der aus makroretikularen Polymeren, Aluminosilikaten, Aluminiumoxid, Siliziumoxid, Kieselgur und 55 Kohlenstoff bestehenden Gruppe ausgewahlt ist.

13. Verfahren nach Anspruch 1, bei dem der Trager ein makroretikulares Polymer ist, das aus Monomeren gebildet wird, die aus der aus Styren, Vinyltoluen, Vinylisopropylbenzen, Vinylnaphtalen, a-Methylsty-

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ren, /3-Methylstyren und Gemischen derselben bestehenden Gruppe ausgewahlt ist.

14. Verfahren nach Anspruch 13, bei dem das Polymer in Gegenwart eines Vernetzungsmittels polymerisiert wurde, das aus der aus Divinylbenzen und Divinylnaphtalen bestehenden Gruppe ausgewahlt ist. 5 15. Verfahren nach Anspruch 13, bei dem das Polymer Poly(styren-Divynilbenzen) ist.

16. Sauberungsmittel, das fur die Reinigung eines gasformigen Gemisches geeignet ist, das (i) eine Primarkomponente aufweist, die aus einem oder mehreren Gliedern der aus Arsin, Phosphin, Ammoni- io ak und Gasen bestehenden Gruppe ausgewahlt ist, die aus der aus einem oder mehreren Gliedern der aus Stickstoff, Wasserstoff, Helium, Argon, Neon, Xenon, Silan, German und gasformigen Kohlenwas- serstoffen bestehenden Gruppe ausgewahlt sind, und (ii) Verunreinigungen aufweist, die aus einem oder mehreren Gliedern der aus Lewis-Sauren und Oxidationsmitteln bestehenden Gruppe ausgewahlt sind, wobei das Sauberungsmittel versehen ist mit: is (a) einem Trager mit einer spezifisichen Oberflache im Bereich von etwa 50 bis etwa 1000 m2 pro Gramm Trager; und (b) einem damit assoziierten, jedoch nicht kovalent verbundenen Anion, das reaktionsfahig ist, urn die Beseitigung der Verunreinigungen zu bewirken, wobei das Anion aus einem oder mehreren Gliedern der aus 20 (1) Carbanionen, deren entsprechende protonierte Verbindungen einen pKa-Wert von etwa 22 bis etwa 36 haben; und (2) durch die Umsetzung dieser Carbanionen mit der Primarkomponente des Gemisches gebildeten Anionen bestehenden Gruppe ausgewahlt ist; und 25 wobei das Sauberungsmittel frei von metallierten funktionellen Seitengruppen ist.

17. Sauberungsmittel nach Anspruch 16, bei dem Trager ein mit dem Gemisch kompatibles Material ist, das aus der aus makroretikularen Polymeren, Aluminosilikaten, Aluminiumoxid, Siliziumoxid, Kieselgur und Kohlenstoff bestehenden Gruppe ausgewahlt ist. 30 18. Sauberungsmittel nach Anspruch 16, bei dem der Trager ein makroretikulares Polymer ist, das aus Monomeren gebildet ist, die aus der aus Styren, Vinyltoluen, Vinylisopropylbenzen, Vinylnaphtalen, a- Methylstyren, /3-Methylstyren und Gemischen derselben bestehenden Gruppe ausgewahlt ist.

35 19. Sauberungsmittel nach Anspruch 18, bei dem das Polymer in Gegenwart eines Vernetzungsmittels polymerisiert wurde, das aus der aus Divenylbenzen und Divenylnaphtalen bestehenden Gruppe ausgewahlt ist.

20. Sauberungsmittel nach Anspruch 16, bei dem der Trager Poly(styren-Divenylbenzen)ist. 40 21. Sauberungsmittel nach Anspruch 16, bei dem der Trager eine signifikante Porisitat aus Poren mit einem Durchmesser im Bereich von etwa 3 bis etwa 200 A hat und bis mindestens etwa 250 °C thermisch stabil ist.

45 22. Sauberungsmittel nach Anspruch 16 mit einer Wasserbeseitigungskapazitat von etwa 0,5 bis etwa 20 Litem gasformigen Wassers pro Liter eines Bettes aus Sauberungsmittel.

23. Sauberungsmittel nach Anspruch 16, bei dem das Anion ein Carbanion ist, dessen entsprechende protonierte Verbindung einen pKa-Wert von etwa 22 bis etwa 36 hat, wobei das Carbanion zur 50 unmittelbaren Reaktion mit den Verunreinigungen geeignet ist.

24. Sauberungsmittel nach Anspruch 23, bei dem die entsprechende protonierte Carbanionverbindung aus der aus Fluoren, Xanthen, Triphenylmethan und Diphenylmethan bestehenden Gruppe ausgewahlt ist.

55 25. Sauberungsmittel nach Anspruch 23, bei dem der Carbanionanteil der Carbanionquellenverbindung wahrend des Inkontaktbringens des Gemisches mit dem Reinigungsmittel durch Lewis-Saure-Verunrei- nigungen protonierbar ist.

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26. Sauberungsmittel nach Anspruch 23, bei dem das Carbanion als ein anionischer Anteil einer Verbin- dung der Formel MA vorliegt, wobei M ein Metall oder Organometall ist und A das Carbanion ist.

27. Sauberungsmittel nach Anspruch 23, das in Kontakt mit dem Gemisch durch die darin vorhandene 5 Primarkomponente im wesentlichen nicht deprotoniert wird.

28. Sauberungsmittel nach Anspruch 23, bei dem das Anion ein Carbanion aufweist, das aus der aus Fluorencarbanionen und Xanthencarbanionen bestehenden Gruppe ausgewahlt ist. io 29. Sauberungsmittel nach Anspruch 16, bei dem das Anion durch Umsetzung eines der Carbanionen mit der Primarkomponente gebildet ist und die Primarkomponente aus einem oder mehreren Gliedern der aus Arsin, Phosphin und Ammoniak bestehenden Gruppe ausgewahlt ist.

30. Sauberungsmittel nach Anspruch 29, bei dem das Anion aus der aus Arsenid- und Phosphidanionen is bestehenden Gruppe ausgewahlt ist.

31. Sauberungsmittel nach Anspruch 16, bei dem das Anion aus einem oder mehreren Gliedern der aus: (1) Carbanionen, die als anionische Anteile von Verbindungen der Formel MA vorliegen, wobei M ein Metall oder Organometall ist und A das Carbanion ist; und 20 (2) durch die Umsetzung dieser Carbanionen mit den Primarkomponenten gebildeten Anionen bestehenden Gruppe ausgewahlt ist.

32. Sauberungsmittel nach Anspruch 31, bei dem A ein Carbanion ist, das durch Deprotonieren einer Vorlauferverbindung gebildet ist, die aus der aus Fluoren, Xanthen, Diphenylmethan und Triphenylme- 25 than bestehenden Gruppe ausgewahlt ist.

33. Sauberungsmittel nach Anspruch 31, bei dem das Anion ein Carbanion der Formel MA ist, wobei M Lithium ist und A Triphenylmethid ist.

30 34. Sauberungsmittel nach Anspruch 31 , bei dem das Anion durch Umsetzung der Primarkomponente mit einem Carbanion der Formel MA gebildet ist, wobei M Lithium ist und A Triphenylmethid ist.

Revendicatlons

35 1. Procede pour purifier un melange gazeux comprenant (i) un constituant principal forme d'un ou plusieurs membres du groupe consistant en une arsine, une phosphine, I'ammoniac et des gaz formes d'un ou plusieurs membres du groupe consistant en azote, hydrogene, helium, argon, neon, xenon, silane, germane et hydrocarbures gazeux, et (ii) des impuretes formees d'un ou plusieurs membres du groupe consistant en acides de Lewis et oxydants, pour eliminer lesdites impuretes de ce melange 40 gazeux, comprenant : la mise en contact du melange avec un accepteur comprenant un support auquel est associe, mais sans liaison covalente, un compose qui, en presence dudit melange, donne un anion qui presente une reactivite permettant I'elimination desdites impuretes, ledit compose etant forme d'un ou plusieurs membres du groupe consistant en : 45 (i) des composes servant de source de carbanions, les composes a carbanions protones correspon- dents ayant une valeur de pKa d'environ 22 a environ 36 ; et (ii) des composes servant de source d'anions, formes par reaction desdits composes servant de source de carbanions avec le constituant principal dudit melange ; ledit accepteur etant depourvu de groupes fonctionnels appendus metalles. 50 2. Procede suivant la revendication 1, dans lequel le compose fournissant des anions est un compose servant de source de carbanions, dont le compose a carbanions protones correspondant a une valeur de pKa d'environ 22 a environ 36, et dont le carbanion reagit directement avec lesdites impuretes.

55 3. Procede suivant la revendication 2, dans lequel le compose a carbanions protones correspondant est choisi dans le groupe consistant en fluorene, xanthene, triphenylmethane et diphenylmethane.

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4. Procede suivant la revendication 2, dans lequel le carbanion du compose servant de source de carbanions est protone par des impuretes consistant en acides de Lewis au cours de la mise en contact du melange avec I'accepteur.

5 5. Procede suivant la revendication 2, dans lequel le compose servant de source de carbanions repond a la formule MA, dans laquelle : M represente un metal ou radical organometallique choisi dans le groupe consistant en le lithium, le sodium, le potassium, un alkylmagnesium et un alkylzinc ; et A represente un carbanion. io 6. Procede suivant la revendication 2, dans lequel le constituant principal est pratiquement non deprotone lors de son contact avec I'accepteur.

7. Procede suivant la revendication 2, dans lequel le constituant principal est une arsine, et le compose servant de source de carbanions comprend un carbanion fluorene. 15 8. Procede suivant la revendication 2, dans lequel le constituant principal est une phosphine, et le compose servant de source de carbanions comprend un carbanion choisi dans le groupe consistant en carbanions fluorene et carbanions xanthene.

20 9. Procede suivant la revendication 1, dans lequel le compose fournissant des anions est un compose servant de source d'anions forme par reaction d'un compose servant de source de carbanions avec le constituant principal du melange, et le constituant principal du melange est forme d'un ou plusieurs membres du groupe consistant en une arsine, une phosphine et 1'ammoniac.

25 10. Procede suivant la revendication 9, dans lequel le constituant principal consiste en une arsine, et le compose servant de source d'anions comprend un anion arseniure.

11. Procede suivant la revendication 9, dans lequel le constituant principal consiste en une phosphine, et le compose servant de source d'anions comprend un anion phospheniure. 30 12. Procede suivant la revendication 1, dans lequel le support est une matiere compatible avec le melange, choisie dans le groupe consistant en polymeres macroreticulaires, aluminosilicates, alumine, silice, kieselguhr et carbone.

35 13. Procede suivant la revendication 1, dans lequel le support est un polymere macroreticulaire forme a partir de monomeres choisis dans le groupe de monomeres consistant en styrene, vinyltoluene, vinylisopropylbenzene, vinylnaphtalene, alpha-methylstyrene, beta-methylstyrene et leurs melanges.

14. Procede suivant la revendication 13, dans lequel le polymere a ete polymerise en presence d'un agent 40 de reticulation choisi dans le groupe consistant en divinylbenzene et divinylnaphtalene.

15. Procede suivant la revendication 13, dans lequel le polymere est un poly(styrene-divinylbenzene).

16. Accepteur, presentant une utilite pour la purification d'un melange gazeux comprenant (i) un constituant 45 principal forme d'un ou plusieurs membres du groupe consistant en une arsine, une phosphine, I'ammoniac et des gaz formes d'un ou plusieurs membres du groupe consistant en azote, hydrogene, helium, argon, neon, xenon, silane, germane et hydrocarbures gazeux, et (ii) des impuretes formees d'un ou plusieurs membres du groupe consistant en acides de Lewis et oxydants, ledit accepteur comprenant : 50 (a) un support ayant une surface specifique comprise dans I'intervalle d'environ 50 a environ 1000 metres carres par gramme de support ; et (b) en association, mais sans liaison covalente, avec ledit support, un anion qui presente une reactivite permettant I'elimination desdites impuretes, ledit anion etant forme d'un ou plusieurs membres du groupe consistant en : 55 (1) des carbanions dont les composes protones correspondants ont une valeur de pKa d'environ 22 a environ 36 ; et (2) des anions formes par reaction desdits carbanions avec le constituant principal dudit melange ; et

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ledit accepteur etant depourvu de groupes fonctionnels appendus metalles.

17. Accepteur suivant la revendication 16, dans lequel le support consiste en une matiere, compatible avec le melange, choisie dans le groupe consistant en polymeres macroreticulaires, aluminosilicates, 5 alumine, silice, kieselguhr et carbone.

18. Accepteur suivant la revendication 16, dans lequel le support est un polymere macroreticulaire forme a partir de monomeres choisis dans le groupe consistant en styrene, vinyltoluene, vinylisopropylbenzene, vinylnaphtalene, alpha-methylstyrene, beta-methylstyrene et leurs melanges. 10 19. Accepteur suivant la revendication 18, dans lequel le polymere a ete polymerise en presence d'un agent de reticulation choisi dans le groupe consistant en divinylbenzene et divinylnaphtalene.

20. Accepteur suivant la revendication 16, dans lequel le support consiste en un poly(styrene-divinylbenze- 15 ne).

21. Accepteur suivant la revendication 16, dans lequel le support presente une porosite importante constitute de pore ayant un diametre compris dans I'intervalle d'environ 3 a environ 2000 angstroms, et est stable a la chaleur au moins jusqu'a environ 250 ° centigrades. 20 22. Accepteur suivant la revendication 16, ayant une capacite d'elimination d'eau d'environ 0,5 a environ 20 litres d'eau a I'etat gazeux par litre d'un lit de cet accepteur.

23. Accepteur suivant la revendication 16, dans lequel I'anion est un carbanion dont le compose protone 25 correspondant a une valeur de pKa d'environ 22 a environ 36, ledit carbanion etant directement reactif avec les impuretes.

24. Accepteur suivant la revendication 23, dans lequel le compose a carbanions protones correspondant est choisi dans le groupe consistant en fluorene, xanthene, triphenylmethane et diphenylmethane. 30 25. Accepteur suivant la revendication 23, dans lequel le carbanion du compose servant de source de carbanions est protonable par des impuretes consistant en acides de Lewis au cours de la mise en contact du melange avec ledit accepteur.

35 26. Accepteur suivant la revendication 23, dans lequel le carbanion est present sous forme d'un groupe- ment anionique d'un compose de formule MA, dans laquelle M represente un metal ou radical organometallique et A represente ledit carbanion.

27. Accepteur suivant la revendication 23, qui, en contact avec le melange, est pratiquement non apte a la 40 deprotonation du constituant principal de ce melange.

28. Accepteur suivant la revendication 23, dans lequel I'anion comprend un carbanion choisi dans le groupe consistant en carbanions fluorene et carbanions xanthene.

45 29. Accepteur suivant la revendication 16, dans lequel I'anion est forme par reaction d'un tel carbanion avec le constituant principal, et ledit constituant principal est forme d'un ou plusieurs membres du groupe consistant en une arsine, une phosphine et I'ammoniac.

30. Accepteur suivant la revendication 29, dans lequel I'anion est choisi dans le groupe consistant en 50 anions arseniures et phosphures.

31. Accepteur suivant la revendication 16, dans lequel I'anion est forme d'un ou plusieurs membres du groupe consistant en : (1) des carbanions presents sous forme de groupements anioniques de composes de formule MA, 55 dans laquelle : M represente un metal ou radical organometallique, et A represente ledit carbanion ; et (2) des anions formes par reaction desdits carbanions avec les constituants principaux.

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32. Accepteur suivant la revendication 31 , dans lequel A represente un carbanion forme par deprotonation d'un compose precurseur choisi dans le groupe consistant en fluorene, xanthene, diphenylmethane et triphenylmethane.

5 33. Accepteur suivant la revendication 31, dans lequel I'anion est un carbanion de formule MA, dans laquelle M represente le lithium et A represente un radical triphenylmethylure.

34. Accepteur suivant la revendication 31, dans lequel I'anion est forme par reaction du constituant principal avec un carbanion de formule MA, dans laquelle M represente le lithium et A represente un io radical triphenylmethylure.

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L30

32 12,