SULFUR AND NITROGEN-CONTAINING HYDROCARBON COMPOUNDS AND PROCESS USING SAME IN RECOVERING AND CONCENTRATING DESIRED IONS FROM SOLUTIONS THEREOF

Abstract: The invention has compositions of matter and process aspects. The compositions of matter aspects relate to a class of new organic compounds, viz., intermediates which are sulfur and nitrogen containing hydrocarbons covalently bonded to trialkoxysilane and those intermediates covalently bonded to a solid inorganic support such as silica. The process aspect comprises two processes, viz., (1) a process for making the new class of compounds, and (2) the process of removing and/or concentrating certain ions such as noble metal ions and other transition metal ions, from solutions thereof admixed with other ions which may be present in much higher concentrations by forming a complex of the desired ion(s) with a compound as stated, e.g., by flowing the solution through a column packed with the compound, breaking the complex, e.g., by flowing a receiving liquid through the column to remove the desired ion(s) in solution in the receiving liquid and recovering the desired ion(s) from the receiving liquid.

Description: The present invention has composition and process aspects. The composition aspect comprises a new class of organic compounds, more particularly, a sulfur and nitrogen-containing hydrocarbon covalently bonded to an inorganic solid support, e.g., sand, silica gel, glass, glass fibers, titania, zirconia, alumina or nickel oxide. The process aspect comprises two processes, viz., (1) a process for making the new class of organic compounds and (2) the process of removing and concentrating certain ions, such as noble metal ions and other transition metal ions, from solutions thereof admixed with other ions which may be present in much higher concentrations. The latter process is accomplished by forming a complex of the desired ions with a compound of the new class of compounds taught herein. The complex can be formed by flowing the solutions through a column packed with a sulfur and nitrogen-containing compound of the inventions. Following the formation of the complex, a receiving liquid of much smaller volume than the volume of the starting solution is passed through the column to remove and concentrate the desired ions in the receiving liquid. The desired ions are then recovered from the receiving liquid. The sulfur and nitrogen-containing materials covalently bonded to an inorganic solid support, e.g., sand, silica gel, glass, glass fibers, titania, zirconia, alumina or nickel oxide., are shown by the structural formula (1). In formula (1), A and B are members selected from the group consisting of N(R³), N(R³)CH₂, O, OCH₂, S and SCH₂, with the further proviso that if A is selected from the group consisting of O, OCH₂, S and SCH₂ then B must be selected from the group consisting of N(R³) and N(R³)CH₂; D is a member selected from the group consisting of H, NH(R₃), SH, OH, lower alkyl and N(R³)[CH₂CH(R¹)CH₂O] b (CH₂) a Si(O-matrix)₃; Y and Z are members selected from the group consisting of Cl, O-matrix, OCH₃, OC₂H₅, methyl, ethyl and halogenated substituents thereof; R¹ is a member selected from the group consisting of H, SH, OH, lower alkyl, and aryl such as phenyl, naphthyl and pyridyl; R² is a member selected from the group consisting of H and lower alkyl; R³ is [(CH₂) f E] g R⁴, where E is selected from the group consisting of S, Se and Te; and R⁴ is a member selected from the group consisting of hydrogen, lower alkyl and aryl; a is from 2 to about 10; b is 0 or 1; c is from 1 to about 2000; d is from 0 to about 2000; f is from 2 to about 10; g is from 1 to about 10; and matrix is selected from the group consisting of sand, silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide. The process of producing the new compounds of formula (1) is described fully hereafter. The components of formula (1) can be used in a novel process of selectively and quantitatively removing and concentrating a selected ion or group of ions present at low concentrations from a plurality of other ions in a multiple ion solution in which the other ions may be present at much higher concentrations. The ions to be recovered and/or concentrated can be noble metal type, e.g., gold, silver the platinum metals, e.g., platinum, palladium, rhodium and iridium. When noble metals are not present, ions of mercury, lead, zinc, and other transition metals can be recovered and/or concentrated. The process of recovering and/or concentrating the selected ions comprises bringing the multiple ion solution into contact with a compound of formula (1) to complex the desired ion(s) with the compound, breaking the complex with a receiving liquid to render the ion(s) soluble in the receiving solution and then recovering the ion(s) from the receiving solution. The preferred embodiment disclosed herein involves carrying out the process by bringing a large volume of the multiple ion solution into contact with a compound of formula (1) in a separation column. The multiple ion solution flows through the column and the desired ion or ions form a complex with the compound of formula (1). A smaller volume of a receiving liquid such as aqueous NH₃, for example, is then passed through the column to break the complex by chemical or thermal means. The receiving liquid further dissolves the desired ions and carries them out of the column. Instead of using a column, the compound of formula (1) may be slurried in a suitable liquid, e.g., water. The multiple ion mixture can be present in the slurring liquid or subsequently added to the slurry. The desired ions(s) complex with the compound of formula (1) in the slurry and the slurry is then filtered. The resulting solids are washed with a receiving liquid to break the complex and recover the desired ion(s) in the receiving liquid. The desired metal ions are recovered from the receiving liquid by well known procedures. In a particularly preferred embodiment of the process a covalent chemical bond is formed between an inorganic solid support, preferably, sand or silica gel, and at least one of the compounds of formula 1. The resulting bonded silica compound of formula is placed in a contacting device such as a tall column. The multiple ion mixture is passed through the column, with the desired metal ions from the multiple ion mixture forming a complex with the bonded silica to separate the desired metal ions from the rest of the mixture which flows out of the column. A small volume of the receiving liquid is thereafter passed through the column to break the complex as well and as to dissolve and carry out of the column the desired metal ions. The desired metal ions are then recovered from the receiving liquid by well known procedures. The process of making the compounds represented by formula 1 is also a part of the invention. The fact is known that macrocyclic polythioethers and certain other sulfur-containing hydrocarbon ligands present as solutes in a solvent such as water are characterized by their ability to selectivity form strong bonds with the noble metal, platinum group metal, and mercury ions or groups of these ions present as solutes in the same solvent. In our article by R.M. Izatt, R.E. Terry, L.K. Hansen, A.G. Avondet, J.S. Bradshaw, K.K. Dalley, T.E. Jensen and J.J. Christensen, A CALORIMETRIC TITRATION STUDY OF UNI- AND BIVALENT METAL ION INTERACTION WITH SEVERAL THIA DERIVATIVES OF 9-CROWN-13, 12-CROWN-4, 15-CROWN-5, 18-CROWN-6, 24-CROWN-8, AND SEVERAL OXATHIAPENTADECANES IN WATER OR WATER-METHANOL SOLVENTS AT 25°C , Inorganica Chimica Acta, 1978, Vol. 20, 1-8, the complexation of silver and mercury ions by open chain sulfur-containing hydrocarbons is disclosed. In another article by S.R. Cooper, CROWN THIOETHER CHEMISTRY , Accounts of Chemical Research, 1988, Vol. 21, 141-146, the complexation of rhodium and silver ions by macrocyclic sulfur-containing ligands is disclosed. However, researchers have not previously been able to incorporate sulfur and nitrogen-containing hydrocarbon ligands into separation systems where the behavior of the sulfur and nitrogen-containing ligands in the separation systems in comparison to that of the sulfur and nitrogen-containing ligand as a solute is unchanged and/or the sulfur and nitrogen-containing ligand will remain in the separation system. Articles such as those entitled SILANE COMPOUNDS FOR SILYLATING SURFACES by E.P. Plueddeman, in "Silanes, Surfaces and Interfaces Symposium, Snowmass, 1985," Ed. by D.E. Leyden, Gordon and Breach, Publishers, 1986, pp. 1-25, and SILANE COUPLING AGENTS by E.P. Plueddemann, Plenum Press, 1982, pp. 1-235, list many different types of organic materials which have been attached to silane compounds and discusses some of their properties. The preparation and uses of sulfur and nitrogen-containing hydrocarbons attached to silane or silica have not been disclosed in the above mentioned article or in any existing patents. Thus, the unique complexing properties of certain sulfur and nitrogen-containing hydrocarbons and the ability to attach these sulfur-containing complexing agents to an inorganic solid support without reducing their ability to complex certain metal ions is of utmost importance in the industrial use of the sulfur and nitrogen-containing hydrocarbon ligands. The process of the present invention accomplished this feat. The compounds of the present invention comprise certain sulfur-containing hydrocarbon ligands covalently bonded to an inorganic solid support, e.g., sand, silica gel, glass, glass fibers, titania, zirconia, alumina or nickel oxide. The compounds are identified above in formula 1. The process of the present invention uses the compounds of formula (1) which are characterized by high selectivity for and removal of desired metal ions or groups of metal ions such as the noble metal ions present at low concentrations from a source phase containing a mixture of the desirable metal ions and other undesirable ions which are often in much greater concentrations in the solution then the desirable ions. The process of selectively removing and concentrating the desired ion(s) is characterized by the ability of the compounds of formula (1) to quantitatively complex desired ion(s) from a large volume of solution in which the desired ion(s) are present at low concentrations. The desired ions are recovered by subsequently contacting the complex with a small volume of a receiving fluid which contains a solubilized reagent which need not be selective, but which will strip the ions from the ligand quantitatively. The recovery of the desired metal ions from the receiving phase is easily accomplished by well known procedures. The process of producing the compounds of formula (1) is an important part of the present invention. The invention will be described and illustrated by reference to a drawing in which: Figure 1 represents schematically a suitable column for holding the silica bonded sulfur and nitrogen-containing hydrocarbon ligand material through which a solution of metal ions can be flowed to complex selectively with a desired ion or group of ions in accordance with the invention. The preferred embodiment of the ion-recovery process of the invention utilizes the new compounds represented by formula (1). sulfur and nitrogen-containing hydrocarbon ligands must be covalently bonded to an inorganic solid support in accordance with the invention. As a specific example, γ-glycidoxypropyltrimethoxysilane was first covalently bonded to silica gel and then ethylenediamine was reacted with the epoxide function. This intermediate was further reacted with ethylene sulfide to give a material containing both sulfur and nitrogen, (CH₃O)₃Si(CH₂)₃OCH₂CH(OH)CH₂NRCH₂CH₂NRH where R is a repeating ethylenethio group. The following two examples are given to illustrate compounds which have been made in accordance with formula 1 of the present invention. These examples are illustrative only and are not comprehensive of the many different compounds which have or can be made within the scope of the present invention. Example 1 Silica gel (30 g, 60-22 mesh) was slowly added to 375 mL of toluene and 7.5 g of γ-gycidoxylropyltrimethoxysilane. The mixture was maintained in suspension by mechanical stirring and was heated at reflux overnight. Ethylenediamine (1.25 g) was then added to the suspension and heated an additional 5 hours. The mixture was allowed to cool and 5.2 g of ethylene sulfide was added. The suspension was stirred at room temperature for 6 hours and then heated to 80°C overnight to effect reaction. The product was isolated by filtration and allowed to air dry. Example 2 Silica gel was covalently attached to γ-glycidoxypropyltrimethoxysilane in the same manner as above. This intermediate was then reacted with pentaethylenehexamine and ethylene sulfide successively as above in a mole ratio of 3 to 1 such that there are three ethylenethio groups per nitrogen. The compounds of formula (1) are covalently bonded to any inorganic solid support which has surface hydroxylic groups which may be covalently modified to include the ligand as shown in the first step of equation (2). The reaction can take place by first, dissolving the compound of formula (1) in a low boiling solvent such as dichloromethane, adding the solid support, removing the low boiling solvent, then heating the coated support at about 120°C for 3 to about 18 hours under vacuum. A second procedure to cause the compounds of formula 1 to react with a solid support is to heat the solid support with the compound of formula 1 in a high boiling solvent such a toluene. Where R₁ is [(CH₂) n NH] m , R₂ is [(CH₂) n NHR₃] m , R₃ is [(CH₂) n G] m , G is selected from the group consisting of S, Se and Te, and n and m are each from about 2 to 10. The metal ion recovery and concentration process of the invention relates to the selective recovery of desired metal ions from mixtures thereof with other metal ions using the compounds of formula 1 of the invention as defined above. Effective methods of recovery and/or separation of metal ions, particularly the noble metal ions, from other metal ions in water supplies, waste solutions, deposits and industrial solutions and silver recovery from waste solutions, e.g., from emulsions on photographic and X-ray film, represent a real need in modern technology. These ions are typically present at low concentrations in solutions containing other ions in much greater concentration. Hence, there is a real need for a process to selectively recover and concentrate these metal ions. The present invention accomplishes this separation effectively and efficiently by the use of compounds selected from the families represented by formula (1). The silica gel material of formula (1) is placed in a column as shown in Figure 1. An aqueous solution containing the desired ion(s), in a mixture of other ions which may be in much greater concentration, is passed through the column. The flow rate may be controlled by applying pressure to the top of the column or by applying vacuum to the receiving vessel at the bottom of the column. After the solution has passed through the column, a volume of a recovery solution, i.e. aqueous sodium thiosulfate, aqueous ammonia, or aqueous sodium cyanide, which forms a stronger complex with the desired noble metal ions, or in their absence other metal ions, as stated above, is passed through the column. This recovery solution contains only the desired metal ions in a more concentrated form. The following examples of separations of metal ions by the silica gel-bound sulfur and nitrogen-containing materials of Examples 1 and 2 are given as illustrations. These examples are illustrative only and are not comprehensive of the many separations of noble metal, platinum group metal, and in some cases transition metal ions that are possible using the materials made within the scope of this invention. Example 3 In this example, 4 g of the silica-bound sulfur and nitrogen-containing hydrocarbon of Example 1 was placed in a column as shown in Figure 1. A 500 mL solution of approximately 10 ppm (parts per million) copper ion in 1 M HCl was drawn through the column using a vacuum pump at 600 torr to increase the flow rate. A 25 mL aqueous solution of 2 M NH₃, 1 M HCl was then passed through the column. Analysis of the recovery solution by atomic absorption spectroscopy (AA) showed greater than 95% of the copper (II) ions originally in the 500 mL solution described above was in the 25 mL recovery solution. Example 4 The experiment of Example 3 was repeated with 10 g of the silica-bound sulfur and nitrogen-containing hydrocarbon of Example 2. A 100 mL solution of 10 ppm Au (I) in 0.01 M KCN was passed through the column. A 10 mL aqueous solution of 5 M KCN was then passed through the column. Analysis of the recovery solution by AA showed that about 90% of the Au (I) ions originally present in the 100 mL Au (I) solution was found in the 10 mL recovery solution. From the foregoing, it will be appreciated that the sulfur and nitrogen-containing hydrocarbon ligands of formula (1) bonded to a solid support such as silica gel of the present invention provide a material useful for the separation and concentration of the noble metal cations from mixtures of those cations with other metal cations and also in the presence of strong acids or strong complexing agents. The noble metals can then be recovered from the concentrated recovery solution by standard techniques known in the science of these materials. In the absence of noble metal ions for other transition metal ions may be recovered.

Claims: 1. A compound of formula wherein A and B are members selected from the group consisting of N(R³), N(R³)CH₂, O, OCH₂, S and SCH₂, with the further proviso that if A is selected from the group consisting of 0, OCH₂, S and SCH₂ then B must be selected from the group consisting of N(R³) and N(R³)CH₂; D is a member selected from the group consisting of H, NH(R³), SH, OH, lower alkyl and N(R³)[CH₂CH(R¹)CH₂O] b (CH₂) a Si(O-matrix)₃; Y and Z are members selected from the group consisting of Cl, O-matrix, OCH₃, OC₂H₅, methyl, ethyl and halogenated substituents thereof, R¹ is a member selected from the group consisting of H, SH, OH, lower alkyl and aryl; R² is a member selected from the group consisting of H and lower alkyl; R³ is [(CH₂) f E] g R⁴, where E is selected from the group consisting of S, Se and Te; and R⁴ is a member selected from the group consisting of hydrogen, lower alkyl and aryl; a is from 2 to about 10; b is 0 or 1; c is from 1 to about 2000; d is from 0 to about 2000; f is from 2 to about 10; g is from 1 to about 10; and matrix is selected from the group consisting of sand, silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide. 2. The compound of claim 1 wherein R¹ is selected from the group consisting of phenyl, naphthyl and pyridyl. 3. The compound of claim 1 wherein a is 3, b is 1, c is 1, d is O, R¹ is hydroxy, R² is hydrogen, A is nitrogen, B is absent since d is O, D is NR³ CH₂CH(R¹)CH₂O b (CH₂) a Si(O-matrix)₃. 4. The compound of claim 1 wherein a is 3, b is 1, c is 4, d is 1, R¹ is hydroxy, R² is hydrogen, A is nitrogen, B is nitrogen, D is NR³ CH₂CH(R¹)CH₂O b (CH₂) a Si-O-matrix)₃. 5. A process of removing and concentrating desirable ions from a mixture thereof in solution with other ions which comprises complexing the desired ions in said solution with a compound comprising a solid support covalently bonded to a sulfur and nitrogen containing hydrocarbon compound from the class consisting of: wherein A and B are members selected from the group consisting of N(R³), N(R³)CH₂, O, OCH₂, S and SCH₂, with the further proviso that if A is selected from the group consisting of O, OCH₂, S and SCH₂ then B must be selected from the group consisting of N(R³) and N(R³)CH₂; D is a member selected from the group consisting of H, NH(R³), SH, OH, lower alkyl and N(R³)CH₂CH(R¹)CH₂O b (CH₂) a Si(O-matrix)₃; Y and Z are members selected from the group consisting of Cl, O-matrix, OCH₃, OC₂H₅, methyl, ethyl and halogenated substituents thereof; R¹ is a member selected from the group consisting of H, SH, OH, lower alkyl and aryl; R² is a member selected from the group consisting of H and lower alkyl; R³ is [(CH₂) f E] g R⁴, where E is selected from the group consisting of S, Se and Te; and R⁴ is a member selected from the group consisting of hydrogen, lower alkyl and aryl; a is from 2 to about 10; b is 0 or 1; c is from 1 to about 2000; d is from 0 to about 2000; f is from 2 to about 10; g is from 1 to about 10; and matrix is selected from the group consisting of sand or silica gel, glass, glass fibers, aluminia, zirconia, titania or nickel oxide; breaking said complex to liberate the complexed ions; dissolving said liberated ions in a receiving liquid in a smaller volume than the volume of said solution from which the desired ions have been removed; and recovering said ions from said receiving liquid. 6. The process of claim 5 wherein R¹ is selected from the group consisting of phenyl, naphthyl and pyridyl. 7. A process of separating a selected noble metal ion or ions from a plurality of other ions in a multiple ion solution characterized by flowing the multiple ion solution through a column packed with a composition of matter comprising a solid support covalently bonded to a sulfur and nitrogen-containing hydrocarbon compound from the class consisting of: wherein A and B are members selected from the group consisting of N(R³), N(R³)CH₂, O, OCH₂, S and SCH₂, with the further proviso that if A is selected from the group consisting of O, OCH₂, S and SCH₂ then B must be selected from the group consisting of N(R³) and N(R³)CH₂; D is a member selected from the group consisting of H, NH(R³), SH, OH, lower alkyl and N(R³)[CH₂CH(R¹)CH₂O] b (CH₂) a Si)O-matrix)₃; Y and Z are members selected from the group consisting of Cl, O-matrix, OCH₃, OC₂H₅, methyl, ethyl and halogenated substituents thereof; R¹ is a member selected from the group consisting of H, SH, OH, lower alkyl and aryl; R² is a member selected from the group consisting of H and lower alkyl; R³ is [(CH₂) f E] g R⁴, where E is selected from the group consisting of S, Se and Te; and R⁴ is a member selected from the group consisting of hydrogen, lower alkyl, and aryl; a is from 2 to about 10; b is 0 or 1; c is from 1 to about 2000; d is from 0 to about 2000; f is from 2 to about 10; g is from 1 to about 10; and matrix is selected from the group consisting of sand, or silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide, complexing the selected noble metal ion or ions with said composition of matter and removing said noble metal ion or ions from said multiple ion solution; separating said multiple ion solution from which said selected ion or ions has been removed from said complex; breaking said complex to liberate the compleyed noble metal ion or ions; dissolving said liberated noble metal ion or ions in a receiving liquid in a smaller volume than the volume of said solution from which the desired noble metal ion or ions have been removed; and recovering said noble metal ion or ions from said receiving liquid. 8. The process of claim 7 wherein R¹ is selected from the group consisting of phenyl, naphthyl and pyridyl. 9. The process of claim 7 in which said solid support is silica gel, a is 3, b is 1, c is 1, d is 0, R¹ is hydroxy, R² is hydrogen, A is nitrogen, B is absent since d is 0, D is NR³[CH₂(R¹)CH₂O] b (CH₂) a Si(O-matrix)₃. 10. The process of claim 7 in which said solid support is silica gel, a is 3, b is 1, c is 4, d is 1, R¹ is hydroxy, R² is hydrogen, A is nitrogen, B is nitrogen, D is NR³[CH₂(R¹)CH₂O] b (CH₂) a Si(O-matrix)₃. 11. The compound of claim 1 wherein Y and Z are (O-matrix).

Inventors: BRADSHAW JERALD S., BRUENING RONALD L., IZATT REED M., TARBET BRYON J.
Applicants: BRIGHAM YOUNG UNIVERSITY
Application year: 1989
Main classification: B01J20
IPC codes: C01G3, C01G7, C09K3, B01J20, B01J45