Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N59/00—Biocides, pest repellants or attractants, or plant growth regulators containing elements or inorganic compounds
  • A01N59/12—Iodine, e.g. iodophors; Compounds thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
  • B01D61/363—Vapour permeation
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B7/00—Halogens; Halogen acids
  • C01B7/13—Iodine; Hydrogen iodide
  • C01B7/14—Iodine

Definitions

• This invention relates to the production of pure elemental iodine.
• Iodine for example in the form of Lugol's solution or tincture of iodine
• U.S. Pharmacopoeia and other similar publications in many countries have documented this property of iodine since 1830. Iodophores have been noted for their similar properties since 1960.
• iodines have been recognized for their bioactivity in man, animals, and in types of bacteria in plants and their seeds. In fact, a deficiency of iodine has been shown to prevent the attainment of maximum health, growth, and reproductive Success.
• thermodynamically free iodine which is uncomplexed or pure elemental iodine d )' as described in the Schmidt and Winicov article "Detergent/Iodine Systems” in Soap and Chemical Specialties, August 1967.
• thermodynamically free iodine when fed to a mammal has a much decreased effect upon the thyroid compared to iodide, or iodine/iodide mixtures or mixtures of polyhalides (see Thrall and Bull in their article "Differences in the Distribution of Iodine and Iodide in the Sprague - Dawley Rat" in Fundamental and Applied Toxicology, 15, 75-81 (1990)).
• thermodynamically free iodine describes iodine that is free from complexing.
• Thermodynamically free iodine in aqueous solution may dissociate into many hydrolyzed forms, depending upon concentration and/or pH, for example HIO (or also known as HOI), some of which are biocidal in nature.
• HIO or also known as HOI
• a solution of aqueous iodine (A + hydrolyzed biocidal forms where appropriate) could be reliably generated at any concentration of thermodynamically free iodine less than supersaturation, and remain stable at that level, it would allow the manufacture of many devices useful in water treatment, instrument sterilization, use as a source of nutritional iodine, plus other medicinal uses including the treatment of IDDs (Iodine Deficiency Disorders), chemical uses, and catalytic uses.
• IDDs Iodine Deficiency Disorders
• thermodynamically free iodine For example, if a device could reliably produce a desired concentration of thermodynamically free iodine into a pH buffered fluid such that the thermodynamically free iodine remained unhydrolyzed and of known concentration despite moderate changes in ambient temperature, it would allow the treatment of many non-thyroidal IDDs and other medical conditions known to respond to treatment with iodine, such as in U.S. Patent No. 4,816,255 of Ghent, with a much reduced toxicity (toxicity meaning thyroid complication found with other forms of iodine, iodides, iodine/iodide mixtures or polyhalides) .
• thermodynamically free iodine in all biocidal iodine solutions is confined to the water phase. Further, thermodynamically free iodine is usually found in solution in concentrations less than that of the total titratable iodine of the solution.
• the solubility of elemental iodine is, increased to, for example, 1% (w/v); however, the amount of thermodynamically free iodine detectable is only circa 0.018% (w/v) or 180 ppm.
• thermodynamically free iodine formulations The germicidal capacity of these iodine formulations is dependent upon the continued release of thermodynamically free iodine from the reservoir of titratable iodine, as the thermodynamically free iodine in solution is depleted through dilution, contamination or biocidal activity. It has therefore been the goal of researchers to develop a practical means of creating this reservoir from which pure thermodynamically free iodine may be released alone, with no other adjuvants, into water in a controlled fashion.
• thermodynamically free iodine cannot prevent the contamination of the iodine reservoir by undesirable substances which may reduce the effectiveness of the reservoir, or facilitate the release of unwanted contaminants into the product stream containing the wanted thermodynamically free iodine and still further cannot provide stable levels of thermodynamically free iodine below the saturation level for iodine in a fluid in contact with the iodine.
• thermodynamically free iodine Attempts have also been made to develop a chemical means of providing a reliable supply of thermodynamically free iodine.
• the chief fault of such systems is that a loss of solvent (i.e. water lost through evaporation) increases the total percentage of iodine in a volume and therefore, given iodine's relative insolubility, increases the toxic effect of the remaining solution (through recrystallization of elemental iodine) and subsequently reduces the availability of thermodynamically free iodine.
• thermodynamically free iodine in water is usually restricted to about 60% of the maximum solubility of thermodynamically free iodine in water
• an iodophore of 3.75% titratable iodine may achieve maximum strength of less than 40 ppm of thermodynamically free iodine after dilution while having 75 ppm of titratable iodine. This discrepancy between the level of thermodynamically free iodine and the amount of titratable iodine makes the field testing for iodine concentration very cumbersome. Where chemical adjuvants are used to increase the reservoir of titratable iodine, the adjuvants may act as an unwanted toxicant.
• P.V.P.I. poly(N-vinyl-2-pyrrolidone)-iodine
• P.V.P.I. poly(N-vinyl-2-pyrrolidone)-iodine
• thermodynamically free iodine should be as pure as practically and economically obtainable, for the end uses to which it is to be put. Any existing chemical means of releasing thermodynamically free iodine will likely release undesirable contaminants into the final product.
• the invention consists of a method, and a device, for producing pure elemental iodine where a source containing thermodynamically free iodine is introduced on one side of a nonporous barrier impervious to solvents and contaminants of thermodynamically free iodine (hereinafter referred to as an iodine solving solid barrier), through which said thermodynamically free iodine passes by dispersion driven by vapour pressure differential between the two sides of the barrier until equilibrium of thermodynamically free iodine vapour pressure is reached across the barrier.
• a source containing thermodynamically free iodine is introduced on one side of a nonporous barrier impervious to solvents and contaminants of thermodynamically free iodine (hereinafter referred to as an iodine solving solid barrier), through which said thermodynamically free iodine passes by dispersion driven by vapour pressure differential between the two sides of the barrier until equilibrium of thermodynamically free iodine vapour pressure is reached across the barrier
• the degree to which the thermodynamically free iodine disperses to the other side of the iodine solving solid barrier may be controlled by means which reduce the vapour pressure of thermodynamically free iodine such as the variation of temperature of the iodine source material or of the other side of the barrier as well as the use of an iodine complexing compound in conjunction or in combination with the source material.
• Figure 1 is a schematic drawing showing a device for producing pure elemental iodine
• Figure 2 is an alternate embodiment of Figure 1
• Figure 3 is an alternate embodiment of Figure 1
• Figure 4 is a cross-sectional view of an alternate embodiment of Figure 1.
• Elemental iodine that is, the diatomic molecule _2 t is only marginally soluble in water (circa 300 ppm).
• iodine may form 2 distinct types of solution, which may be differentiated by their color (i.e. in organic solvents such as carbon tetrachloride, iodine imparts a violet color upon dissolution, whereas in water, a clear amber color is produced in the absence of polyhalides, complexing agents or other colorants. In the presence of polyhalides, a black color is produced).
• iodine exhibits a vapour pressure and also has a maximum solubility limit.
• Iodine In the presence of polyhalides and/or iodine complexing compounds, the iodine's vapour pressure is reduced. Iodine also has the special property of being soluble in some solids. To iodine, these solids appear to behave as a liquid solvent (in the traditional sense of the properties of a liquid). When iodine is introduced to these solids, the solid is permeated by the iodine, imparting one of the two colors observed when iodine dissolves in liquids.
• the iodine exhibits a vapour pressure and within the solid also has a solubility limit, both of which may be affected by complexing of I_ either within the solid, or from the I ⁇ reservoir, or intermediate to the solid and reservoir.
• the ultimate concentration on the other side of the barrier may be accurately controlled for a given temperature and solvent on the other side of the barrier, and even made stable irrespective of moderate temperature change of the donating source, barrier, or solvent on the other side of the barrier.
• the vapour pressure of thermodynamically free iodine may be accurately controlled to provide a desired concentration ultimately reached on the other side of the barrier.
• Figure 1 of the drawings shows a container 10 which iodine molecules cannot penetrate, such as glass, a solid barrier 12 constructed from an iodine solving solid, a source of iodine 14 in chamber 16 containing a fluid and a second chamber 18 on the other side of barrier 12 containing a material into which the thermodynamically free iodine, dispersing through barrier 12, will pass until vapour pressure equilibrium is reached.
• Chamber 18 may be a fluid such as water, a vacuum chamber, an iodine solving solid used to retain the thermodynamically free iodine, an iodine complexing compound or adjuvant or other material to which one desires to expose a controlled amount of iodine.
• FIG. 1 shows an alternate arrangement of the components of Figure 1 where the iodine solving solid 20 encapsulates the source quantity of iodine (ie. water plus a quantity of thermodynamically free iodine donating material).
• the capsule would be capable of releasing a quantity of thermodynamically free iodine for the purposes of achieving a desired level of thermodynamically free iodine in the material contained in chamber 22.
• the encapsulation prevents direct physical contact by solvents or contaminants with the contents of the capsule.
• the encapsulating process should be effected using materials which add a minimum of iodine demand.
• the capsule may be formed as a ridged or non-ridged pillow. Upon being placed in chamber 22, capsule 20 will facilitate the transfer of I ? molecules to the material in chamber 22 and will do so until the reservoir of iodine is depleted, or an equilibrium is attained between reservoir 14 and chamber 22.
• FIG. 3 of the drawings shows an alternate construction in which the iodine solving solid barrier 12 is flexible and carries within it an iodine non- solving frangible container 22 containing iodine source 14.
• Use of this embodiment entails the squeezing of flexible barrier 12 in order to fracture the non-solving barrier 22 so that the source solution of iodine has access to the solving barrier.
• the entire construction is delivered to the material in which the thermodynamically free iodine, which subsequently diffuses through barrier 12, is required.
• iodine source 14 material would be potassium iodide (KI) and a possible fluid surrounding frangible container 22 and confined by solid solving barrier 12 could be a water and chloramine mixture.
• frangible container 22 is broken, the chemical reaction between the potassium iodide and chloramine would produce potassium chloride and thermodynamically free iodine (plus some free amines).
• the device shown in Figure 4 of the drawings consists of a unit 30 comprising a cup 31 which fits into a container 32, in a manner such that an annular cavity 34 is created between the two. Both cup 31 and container 32 are constructed of materials impenetrable to iodine (such as glass).
• a removable screw cap fits on cup 31 by engaging a thread 36.
• Cup 31 has an annular flange 37 which seals onto rim 38 of container 32.
• the annular cavity between cup 31 and container 32 is filled with an iodine source material 35 from which the thermodynamically free iodine will be extracted.
• the outer surface of cup 31 below flange 37 is coated with an iodine solving solid layer 39.
• a ring of apertures 42 around cup 31 and a series of apertures 44 in the bottom of cup 31 exposes the contents of cup 31 to one surface of the iodine solving solid barrier 39.
• the bottom of cup 31 is spaced from the surface of container 32 by a ring flange 46 which has notches 48 spaced about its perimeter.
• the iodine solving barrier may be constructed of, but is not restricted to, materials such as linear polyethylene, isotactic polyethylene, polyoxymethylene and polybutylene terephthalate. The barrier will be selected so as not to contribute detrimentally to the products final use.
• thermodynamically free iodine source material may be a variety of compounds, including but not restricted to technical grade iodine which contains thermodynamically free iodine.
• iodine complexing compounds known to lower the maximum level of thermodynamically free iodine by complexing I 2 iodine and therefore lowering the vapour pressure of iodine over the iodine/complexing compound mixture, may be used to accurately control the equilibrium concentrations of thermodynamically free iodine on the other side of the barrier. This may be achieved by combining the iodine and complexing compound and using the mixture as the source of thermodynamically free iodine. Another method is to separate the iodine source from the iodine solving solid barrier with another like barrier, and placing the iodine complexing compound between the two. The effectiveness of the complexing compound can be varied with type and concentration.
• iodine complexing compounds are poly(N-vinyl-2-pyrrolidone) , polyoxypropylene and nonyl phenol. A more extensive listing can be found in U.S. Patent no. 3,028,299 by Winicov and Schmidt.
• the other side of the solid solving barrier may contain a fluid (liquid or gas) or a solid.
• the fluid or solid may be either iodine-solvent or iodine- insolvent.
• the other side may also be a vacuum into which the thermodynamically free iodine would form an iodine vapour, whose concentration in the vacuum is controlled by the vapour pressure exerted by the iodine source.
• the other side of the iodine solving solid barrier may contain an iodine complexing compound which would complex the thermodynamically free iodine which crosses the barrier.
• the temperature of the iodine source of the iodine solving solid barrier or of a material on the other side of the barrier may be adjusted to control the thermodynamically free iodine vapour pressure in that iodine source, iodine solving solid barrier or material on the other side of the barrier and by this means control the extent to which the thermodynamically free iodine passes through the barrier.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Life Sciences & Earth Sciences (AREA)
• Inorganic Chemistry (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Agronomy & Crop Science (AREA)
• Health & Medical Sciences (AREA)
• Dentistry (AREA)
• General Health & Medical Sciences (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Environmental Sciences (AREA)
• Plant Pathology (AREA)
• Pest Control & Pesticides (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 1989
  • 1989-09-28 CA CA000613953A patent/CA1340947C/en not_active Expired - Fee Related
• 1990
  • 1990-08-20 JP JP2511166A patent/JPH05500354A/ja active Pending
  • 1990-08-20 EP EP90911944A patent/EP0494150A1/en not_active Withdrawn
  • 1990-08-20 HU HU9201028A patent/HUT60696A/hu unknown
  • 1990-08-20 BR BR909007705A patent/BR9007705A/pt unknown
  • 1990-08-20 WO PCT/CA1990/000265 patent/WO1991004940A1/en not_active Application Discontinuation
• 1992
  • 1992-03-25 NO NO921168A patent/NO308697B1/no unknown
  • 1992-03-27 FI FI921354A patent/FI921354A0/fi not_active Application Discontinuation

Non-Patent Citations (1)

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