MXPA98002944A - Anchorless life improvement for sterilizing mixtures of ethyl oxide - Google Patents

Abstract

A method for increasing the shelf life of a sterilizing mixture of ethylene oxide and one or more halocarbons when the mixture is in contact with iron oxide on the surface of a storage container. Sufficient carbon dioxide is added to the mixture to reduce the reactivity of iron oxide to convert ethylene oxide into reaction products of ethylene oxide. In an alternative embodiment a hollow carbon steel vessel is retained a mixture of ethylene oxide and a halocarbon as a sterilizing gas has its inner passivated surface forming a reaction product of iron oxide and carbon dioxide

Description

ANCHOREL LIFE IMPROVEMENT FOR STERILIZING MIXTURES OF ETHYLENE OXIDE BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to the field of sterilization gases and more particularly to sterilization based on the use of ethylene oxide.

Description of the Prior Art It is known in the art to sterilize articles by applying boiling water or steam to the article to be sterilized. However, in the medical field among others, there is a need to employ sterilizing compositions because many articles can not withstand the temperature or humidity associated with steam sterilization. Sterilization with a germicidal agent, such as ethylene oxide or ethylene oxide gas containing gas mixtures has played an important role in the materials of heating by sterilization or sensitive to moisture. Ethylene oxide is a widely used sterilant since both an inherently effective sterilant and its residues rapidly volatilize from the article to be sterilized. While ethylene oxide can only be used to carry out sterilization, this is not done because ethylene oxide is a highly flammable gas. Ethylene oxide forms explosive mixtures in air of about 3.0 volume percent to 100 volume percent ethylene oxide. In this way, when ethylene oxide is used alone as a sterilization gas, precautions such as explosion-proof equipment are necessary. Therefore, the ethylene oxide sterilizer is generally used in a mixture with a flame retardant. Gaseous sterilization of reusable medical and surgical equipment that uses a non-flammable mixture of ethylene oxide and a carrier gas has proven to be a reliable, cost-effective technology for many hospitals. The flame retardant component must complement the properties of ethylene oxide or the beneficial effects of ethylene oxide will be lost. The inert carrier gases inhibit the flammability of the ethylene oxide and provide sufficient autogenous vapor pressure to deliver the liquid mixture from the source cylinder to the heat exchanger of the sterilizer vessel wherein the liquid mixture vaporizes. The most typical flame retardant selected for use with ethylene oxide in a sterilizing mixture has dichlorodifluoromethane which is known in the industry as CFC-12. The most commonly used sterilizing mixture is a mixture of 12 weight percent ethylene oxide and 88 weight percent CFC-12. This mixture is commonly referred to in the industry as 12-88. In recent years, CFC-12 has become undesirable since it is a chlorofluorocarbon that is believed to cause significant damage to the ozone layer in the upper atmosphere. Consequently, the worldwide reduction and elimination of the use of CFC-12 is now underway. This has created a problem for the use of ethylene oxide as a sterilant. Another flame retardant known to be used with ethylene oxide is carbon dioxide. However, a non-flammable mixture of ethylene oxide / carbon dioxide contains less than 40 percent ethylene oxide per unit volume as does 12-88. In this way, the sterilization must be carried out either at higher pressures or during longer contact times. Additionally, the large difference in vapor pressures of ethylene oxide and carbon dioxide causes the mixture to separate as it is removed from the storage tank or cylinder, increasing the danger of delivering a sterilizing mixture rich in carbon dioxide. carbon, which will not sterilize, or rich in ethylene oxide. which is explosive As a result, improved sterilizing blends employing ethylene oxide and other flame retardant halocarbons have been developed. These are exemplified in U.S. Patents 5,342,579; 5,378,333 and 5,039,485 which are incorporated herein by reference. Although the main purpose of the inert carrier gas component in these sterilization gas mixtures is to mask the flammability characteristics of ethylene oxide, the simple substitution of an arbitrary non-flammable gas does not necessarily ensure a useful sterilization gas mixture. Almost universally, sterilizing mixtures employing ethylene oxide and a flame retardant halocarbide are produced in manufacturing facilities whose pipe and other containers comprise carbon steel. In addition, the sterilizing mixture is stored, transported and used in refillable pressure cylinders comprising carbon steel. Unfortunately, carbon steel eventually breaks down iron oxide. It has been found that this iron oxide, in both of its alpha and gamma forms, assists in the degradation of ethylene oxide to reaction products of ethylene oxide such as acetaldehyde, ethylene glycol, polyethylene glycol and other reaction products. These reaction products form oils, contaminate the sterilizing mixture, stain medical devices, seal lines and tubing and render the sterilizing mixture unusable. The storage life of the mixture is only a few months at best. It has now been unexpectedly found that when the surface of the containers in contact with the sterilizing mixture has been treated by exposure to carbon dioxide, the shelf life or shelf life is prolonged. There is a substantial decrease in the production of ethylene oxide reaction products and the sterilizing mixture has a substantially long shelf life. In another embodiment of the invention, the carbon dioxide gas is intimately mixed with the ethylene oxide and hydrohalocarbon. The carbon dioxide contained in this last mixture reaches the passivation of iron oxide in the container, avoids the subsequent staining, however, the general mixture retains its favorable properties sterilizers, non-explosive and flame retardant. This result using the ethylene oxide, halocarbon and carbon dioxide is surprising since, the use of carbon dioxide in sterilizing atmospheres has been shown to be a polymerization promoter. Tests have shown that ethylene oxide growth regimes are ten to twenty times faster in the presence of carbon dioxide than CFC-12. See Conviser, Stephen A., "Hospital Sterilization Using Ethylene Oxide - What's Next?", Journal of Healthcare Material Management, July 1989. Therefore, it would be desirable to provide an improved sterilizing mixture of ethylene oxide / hydrohalocarbon, which it has a substantially reduced production of unwanted reaction products of ethylene oxide. Additionally, sterilization is carried out with the composition of this invention at acceptable pressures and contact times and without unacceptable mixing separation during withdrawal from the storage cylinder.

SUMMARY OF THE INVENTION The invention provides a method for reducing the conversion of ethylene oxide to reaction products of ethylene oxide when said ethylene oxide is present in a mixture with one or more halocarbons and the mixture is disposed in contact with a surface from a container that contains iron oxide. The method comprises contacting the iron oxide-containing surface of the container with a sufficient amount of carbon dioxide under conditions! Sufficient to reduce its reactivity to convert ethylene oxide into reaction products of ethylene oxide. The iron oxide-containing surface of the container may be contacted with the carbon dioxide either before or during surface contact with the mixture of ethylene oxide and one or more halocarbons. The invention also provides a composition comprising an intimate mixture of ethylene oxide, one or more halocarbons and carbon dioxide. The invention further provides an article comprising a hollow carbon steel vessel, capable of receiving, retaining and dispensing a gas, which vessel has an inner surface comprising the reaction product of iron oxide and carbon dioxide. A mixture is contained in the container, which mixture comprises ethylene oxide and one or more halocarbons. The mixture may further comprise carbon axis dioxide.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY One embodiment of the invention provides a sterilant comprising a mixture of ethylene oxide, one or more halocarbons and carbon dioxide. The halocarbon may be a single halocarbon or a mixture of halocarbons. Preferably, the allocarbide is a hydrohalocarbon such as hydrofluorocarbon or hydrochlorofluorocarbon and more preferably a monochlorotetrafluoroethane, pentafluoroethane or dichlorotrifluoroethane. Suitable halocarbons include, but are not limited to, 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) 1,1,2,2, 2-petafluoroethane (HFC-125) 1,1,2,2, -tetrafluoroethane (HFC-134) 1,2,2, 2-tetrafluoroethane (HFC-134a) 1-chloro-l, 2,2,2 -tetrafluoroethane (HCFC-124) 1-chloro-l, 1,2, 2-tetrafluoroethane (HCFC-124a) chlorodifluoromethane (HCFC-22), dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), tetrafluoromethane (HFC-14), trifluoromethane) HFC- 23), heptafluoropropane (HFC-227) and hexafluoropropane (HFC-236). When the composition of the invention comprises each of ethylene oxide, one or more halocarbons and carbon dioxide, it comprises sufficient ethylene oxide to produce an effective sterilizing composition. It preferably comprises from about 6.3 to about 99 volume percent, and more preferably from about 14 to about 30 volume percent ethylene oxide. The ethylene oxide acts as the active sterilizer, while the halocarbon acts as a flame retardant. The composition comprises sufficient halocarbon to render the composition nonflammable. In order for a sterilizing mixture to be non-flammable, it must be non-flammable at all air concentrations, ie from 0 to 100 percent air. The composition preferably comprises from about 1 to about 94 volume percent, or more preferably, from about 70 to about 95 volume percent of halocarbon. At halocarbide concentrations less than the specified amount, sufficient flame retardancy in the mixture may not be present to avoid a potentially dangerous flammability situation, and at halocarbide concentrations greater than the specified amount, effective sterilization may not be possible without the use of undesirably high temperatures, pressures and / or contact times. The composition also comprises sufficient carbon dioxide to passively make the iron oxide on the inner surface of the container that makes contact with the mixture and reduces its reactivity with ethylene oxide to produce reaction products of ethylene oxide. The composition preferably comprises from about 0.1 to about 30 volume percent, or more preferably, from about 0.1 to about 10 volume percent carbon dioxide. The carbon dioxide in the mixture has also been found to increase the vapor pressure of the total mixture compared to a mixture without carbon dioxide. In the preferred embodiment, the vapor pressure of the mixture is such that a pump is not required to separate the mixture from its storage container. The preferred vapor pressure of the mixture ranges from about 1,687.36 kg / cm2 absolute to about 43.238.62 kg / cm2 absolute, or more preferably, from about 2.812.27 kg / cm2 absolute to about 24.607.35 kg / cm2 absolute, as measured at temperatures environmental, that is, at approximately 21aC. In an alternative embodiment of the invention, the interior surface of a container containing iron oxide is previously passivated by contact with carbon dioxide before loading the container with the sterilant. The carbon dioxide is charged to the vessel in a sufficient amount and for a sufficient reaction time to passivate the catalyst (iron oxide) and prevent converting the ethylene oxide to reaction products of ethylene oxide. These amounts can be easily determined by those skilled in the art. Useful amounts of carbon dioxide for this purpose can be that amount which reaches an internal container pressure ranging from about 0.1 atmospheres to about 10 atmospheres, however, this scale is not critical and can vary allowing more or less time to contact for passivation. A useful reaction time may vary from about 1 hour to about 48 hours, depending on the amount of carbon dioxide present. The sterilant may then comprise either a mixture of only the ethylene oxide and hydrohalocarbon as is known in the art, for example from the U.S.A. above, or the intimate mixture described above of ethylene oxide, halocarbon and carbon dioxide. The sterilant mixture of this invention can be used to sterilize medical equipment such as diagnostic endoscopes.; plastic items such as syringes; test tubes; incubators; step markers; rubber articles such as tubing, gloves, catheters and sheets; instruments such as needles and scalpels; and other items such as dilators, pumps and intraocular lenses. In addition, the sterilizing mixture of this invention can be used as a fumigator for articles outside the medical field. These items include certain food materials such as spices; skins, pads, art cu ^ O of paper and transport equipment such as cargo rep of airplanes, trains and ships.

The sterilant mixture of this invention is effective against insects, bacteria, viruses, molds, fungi and other unwanted microorganisms. The sterilant mixture of this invention can be prepared using any effective mixing technique well known to those skilled in the art. For example, each compound in the mixture can be pumped gravimetrically through a distributor into a sterilizing container, and the container rolled to intermix the compounds into a homogeneous mixture. Alternatively, the compounds can be pumped into a mixing tank, recirculated in the tank until a completely homogenous mixture is formed, and then pumped from the mixing tank into a sterilizer container. The sterilizing mixture of this invention can be packaged in storage containers of appropriate design such as those that are filled by Specification 4BA 240, 4BA 300, 4BW 240 of the United States Department of Transportation (DOT) or other work pressure cylinders or trailers. appropriate to the DOT specification. The sterilizing mixture can also be packaged in appropriate storage containers from the American Society of Mechanical Engineers (ASME). ¡1 storage cylinder can be delivered to the site of use by keeping the sterilizing mixture at a pressure generally within the range of approximately 4,921.47 to 13,358.27 gr / cm2 absolute at 21 aC, and connected through a series of valves, valves, Vaporizer control and appropriate conduit to a sterilizer to carry out the sterilization. The basic gaseous sterilization process consists in evacuating the sterilization chamber containing the articles to be sterilized, preconditioning the articles to an optimum relative humidity, admitting the sterilization gas at a pressure and appropriate temperatures, maintaining contact between the atmosphere of sterilization and the articles to be sterilized for an appropriate time, and finally discharge and evacuate the chamber to eliminate the sterilizing gas. The sterilizing mixture of this invention can be used with any commonly used sterilizer known in the art. Even though there are many variations in the basic process, the main factors that have to be controlled in order to effect sterilization are exposure time, temperature, ethylene oxide pressure or partial pressure and relative humidity. A description of conventional sterilization processes and apparatuses with which the gaseous sterilization agents of the invention are useful can be found in Principles and Methods of Sterilization, by J. J. Perkins, at 501-530 (2a., 1969); and Ethylene Oxide Gaseous Sterilization for Industrial Applications, Industrial Sterilization International Symposium, 181-208 (1972); Patents of E.U.A. 3,068,064 and 3,589,861. The sterilization chambers can vary in size from top-of-table to room-size models and even larger ones. After the items are placed inside the sterilization chamber, the chamber is generally heated to a temperature within the range of 38 ° C to 60 ° C. Generally, the higher the temperature, the shorter exposure time is required. After the chamber is brought to the operating temperature, a partial vacuum is drawn into the chamber by pumping air outward. The removal of air serves both to prevent dilution of the sterilizing mixture and to reduce the exposure pressure. Since a moisture microorganism is more susceptible to the action of the sterilant, water vapor is preferably used to create a relative humidity within the chamber in the range of about 20 to about 80 percent. The pressure at which the sterilization occurs within the chamber can be from about 1,406.13 to 2,812.27 gr / cm2 absolute. Sterilization time varies depending on a number of factors including temperature, concentration of humidity level, the specific sterilization mixture used, the chamber load, the bioburden, the desired safety level of sterility and the material being sterilized. For example, porous articles require shorter exposure time to achieve sterility than articles sealed in polyethylene bags. Additionally, some bacteria are especially resistant, and in this way, take more time to destroy themselves. Following the required exposure time, the sterilizing mixture is evacuated from the chamber by flooding with air, nitrogen, steam or carbon dioxide. The sterilized material is then removed from the chamber and, if necessary, aerated for the removal of residual sterilant, before use. The following non-limiting example serves to illustrate the invention.

EXAMPLE 1 Oxyfume 2000 is a mixture of 8.6 weight percent ethylene oxide and the rest HCFC-124 which is commercially available from AlliedSignal Inc. of Morristown, New Jersey. Oxyfume 12 is a mixture of 12.0 weight percent oxyethylene (J) of ethylene and the rest CFC-12 which is also available commercially from AlliedSignal Inc. of Morrietown, New Jersey This example demonstrates the reduction of the regime of development of non-volatile waste (NVR) in Oxyfume 2000 and the increase of vapor pressure as much as possible without significantly altering the product.A previously used kit of cylinders F, a flood of 100 milliliters with HCFC- is provided 124 pure to eliminate any residual NVR A normal fill density of Oxyfume 2000 of 115 percent and a nominal water fill weight of an empty F cylinder of 2890 grams allows a maximum of 3324 grams of mix in each container. filling of 3000 grams of mixture is selected for convenience of calculating and filling to scale.A series of cylinders is connected to a laboratory filling rack, evacuated and placed in a bath of ice on a scale weighing 30 kilograms. The cylinders are tared to zero and 258.5, 257.7 and 258.0 grams of ethylene oxide vapor condenses to the cylinders numbered F-9982, F-1531 and F-634235E respectively. The cylinders are then carried to 3000.9, 3000.3 and 3000.5 grams of total weight respectively, transferring the liquid phase of HCFC-124 to each container. Condensed ethylene oxide vapor is used in all steps to minimize any contaminant load from the cylinder of origin. The percentages by weight of ethylene oxide for the cylinders are 8.61, 8.59 and 8.59, respectively. Each cylinder is rotated for 15 minutes to ensure complete mixing. Immediately after mixing, 0.45 percent by weight (1.15 mole percent) of carbon dioxide is added to the cylinders F-9982 and F-1531 to determine if the development of NVR could be slowed down or prevented. F-1531 is selected for the addition of carbon dioxide, because it previously showed significant polymer development. F-9982 is also selected for the addition of carbon dioxide. The cylinders are again mechanically stirred to ensure complete mixing. Then the cylinders are returned to ambient temperatures and the vapor pressure is measured by gauge which is approximately 2,179.51 gr / cm2 gauge. The first NVR test is done the next day.

Non-Volatile Residue Measurement The following procedure is used to make the NVR determinations. Twelve beaker glasses of 150 mL size cleaned with detergent and dried beakers in an oven at 105 ° C. The pointed vessels are allowed to cool in a dryer for at least 30 minutes. Weigh beakers are weighed on an analytical balance to the nearest 0.1 mg. The weight of the mixing cylinders and the discharge of approximately 100 grams each of liquid to three beakers from each cylinder. The liquid is allowed to evaporate under a hood. The three unused weighted vessels act as controls. The mixing cylinders are weighed again. After all the liquid has evaporated, the beakers are placed in a 105SC oven for 15 minutes. The pointed vessels are allowed to cool in a dryer for at least 30 minutes. Weigh beakers are weighed on an analytical balance to the nearest 0.1 mg. The number of milligrams of NVR per 100 grams of Oxyfume 2000 contained in the product discharged from the cylinders is calculated.

Results A summary of the number of milligrams of NVR experimentally found per 100 grams of product is determined for the test cylinders as a function of days at 21 degrees Celsius and is given in Table II. Table 1 is a control test of a similar composition without carbon dioxide for comparison purposes. In all cases, the liquid samples observed in the weeping vessel were clear, colorless and very mobile. The final NVR levels were 5.71 + 0.26, 11.39 ± 0.57 and 31.16 ± 0.66 milligrams per 100 grams of Oxyfume 2000 for cylinders F-9982 (carbon dioxide), F-1531 (carbon dioxide) and F-634235E (without Carbon Dioxide) respectively. The results obtained from the comparative round of tests without any carbon dioxide were 13.3 + 0.5, 45.1 ± 1.8 and 20.4 +0.1 milligrams per 100 grams of Oxyfume 2000 for the cylinders F-9982, F-1531 and F- 634235E, respectively. The results of the first test (without carbon dioxide - Table I) will be recorded as (1) and the second test (with carbon dioxide - table II) as (2). The cylinder F-634235E was actually used as a control for the two tests. The controls for tests (1) and (2) were conducted with only Oxyfume 2000. A comparison of results (1) and (2) for cylinder F-634235E shows a very similar growth regime. This is notorious since the second test in a series generally shows a reduction in NVR growth due to the internal passivation of the first test. This is known as the flood and fill effect. There is no total appearance of this effect in this series since the results of day 160 are approximately the same.

The most dramatic results were obtained with F-1531. Test 81) showed a rapidly accelerating growth regime that would render the product unusable. test (2) is clearly under control with a much slower growth regime. The results of the test (1) of the cylinder F-9982 were the best of that series. In test 82) the NVR is further reduced to even lower levels. A general comparison of tests (2) and (1) for cylinders F-9982 and F-1531 shows an approximately 50 percent reduction in NVR growth regimen. These are excellent results and make the Oxyfume 2000 regimen comparable to the Oxyfume regimen 12. An additional benefit to this method is an increase of approximately 12 percent in vapor pressure at room temperature. It is evident from these results that the addition of carbon dioxide to Oxyfume 2000 reduces the regimen of NVR growth. For comparison, in the absence of carbon dioxide, the NVR growth regimen of Oxyfume 2000 is approximately twice the NVR growth rate of Oxyfume 12. The reduced regimen compares favorably with the NVR growth regimen of Oxyfum? 12 TABLE 1 (Test 1 - Comparison - All Cylinders Without Carbon Dioxide) Summary of Data from Experimental NVR Determinations (milligrams of NVR per 100 grams of Oxyfume 2000) Time Trans-Cylinder Cylinder Cylindrical curled (days) F-9982 F- 1531 F-634235E 1 1.1 + 0.2 0.6 + 0.2 0.9 + 0.1 34 2.5 + 0.3 1.9 + 1.4 1.4 + 0.6 69 3.9 + 0.1 14.1 + 1.1 7.0 + 1.4 99 8.9 + 0.2 27.9 ± 0.4 11.6 + 1.0 133 11.3 + 0.8 36.2 + 3.5 15.0 ± 0.6 162 13.3 + 0.5 45.1 ± 1.8 20.4 + 0.1 All samples were triple determinations with a blank correction. All cylinders are stored at 21 degrees Celsius. The results of day 34 were calculated without a blank correction.

TABLE II Summary of Experimental NVR Determination Data (milligrams of NVR per 100 grams of Oxyfume 2000) Time Trans- Cylinder Cylinder Cylindrical cylinder (days) F-9982 F-1531 F-634235E (p / C02) (p / C02) (p / o C02) 1 0.47 + 0.17 0.64 + 0.66 0.53 + 0.30 32 1.01 ± _0.27 1.67 ± 0.46 1.97 + 0.24 57 0.94 ± 0.19 1.74 + 0.16 2.78 + 0.08 86 1.69 ± 0.58 3.31 + 0.45 5.83 + 0.51 120 2.94 + 0.64 5.79 ± 0.32 10.26 + 0.38 149 2.92 + 0.56 6.24 + 0.12 16.42 + 0.62 179 5.75 + 0.26 11.39 + 0.57 31.16 + 0.66 All samples were triple determinations with a blank belt. all cylinders were stored at 21 degrees Celsius.

EXAMPLE 2 This example demonstrates a pre-treatment (passivation) of the inner surface of a cylinder surface. A container such as a pressure cylinder, tank or truck is purged with nitrogen gas to remove residual air and moisture. Purging with nitrogen is done to remove air and moisture to reduce flammability and contamination. The removal of moisture is important since water can hydrolyze ethylene oxide to ethylene glycol, the first step of polymerization. The purge with nitrogen is carried out by filling the vessels to two or three atmospheres with nitrogen from the process (99.5% or better purity). The nitrogen is then vented. Filling with nitrogen is usually repeated two or three times. The containers are evacuated to a negative pressure of 68.58 centimeters of mercury. The containers are then filled at a pressure of two atmospheres with carbon dioxide. They are allowed to stand overnight (sixteen hours) to passivate the interior surface of the container. The containers can then be treated in one of two ways. The carbon dioxide can be left in the container and a mixture of ethylene oxide and HCFC-124 can be filled directly into the container. Alternatively, the vessel was evacuated and filled with a mixture of carbon dioxide, ethylene oxide and HCFC-124. The process for preparing a mixture of ethylene oxide and HCFC-124 typically involves the use of a mixing tank of 2, 268 kilograms (or more) mounted on a scale platform. Ethylene oxide and HCFC-124 are added separately to this tank by pumping from rail cars, storage tank or portable containers of origin. The mixture is produced by weighing the appropriate amounts of ethylene oxide and HCFC-124. The batch is then mixed by a circulation pump. This mixed product is then pumped into previously evacuated containers. For a mixture of carbon dioxide, ethylene oxide and HCFC-124, this approach should be modified slightly to allow the addition of the appropriate weight of carbon dioxide after HCFC-124 is added to the mixing tank. Then the normal circulation would completely mix the product. The mixed product can then be transferred to evacuated cylinders or trucks for distribution and use.

Claims (10)

CLAIMS:

1. - A method for increasing the shelf life or storage of a mixture of ethylene oxide and one or more halocarbons when the mixture is in the presence of iron oxide, which comprises adding carbon dioxide to the mixture in an amount sufficient to reduce the reactivity of iron oxide to convert ethylene oxide into reaction products of ethylene oxide.

2. The method of claim 1, wherein the one or more halocarbons comprises one or more components selected from the group consisting of monochlorotetrafluoroethanes, dichlorotrifluoroethanes, pentafluoroethanes, tetrafluoroethanes, heptafluorpentanes and hexafluorpropanes.

3. A method for reducing the conversion of ethylene oxide to reaction products of ethylene oxide when said ethylene oxide is present in a mixture with one or more halocarbons and the mixture is placed in contact with a surface of a container that contains iron oxide, which method comprises contacting the iron oxide containing surface of the container with a sufficient amount of carbon dioxide under conditions sufficient to reduce its reactivity to convert ethylene oxide to reaction products of ethylene oxide. .

4. The method of claim 3, wherein the iron oxide-containing surface of the container is contacted with the carbon dioxide prior to contacting the surface with the mixture of ethylene oxide and one or more halocarbons.

5. The method of claim 3, wherein the iron oxide-containing surface of the container is contacted with the carbon dioxide during surface contact with the mixture of ethylene oxide and one or more halocarbons.

6. The method of claim 3, wherein the iron oxide-containing surface of the container is contacted with the carbon dioxide both before and during surface contact with the ethylene oxide mixture and one or more halocarbons.

7. A composition comprising an intimate mixture of ethylene oxide, one or more halocarbons and carbon dioxide.

8. The composition of claim 7, comprising from about 6.3 to about 99 volume percent of ethylene oxide; from about 1 to about 94 volume percent of one or more halocarbons; and from about 0.1 to about 30 volume percent carbon dioxide.

9. The composition of claim 7, wherein the one or more halocarbons comprises one or more components selected from the group consisting of monochlorotetrafluoroethanes, dichlorotrifluoroethanes, pentafluoroethanes, tetrafluoroethanes, heptafluorpentanes and hexafluoropropanes.

10. An article comprising a hollow container capable of receiving, retaining and dispensing a gas, the container having an interior surface comprising the reaction product of iron oxide and carbon dioxide; and a mixture disposed in the container, which mixture comprises ethylene oxide and one or more halocarbons.