Use of low gwp refrigerants comprising cf3i with stable lubricants

Abstract

The invention pertains to heat transfer compositions, particularly to automobile refrigerants comprising a hydrofluoroalkene, an iodocarbon, and at least one lubricant having hydrogen atoms and carbon atoms, wherein no more than 17% of the total number of hydrogen atoms which are attached to a carbon atom are tertiary hydrogen atoms.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of U.S. provisional patent application Ser. No. 60 / 865,659 filed on Nov. 14, 2006, which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention pertains to heat transfer compositions. More particularly the invention relates to automobile refrigerants comprising a hydrofluoroalkene, an iodocarbon, and at least one lubricant having hydrogen atoms and carbon atoms, wherein no more than 17% of the total number of hydrogen atoms which are attached to a carbon atom are tertiary hydrogen atoms.[0004]2. Description of the Related Art[0005]Compositions containing iodocarbon compounds have been disclosed as being particularly useful as heat transfer fluids. For example, international application PCT / US05 / 46982, filed Dec. 21, 2005, which is incorporated herein by reference, discloses compositions containing one or more fluoroolefins and the iodocar...

AI Technical Summary

Benefits of technology

[0014]Applicants have found that such EO / PO molecules, which are also referred to herein as “dual capped EO / PO molecules” due to the presence of the methyl radical on each end of the molecule, or alternatively other relatively low chain length alkyl group” can provide the ability to adjust, to suit each particular application, the n and the m values. In this way, a lubricant molecule can be selected to achieve a highly advantageous combination of miscibility and stability. An advantage that dual capped molecules perform substantially better in many respects and similar molecules which are only capped at one end, as illustrated in the examples below. U.S. Pat. No. 4,975,212, which is incorporated herein by reference, discloses techniques for capping molecules of this type. Although it is not generally preferred, is also possible to combine the preferred lubricants of the present invention with one or more conventional lubricants.

Problems solved by technology

However, iodinated compounds, such as trifluoroiodomethane, tend to be relatively unstable, and often significantly less stable than certain CFCs, HCFCs and HFCs, especially under conditions that tend to occur in heat transfer systems in general and in refrigeration / air conditioning systems in particular.

Although compositions containing iodocarbons, and in particular CF3I, can have substantial advantages when used in heat transfer applications, the use of such compositions presents heretofore unencountered and / or unrecognized problems.

By way of example, compositions comprising iodocarbons, particularly compositions which comprise fluorinated olefins and iodocarbons, are frequently involved in a relatively complex chemical system under conditions of use, particularly as heat transfer fluids, that can cause unexpected results.

While compositions containing stabilizers for trifluoroiodomethane may enjoy a certain degree of success the use of a stabilizing agent alone may leave several embodiments of such compositions practically ineffective for use in commercially acceptable heat transfer systems.

Furthermore, the stabilizing agent can contribute to unwanted and / or undesirable reactions in heat transfer systems.

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