Abstract:
Provided are fluorinated polyethers and polyether oils and methods of preparation. The preparation involves a catalytic oxidation process of fluorinated vinyl ethers employing free oxygen.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/975,700, filed Sep. 27, 2008, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     SUMMARY 
       [0002]    The present description relates to fluorinated polyethers and polyether oils and methods of preparation. In particular the present description relates to fluorinated polyether oils, which may contain end groups like esters, acid halides, acids, ethers or the like. 
         [0003]    Fluorinated, especially highly fluorinated, polyethers and polyether oils have a number of industrial uses, including, for instance, as lubricating oils for high temperature applications. For these applications the initially made fluorinated polyether or polyether oils may be stabilized, for instance, by the introduction of appropriate end groups. 
         [0004]    The present description provides, in one aspect, a process comprising reacting a vinyl ether of the formula (I) 
         [0000]      R f —O—CF═CF 2    (I) 
         [0000]    wherein R f  is a fluorinated linear or branched aliphatic group, with an oxygen-containing gas in the presence of a Lewis acid catalyst to yield a fluorinated polyether oil. The fluorinated polyether oil may be stabilized and/or end capped to enhance its performance in high temperature applications. 
         [0005]    In another aspect, the present description provides a process comprising reacting a vinyl ether of formula (I) 
         [0000]      R f —O—CF═CF 2    (I) 
         [0000]    wherein R f  is a fluorinated linear or branched aliphatic group, with an oxygen-containing gas in the presence of a graphite intercalated by a Lewis acid catalyst (such as SbF 5 ) to yield a fluorinated polyether oil. 
     
    
     DETAILED DESCRIPTION 
       [0006]    It has been found that fluorinated vinyl ethers may react with oxygen to yield fluorinated polyether oils. The reactions described herein may be carried out in the presence of an oxygen-containing gas and a Lewis acid catalyst. 
         [0007]    Oxygen-containing gas includes, for instance, pure oxygen, oxygen diluted in a non-reactive carrier gas such as nitrogen, and air. Other oxygen delivering materials such as, for example, inorganic peroxo compounds may be used as well. 
         [0008]    In some embodiments, fluorinated vinyl ethers described herein are those having the formula (I) 
         [0000]      R f —O—CF═CF 2    (I) 
         [0000]    wherein R f  is a fluorinated linear or branched aliphatic group. By aliphatic group, it is meant an alkyl group, an aryl group, a cycloalkyl group, an aralkyl group, a cyclic aralkyl group, and the like. Any of these groups may optionally be interrupted by one or more oxygen atoms. By “interrupted by one or more oxygen atoms”, is meant that the aliphatic groups may contain ether linkages. 
         [0009]    In particular embodiments, fluorinated vinyl ethers described herein are those having an R f  according to the formula (III) 
         [0000]      A-(OCF(R 2   f )CF 2 ) n —(O(CF 2 ) m ) p —  (III) 
         [0000]    where each n is from 0 to 10, each m is from 1 to 10, each p is from 0 to 10, A is selected from X and XC a F 2a , where X is a halogen, hydrogen, or a functional group such as SO 2 Y (with Y being F or Cl) or COOR′ with R′ being lower alkyl like methyl or ethyl, and a is from 1 to 10, and R 2   f  is a fluorinated aliphatic group of from 1 to 10 carbon atoms. It should be understood that, as used in formula (III) where the phrase “each m is from 0 to 10” is used, it is meant that if p is greater than 1, then each value of m included in a repeated unit p is independently chosen from 1 to 10. Not all values of m in a given molecule need be the same. For instance, for a particular embodiment of formula (III): 
         [0000]      CF 3 —(OCF(CF 3 )CF 2 ) n —(OCF 2 )—(OCF 2 CF 2 CF 2 )— 
         [0000]    p is equal to two, R 2   f  is CF 3 , and therefore there are two values for m, in this instance, one is 1 and the other is 3. Accordingly, each is selected from 1 to 10, but not every value of m is the same. 
         [0010]    In particular embodiments of formula (III), X may be F and a may be from 1 to 4. In such embodiments, the terminal chain length of the R f  group is not more than four carbons long. Examples of such embodiments include, for instance, CF 3 —O—(CF 2 ) 3 —O—, corresponding to the fluorinated vinyl ether CF 3 —O—(CF 2 ) 3 —O—CF═CF 2 . 
         [0011]    In yet further embodiments, X is F, a is from 1 to 4, and m is from 1 to 4. Other embodiments include those in which n is 0. In such cases, the corresponding vinyl ether is a linear vinyl ether that contains no R 2   f  groups. 
         [0012]    Additional embodiments of formula (III), and thus the vinyl ethers of formula (I), include those wherein X is Br. When X is Br, for instance, the vinyl ether described can be further functionalized. Such further functionalization may take place either before or after the reaction of the vinyl ether of formula (I) to yield a fluorinated polyether oil. 
         [0013]    Such further functionalization may include grafting onto a fluorinated polyether oil. Such grafting reactions may self-stabilize the fluorinated polyether oil. Accordingly, the result may be a functionalized fluorinated polyether oil containing grafted units. Such functionalized polymers may themselves be useful as surfactants in emulsion polymerization reactions of fluorinated monomers (optionally copolymerized with non-fluorinated monomers). One potential advantage to such functionalized fluorinated polyether oils may be that the resultant fluorinated polymers from the emulsion polymerization reactions may have low levels of extractable materials. 
         [0014]    When X is Br, the resultant fluorinated polyether oils may further present an ability for the resultant fluorinated polyether oils to act as a surfactant in the polymerization of fluorinated monomers (optionally copolymerized with non-fluorinated monomers). Such brominated fluorinated polyether oils may act as a chain transfer agent in the polymerization reactions described. As a result, such polymerization reactions may lead to fluoropolymers of lower molecular weight than fluoropolymers prepared in the presence of non bromine-containing fluorinated polyether oils. 
         [0015]    In further particular embodiments, X is F. When X is F, the fluorinated polyether oil may be relatively stable to further reactions. 
         [0016]    The fluorinated vinyl ethers described by formula (I) and further described in formula (III) may be converted to a fluorinated polyether oil by reaction with an oxygen-containing gas in the presence of a catalytic amount of Lewis acid catalyst (which catalyst may be selected from, for instance, SbF 5 , and may further intercalated into a non-reactive substance such as graphite). In some embodiments, the fluorinated vinyl ethers described by formula (I) may be converted to fluorinated polyether oils consisting of repeating fluorinated units and end groups according to one or more of the following formulae: 
         [0000]      —(CF 2 —CF(OR f )—O)— —(CF(O—R f )—O)— —(CF 2 —O)— —O— -A —(COZ) 
         [0000]    wherein R f  has the same meaning as above, A is perfluoroalkyl, perfluoroalkoxyalkyl, and Z may be halogen, especially fluorine, —OM wherein M may be a metal ion chosen from the group of e.g. alkali metal ion, and OR wherein R may consist of lower alkyl with up to 6 carbon atoms. The combination of the above described groups is random and thus may include peroxidic groups. The molecular weight of the fluorinated polyethers derived from the combination of the above described groups may be from 500 to up to 30000. 
         [0017]    In yet further embodiments, the present description relates to reacting a plurality of chemically distinct vinyl ethers to provide the fluorinated polyether oils described herein. Such processes may include, for instance, methods wherein the fluorinated oil has the general formula: 
         [0000]      A-(O) s —(CF 2 ) t —(CF 2 —CF(OR f )—O) p —(CF(O—R f )—O) q —(CF 2 —O) r —(CF 2 ) t —COZ 
         [0000]    wherein each R f  is defined as above, A is R 3 f, with R 3 f being perfluoroalkyl or perfluoroalkoxyalkyl or COZ, p,q, and r are independently chosen from 0 to 100, s and t being independently 0 or 1 and Z is defined as above. The general formula is meant to illustrate the scope of functional groups which may be present in the fluorinated polyether oil but is not understood to be limiting to the actual scope of functional groups which may be considered by a person skilled in the art. 
         [0018]    The processes described herein may include reacting the vinyl ethers described herein with one or more additional fluorinated monomers. In further embodiments, the additional fluorinated monomer is selected from hexafluoropropylene, tetrafluoroethylene, perfluoro(alkyl allyl)ether, perfluoro(alkoxyalkyl allyl)ether, and combinations thereof. 
         [0019]    In particular embodiments wherein an additional fluorinated monomer is reacted with the vinyl ethers described, the fluorinated polyether oil may additionally contain repeating fluorinated units according to one or more of the following formulae: 
         [0000]      —(CF 2 CF 2 —O)— —(CF(CF 3 )CF 2 —O)— —(CFCF 3 —O)— —(CF(CF 2 OR f )CF 2 —O)— —(CF(CF 2 OR f )—O)— 
         [0000]    wherein each R f  is a fluorinated linear or branched aliphatic group which may contain ether links. The above described groups may be randomly incorporated in the general formula for the fluorinated polyether oil as shown below 
         [0000]      A-(O)s-(CF 2 ) t —(CF 2 —CF(OR f )—O) p —(CF(O—R f )—O) q —(CF 2 —O) r —(CF 2 CF 2 —O) u —(CF(CF 3 )CF 2 —O) v —(CFCF 3 —O) w —(CF(CF 2 OR f )CF 2 —O) x —(CF(CF 2 OR f )—O) y —(CF 2 ) t —COZ 
         [0000]    wherein each of p, q, r, s, t, A, and Z independently has the same meaning as above and each of u, v, w, x, and y are independently chosen from 0 to 100. 
         [0020]    The conclusion of reacting at a reaction temperature, a vinyl ether with an oxygen-containing gas, as described herein, may be characterized by a negligible exotherm and an unusual pressure increase indicating the cessation of consumption of the oxygen-containing gas by the reaction system. Another test for whether the end of the reaction has been reached may be a pressure drop after the oxygen line has been closed; so long as a pressure drop is observed, the reaction is not complete and the oxygen-containing gas may be further fed into the reaction system. 
         [0021]    In the present processes, also produced in the reaction are co-products such as, for example, acid fluorides. Due to the toxicity and high reactivity of acid fluoride co-products, it may be preferable to carry out separation of the fluorinated polyether oil from other reaction co-products not on an acid fluoride itself, but on an acid fluoride derivative. Suitable derivatives are known to those skilled in the art and include carboxylic acids, esters, amides, and carboxylate salts. 
         [0022]    The separation of the fluorinated polyether oils and the reaction co-products (such as acid fluorides) (sometimes referred to in the art as the “work up”), may include, for instance, first adding a nucleophilic compound capable of forming an acid fluoride derivative. For instance, to form an ester, an aliphatic alcohol may be added. To form a carboxylic acid or carboxylate salt, water may be added and the pH may be adjusted accordingly. To form an amide, ammonia or a primary or secondary an amine may be added. 
         [0023]    In one embodiment, separation of the fluorinated polyether oils and co-products (such as acid fluorides) may be accomplished by pumping aqueous metal hydroxide (for instance, potassium or sodium hydroxide) solution into the reactor in an amount to ensure that the resultant pH value of the reactor is greater than 7 after the feed. In this embodiment, the reactor content separates into three phases. The lower most aqueous phase contains a carboxylate salt derivative of the acid fluoride. This later may be separated from the other two layers. Further reaction of the separated lower phase with methanol, water, and acid, followed by flash distillation, may result in a further two phase distillate. The upper phase of the distillate may be returned to the distillation flask, while the lower phase may be separated to yield the ester, for instance, by subsequent fractionation. In general, the work-up further yields a heavy phase with high viscosity which contains the desired fluorinated polyether oil. 
         [0024]    Lewis acid catalysts described herein may be any type of Lewis acid catalyst known in the art. Such catalysts include, for instance, boron-containing Lewis acids. Boron-containing Lewis acids include those of the general formula BZ 3 , where Z is selected from F and an alkoxide (e.g., BF 3 , B(OCH 3 ) 3 , etc). From a practical standpoint, one of ordinary skill in the art will recognize the preference to use Boron-containing Lewis acids with oxygen-containing solvents such as alcohols and ethers. The Boron-containing Lewis acids themselves may be a gas under normal handling conditions, such gas may give off toxic or otherwise undesirable fumes. Furthermore, the Lewis acid-solvent liquid complexes may be easier to handle. 
         [0025]    In some embodiments, the Lewis acids may be intercalated into a non-reactive material. Such non-reactive materials include graphite. For instance, when the Lewis acid SbF 5  is used, it may be intercalated into graphite. Neat SbF 5  produces fumes and may not be easy to handle. Accordingly, by intercalating SbF 5  into graphite, the present invention provides a catalyst system that is easier and safer to handle than neat SbF 5 . In some further embodiments, using a Lewis acid intercalated into a non-reactive material may allow for better temperature control during the reaction of the vinyl ether with the oxygen-containing gas, thereby avoiding or at least minimizing the resultant exotherm, putting less stress on the reactor system and allowing a more uniform reaction condition (e.g., avoiding localized heating and temperature spikes during reaction). 
         [0026]    Surprisingly, the present description shows that such intercalated Lewis acid catalysts display suitable reactivity despite their intercalation into non-reactive media. 
         [0027]    A catalytic amount of Lewis acid catalyst may be used in the processes described herein. A catalytic amount may be, for instance, from 0.01 to 20 mol %, based upon the amount of vinyl ether used in the reaction. 
         [0028]    In one embodiment, the process relates to reacting a vinyl ether of formula (I) with an oxygen-containing gas or oxygen delivering substance like inorganic peroxides (also referred to herein as inorganic peroxo compounds) in the presence of a Lewis acid catalyst to yield a fluorinated polyether oil. In yet further embodiments, the reaction may be carried out at from −30° C. to 200° C., from −20° C. to 150° C., or from −10° C. to 100° C. In some embodiments, the temperature is kept as low as possible to yield reaction of the vinyl ether with the oxygen containing gas. Maintenance of a low temperature may help to inhibit explosion of the oxygen-containing reaction system (due to rapid exothermic heat generation, combustion of reactor constituents, or a combination thereof). Thus, in some embodiments, it may be preferred that the temperature of the reactor is controlled during the reaction. In particular, it may be preferred to keep the temperature of the reactor within 50° C. of the starting temperature, within 30° C. of the starting temperature, within 10° C. of the starting temperature, even within 2° C. of the starting temperature. 
         [0029]    In other embodiments, when a catalytic amount of graphite intercalated by SbF 5  is used as the Lewis acid catalyst, control of the reaction temperature may not be as critical. However, it may be observed in some embodiments that the use of graphite intercalated by SbF 5  allows for a high degree of control over the reaction temperature, for instance, keeping the reaction temperature within 5° C. of the starting temperature. 
         [0030]    The oxygen pressure in the reactor is, in principle, not critical for the reaction and may vary from negligible amounts to several bar. But, according to the potential risk of explosion caused by the uncontrolled reaction of the vinyl ether with oxygen, it is preferred to keep the oxygen pressure as low as possible without limiting the rate of reaction. 
         [0031]    In some embodiments, the processes described herein may yield improvements in the production of fluorinated polyether oils. For instance, the processes described herein may allow for improved conversion of vinyl ether to the corresponding fluorinated polyether oil. Furthermore, by allowing for better control of reaction temperature, some embodiments of the processes described herein lower the risk of explosion. 
         [0032]    The fluorinated polyether oils made by the process described above may be used as such, but may also be stabilized before use to remove any existing peroxidic groups and to replace the end groups COZ by e.g. fluorine or halogen resulting in fluoroalkyl or halogen containing fluoroalkyl groups. Such stabilization may be carried out by methods described in the literature and is well known by persons skilled in the art. COZ end groups may be converted to amide end groups like CONH 2 , CONHR, and CONR 2  by well known methods. 
         [0033]    Applications of the fluorinated polyether oils include, optionally after further treatment according to the intended use, the use as oils, hydraulic liquids, heat carrier fluids, working fluids, coating materials, ionic liquids, and the like. 
       Examples 
     General Description of the Procedure 
       [0034]    The reactions were, unless otherwise noted, carried out in a stainless steel pressure vessel. The reactor was equipped with a stirrer, heating/cooling jacket, and temperature and pressure probes. 
         [0035]    The dry reactor was flushed with nitrogen to remove oxygen. The vinyl ether was pumped into the reactor. The addition of the catalyst depended on the physical state of the compound. Solids were placed in the reactor before flushing with nitrogen, liquids were pumped in, and gases were added via a line directly from the cylinder. 
         [0036]    Where noted, the reactor was pressurized with nitrogen to dilute the oxygen fed later. 
         [0037]    The stirrer was started and adjusted to the desired speed rate. 
         [0038]    After heating the reactor to the predetermined reaction temperature, oxygen was fed to the reactor. Usually less than 1 bar pressure increase was allowed on the initial oxygen feed. 
         [0039]    Start of the reaction was indicated by an exotherm and pressure drop. The reaction generally did not start immediately. There was a delay observed which varied from several minutes to several hours. 
         [0040]    As soon as the reaction had started, the oxygen feed was resumed. During the oxygen feed a pressure increase was observed which was not caused by the oxygen feed but mainly by the formation of fluorophosgene as side product. 
         [0041]    The feed rate of oxygen was controlled to ensure a low oxygen content in the reactor. The end of the reaction was indicated by a negligible exotherm and an unusual pressure increase. 
         [0042]    Another indicator for the end of reaction was a pressure drop upon closing the oxygen feed. As long as the pressure drop was observed, the reaction was continuing and thus the oxygen feed was resumed. 
         [0043]    After the end of the oxygen feed, the reactor was cooled to room temperature followed by a work-up procedure. Due to the toxicity and the high reactivity of acid fluoride co-products, a direct purification of the acid fluorides was not desirable although it is in principle possible, e.g. by fractional distillation. If fractional distillation is used as work up procedure, the fluorinated polyether oil is separated as high boiling residue which may be converted further according to the desired stabilization procedure. 
         [0044]    The following work-up procedures were used to separate the fluorinated polyether oil from the reaction mixture:
       a) Aqueous potassium hydroxide solution was pumped into the reactor in an amount to ensure a pH value of greater than 7 after the feed. The reactor contents formed three phases. The two aqueous phases contain the fluorinated acid salt formed in the oxidation reaction and the potassium fluoride formed in the saponification reaction. The third phase consists of a heavy phase with high viscosity which contained the desired fluorinated polyether oil. The crude fluorinated polyether oil may be separated from the aqueous phases by phase separation.   b) Excess of alcohol (e.g. methanol) was pumped into the reactor at room temperature. The conversion caused an exotherm which was controlled by cooling. Addition of water resulted in two phases which were separated. The lower phase contained the fluorinated polyether in addition to fluorinated esters and acids. The lower phase was reacted with methanol, water, and sulphuric acid, followed by a flash distillation. After removal of the volatile fluoro-organic material by distillation, a two phase residue remained in the distillation flask. The lower viscous phase contains of the crude fluorinated polyether oil.   c) Alcohol was added to the reactor according to b). Trialkylamine (e.g. trimethylamine) was pumped into the reactor in a molar amount that was close to one third of the generated HF. Where indicated, water was further added to the mixture. The reaction mixture consisted of two phases. The lower phase contained the fluorinated polyether in addition to fluorinated esters and acids. The lower phase was reacted with methanol, water, and sulphuric acid, followed by a flash distillation. After removal of the volatile fluororganic material by distillation, a two phase residue remained in the distillation flask. The lower viscous phase contains of the crude fluorinated polyether oil.       
 
       Example 1 
       [0048]    4854 g CF3O(CF 2 ) 3 OCF═CF 2  (MV31) was reacted with 304 g oxygen, and 10.5 g SbF 5 /graphite (50% SbF 5 ) at 85° C. Work up according to procedure b) including fractionation resulted in 264 g high boiling fluorinated polyether oil. 
       Example 2 
       [0049]    Example 1 was repeated using 3977 g MV31, 244 g oxygen, and 10.9 g SbF 5 /graphite at 75° C. Work up including fractionation resulted in 253 g high boiling fluorinated polyether oil. Viscosity of the degassed oil was 0.08 Pa·s at a shear rate of 20 l/s (20° C.). 
       Example 3 
       [0050]    3264 g MV31 was reacted with 200 g of oxygen. 18 g of BF 3  was used as catalyst. The reaction temperature was 80° C. Work up according to method b) including fractionation resulted in 360 g high boiling fluorinated polyether oil. Viscosity of the degassed oil was 29 Pa·s at a shear rate of 20 l/s (20° C.). 
       Example 4 
       [0051]    Example 3 was repeated using 3734 g MV31, 220 g of oxygen and 14 g BF 3  at 75° C. Work up according to method b) resulted 394 g high boiling fluorinated polyether oil. 
       Example 5 
       [0052]    Example 3 was repeated using 3582 g MV31, 240 g oxygen, and 14 g BF 3  at 85° C. Work up according to method b) gave 405 g high boiling fluorinated polyether oil. 
       Example 6 
       [0053]    3778 g MV31, 228 g oxygen, and 4 g BF 3  were reacted at 85° C. Work up according to method c) using 1558 g methanol and 642 g triethylamine, followed by a flash distillation of the lower phase resulted in 433 g of high boiling fluorinated polyether oil. Viscosity of the degassed oil was 4.1 Pa·s at a shear rate of 20 l/s and 3.9 at a shear rate of 50 l/s (20° C.). 
       Example 7 
       [0054]    3582 g MV31 and 216 g oxygen were reacted in the presence of 40 g B(OCH 3 ) 3  and 60 g of methanol at 85° C. Work up by method c) using 1600 g methanol and 640 g triethylamine resulted in a two phase mixture. The phases were separated and the upper phase was diluted with about 20 weight % of water. The resulting lower phase was combined with the lower phase from the reactor resulting in a total amount of 3554 g. Flash distillation in the presence of water methanol and sulphuric acid gave 322 g high boiling fluorinated oil. 
       Example 8 
       [0055]    3581 g MV31, 248 g oxygen, 16 g BF 3 , and 9 g water were reacted at 85° C. Work up with 1600 g methanol and 641 g triethylamine resulted in 3552 g lower phase after addition of water to the upper phase. Flash distillation according to Example 7 gave 403 g high boiling fluorinated oil isolated as lower phase after removal of all volatile fluoroorganic material. 
       Example 9 
       [0056]    3577 g MV31, 240 g oxygen, and 10 g BF 3  were reacted at 85° C. The resulting acid fluoride containing mixture reacted at 20-40° C. with 3000 g of 40% aqueous KOH (method a)) resulting in a three phase product mixture consisting of two aqueous phases and a heavy fluoroorganic phase. The aqueous phases were separated. The remaining non aqueous fluorinated phase contained fluorinated polyether oil. 
       Example 10 
       [0057]    87.9 kg MV31 was reacted with 5.5 kg oxygen in the presence of 554 g BF 3  and 100 g methanol at 85° C. Work up was carried out according to c) using 39.25 kg methanol and 15.1 kg triethylamine. 12 kg of water was added to the reaction mixture while stirring. The lower phase of the resulting two phase mixture was separated (91.315 kg). An aliquot of 558 g lower phase was flash distilled after addition of methanol, water, and sulphuric acid resulting in 79.5 g high boiling fluorinated polyether oil. This corresponds to a total amount of 13 kg oil in the lower phase. 
       Example 11 
       [0058]    3581 g MV31, 248 g oxygen, 20 g BF 3 , and 52 g CH 3 OCF 2 CF 2 H were reacted at 85° C. Work up resulted in 403 g high boiling fluorinated polyether oil. 
         [0059]    Thermal Stability of the Fluorinated Oil from Example 2 
         [0060]    The crude fluorinated polyether oil recovered in Example 2 was degassed by gradually heating from 20° C. to 100° C. at 1 hPa pressure (4 h). A Sample 1 was taken and analyzed by F-NMR. The degassed oil was heated according to the following table. No apparent changes of the fluorinated oil were observed during the heating period. At 300° C. a small amount of volatile material (3% of the total amount) was collected. Samples were taken according to the following list and analyzed by F-NMR spectroscopy (integration of ppm areas as given in the following table). The table indicates that there is no change in area up to 280° C. within the accuracy limits of NMR spectroscopy integration while there is a minor change at 300° C. 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 100° C. at 1 hPa 
                   
                 sample 1 
               
               
                   
                 110-260° C., 
                 5 h+ 
               
               
                   
                 260° C. 
                 1 h 
                 sample 2 
               
               
                   
                 280° C. 
                 6 h 
                 sample 3 
               
               
                   
                 300° C. 
                 6 h 
                 sample 4 
               
               
                   
                   
               
             
          
         
       
     
         [0061]    Analytical Results 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Sample # 
                 50-60 ppm 
                 75-85 ppm 
                 85-87 ppm 
                 87-100 ppm 
                 115-118 ppm 
                 128-130 ppm 
                 130-140 ppm 
               
               
                   
               
             
             
               
                 Sample 1 
                 100 
                 6.2 
                 43.6 
                 4.8 
                 0.1 
                 23.8 
                 0.0 
               
               
                 Sample 2 
                 100 
                 5.4 
                 45.3 
                 6.6 
                 0.3 
                 25.9 
                 0.0 
               
               
                 Sample 3 
                 100 
                 5.9 
                 44.6 
                 6.3 
                 0.4 
                 25.4 
                 0.0 
               
               
                 Sample 4 
                 100 
                 6.4 
                 42.8 
                 7.2 
                 0.7 
                 23.5 
                 0.4 
               
               
                   
               
             
          
         
       
     
         [0062]    Thermogravimetric Analysis of Crude Fluorinated Polyether Oils 
         [0063]    All thermogravimetric analyses were carried out in open crucibles. The following table shows the results. Heating rate was 10° C. per minute starting from room temperature. According to the results in the thermostability test, the observed weight loss below 300° C. is primarily due to evaporation instead of thermal degradation. 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Weight 
                 Weight 
                 Weight 
                 Weight 
               
               
                   
                 Fluorinated oil 
                 loss 
                 loss 
                 loss 
                 loss 
               
               
                   
                 sample from 
                 1% at 
                 10% at 
                 20% at 
                 100% at 
               
               
                   
                   
               
             
             
               
                   
                 Example 2 
                  92° C. 
                 196° C. 
                 223° C. 
                 356° C. 
               
               
                   
                 Example 3 
                 214° C. 
                 298° C. 
                 317° C. 
                 362° C. 
               
               
                   
                 Example 6 
                 163° C. 
                 302° C. 
                 325° C. 
                 343° C.