APROTIC CATALYSTS FOR THE HYDROLYSIS / CONDENSATION OF ORGANOALKOXYSILANES

Abstract

Provided are methods for hydrolyzing and condensing organooxysilanes using aprotic catalysts comprising silanes containing one or more groups that are the anions derived from strong acids, and/or aprotic catalysts comprising aprotic derivatives of strong acids such as acid esters, acid chlorides, or acid anhydrides. The methods are applicable, e.g., to restoration of dielectric properties of electrical cables by injecting a dielectric enhancement fluid composition containing one or more of the disclosed aprotic catalysts into the interior of an electrical cable having a central stranded conductor encased in a polymeric insulation jacket and having an interstitial void volume in the region of the conductor. Relative to use of protic strong acid catalysts, the disclosed aprotic catalyst methods have utility to reduce or eliminate corrosion of the conductor during treatment with the dielectric enhancement fluid.

Claims

1. A method for enhancing the dielectric properties of an electrical cable having a central stranded conductor encased in a polymeric insulation jacket and having an interstitial void volume in the region of the conductor, the method comprising introducing a dielectric enhancement fluid composition into the interstitial void volume, wherein the composition comprises: a. at least one organoalkoxysilane; and b. one or more aprotic hydrolysis/condensation catalysts for said organoalkoxysilane(s), selected from:
Y.sub.pZ.sub.qSi(A.sup.1).sub.n, wherein  formula (i) n=1 to 3, p+q=4−n), Y is an organo group R.sup.1, and Z is an oxyorgano group OR.sup.2 where R.sup.1 and R.sup.2 are independently selected from alkyl, aryl, or alkaryl, any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, chlorine, bromine, fluorine, and iodine, and A.sup.1 is an anion of a monoprotic strong acid selected from sulfonate, nitrate, chloride, bromide, or iodide; and/or
(Y.sub.pZ.sub.qSi).sub.2A.sup.2, wherein  formula (ii) p+q=3, Y and Z are defined as for formula (i), and A.sup.2 is an anion of a diprotic strong acid selected from sulfate or chromate; and/or
(Y.sub.pZ.sub.qSi).sub.3A.sup.3, wherein  formula (iii) p+q=3 Y and Z are defined as for formula (i), and A.sup.3 is an anion of a triprotic strong acid selected from phosphate; and/or ##STR00012##  wherein X is F, Cl, R.sup.3, or —OR.sup.5, where R.sup.5 is methyl or ethyl, and R.sup.3 and R.sup.4 are independently defined as for R.sup.1; and/or ##STR00013##  wherein R.sup.6 is defined as for R.sup.1; and/or ##STR00014##  wherein R.sup.7 and R.sup.8 are independently defined as for R.sup.1; and/or methyl nitrate, ethyl nitrate, dinitrogen pentoxide, sulfur trioxide, and phosphorus pentoxide, wherein oligomerization of the organoalkoxysilane monomers is catalyzed and dielectric properties are enhanced by retained oligomers.

2. The method of claim 1, wherein independently for R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7 and R.sup.8: alkyl is linear or branched C.sub.1-6 alkyl; aryl is phenyl or substituted phenyl having one or more substituents independently selected from linear or branched C.sub.1-12 alkyl, or naphthyl; and alkaryl is —C.sub.1-6 alkyl phenyl, any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, and iodine.

3. The method of claim 1, wherein independently for R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7 and R.sup.8: alkyl is selected from methyl, ethyl, isopropyl, and tert-butyl; aryl is selected from phenyl, tolyl, naphthyl, and dodecylphenyl; and alkaryl is selected from phenethyl, benzyl, and phenylisopropyl; any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, and iodine.

4. The method of claim 1, wherein A.sup.1 in formula (i) is the anion of a monoprotic acid selected from methanesulfonate, trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate, chlorosulfonate, fluorosulfonate, perfluorobutanesulfonate, nitrate, chloride, bromide, and iodide.

5. The method of claim 1, wherein A.sup.2 in formula (ii) is sulfate.

6. The method of claim 1, wherein A.sup.3 in formula (iii) is phosphate.

7. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalyst comprises at least one selected from TIPS triflate (triisopropylsilyltrifluoromethanesulfonate), DTBS ditriflate (Di-tert-butylsilylbis(trifluoromethanesulfonate), and TTMSP (tris(trimethylsilyl)phosphate).

8. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid ester selected from methyl methanesulfonate, ethyl methanesulfonate, methyl trifluoromethanesulfonate, methyl ethanesulfonate, isopropyl ethanesulfonate, methyl octanesulfonate, methyl benzenesulfonate, ethyl benzenesulfonate, methyl p-toluenesulfonate, and ethyl p-toluenesulfonate.

9. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid ester selected from methyl fluorosulfonate, methyl chlorosulfonate, dimethyl sulfate, diethylsulfate, methylnitrate, and ethylnitrate.

10. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid chloride selected from methanesulfonylchloride, ethanesulfonylchloride, benzenesulfonylchloride, and p-toluenesulfonylchloride.

11. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid anhydride selected from methanesulfonic anhydride, trifluoromethanesulfonic anhydride, ethanesulfonic anhydride, benzenesulfonic anhydride, p-toluenesulfonic anhydride, and dodecylbenzenesulfonic anhydride.

12. The method of claim 1, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one inorganic anhydride selected from dinitrogen pentoxide, sulfur trioxide, and phosphorus pentoxide.

13. The method of claim 1, wherein the organoalkoxysilane is one or more selected from tolylethylmethyldimethoxysilane (TEM), 3-cyanobutylmethyldimethoxysilane, dimethyldi-n-butoxysilane, and phenylmethyldimethoxysilane.

14. The method of claim 1, wherein corrosion of the conductor during treatment with the dielectric enhancement fluid is reduced or eliminated by the use of the one or more aprotic hydrolysis/condensation catalysts relative to use of protic strong acid catalysts.

15. The method of claim 14, wherein the conductor comprises aluminum, and wherein corrosion of the aluminum is reduced or eliminated.

16. The method of claim 1, wherein a PE retention of greater than 0.5 wt % is achieved.

17. A method for catalyzing the hydrolysis/condensation reaction of organooxysilanes, comprising contacting, under suitable reaction conditions, at least one organooxysilane with one or more aprotic hydrolysis/condensation catalysts for said organooxysilane selected from:
Y.sub.pZ.sub.qSi(A.sup.1).sub.n, wherein  formula (i) n=1 to 3, p+q=4−n), Y is an organo group R.sup.1, and Z is an oxyorgano group OR.sup.2, where R.sup.1 and R.sup.2 are independently selected from alkyl, aryl, or alkaryl, any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, chlorine, bromine, fluorine, and iodine, and A.sup.1 is an anion of a monoprotic strong acid selected from sulfonate, nitrate, chloride, bromide, or iodide; and/or
(Y.sub.pZ.sub.qSi).sub.2A.sup.2, wherein  formula (ii) p+q=3, Y and Z are defined as for formula (i), and A.sup.2 is an anion of a diprotic strong acid selected from sulfate or chromate; and/or
(Y.sub.pZ.sub.qSi).sub.3A.sup.3, wherein  formula (iii) p+q=3 Y and Z are defined as for formula (i), and A.sup.3 is an anion of a triprotic strong acid selected from phosphate; and/or ##STR00015##  wherein X is F, Cl, R.sup.3, or —OR.sup.5, where R.sup.5 is methyl or ethyl, and R.sup.3 and R.sup.4 are independently defined as for R.sup.1; and/or ##STR00016##  wherein R.sup.6 is defined as for R.sup.1; and/or ##STR00017##  wherein R.sup.7 and R.sup.8 are independently defined as for R.sup.1; and/or methyl nitrate, ethyl nitrate, dinitrogen pentoxide, sulfur trioxide, and phosphorus pentoxide, wherein oligomerization of the organoalkoxysilane monomers is catalyzed.

18. The method of claim 17, wherein independently for R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7 and R.sup.8: alkyl is linear or branched C.sub.1-6 alkyl; aryl is phenyl or substituted phenyl having one or more substituents independently selected from linear or branched C.sub.1-12 alkyl, or naphthyl; and alkaryl is —C.sub.1-6 alkyl phenyl, any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, and iodine.

19. The method of claim 17, wherein independently for R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7 and R.sup.8: alkyl is selected from methyl, ethyl, isopropyl, and tert-butyl; aryl is selected from phenyl, tolyl, naphthyl, and dodecylphenyl; and alkaryl is selected from phenethyl, benzyl, and phenylisopropyl; any of which alkyl, aryl, or alkaryl groups may also contain one or more hetero atoms selected from nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, and iodine.

20. The method of claim 17, wherein A.sup.1 in formula (i) is the anion of a monoprotic acid selected from methanesulfonate, trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate, chlorosulfonate, fluorosulfonate, perfluorobutanesulfonate, nitrate, chloride, bromide, and iodide.

21. The method of claim 17, wherein A.sup.2 in formula (ii) is sulfate.

22. The method of claim 17, wherein A.sup.3 in formula (iii) is phosphate.

23. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalyst comprises at least one selected from TIPS triflate (triisopropylsilyltrifluoromethanesulfonate), DTBS ditriflate (Di-tert-butylsilylbis(trifluoromethanesulfonate), and TTMSP (tris(trimethylsilyl)phosphate).

24. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid ester selected from methyl methanesulfonate, ethyl methanesulfonate, methyl trifluoromethanesulfonate, methyl ethanesulfonate, isopropyl ethanesulfonate, methyl octanesulfonate, methyl benzenesulfonate, ethyl benzenesulfonate, methyl p-toluenesulfonate, and ethyl p-toluenesulfonate.

25. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid ester selected from methyl fluorosulfonate, methyl chlorosulfonate, dimethyl sulfate, diethylsulfate, methylnitrate, and ethylnitrate.

26. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid chloride selected from methanesulfonylchloride, ethanesulfonylchloride, benzenesulfonylchloride, and p-toluenesulfonylchloride.

27. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one acid anhydride selected from methanesulfonic anhydride, trifluoromethanesulfonic anhydride, ethanesulfonic anhydride, benzenesulfonic anhydride, p-toluenesulfonic anhydride, and dodecylbenzenesulfonic anhydride.

28. The method of claim 17, wherein the one or more aprotic hydrolysis/condensation catalysts comprises at least one inorganic anhydride selected from dinitrogen pentoxide, sulfur trioxide, and phosphorus pentoxide.

29. The method of claim 17, wherein the organoalkoxysilane is one or more selected from tolylethylmethyldimethoxysilane (TEM), 3-cyanobutylmethyldimethoxysilane, dimethyldi-n-butoxysilane, and phenylmethyldimethoxysilane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] FIG. 1 shows a typical prior art construction of a medium voltage power cable.

[0087] FIG. 2 shows, according to the prior art (U.S. Pat. No. 7,700,871), plots of elapsed time vs. % fluid remaining, demonstrating that in a model cable setup strong acids such as trifluoromethane sulfonic acid, provide significantly better retention of tolylethylmethyldimethoxysilane (TEM) hydrolysis and condensation products in the cable than organometallic catalysts of titanium or tin that were tested.

[0088] FIG. 3 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. cable retention of TEM hydrolysis/condensation products with various acids in the context of an extended model cable as described and tested herein. The results are consistent with the results in 7,700,871, and show a moderate but significant advantage for the strong acid catalysts.

[0089] FIG. 4 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. polyethylene (PE) retention of TEM hydrolysis/condensation products with the various acids used for FIG. 3 in the context of the extended model cable as described and tested herein. The results demonstrate an 8-9 fold improvement in PE retention for the strong acid catalysts compared to the titanium and tin catalysts.

[0090] FIG. 5 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. cable retention of phenylmethyldimethoxysilane (PhMe) hydrolysis/condensation products with various acid anion catalysts in the context of the extended model cable as described and tested herein.

[0091] FIG. 6 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. PE retention of PhMe hydrolysis/condensation products with the various acid anion catalysts used for FIG. 5 in the context of the extended model cable as described and tested herein.

[0092] FIG. 7 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. cable retention of tolylethylmethyldimethoxysilane (TEM) hydrolysis/condensation products with various catalysts in the context of the extended model cable as described and tested herein. The plots compare the performance of a typical strong acid catalyst, DDBSA, and a typical organometallic catalyst, tetraisopropyltitanate, with several examples of aprotic catalysts according to the present invention.

[0093] FIG. 8 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. PE retention of TEM hydrolysis/condensation products with the various catalysts used for FIG. 7 in the context of the extended model cable as described and tested herein.

[0094] FIG. 9 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. cable retention of hydrolysis/condensation products of a multicomponent cable rejuvenation formulation with various aprotic catalysts, in comparison with DDBSA, in the context of the extended model cable as described and tested herein. The cable retentions of all four catalysts are virtually identical.

[0095] FIG. 10 shows, by way of non-limiting examples of the present invention, plots of elapsed time vs. PE retention of hydrolysis/condensation products of the multicomponent cable rejuvenation formulation with the various catalysts used for FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

[0096] One skilled in the art will recognize that, while it is useful to know how much of the organoalkoxysilane hydrolysis/condensation product is retained in the cable, how it is distributed among the cable regions is more critical. Organoalkoxysilane hydrolysis/condensation product contained in the cable interstices around the conductors will not help prevent water-treeing or failure of the cable insulation. Only material contained in the insulation will provide that protection. To that end, the “model cable” test described in U.S. Pat. No. 7,700,871 was modified as follows. Five or more tubes were prepared for each sample fluid as previously described, the tubes were aged in water (wet) or diatomaceous earth (dry) at the desired temperature, and periodically, each tube was removed, dried, cleaned, weighed to determine the cable retention, and replaced in the aging bath. At desired intervals, one tube was further analyzed after the determination of cable retention as follows. The sealed ends of the tube were removed and retained, the wire was pushed out of the tube, and the tube, wire and tube ends were cleaned.

[0097] Comparison of the weight of the tube and tube ends with the original weight of the tube quantifies the amount of hydrolysis/condensation product dissolved in the plastic insulation, hereinafter referred to as “PE retention”, which is expressed as a wt % of the original tube weight. For example, a polyethylene tube which weighed 2.0000 g before the experiment and weighed 2.0200 g after the experiment would have a 1% PE retention value. Comparison of the weight of the wire with its original weight quantifies any corrosion occurring.

[0098] Using the extended “model cable” test, experiments were conducted with TEM containing 0.21 mol % catalyst with aging at 55° C. in water. FIG. 3 shows cable retention over time for several catalysts. The retention plateaus were somewhat higher than the corresponding results in 7,700,871 because the catalyst level was 0.21 mol % compared to 0.13 mol % in 7,700,871; however, the ordering of the various catalysts and the spacing between them were the same. The strong acid catalysts achieved an absolute level of cable retention 10% higher than the tetraisopropyltitanate catalyst and 20% higher than the dibutyltindilaurate catalyst. This corresponds to a 1.2-1.4 times improvement in cable retention. The weaker acid catalyst, trifluoroacetic acid gave cable retention slightly lower than the tetraisopropyltitanate but higher than the dibutyltindilaurate catalyst. These results correspond closely with the results in 7,700,871 and show a moderate but significant advantage in cable retention for the strong acid catalysts.

[0099] The extended “model cable” test also provides a quantitative measure of hydrolysis/condensation products dissolved in the polyethylene of the tubes, the PE retention. FIG. 4 plots these values over time for the same catalysts shown in FIG. 3. The differences between the PE retention values for the various catalysts is much more dramatic than the cable retention differences. The strong acid catalysts achieve 3-4 wt % PE retention compared to 1 wt % for the weaker acid (CF.sub.3COOH) and less than 0.5 wt % for the titanium and tin catalysts. This represents an 8-9 fold improvement in PE retention for the strong acid catalysts compared to the titanium and tin catalysts.

[0100] Thus, the strong acid catalysts described in U.S. Pat. No. 7,700,871 represent the best existing method for retaining dielectric enhancement fluid components in the insulation of electric cables.

Aprotic Catalysts for the Hydrolysis/Condensation of Organoalkoxysilanes

[0101] Unless stated otherwise, the term “hydrolysis/condensation catalyst” or “hydrolysis condensation catalyst” or “hydrolysis and condensation catalyst”, as used herein refers to a catalyst that catalyzes the hydrolysis and subsequent condensation of organoalkoxysilane monomers, each having at least two water reactive groups, to form organoalkoxysilane oligomers.

[0102] Triisopropylsilyltrifluoromethanesulfonate, TIPS triflate or TIPS Tf, is used in organic synthesis as a reagent to introduce a triisopropylsilyl protecting group. It is commercially available from several sources including Gelest, Inc., Sigma-Aldrich, and Alfa. Its use as a hydrolysis/condensation catalyst for alkoxysilanes has not been reported.

##STR00007##

[0103] A number of structurally similar silane derivatives are also available commercially including, t-butyldimethylsilyltrifluoromethanesulfonate, di-t-butylisobutylsilyltrifluoromethanesulfonate, di-t-butylsilylbis(trifluoromethanesulfonate), di-isopropylsilylbis(trifluoromethanesulfonate), triethylsilyl trifluoromethanesulfonate, trimethylsilylbenzenesulfonate, trimethylsilylchlorosulfonate, trimethylsilylmethanesulfonate, trimethylsilylperfluorobutanesulfonate, and trimethylsilyltrifluoromethanesulfonate.

[0104] These materials are representative of Class (i) structures (Formula (i) structures), R.sub.p(OR).sub.qSiA.sup.1.sub.n (n=1 to 3 and p+q=4−n) where R is an organo group including alkyl groups such as methyl, ethyl, isopropyl, and tert-butyl; aryl groups such as phenyl, tolyl, naphthyl, and dodecylphenyl; alkaryl groups such as phenethyl, benzyl, and phenylisopropyl; any of the aforementioned organo groups also containing one or more hetero atoms such as nitrogen, phosphorus, oxygen, sulfur, chlorine, bromine, and iodine, and OR is an oxyorgano group including oxyalkyl groups such as methoxy, ethoxy, isopropoxy, and tert-butoxy; oxyaryl groups such as phenoxy, tolyloxy, naphthyloxy, and dodecylphenoxy; oxyalkaryl groups such as phenylethoxy, benzoxy, phenylisopropoxy; and any of the aforementioned oxyorgano groups also containing one or more hetero atoms such as nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine, and iodine in addition to the oxygen atom terminating the group. In this structural class, A.sup.1 is the anion of a strong, monoprotic acid. For example, A.sup.1 can include methanesulfonate, trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate, chlorosulfonate, fluorosulfonate, perfluorobutanesulfonate, nitrate, chloride, bromide, and iodide.

##STR00008##

[0105] Class (ii) structures (Formula (ii) structures), (R.sub.p(OR).sub.qSi).sub.2A.sup.2 (p+q=3), where R and OR are the same as described for Class (i), differ from Class (i) in that A.sup.2 is the anion of a diprotic strong acid such as sulfate or chromate. Commercial examples of Class (ii) include bis(trimethylsilyl)sulfate and bis(triphenylsilyl)chromate.

##STR00009##

[0106] Class (iii) structures (Formula (iii) structures), (R.sub.p(OR).sub.qSi).sub.3A.sup.3 (p+q=3), where R and OR are the same as described for Class (i), differ from Class (i) in that A.sup.3 is the anion of a triprotic strong acid such as phosphate. A commercial example of Class (iii) is tris(trimethylsilyl)phosphate available from Gelest.

##STR00010##

[0107] Class (iv), (v), and (vi) structures are derivatives of strong acids including acid esters, acid chlorides and acid anhydrides, respectively. Illustrated here are derivatives of organosulfonic acids where R is the same as described for Class (i) structures, and R.sup.1 is the same as described for R and may be the same as or different from R within any particular representative of the class. Representative members of Class (iv) include but are not limited to methyl methanesulfonate, ethyl methanesulfonate, methyl trifluoromethanesulfonate, methyl ethanesulfonate, isopropyl ethanesulfonate, methyl octanesulfonate, methyl benzenesulfonate, ethyl benzenesulfonate, and methyl p-toluenesulfonate. Class (iv) can also include esters of other strong acids such as methyl fluorosulfonate, methyl chlorosulfonate, dimethyl sulfate, diethylsulfate, methylnitrate, and ethylnitrate. Representative members of Class (v) include but are not limited to methanesulfonylchloride, ethanesulfonylchloride, benzenesulfonylchloride, p-toluenesulfonylchloride, and benzenesulfonylfluoride. Representative members of Class (vi) include, but are not limited to methanesulfonic anhydride, trifluoromethanesulfonic anhydride, ethanesulfonic anhydride, benzenesulfonic anhydride, and p-toluenesulfonic anhydride. Inorganic anhydrides such as dinitrogen pentoxide, sulfur trioxide, and phosphorus pentoxide could also be included in the Class (vi) catalyst structures. The toxicity and/or explosivity of some members of Classes (iv), (v), and (vi) may prohibit their use even though they may be effective catalysts for the hydrolysis and condensation of alkoxysilanes.

##STR00011##

Example 1

An Extended “Model Cable” Test was Used to Compare the Performance of a Typical Strong Acid Catalyst, DDBSA, with Several Examples of the Acid Anion Silanes of Class (i) and Class (iii)

[0108] The extended “model cable” test was used to compare the performance of a typical strong acid catalyst, DDBSA, with several examples of the acid anion silanes of Class (i) and Class (iii). These tests were performed with phenylmethyldimethoxysilane (PhMe) as substrate primarily using a catalyst concentration of 9.19 mmol/L. Five tubes were prepared for each catalyst, DDBSA (dodecylbenzesulfonic acid), TIPS triflate (triisopropylsilyltrifluoromethanesulfonate), DTBS ditriflate (Di-tert-butylsilylbis(trifluoromethanesulfonate), and TTMSP (tris(trimethylsilyl)phosphate), and the tubes were aged in tap water at 55° C. DTBS ditriflate has two “acid anion” groups, so a set of tubes was also prepared with 3.78 mmol/L DTBS ditriflate. The cable retentions for these experiments are shown in FIG. 5. DTBS ditriflate at 9.19 mmol/L gave about 70% cable retention while TIPS triflate and DTBS ditriflate at the lower concentration achieved cable retention in the lower 60% range, slightly ahead of DDBSA at 60%. TTMSP was much lower at around 45% cable retention.

[0109] Referring to FIG. 6, the PE retention values for the acid anion silanes compared to DDBSA were qualitatively similar to the Cable retention results in that DTBS DiTf at 9.19 mmol/L performed significantly better than TIPS Tf or DDBSA at 9.19 mmol/L. DTBS DiTf at 3.78 mmol/L had slightly lower PE retention than TIPS Tf at 9.19 mmol/L but significantly better PE retention than DDBSA at 9.19 mmol/L. TTMSP gave much lower PE retention than the other acid anion catalysts or DDBSA. These results are summarized in Table 1. This data shows that, at the same level of catalyst equivalents, some of the Class (i) aprotic catalysts perform significantly better than a typical acid catalyst for the retention of phenylmethyldimethoxysilane.

TABLE-US-00001 TABLE 1 PE Retention of PhMeSi(OMe).sub.2 with Acid Anion Silane Catalysts. PE Retention of PhMeSi(OMe).sub.2 with Acid Anion Silane Catalysts DTBS DTBS DDBSA TIPS Tf DiTf DiTf TTMSP 9.161 9.159 9.160 3.765 9.159 Catalyst mmol/l mmol/l mmol/l mmol/l mmol/l 3.98% 4.64% 5.69% 4.10% 0.58% 4.01% 4.86% 5.58% 4.24% 0.58% 3.81% 5.04% 5.72% 4.44% 0.93% 3.36% 5.19% 6.13% 4.46% 0.79% 4.17% 5.45% 6.21% 4.87% 0.88% Average 3.87% 5.03% 5.87% 4.42% 0.75%

Example 2

The Extended “Model Cable” Test was Used to Compare the Performance of a Typical Strong Acid Catalyst, DDBSA, and a Typical Organometallic Catalyst, Tetraisopropyltitanate, with Several Examples of Classes (iv), (v), and (vi) Catalysts and One Additional Class (i) Catalyst

[0110] The extended “model cable” test was also run to compare the performance of a typical strong acid catalyst, DDBSA, and a typical organometallic catalyst, tetraisopropyltitanate, with several examples of Classes (iv), (v), and (vi) catalysts and one additional Class (i) catalyst. These experiments used tolylethylmethyldimethoxysilane (TEM) as the substrate at a catalyst concentration of 9.2 mmol/L for all catalysts except p-toluenesulfonic anhydride. Since the anhydride could have two catalytically active sites per molecule, its concentration was cut to 4.6 mmol/L. Five tubes were prepared for each catalyst in TEM solution, and the tubes were aged in tap water at 55° C. The cable retentions of the eight catalysts are shown in FIG. 7. DDBSA, methyltriflate, and p-toluenesulfonic anhydride gave cable retentions above 70%, with tetraisopropyltitanate somewhat lower. Triisopropylsilylchloride was intermediate at 35%, while the other potential catalysts were below 15%.

[0111] The PE retentions for these same eight catalysts are shown in FIG. 8. The PE retentions of methyl triflate and p-toluenesulfonic anhydride were in the 3-4% range, comparable to the results for DDBSA and other strong acids. Triisopropylsilylchloride gave an intermediate PE retention value while methylmethanesulfonate was lower. Ethyl p-toluenesulfonate and p-toluenesulfonylchloride were at or below 0.5 wt %. Tetraisopropyltitanate had a PE retention below 0.5 wt % even though it gave a much better cable retention than triisopropylsilylchloride, methylmethanesulfonate, ethyl p-toluenesulfonate, and p-toluenesulfonylchloride.

Example 3

The Extended “Model Cable” Test was Used to Evaluate Aprotic Catalysts with a Multicomponent Cable Rejuvenation Formulation

[0112] Several of the aprotic catalysts have also been evaluated in a multicomponent cable rejuvenation formulation containing 3-cyanobutylmethyldimethoxysilane, tolylethylmethyldimethoxysilane, a silane-bound antioxidant, and a silane-bound uv absorber. Catalysts including, trimethylsilylmethanesulfonate, triisopropylsilyltrifluoromethanesulfonate, and p-toluenesulfonic anhydride were tested to compare with a typical strong acid catalyst, dodecylbenzenesulfonic acid. The concentrations of the four catalysts were 9.61 mmol/L, 9.19 mmol/L, 9.19 mmol/L, and 9.17 mmol/L respectively. FIG. 9 shows the cable retention of these formulations. The cable retentions of all four catalysts are virtually identical.

[0113] In contrast, the PE retentions shown in FIG. 10 show dodecylbenzenesulfonic acid, p-toluenesulfonic anhydride, and trimethylsilylmethanesulfonate give fairly similar retentions, but triisopropylsilyltrifluoromethanesulfonate is considerably lower. It should be noted that p-toluenesulfonic anhydride contains potentially two catalyst moieties per molecule while the other catalysts have only one.

Example 4

The Extended “Model Cable” Test was Used to Compare Several Aprotic Catalysts of the Present Invention to a Strong Acid Catalyst, DDBSA, for the Exudation of Phenylmethyldimethoxysilane

[0114] Using the extended “model cable” test, several aprotic catalysts of the present invention were compared to a strong acid catalyst, DDBSA, for the exudation of phenylmethyldimethoxysilane. For this example, the optional anti-oxidant additive was omitted from the fluid formulations. Specifically, changes in the weight of the aluminum wires were compared to assess any corrosion effects. From Table 2, the aluminum wires in samples using DDBSA declined in weight indicating some corrosion. In contrast, all the wires in the aprotic catalyst samples gained weight, likely due to the formation of an adherent coating. As a result, it may be possible to reduce or eliminate the need for the anti-oxidant additive when aprotic catalysts are used.

TABLE-US-00002 TABLE 2 Weight Changes of Al Wire Over Time in PhMe Exudation Wt Changes of Al Wire over Time in PhMe Exudation Catalyst Conc Al Wire % Wt Change with Time Type (mmol/L) 1000 h 2000 h 3000 h 4000 h DDBSA 9.161 −0.01 −0.03 −0.03 TIPS Tf 9.159 0.06 0.05 0.11 0.15 DTBS Tf 9.160 0.09 0.08 0.08 0.21 DTBS Tf 3.765 0.04 0.03 0.07 0.15 TTMSP 9.159 0.04 0.04 0.05

[0115] A similar study was conducted with DDBSA at various concentrations compared to some of the aprotic catalysts of the present invention for the exudation of a fully formulated cable rejuvenation fluid. The results are shown in Table 3. As the concentration of DDBSA is increased, the weight loss of the aluminum wires generally increases as would be expected. Trim ethylsilylmethanesulfonate produced a weight gain in the aluminum wires for the fully formulated rejuvenation fluid as it did for phenylmethyldimethoxysi lane. Toluenesulfonic anhydride did not give a definitive trend, while triisopropylsilyltrifluoromethane sulfonate showed a weight loss in contrast to its result with phenylmethyldimethoxysilane. These results indicate that strong acid catalysts consistently produce a variable level of weight loss of the aluminum wires while aprotic catalysts of the present invention can lead to a consistent weight gain for some combinations of catalyst and fluid.

TABLE-US-00003 TABLE 3 Weight Changes of Al Wire Over Time in Rejuvenation Fluid Exudation Wt Changes of Al Wire over Time in Rejuvenation Fluid Exudation Catalyst Conc Al Wire % Wt Change with Time Type (mmol/L) 1000 h 2000 h 3000 h 4000 h DDBSA 18.46 −0.03% −0.01% −0.04% −0.03% DDBSA 27.43 −0.01% −0.04% −0.03% DDBSA 45.79 −0.06% −0.07% −0.04% −0.04% DDBSA 61.21 −0.07% −0.14% −0.06% −0.06% DDBSA 76.49 −0.04% −0.08% −0.12% DDBSA 91.75 −0.11% −0.07% −0.08% DDBSA 107.22 −0.08% −0.12% DDBSA 122.93 −0.25% −0.15% (Me3SiO)MeSO2 12.21 0.07% 0.05% p-TolSulfAnhydride 9.19 0.08% −0.01% TIPS Tf 9.19 −0.02% −0.06% −0.07% −0.08%