CA1124733A - Stabilization of cyclohexene oxide - Google Patents
Stabilization of cyclohexene oxideInfo
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- CA1124733A CA1124733A CA330,153A CA330153A CA1124733A CA 1124733 A CA1124733 A CA 1124733A CA 330153 A CA330153 A CA 330153A CA 1124733 A CA1124733 A CA 1124733A
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Abstract
ABSTRACT OF THE DISCLOSURE
Cyclohexene oxide is stabilized against peroxidative decomposition by inclusion therein of a stabilizing amount of dialkylsulfoxide. The stabilized cyclohexene oxide is then used to stabilize unsaturated chlorinated solvents such as perchloroethylene against metal induced decomposition.
Cyclohexene oxide is stabilized against peroxidative decomposition by inclusion therein of a stabilizing amount of dialkylsulfoxide. The stabilized cyclohexene oxide is then used to stabilize unsaturated chlorinated solvents such as perchloroethylene against metal induced decomposition.
Description
1124~33 Background of the Invention Oxirane compounds such as ep~chlorohydrin, cyclohexene oxide, glycidol, glycidyl ethers, and the like, usually in combination with other compounds such as alkoxynitriles, amines, amides, alcohols, and esters, are commonly used to stabilize chlorinated solvents, such as perchloroethylene, against metal induced decompvsition.
Of the oxirane compounds, epichlorohydrin is perhaps most commonly used due to its proven effectiveness and ready availability.
However, since epichlorohydrin hàs been shown by the Ames Test to exhibit mutagenic activity, its continued permissible use in chlorinated solvent stabilization systems is questionable for reasons of health and safety.
Cyclohexene oxide has been demonstrated to be an acceptable non~mutagenic substitute for epichlorohydrin in chlorinated solvent stabilization systems; however, cyclohexene oxide suffers from the disad-vantage that it, itself, is unstable and develops acidity upon storage,especially when exposed to air.
It is believed that cyclohexene oxide autoperoxidizes to form a tecomposition product which is believed to be cyclopentane carboxylic acid, which decomposition product causes severe pitting and corrosion of metals, particularly aluminum. Consequently, before cyclohexene oxide .y . .. , ~ .
llZ4733 can be effectively used to stabilize chlorinated solvents against metal induced decomposition, the cyclohexene oxide itself must be stabilized against peroxidative decomposition.
Cyclohexene oxide is usually stabilized against decomposition by the inclusion of a stabili~ing amount of butylated hydroxytoluene (BHT). However, it has been found that BHT stabiliæed cyclohexene oxide is not very effective in stabilizing unsaturated cblorinated solvents, for example, perchloroethylene, a~ainst metal, particularly aluminum, induced decomposition, especially when the solvent is used in degreasing operations.
It i9 desirable, therefore, to devise means of stabilizing cyclohexene oxide against decomposition, which stabilized cyclohexene oxide would be particularly effective in stabilizing unsaturated chlorinated solvents against metal induced decomposition in addition to having the capacity to neutralize any hydrochloric acid decomposition product.
Description of the Invention In accordance with this invention, it has been found that cyclohexene oxide is stabilized against peroxidative decomposition by the inclusion therein of a stabilizing amount of di-n-butyl sulfoxide.
A~though di-n-butyl sulfoxide has been found to be particularly effèctive in stabilizing cyclohexene oxide against peroxidative decomposition, it is contemplated that other dialkyl sulfoxides would be suitable for use in the invention. Such other dialkyl sulfoxides may be represented by the general formula, R2S = 0, wherein R is a C2 to C8, preferably C2 to C4, aliphatic radical that must contain at least one hydrogen atom on a beta-carbon atom. Some other aliphatic radicals of which R is representative include, for example, ethyl, n-propyl, isopropyl, t-butyl, sec-butyl, isobutyl, hexyl, cyclohexyl, 2-ethylhexyl, 2-phenoxyetbyl, and the like. The quantity ~Z4733 of dialkyl sulfoxide used to stabilize cyclohexene oxide may vary over a range of from about 0.3 percent to 20 percent by weight, preferably from about 0.5 percent to 5.0 percent by weight, and most preferably from about 0.9 percent to 2.0 percent by weight based on the weight of cyclohexene oxide.
The dialkyl sulfoxide stabilized cyclohexene oxide is particularly effective in stabilizing chlorinated solvents such as perchloroethylene against aluminum induced decomposition. When used to stabilize chlorinated solvents, the dialkyl sulfoxide stabilized cyclohexene oxide is employed in typical stabilizing amount, usually rom about 0.01 to 0.5 percent, prefer-ably from about 0.1 to 0.3 percent by weight of cyclohexene oxide based on the weight of solvent, although as much as 5.0 percent by weight may be used.
The cyclohexene oxide may be stabilized with dialkyl sulfoxide ~15 prior to stabilizing the solvent or unstabilized cyclohexene oxide anddialkyl sulfoxide may be added separately to the solvent thus stabilizing the cyclohexene oxide in situ.
The stabilization afforded cyclohexene oxide by dialkyl sulfoxide is not appreciably affected by the presence of stabilizing amounts of other commonly used chlorinated solvent stabilizing components such as, for example, phenols, alcohols, esters, amines, amides, nitriles, and the like.
The invention is further illustrated but is not intended to be limited by the following examples.
~1247~3 Example 1 A series of stabilized perchloroethylene samples was prepared using the following stabilization systems. The stabilizing materials are expressed as percent by weight based on the weight of perchloroethylene:
Sample No. 1 2 3 4 5 CH0 0.27 0.27 0.27 0.27 0.27 HQMME 0.01 0.01 0.01 0.01 0.01 NMM 0.005 0.005 0.005 0.005 0.005 EPN 0.06 0.06 0.06 0.06 0.06 BHT 0.00135(a) ~
DNBS ~~ - O.OOl(b) 0.0025(c) 0.005(d) (a) 0.5 weight percent BHT based on weight of CH0 (b) 0.37 weight percent DNBS based on weight of CH0 (c) 0.93 weight percent DNBS based on weight of CH0 (d) 1.86 weight percent DNBS based on weight of CH0 Le8end: CH0 - cyclohexene oxide MQMNE - hydroquinone monomethyl ether NMM - N-methylmorpholine EPN - beta-ethoxypropionitrile BHT - butylated hydroxytoluene DNBS - di-n-butyl sulfoxide 4~:~3 100 milliliters of each of the above stabilized solvents were placed in individual 250 milliliter Erlenmeyer flasks. A 2024 aluminum coupon measuring 112 inch x 4 inches x 1/32 inch was placed in each flask.
Each coupon was polished with a crocus cloth and cleaned with acetone immediately prior to its being placed in its respective flask. Each flask was provided with a reflux condenser and heated to refluxing temperature.
The flask contents were refluxed until visible signs of corrosion, i.e., black spots, appeared on the coupons. Under the microscope, these spots appeared as small craters covered with a reddish-brown powder.
The results of the reflux tests are as follows: -Days Until Days Until SampleCorrosion Observed Test Terminated
Of the oxirane compounds, epichlorohydrin is perhaps most commonly used due to its proven effectiveness and ready availability.
However, since epichlorohydrin hàs been shown by the Ames Test to exhibit mutagenic activity, its continued permissible use in chlorinated solvent stabilization systems is questionable for reasons of health and safety.
Cyclohexene oxide has been demonstrated to be an acceptable non~mutagenic substitute for epichlorohydrin in chlorinated solvent stabilization systems; however, cyclohexene oxide suffers from the disad-vantage that it, itself, is unstable and develops acidity upon storage,especially when exposed to air.
It is believed that cyclohexene oxide autoperoxidizes to form a tecomposition product which is believed to be cyclopentane carboxylic acid, which decomposition product causes severe pitting and corrosion of metals, particularly aluminum. Consequently, before cyclohexene oxide .y . .. , ~ .
llZ4733 can be effectively used to stabilize chlorinated solvents against metal induced decomposition, the cyclohexene oxide itself must be stabilized against peroxidative decomposition.
Cyclohexene oxide is usually stabilized against decomposition by the inclusion of a stabili~ing amount of butylated hydroxytoluene (BHT). However, it has been found that BHT stabiliæed cyclohexene oxide is not very effective in stabilizing unsaturated cblorinated solvents, for example, perchloroethylene, a~ainst metal, particularly aluminum, induced decomposition, especially when the solvent is used in degreasing operations.
It i9 desirable, therefore, to devise means of stabilizing cyclohexene oxide against decomposition, which stabilized cyclohexene oxide would be particularly effective in stabilizing unsaturated chlorinated solvents against metal induced decomposition in addition to having the capacity to neutralize any hydrochloric acid decomposition product.
Description of the Invention In accordance with this invention, it has been found that cyclohexene oxide is stabilized against peroxidative decomposition by the inclusion therein of a stabilizing amount of di-n-butyl sulfoxide.
A~though di-n-butyl sulfoxide has been found to be particularly effèctive in stabilizing cyclohexene oxide against peroxidative decomposition, it is contemplated that other dialkyl sulfoxides would be suitable for use in the invention. Such other dialkyl sulfoxides may be represented by the general formula, R2S = 0, wherein R is a C2 to C8, preferably C2 to C4, aliphatic radical that must contain at least one hydrogen atom on a beta-carbon atom. Some other aliphatic radicals of which R is representative include, for example, ethyl, n-propyl, isopropyl, t-butyl, sec-butyl, isobutyl, hexyl, cyclohexyl, 2-ethylhexyl, 2-phenoxyetbyl, and the like. The quantity ~Z4733 of dialkyl sulfoxide used to stabilize cyclohexene oxide may vary over a range of from about 0.3 percent to 20 percent by weight, preferably from about 0.5 percent to 5.0 percent by weight, and most preferably from about 0.9 percent to 2.0 percent by weight based on the weight of cyclohexene oxide.
The dialkyl sulfoxide stabilized cyclohexene oxide is particularly effective in stabilizing chlorinated solvents such as perchloroethylene against aluminum induced decomposition. When used to stabilize chlorinated solvents, the dialkyl sulfoxide stabilized cyclohexene oxide is employed in typical stabilizing amount, usually rom about 0.01 to 0.5 percent, prefer-ably from about 0.1 to 0.3 percent by weight of cyclohexene oxide based on the weight of solvent, although as much as 5.0 percent by weight may be used.
The cyclohexene oxide may be stabilized with dialkyl sulfoxide ~15 prior to stabilizing the solvent or unstabilized cyclohexene oxide anddialkyl sulfoxide may be added separately to the solvent thus stabilizing the cyclohexene oxide in situ.
The stabilization afforded cyclohexene oxide by dialkyl sulfoxide is not appreciably affected by the presence of stabilizing amounts of other commonly used chlorinated solvent stabilizing components such as, for example, phenols, alcohols, esters, amines, amides, nitriles, and the like.
The invention is further illustrated but is not intended to be limited by the following examples.
~1247~3 Example 1 A series of stabilized perchloroethylene samples was prepared using the following stabilization systems. The stabilizing materials are expressed as percent by weight based on the weight of perchloroethylene:
Sample No. 1 2 3 4 5 CH0 0.27 0.27 0.27 0.27 0.27 HQMME 0.01 0.01 0.01 0.01 0.01 NMM 0.005 0.005 0.005 0.005 0.005 EPN 0.06 0.06 0.06 0.06 0.06 BHT 0.00135(a) ~
DNBS ~~ - O.OOl(b) 0.0025(c) 0.005(d) (a) 0.5 weight percent BHT based on weight of CH0 (b) 0.37 weight percent DNBS based on weight of CH0 (c) 0.93 weight percent DNBS based on weight of CH0 (d) 1.86 weight percent DNBS based on weight of CH0 Le8end: CH0 - cyclohexene oxide MQMNE - hydroquinone monomethyl ether NMM - N-methylmorpholine EPN - beta-ethoxypropionitrile BHT - butylated hydroxytoluene DNBS - di-n-butyl sulfoxide 4~:~3 100 milliliters of each of the above stabilized solvents were placed in individual 250 milliliter Erlenmeyer flasks. A 2024 aluminum coupon measuring 112 inch x 4 inches x 1/32 inch was placed in each flask.
Each coupon was polished with a crocus cloth and cleaned with acetone immediately prior to its being placed in its respective flask. Each flask was provided with a reflux condenser and heated to refluxing temperature.
The flask contents were refluxed until visible signs of corrosion, i.e., black spots, appeared on the coupons. Under the microscope, these spots appeared as small craters covered with a reddish-brown powder.
The results of the reflux tests are as follows: -Days Until Days Until SampleCorrosion Observed Test Terminated
2 6 6
3 10 10
4 None 35 None 35 Example 2 A simulated glass degreaser was constructed from a three-liter capacity, one-neck, round bottom flask, a two-liter capacity flask, and a water-cooled condenser.
The condenser outlet was connected by rubber tubing to a safety trap and a silver nitrate trap connected in series. The two-liter flask was modified by inserting and fusing a piece of glass tubing with a 24/40 T male joint through the bottom of the flask. One end of the tube extended about halfway into the flask such that about one liter
The condenser outlet was connected by rubber tubing to a safety trap and a silver nitrate trap connected in series. The two-liter flask was modified by inserting and fusing a piece of glass tubing with a 24/40 T male joint through the bottom of the flask. One end of the tube extended about halfway into the flask such that about one liter
- 5 -l~lZ~33 of solvent could be collected before overflowing back into the bottom three-liter flask ~simulated boiling sump). Before starting the test, about 60 grams each of 2024 and 7075 aluminum turnings, 200 milliliters of Limex #78 oil and two liters of perchloroethylene were added to the boiling sump. The modified two-liter flask (simulated rinse tank) was fitted to the three-liter flask and 500 milliliters of perchloroethylene were added to the two-liter flask. The assembly was heated to and maintained at reflux temperature by means of a Variac controlled heating mantle.
Solvent decomposition was indicated by the appearance of a white silver chloride precipitate in the silver nitrate trap.
One test was run using perchloroethylene that was stabilized by the addition thereto of 0.27 weight percent cyclohexene oxide, 0.005 weight percent di-n-butyl sulfoxide, 0.01 weight percent hydroquinone monomethyl ether, 0.06 weight percent beta-ethoxyproprionitrile and o.oa5 weight percent N-methylmorpholine (solvent A).
Another test was run using perchloroethylene stabilized as above except that no di-n-butyl sulfoxide was added ~solvent B).
Samples of perchloroethylene were taken from the boiling sump at periodic intervals and analyzed acid acceptance. The results of these tests are summQrized as follows: -Solvent A Solvent B
Days Acid Acid Reflux pH Acceptance,%pHAcceptance,%
0 8.60 0.10l 8.350.1043 1 - -- 8.400.0859
Solvent decomposition was indicated by the appearance of a white silver chloride precipitate in the silver nitrate trap.
One test was run using perchloroethylene that was stabilized by the addition thereto of 0.27 weight percent cyclohexene oxide, 0.005 weight percent di-n-butyl sulfoxide, 0.01 weight percent hydroquinone monomethyl ether, 0.06 weight percent beta-ethoxyproprionitrile and o.oa5 weight percent N-methylmorpholine (solvent A).
Another test was run using perchloroethylene stabilized as above except that no di-n-butyl sulfoxide was added ~solvent B).
Samples of perchloroethylene were taken from the boiling sump at periodic intervals and analyzed acid acceptance. The results of these tests are summQrized as follows: -Solvent A Solvent B
Days Acid Acid Reflux pH Acceptance,%pHAcceptance,%
0 8.60 0.10l 8.350.1043 1 - -- 8.400.0859
6 8.35 0.089 --11 8.41 0.0818 7.550.0276 ~ ~ra4~ ~1aY~ .
~lZ~733 Solvent A Solvent B
Days Acid Acid Reflux pHAcceptance,% pHAcceptance,%
13 8.43 0.0818 14 -- 5.15-0.0356 18 8.36 0.0815 --8.33 0.0807 - --As seen from the above, perchloroethylene stabilized with unstabilized cyclohexene oxide ~solvent B) de~elops acidity quite rapidly under simulated degreasing conditions as compared with perchloroethylene stabilized with di-n-butyl sulfoxide stabilized cyclohexene oxide (solvent A). Moreover, examination of the aluminum turnings showed no attack from solvent A whereas the aluminum turnings were severely pitted from solvent B.
The acid acceptance of the solvent is a measure of the capa-city of the solvent to neutralize hydrochloric acid ant is expressed in percent by weight of equivalent sodium hydroxide. The acid acceptance is determined as follows. To an Erlenmeyer flask is added 25 milli-liters of 0.1 N hydrochloric acid in isopropyl alcohol, 10 milliliters of solvent, and 25 milliliters of isopropyl alcohol. The contents of the flask are thoroughly mixed, the flask is stoppered and allowed to stand for 10 minutes at room temperature. Three drops of bromophenol blùe indicator are added and the flask contents are titrated with 0.1 N
sodium hydroxide to the blue-green end point.
A blank determination is made by titrating 25 milliliters of 0.1 N hydrochloric acid in isopropyl alcohol and 25 milliliters of iso-propyl alcohol with 0.1 N sodium hydroxide to the blue-green bromophenol blue end point.
~33 Acid acceptance in weight percent equivalent sodium hydroxide is calculated as follows:
Acid Acceptance = (K-S)N x 0.04 x 100 W
wherein:
K = milliliters of NaOH solution required for the blank titration;
S = milliliters of NaOH solution required for the sample titration;
N = normality of the NaOH solution; and W = grams of sample (volume in milliliters x specific gravity).
Example 3 The perchloroethylene solvents A and B prepared as described in Example 2 were tested in a Baron-Blakeslee model ~VW-125 vapor-Ypray degreaser.
After 814 hours of operation, a sample of solvent A taken from the boiling sump had a pH of 7. 91 and an acid acceptance of 0.112 percent. No sign of corrosion was observed on a 2024 aluminum test panel that had been immersed in the solvent in the boiling sump throughout the test period.
After 574 hours of operation, a ~ample of solvent B taken from the boiling ~ump had a pH of 7. 7 and an acid acceptance of 0.094 percent. A 2024 aluminum test panel that had been immersed i~33 in the boiling sump throughout the test period was severely corroded and pitted.
Although the invention has been described with specific ref-erences and specific details of embodiments thereof, it is to be understood that It is not intended to be so limited since changes and alterations therein may be made by those skilled in the art which are within the full intended scope of this invention as defined by the appended claims.
~247~3 SUPPLEr~lENTARY DISCLOSURE
The principal disclosure of this application specifies the dialkyl sulfoxide used to stabilize cyclohexene oxide according to the invention as being of the formula R2S=O wherein R is an aliphatic radical containing 2 to 8 carbon atoms having at least one hydrogen atom on a beta-carbon atom. The definition of the R groups was specified in that manner to clearly exclude dimethyl sulfoxide. It has now been found, however, that dimethyl sulfoxide is an effective stabilizer for cyclohexene oxide against peroxidative decomposition and in fact is one of the most preferred dialkyl sulfoxides for this purpose, the other most preferred being di-n-butyl sulfoxide as set out in the principal disclosure.
FurtheL-more~ in the general formula representing the dialkyl sulfoxides which can be used according to the present invention, the alkyl groups need not be the same but can be different.
Thus, according to the present invention cyclohexene oxide is stabilized against peroxidative decomposition by the inclusion therein of a stabilizing amount of dialkyl sulfoxide o~ formula R
~=0 Rll wherein R and R are the same or different and represent alkyl radicals of 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.
The amounts of dialkyl sulfoxide according to the aforementioned formula which may be used are those set out in the principal disclosure for the dialkyl sulfoxides disclosed therein as stabilizers and the other - 9a -conditions and considerations of the principal disclosure apply here also.
The following examples further illustrate the invention but are not to be taken as limiting thereto.
Example 4 Perchloroethylene solvent stabilized by the addition thereto of 0.27 weight percent cyclohexene oxide, 0.0035 weight percent dimethylsulfoxide, 0.01 weight percent hydroquinone monomethyl ether, 0.06 weight percent beta-ethoxyproprionitrile and 0.005 weight percent N-methylmorpholine was tested in the Baron-Blakeslee MVW vapor-spray degreaser referred to in Example L0 3 of the principal disclosure.
The stabilized perchloroethylene had an initial p~/titer of 8.27/1.2. After 744 hours of operation, a sample of solvent taken from the boiling sump had a pH/titer of 7.83/0.5. No si~n of corrosion was observed on a 2024 aluminum test panel that had been immersed in the solvent in the boiling sump throughout the test period.
Example 5 Perchloroethylene was stabilized by the addition thereto of 0.27 weight percent of cyclohexene oxide, 0.01 weight percent of hydroquinone monomethyl ether, 0.005 weight percent of N-methylmorpholine, 0.06 weight percent of beta-ethoxypropionitrile and 0.0035 weight percent of dimethyl sulfoxide. To a 250milliliter Erlenmeyer flask was added 100 ~illiliters of the stabilized p~rchloroethylene. One strip each ~measuring 0.5 x 2~5 inches~
of polished type 3003 aluminum, pure copper and type 1010 mild steel were placed in the flask such that each strip was partly immersed in the liquid and partly exposed to the vapor phase. The flask was heated to reflux and maintained at reflux for 168 hours. At the end of the reflux period, the metal strips were inspected and showed no visible signs of discoloration or corrosion.
~1^"'`
- 9b -, :
~lZ~733 Solvent A Solvent B
Days Acid Acid Reflux pHAcceptance,% pHAcceptance,%
13 8.43 0.0818 14 -- 5.15-0.0356 18 8.36 0.0815 --8.33 0.0807 - --As seen from the above, perchloroethylene stabilized with unstabilized cyclohexene oxide ~solvent B) de~elops acidity quite rapidly under simulated degreasing conditions as compared with perchloroethylene stabilized with di-n-butyl sulfoxide stabilized cyclohexene oxide (solvent A). Moreover, examination of the aluminum turnings showed no attack from solvent A whereas the aluminum turnings were severely pitted from solvent B.
The acid acceptance of the solvent is a measure of the capa-city of the solvent to neutralize hydrochloric acid ant is expressed in percent by weight of equivalent sodium hydroxide. The acid acceptance is determined as follows. To an Erlenmeyer flask is added 25 milli-liters of 0.1 N hydrochloric acid in isopropyl alcohol, 10 milliliters of solvent, and 25 milliliters of isopropyl alcohol. The contents of the flask are thoroughly mixed, the flask is stoppered and allowed to stand for 10 minutes at room temperature. Three drops of bromophenol blùe indicator are added and the flask contents are titrated with 0.1 N
sodium hydroxide to the blue-green end point.
A blank determination is made by titrating 25 milliliters of 0.1 N hydrochloric acid in isopropyl alcohol and 25 milliliters of iso-propyl alcohol with 0.1 N sodium hydroxide to the blue-green bromophenol blue end point.
~33 Acid acceptance in weight percent equivalent sodium hydroxide is calculated as follows:
Acid Acceptance = (K-S)N x 0.04 x 100 W
wherein:
K = milliliters of NaOH solution required for the blank titration;
S = milliliters of NaOH solution required for the sample titration;
N = normality of the NaOH solution; and W = grams of sample (volume in milliliters x specific gravity).
Example 3 The perchloroethylene solvents A and B prepared as described in Example 2 were tested in a Baron-Blakeslee model ~VW-125 vapor-Ypray degreaser.
After 814 hours of operation, a sample of solvent A taken from the boiling sump had a pH of 7. 91 and an acid acceptance of 0.112 percent. No sign of corrosion was observed on a 2024 aluminum test panel that had been immersed in the solvent in the boiling sump throughout the test period.
After 574 hours of operation, a ~ample of solvent B taken from the boiling ~ump had a pH of 7. 7 and an acid acceptance of 0.094 percent. A 2024 aluminum test panel that had been immersed i~33 in the boiling sump throughout the test period was severely corroded and pitted.
Although the invention has been described with specific ref-erences and specific details of embodiments thereof, it is to be understood that It is not intended to be so limited since changes and alterations therein may be made by those skilled in the art which are within the full intended scope of this invention as defined by the appended claims.
~247~3 SUPPLEr~lENTARY DISCLOSURE
The principal disclosure of this application specifies the dialkyl sulfoxide used to stabilize cyclohexene oxide according to the invention as being of the formula R2S=O wherein R is an aliphatic radical containing 2 to 8 carbon atoms having at least one hydrogen atom on a beta-carbon atom. The definition of the R groups was specified in that manner to clearly exclude dimethyl sulfoxide. It has now been found, however, that dimethyl sulfoxide is an effective stabilizer for cyclohexene oxide against peroxidative decomposition and in fact is one of the most preferred dialkyl sulfoxides for this purpose, the other most preferred being di-n-butyl sulfoxide as set out in the principal disclosure.
FurtheL-more~ in the general formula representing the dialkyl sulfoxides which can be used according to the present invention, the alkyl groups need not be the same but can be different.
Thus, according to the present invention cyclohexene oxide is stabilized against peroxidative decomposition by the inclusion therein of a stabilizing amount of dialkyl sulfoxide o~ formula R
~=0 Rll wherein R and R are the same or different and represent alkyl radicals of 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.
The amounts of dialkyl sulfoxide according to the aforementioned formula which may be used are those set out in the principal disclosure for the dialkyl sulfoxides disclosed therein as stabilizers and the other - 9a -conditions and considerations of the principal disclosure apply here also.
The following examples further illustrate the invention but are not to be taken as limiting thereto.
Example 4 Perchloroethylene solvent stabilized by the addition thereto of 0.27 weight percent cyclohexene oxide, 0.0035 weight percent dimethylsulfoxide, 0.01 weight percent hydroquinone monomethyl ether, 0.06 weight percent beta-ethoxyproprionitrile and 0.005 weight percent N-methylmorpholine was tested in the Baron-Blakeslee MVW vapor-spray degreaser referred to in Example L0 3 of the principal disclosure.
The stabilized perchloroethylene had an initial p~/titer of 8.27/1.2. After 744 hours of operation, a sample of solvent taken from the boiling sump had a pH/titer of 7.83/0.5. No si~n of corrosion was observed on a 2024 aluminum test panel that had been immersed in the solvent in the boiling sump throughout the test period.
Example 5 Perchloroethylene was stabilized by the addition thereto of 0.27 weight percent of cyclohexene oxide, 0.01 weight percent of hydroquinone monomethyl ether, 0.005 weight percent of N-methylmorpholine, 0.06 weight percent of beta-ethoxypropionitrile and 0.0035 weight percent of dimethyl sulfoxide. To a 250milliliter Erlenmeyer flask was added 100 ~illiliters of the stabilized p~rchloroethylene. One strip each ~measuring 0.5 x 2~5 inches~
of polished type 3003 aluminum, pure copper and type 1010 mild steel were placed in the flask such that each strip was partly immersed in the liquid and partly exposed to the vapor phase. The flask was heated to reflux and maintained at reflux for 168 hours. At the end of the reflux period, the metal strips were inspected and showed no visible signs of discoloration or corrosion.
~1^"'`
- 9b -, :
Claims (22)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A composition comprising cyclohexene oxide containing a stabilizing amount of dialkylsulfoxide represented by the general formula R2S = O wherein R is an alkyl radical containing from 2 to 8 carbon atoms having at least one hydrogen atom on a beta-carbon atom, wherein the cyclohexene oxide contains from about 0.3 percent to about 20 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
2. The composition of Claim 1 wherein the dialkyl sulfoxide is di-n-butyl sulfoxide.
3. The composition of Claim 1 wherein the cyclohexene oxide contains from about 0.5 percent to 5.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
4. The composition of Claim 3 wherein the cyclohexene oxide contains from about 0.9 percent to 2.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
5. A composition comprising an unsaturated chlorinated solvent containing a stabilizing amount of cyclohexene oxide and from about 0.3 percent to 20 percent by weight based on the weight of cyclohexene oxide of dialkyl sulfoxide represented by the general formula R2S = O wherein R is an alkyl radical containing from 2 to 8 carbon atoms having at least one hydrogen atom on a beta-carbon atom.
6. The composition of claim 5 wherein the solvent is perchloroethylene.
7. The composition of Claim 5 or 6 containing from about 0.5 percent to 5.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
8. The composition of Claim 5 or 6 containing from about 0.9 percent to 2.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
9. The composition of Claim 5 or 6 wherein the dialkyl sulfoxide is di-n-butyl sulfoxide.
10. The composition of claim 5 or 6 containing from about 0.01 percent to 5.0 percent by weight cyclohexene oxide based on the weight of solvent.
11. The composition of Claim 5 or 6 containing from about 0.1 to 0.5 percent by weight cyclohexene oxide based on the weight of solvent.
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE
12. cyclohexene oxide stabilized against peroxidative auto-decomposition by inclusion therein of from about 0.3 percent to about 20 percent by weight of dialkyl sulfoxide represented by the formula wherein R and R1 are the same or different and represent alkyl radicals containing 1 to 8 carbon atoms.
13. The composition of claim 12 wherein the dialkyl sulfoxide is dimethyl sulfoxide.
14. The composition of claim 12 or 13 wherein the cyclohexene oxide contains from about 0.5 percent to 5.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
15. The composition of claim 12 or 13 wherein the cyclohexene oxide contains from about 0.9 percent to 2.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
16. An unsaturated chlorinated solvent stabilized against metal induced decomposition by inclusion therein of a stabilizing amount of cyclohexene oxide and from about 0.3 percent to 20 percent by weight based on the weight of cyclohexene oxide of dialkyl sulfoxide represented by the general formula wherein R and R1 are the same or different and represent alkyl radicals containing 1 to 8 carbon atoms.
17. The composition of claim 16 wherein the dialkyl sulfoxide is dimethyl sulfoxide.
18. The composition of claim 16 or 17 containing from about 0.5 to 5.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
19. The composition of Claim 16 or 17 containing from about 0.9 percent to 2.0 percent by weight dialkyl sulfoxide based on the weight of cyclohexene oxide.
20. The composition of Claim 16 or 17 containing from about 0.01 percent to 5.0 percent by weight cyclohexene oxide based on the weight of solvent.
21. The composition of Claim 16 or 17 containing from about 0.1 to 0.5 percent by weight cyclohexene oxide based on the weight of solvent.
22. The composition of Claim 16 or 17 wherein the solvent is perchloroethylene.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US92526878A | 1978-07-17 | 1978-07-17 | |
| US925,268 | 1978-07-17 | ||
| US22049580A | 1980-12-29 | 1980-12-29 | |
| US220,495 | 1980-12-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124733A true CA1124733A (en) | 1982-06-01 |
Family
ID=26914926
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA330,153A Expired CA1124733A (en) | 1978-07-17 | 1979-06-20 | Stabilization of cyclohexene oxide |
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| Country | Link |
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| CA (1) | CA1124733A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8858820B2 (en) | 2011-10-07 | 2014-10-14 | American Pacific Corporation | Bromofluorocarbon compositions |
-
1979
- 1979-06-20 CA CA330,153A patent/CA1124733A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8858820B2 (en) | 2011-10-07 | 2014-10-14 | American Pacific Corporation | Bromofluorocarbon compositions |
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