Corrosion inhibited solvent compositions

2-Alkylidene-1,3-dioxolanes and 2-(1-alkylalkylidene)-1,3-dioxolanes are employed as acid acceptors in methylchloroform, trichloroethylene or mixtures thereof. The preferred acid acceptor is 2-methylene-1,3-dioxolane. In another aspect of the invention, aliphatic aldehyde hydrazone is employed to stabilize 2-alkylidene-1,3-dioxolane and 2-(1-alkylalkylidene)-1,3-dioxolane. The preferred aliphatic aldehyde hydrazone is acetaldehyde dimethylhydrazone.

BACKGROUND OF THE INVENTION 
Methylchloroform (i.e., 1,1,1-trichloroethane) and trichloroethylene are 
industrial solvents widely used for degreasing. Their usefulness in 
degreasing metals, especially light metals such as aluminum, is restricted 
because of their high degree of sensitivity to decomposition in the 
presence of aluminum. This sensitivity is particularly acute when 
methylchloroform and/or trichloroethylene contacts aluminum containing 
freshly exposed surfaces such as when the aluminum is scratched while 
submerged in the chlorinated hydrocarbon. Without the protection offered 
by formulating with the appropriate additive under such circumstances, 
methylchloroform and trichloroethylene decompose to various undesirable 
reaction products. Methylchloroform in particular decomposes into an 
unmanageable black tarry mass in a relatively brief period. It is thus 
commonplace to add to solvent compositions containing methylchloroform 
and/or trichloroethylene certain additives to protect against 
decomposition of these materials, including that type of decomposition 
which is particularly acute in the presence of freshly exposed surfaces of 
aluminum. 
Even though stabilized with appropriate additives, methylchloroform and 
trichloroethylene do decompose, albeit at a much reduced rate as compared 
to solvent compositions not containing the additives. Unfortunately, 
whether stabilized with such additives or not, the decomposition products 
of methylchloroform and trichloroethylene include acid species which are 
corrosive to many of the metals being degreased. An acid species which is 
particularly troublesome is hydrogen chloride. It has accordingly been the 
usual practice to add an acid acceptor to methylchloroform and/or 
trichloroethylene to remove acidic species from the system. Epoxy 
compounds such as the 1,2 and 2,3 isomers of butylene oxide have been used 
for this purpose. Not only must the acid acceptor be compatible with other 
materials in the solvent system and perform its acid accepting function, 
but the products of the acid accepting reaction must be stable, compatible 
and essentially non-corrosive toward metals being degreased. These 
constraints impose considerable limitations on the types of acid acceptors 
which may be used in these chlorinated hydrocarbon systems. 
THE INVENTION 
It has now been found that 2-alkylidene-1,3-dioxolanes and 
2-(1-alkylalkylidene)-1,3-dioxolanes are effective as acid acceptors in 
methylchloroform and/or trichloroethylene solvent compositions. 
Accordingly, the invention contemplates solvent composition comprising (a) 
a member selected from the group consisting of methylchloroform, 
trichloroethylene and a mixture thereof, and (b) a corrosion inhibiting 
amount of acid acceptor represented by the structural formula 
##STR1## 
wherein R.sub.1 and R.sub.2 are each independently hydrogen, methyl or 
ethyl and wherein R.sub.3 and R.sub.4 are each independently hydrogen or 
alkyl containing from 1 to about 6 carbon atoms. R.sub.1 and R.sub.2 are 
preferably both hydrogen. When R.sub.3 and/or R.sub.4 are alkyl, they may 
be straight or branched, but if branched, they should not be so highly 
branched as to significantly hinder the formation of stable products of 
the acid accepting reaction. Straight alkyl groups are preferred. 
Typically, R.sub.3 and R.sub.4 are each independently hydrogen or lower 
alkyl containing from 1 to 4 carbon atoms. Preferably, R.sub.3 and R.sub.4 
are each independently hydrogen, methyl or ethyl. It is particularly 
preferred that R.sub.3 and R.sub.4 both be hydrogen. 
Examples of acid acceptors which are satisfactory for use in the invention 
include 2-methylene-1,3-dioxolane, 2-methylene-4-methyl-1,3-dioxolane, 
2-methylene-4-ethyl-1,3-dioxolane, 2-methylene-4-propyl-1,3-dioxolane, 
2-methylene-4-butyl-1,3-dioxolane, 2-methylene-4-isobutyl-1,3-dioxolane, 
2-methylene-4-hexyl-1,3-dioxolane, 2-methylene-4,5-dimethyl-1,3-dioxolane, 
2-methylene-4,5-diethyl-1,3-dioxolane, 
2-methylene-4,5,-dipropyl-1,3-dioxolane, 
2-methylene-4,5-dibutyl-1,3-dioxolane, 
2-methylene-4,5-diisobutyl-1,3-dioxolane, 
2-methylene-4-methyl-5-ethyl-1,3-dioxolane, 
2-methylene-4-methyl-5-isobutyl-1,3-dioxolane, 
2-methylene-4-butyl-5-isobutyl-1,3-dioxolane, 2-ethylidene-1,3-dioxolane, 
2-ethylidene-4-methyl-1,3-dioxolane, 2-ethylidene-4-ethyl-1,3-dioxolane, 
2-ethylidene-4-hexyl-1,3-dioxolane, 
2-ethylidene-4,5-dimethyl-1,3-dioxolane, 2-isopropylidene-1,3-dioxolane, 
2-isopropylidene-4-methyl-1,3-dioxolane, 
2-isopropylidene-4-ethyl-1,3-dioxolane, 
2-isopropylidene-4,5-dimethyl-1,3-dioxolane, 
2-(1-methylpropylidene)-1,3-dioxolane, 
2-(1-methylpropylidene)-4-methyl-1,3-dioxolane, 2 
-(1-methylpropylidene)-4,5-dimethyl-1,3-dioxolane, 
2-(1-ethylpropylidene)-1,3-dioxolane, 
2-(1-ethylpropylidene)-4-methyl-1,3-dioxolane, 
2-(1-ethylpropylidene)-4,5-dimethyl-1,3-dioxolane, and 
2-(1-ethylpropylidene)-4-methyl-5-ethyl-1,3-dioxolane. The especially 
preferred acid acceptor is 2-methylene-1,3-dioxolane. Only one or a 
mixture of any of the various unsaturated 1,3-dioxolane compounds of 
Formula I may be used as desired. 
The amounts of the various components present in the compositions of the 
invention are subject to wide varation. Typically the methylchloroform, 
trichloroethylene or a mixture thereof constitutes from about 85 percent 
to about 99.99 percent by weight of the solvent composition. From about 94 
percent to about 99.6 percent by weight is preferred. While mixtures 
containing significant amounts of both methylchloroform and 
trichloroethylene may be employed, the usual practice is to use either 
methylchloroform or trichloroethylene. 
Chlorinated hydrocarbons other than methylchloroform and/or 
trichloroethylene may be present in the solvent compositions of the 
invention, but if present they ordinarily constitute a minor amount, e.g., 
less than about 20 percent by weight, of such solvent compositions. In 
some cases one or more of these other chlorinated hydrocarbons may be 
added in significant amounts for a particular purpose, but normally they 
are present, if at all, as impurities in low amounts typical of the 
commercial manufacture of methylchloroform or trichloroethylene. 
The concentration of the 2-alkylidene-1,3-dioxolane and/or 
2-(1-alkylalkylidene)-1,3-dioxolane material, whether or not alkyl 
substituted on the ring, in the solvent composition is also subject to 
wide variation. It ordinarily constitutes from about 0.01 percent to about 
10 percent by weight of the methylchloroform, trichloroethylene or 
mixtures thereof present in the solvent composition. From about 0.2 
percent to about 1 percent by weight is preferred. 
The unsaturated compounds represented by Formula I are not the only 
additives which may be incorporated in the solvent compositions of the 
invention. Other additives may optionally also be included. 
Besides the compounds of Formula I, other 1,3-dioxolanes may be included. 
These include saturated 1,3-dioxolanes containing up to two alkyl 
substituents, each of the alkyl substituents having from 1 to 2 carbon 
atoms, such as 1,3-dioxolane, 4-methyl-1,3-dioxolane, 
2-ethyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 
4,4-diethyl-1,3-dioxolane, 2,4-dimethyl-1,3-dioxolane, 
2-methyl-4-ethyl-1,3-dioxolane and the like (including those enumerated in 
column 6 of U.S. Pat. No. 3,397,148, the disclosure of which is 
incorporated herein by reference). Generally, those 1,3-dioxolanes 
normally boiling within the range of 50.degree. C. to about 120.degree. 
C., more ideally in the range of 65.degree. to 85.degree. C. are 
preferable. The preferred saturated dioxolane is 1,3-dioxolane. 
Nitroalkanes having from 1 to about 3 carbon atoms may be employed. 
Examples include nitromethane, nitroethane, 1-nitropropane and 
2-nitropropane. Nitromethane is preferred. One nitroalkane or a mixture of 
nitroalkanes may be used as desired. 
One or more other acid accepting compounds may also be included. These may 
be exemplified by epoxide compounds such as 1,2-butylene oxide, 
2,3-butylene oxide, epichlorohydrin, glycidol, propylene oxide, 
cis-2,3-pentene oxide, 2-methyl-2,3-epoxybutane, 1,2-epoxycyclopentane, 
2,3-dimethyl-2,3-epoxybutane, 2-chloro-3,4-epoxybutane, 
1-chloro-2,3-epoxybutane, styrene oxide, 1,2-epoxycyclohexane and the 
like. Preference is for saturated aliphatic monoepoxides containing from 
about 3 to about 8 carbon atoms, ideally from about 4 to about 6 carbon 
atoms, and saturated cycloaliphatic monoepoxides containing from about 6 
to about 8 carbon atoms. Either or both of the butylene oxide isomers are 
especially preferred. 
Additionally, the solvent compositions often may be improved by the 
incorporation therein of other additives including acetylenic alcohols, 
that is alkynols, and short chain aliphatic monohydric saturated alcohols. 
Useful acetylenic alcohols include those which contain from 3 to about 12 
carbon atoms and a single triple bond. By way of illustration such 
acetylenic alcohols include 2-methyl-3-butyn-2-ol, propargyl alcohol, 
2-butyn-1-ol, 3-butyn-2-ol, 2,5-dimethyl-3-hexyn-2,5-diol, 
3,6-dimethyl-4-octyn-3,6-diol and the like. The particular useful 
saturated monohydric alcohols have from 1 to about 8 carbon atoms among 
which may be mentioned the alkanols methanol, n-propanol, isopropanol, 
sec-butanol, t-butanol, n-butanol, isobutanol, t-amyl alcohol, hexanol, 
octanol and mixtures thereof. n-Propanol, isobutanol and t-butanol are 
preferred. 
Aliphatic aldehyde hydrazones having from 1 to about 7 carbon atoms and 
with no aliphatic group having more than about 4 carbon atoms, may also 
optionally be included in the solvent compositions of the invention. Such 
aliphatic aldehyde hydrazones may be represented by the formula 
##STR2## 
wherein R.sub.5, R.sub.6 and R.sub.7 may each independently be hydrogen or 
an aliphatic group, including saturated and unsaturated aliphatic groups, 
of from 1 to about 4 carbon atoms with the proviso that the aliphatic 
aldehyde hydrazone have from 1 to about 7 carbon atoms. For most of the 
aliphatic aldehyde hydrazones, the sum of the carbon atoms in the 
aliphatic groups is preferably not in excess of 5. Often the aliphatic 
groups of the aliphatic aldehyde hydrazone are alkyl groups. Aliphatic 
aldehyde hydrazones are described in U.S. Pat. No. 3,043,888 and U.S. Pat. 
No. 4,026,956, the disclosures of which are incorporated herein by 
reference. Examples of aliphatic aldehyde hydrazones include formaldehyde 
hydrazone, formaldehyde diethyl hydrazone, formaldehyde dimethyl 
hydrazone, formaldehyde methyl ethyl hydrazone, acetaldehyde methyl 
hydrazone, acetaldehyde methyl ethyl hydrazone, formaldehyde propyl 
hydrazone, formaldehyde isopropyl hydrazone, n-butyraldehyde dimethyl 
hydrazone and propionaldehyde hydrazone. Acetaldehyde dimethylhydrazone is 
preferred. One or a mixture of any of the various aliphatic aldehyde 
hydrazones may be used as desired. 
Another class of additives which may be used are aromatic compounds having 
a phenolic hydroxyl group linked directly to a ring carbon such as phenol, 
thymol, catechol, para-cresol, guaicol, methyl salicylate, eugenol, 
isoeugenol, hydroquinone monomethyl ether, 2,6-di-tert-butyl-p-cresol and 
like phenols having a normal boiling temperature in the range of from 
about 180.degree. C. to about 250.degree. C. One phenol or a mixture of 
phenols may be used when desired. 
A wide variety of amines may also be present. Among the typical amines are 
diethylamine, triethylamine, dipropylamine, tripropylamine, 
triisopropylamine, dibutylamine, di-sec-butylamine, di-isobutylamine, 
diisopropylamine, diethanolamine, morpholine, N-methylmorpholine, 
triethanolamine, beta-picoline, pyridine and aniline. Other nitrogenous 
additives which may be present include pyrroles such as N-methylpyrrole. 
One amine or a mixture of amines may be used as desired. 
Other optional additives which often impart desirable properties to the 
solvent compositions of the invention include 1,4-dioxane; trioxane; 
tetrahydrofuran; alkanoic acid esters such as methyl alpha-hydroxy 
isobutyrate, ethyl acetate, etc.; ketones such as acetone, methyl ethyl 
ketone, methyl isopropyl ketone, diethyl ketone, 2-hexanone, methyl 
tert-butyl ketone, acetyl acetone, mesityl oxide, phorone, cyclohexanone, 
acetophenone, etc.; nitriles exemplified by acetonitrile, propionitrile 
and acrylonitrile; ketols such as acetol, 4-hydroxy-2-butanone and 
5-hydroxy-3-pentanone; dialkyl sulfoxides such as dimethyl sulfoxide, 
di-isopropyl sulfoxide and methyl ethyl sulfoxide; organic nitrates such 
as isopropyl nitrate, ethyl nitrate and methyl nitrate; dimethoxymethane; 
dialkyl ethers of diols (notably the dialkyl ethers specifically numerated 
in U.S. Pat. No. 3,128,315 exemplified by dimethoxyethane; the disclosure 
of U.S. Pat. No. 3,128,315 is incorporated herein by reference). Liquid 
hydrocarbons (aliphatic and aromatic) can be included. For example, 
toluene, n-hexane, pentane or like hydrocarbon is often a useful component 
in providing an all-purpose chlorinated solvent composition. 
The total concentration of all stabilizer additives, including the 
2-alkylidene-1,3-dioxolane and 2-(1-alkylalkylidene)-1,3-dioxolane 
compounds as well as any optional additives, incorporated with 
methylchloroform, trichloroethylene, or a mixture thereof should generally 
be in the range of from about 0.01 percent to about 15 percent by weight 
of the solvent composition. Preferably the total concentration of all 
stabilizer additives is in the range of from about 0.4 percent to about 6 
percent by weight of the solvent composition. In those solvent 
compositions containing a plurality of additives, it is generally good 
practice to minimize the concentration of any one particular additive 
recognizing the impact upon total additive concentration the other 
additives impose. Rarely will the concentration of any one additive exceed 
5 percent by weight; more aptly it will be in the range of from about 0.1 
weight percent to about 31/2 weight percent. 
The compositions of the invention are conveniently prepared by admixing the 
various ingredients. 
The compounds of Formula I may be prepared by dehydrohalogenation of the 
corresponding 2-(1-haloalkyl)-1,3-dioxolane represented by the formula 
##STR3## 
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as previously described 
with respect to Formula I and X is chloro or bromo. The 
dehydrohalogenation may be accomplished, for example, by potassium 
tert-butoxide in tert-butyl alcohol; see McElvain and Curry, Journal of 
the American Chemical Society, volume 70 (November 1948), pages 3781-3786. 
Dehydrohalogenation is preferably accomplished by sodium amide or 
potassium amide in anhydrous liquid ammonia. The sodium amide or the 
potassium amide may conveniently be prepared in situ from metallic sodium 
or metallic potassium. See U.S. Pat. No. 3,431,281, the disclosure of 
which is incorporated herein by reference. 
The compounds of Formula III may be prepared by reacting the corresponding 
haloacetal represented by the formula. 
##STR4## 
with an alkanediol represented by the structural formula 
##STR5## 
where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as previously described 
with respect to Formula I, R is lower alkyl, and X is chloro or bromo. 
Typically, R is methyl or ethyl. An acid catalyst or an acidic cation 
exchange resin and elevated temperatures are generally employed in the 
reaction. Examples of suitable alkanediols include 1,2-ethanediol, 
1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 
1,2-octanediol, 2,3-butanediol, 3,4-hexanediol, 4,5-octanediol, 
5,6-decanediol, 2,7-dimethyl-4,5-octanediol, 2,3-pentanediol, 
5-methyl-2,3-hexanediol and 2-methyl-4,5-nonanediol. 
The compounds of Formula IV may be prepared by reacting the corresponding 
haloaldehyde represented by the formula 
##STR6## 
with a lower alkanol represented by the formula 
EQU ROH (VII) 
wherein R.sub.1 and R.sub.2 are as previously described with respect to 
Formula I, X is chloro or bromo and R is lower alkyl, usually methyl or 
ethyl. The reaction is conducted under conditions customarily associated 
with acetal formation. Examples of suitable Formula VI compounds include 
chloroacetaldehyde, 2-chloropropionaldehyde, 2-chlorobutyraldeyde 
2-methyl-2-chloropropionaldehyde, 2-methyl-2-chlorobutyraldehyde, 
2-ethyl-2-chlorobutyraldehyde and the corresponding 2-bromo analogs. 
In another method, the compounds of Formula III may be prepared by reacting 
the corresponding haloaldehyde represented by Formula VI with an 
alkanediol of Formula V wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are 
as previously described with respect to Formula I and X is chloro or 
bromo. An acid catalyst or an acidic cation exchange resin and elevated 
temperatures are generally employed in the reaction. See British Patent 
Specification No. 739,022, the disclosure of which is incorporated herein 
by reference. 
The unsaturated 1,3-dioxolane compounds of Formula I are ordinarily 
difficult to purify and store because they have a pronounced tendency to 
spontaneously polymerize. It has been discovered that the presence of a 
stabilizing amount of one or more aldehyde hydrazones serves to reduce the 
tendency of the Formula I compounds to spontaneously polymerize. 
Purification of these unsaturated 1,3-dioxolane compounds by distillation 
at reduced pressure is ordinarily accomplished with less spontaneous 
polymerization if the aldehyde hydrazone is present than when it is 
absent. Similarly, storage of the unsaturated 1,3-dioxolane compounds is 
usually accomplished with less spontaneous polymerization when the 
aldehyde hydrazone is present than when it is absent. 
Accordingly, the invention contemplates a composition comprising (a) 
unsaturated 1,3-dioxolane represented by the structural formula of Formula 
I, above, wherein R.sub.1 and R.sub.2 are each independently hydrogen, 
methyl or ethyl and wherein R.sub.3 and R.sub.4 are each independently 
hydrogen or alkyl containing from 1 to about 6 carbon atoms, and (b) a 
stabilizing amount of aliphatic aldehyde hydrazone represented by the 
structural formula of Formula II wherein R.sub.5, R.sub.6 and R.sub.7 are 
each independently hydrogen or an aliphatic group, including saturated and 
unsaturated aliphatic groups with the proviso that the aliphatic aldehyde 
hydrazone has from 1 to 7 carbon atoms. The earlier discussion respecting 
R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is applicable here, as are the 
examples of 2-alkylidene-1,3-dioxolane and 
2-(1-alkylalkylidene)-1,3-dioxolane compounds previously set forth. The 
preferred Formula I compound is 2-methylene-1,3-dioxolane. One unsaturated 
1,3-dioxolane or a mixture of unsaturated 1,3-dioxolanes may be used as 
desired. Similarly, the earlier discussion respecting R.sub.5, R.sub.6 and 
R.sub.7 is applicable here, as are the examples of aliphatic aldehyde 
hydrazones previously set forth. The preferred aliphatic aldehyde 
hydrazone is acetaldehyde dimethylhydrazone. One aliphatic aldehyde 
hydrazone or a mixture of such compounds may be used as desired. The 
preferred stabilizing material is acetaldehyde dimethylhydrazone. 
The concentration of the aliphatic aldehyde hydrazone in the composition is 
subject to wide variation. It ordinarily constitutes from about 0.1 
percent to about 10 percent by weight of the Formula I compounds present. 
From about 0.3 percent to about 5 percent by weight is preferred. The 
stabilized unsaturated 1,3-dioxolane compositions may be produced by 
admixing the various ingredients. 
In the illustrative examples which follow, all parts are parts by weight 
and percentages are percent by weight unless otherwise specified. 
The pH/titer tests are conducted as follows. A dilute sodium chloride 
solution is prepared by dissolving 1 gram sodium chloride in 1 gallon 
neutral distilled water. A 25 milliliter sample of the solvent composition 
to be tested is placed in a 250 milliliter beaker containing 75 
milliliters of the dilute sodium chloride solution. The charged materials 
are mechanically stirred while the pH is determined using a pH meter 
employing a glass electrode and a calomel electrode. Depending on the pH 
observed, the sample is titrated with 0.01 N sodium hydroxide or 0.01 N 
hydrochloric acid until a neutral value of pH 7 is obtained. The material 
is considered to be neutral when it retains a pH in the range of from 7.0 
to 7.3 for at least 30 seconds. The titer is reported as the milliliters 
of 0.01 N sodium hydroxide or 0.01 N hydrochloric acid used to obtain 
neutrality. 
The blender agitation test is conducted as follows. Forty grams of aluminum 
chips (7075-T6) is placed in the one-quart glass jar of a Model 700 
one-speed Waring Blender. After adding 210 milliliters of the solvent 
composition to be tested, the solvent composition and the aluminum chips 
are agitated by the blender until decomposition occurs or agitation has 
proceeded for 10 minutes. The appearance of the solvent as observed 
immediately after blending, after standing 30 minutes and after filtering 
is generally reported. The pH/titer and APHA color of the filtrate are 
measured. 
The aluminum turnings-cutting oil reflux test is conducted as follows. A 
500 milliliter Erlenmeyer flask having a ground glass outer joint is tared 
and charged with 20 grams Houghton 3105 cutting oil, 300 milliliters of 
the solvent to be tested, 45 milliliters Ashland 330 solvent (a neutral 
oil), 7.5 milliliters Shell K-13 oil, 8 grams 2024 alloy aluminum chips, 8 
grams 7075 alloy aluminum chips, several silica boiling chips, and three 
1/2 inch by 11/4 inch by 1/16 inch mild steel strips which have been 
etched with concentrated hydrochloric acid, rinsed with water, dried, 
buffed with a wire wheel and rinsed with acetone. A copper wire is run 
through a water-cooled condenser and bent over the top rim. A 3/32 inch 
hole is drilled in a buffed 2024 alloy aluminum strip measuring 1/2 inch 
by 3 inches. The aluminum strip is rinsed with acetone and hooked to the 
copper wire so that condensate will run down the suspended strip. The 
contents of the flask are thoroughly mixed and a 50 milliliter portion of 
the solvent and oil mixture is removed to a tared graduate. The weight of 
the mixture is recorded and the density is calculated. The flask joint is 
connected to the condenser using a polytetrafluoroethylene sleeve. A hot 
plate is placed under the flask and the time at which refluxing begins is 
noted. Using a hypodermic syringe and needle, 50 milliliter samples of 
liquid are withdrawn through the condenser after refluxing 24 hours and 48 
hours, respectively. After refluxing a total of 168 hours, heating is 
terminated and a sample of the liquid is taken. The samples are tested for 
pH/titer. 
The blade aluminum scratch test is conducted as follows. A scribe is made 
from a 5 to 7 inch length of 5/16 inch diameter stainless steel rod. One 
end is ground to a knife edge so that the edge is at a 45 degree angle to 
the axis of the rod. The other end is inserted into a rubber stopper or a 
wooden file handle. A 2 ounce wide-mouthed bottle is clamped to a table. A 
2024 alloy aluminum test strip measuring 1/2 inch by 15/8 inch by 1/16 
inch is placed in the bottle. Sufficient solvent composition is added to 
cover the entire strip. Three scratches are slowly made the length of the 
strip with the scribe blade while maximum pressure is exerted on the 
scribe by the operator. The sample is then allowed to stand undisturbed 
for 24 hours with the bottle cap lying (not tightened) on the top of the 
bottle. A numerical value is assigned for the appearance of the solvent, 
precipitate and strip after 24 hours and an average figure is reported. 
The rating system is shown in Table 1. In the case of complete solvent 
decomposition, the formulation is given a rating of 10. The scribe is 
resharpened with a file after each test. 
TABLE 1 
______________________________________ 
Blade Aluminum Scratch Test Rating System 
Solvent Precipitate or Haze 
Strip 
Color Rating Condition Rating 
Condition Rating 
______________________________________ 
Colorless 
1 None 1 No scar or 
1 
solid on strip 
Slight 2 Slight haze 
2 Very sl. white 
2 
color solid in scratch 
Yellow 3 Haze 3 Sl. scar or 
3 
or med. and/or solid in scratch 
amber sl. ppt. 
Dark 4 Precipitate 
4 Scar 4 
amber 
Black 5 Heavy 5 Enlarged scar 
5 
precipitate 
______________________________________ 
The Federal Accelerated Oxidation test is described in Military 
Specification MIL-T-7003, Sept. 5, 1950 and O-T-634a, Apr. 17, 1956. A 500 
milliliter Erlenmeyer flask having a ground glass joint is charged with 
200 milliliters of the solvent to be tested. A 1/4 inch by 3/4 inch by 
1/16 inch steel (SAE 1020 to 1040) strip is placed in the bottom of the 
flask. A 1/2 inch by 2 inch by 1/16 inch steel (SAE 1020 to 1040) strip is 
suspended by means of a copper wire running through a water-cooled 
condenser having ground glass joints such that when the condenser is mated 
to the flask, the latter steel strip is suspended above the surface of the 
liquid in the flask. An oxygen delivery tube is passed through the 
condenser to within 1/4 inch of the bottom of the flask. A 150 watt 
frosted electric light bulb is positioned vertically within a polished 
plated steel sleeve having four vent holes near the bottom. A 1/4 inch 
Transite board having a 31/4 inch hole is positioned on top of the sleeve 
with the hole over the light bulb. The flask is positioned on the board 
and over the hole. The bottom of the flask is about 1/2 inch from the top 
of the light bulb. Water is circulated through the condenser, the light 
bulb is switched on and oxygen is admitted through a bubble counter and 
the delivery tube at the rate of one bubble every 5 to 7 seconds. After 48 
hours of continuous refluxing, the contents of the flask are allowed to 
cool to room temperature. A 25 millilter sample of the liquid is removed 
and tested according to the pH/titer tests described above. 
The mild steel reflux test is conducted as follows: A 1/2 inch by 4 inch by 
1/16 inch mild steel strip which has been etched with concentrated 
hydrochloric acid, rinsed with water, dried, polished with a wire wheel 
and rinsed with acetone, is placed in a 500 milliliter Erlenmeyer flask 
having a ground glass joint. Next, 250 milliliters of the solvent to be 
tested is added to flask, resulting in immersion of about one-half of the 
steel strip. The flask is fitted with a water-cooled reflux condenser, 
placed on a hot plate and refluxed for 24 hours. The APHA color of the 
liquid is ascertained. A sample of the liquid is tested according to the 
pH/titer tests described above. 
The standard stability test is conducted in apparatus used in the Federal 
Accelerated Oxidation test except that (1) the oxygen delivery tube (now 
an air delivery tube) passing through the condenser also passes through a 
two-hole rubber stopper located in the top of the condenser, (2) tubing 
passing through the second hole of the rubber stopper directs gases 
venting from the condenser through a normally empty safety trap and then 
through a trap containing 0.1 N silver nitrate solution acidified with 
nitric acid, and (3) the 1/4 inch Transite board has a 3/4 inch hole. A 
solution is prepared by admixing 87.5 parts by volume of the solvent to be 
tested and 12.5 parts by volume Houghton H-3105 drawing compound. The 500 
milliliter Erlenmeyer flask is charged with 250 milliliters of the 
solution, 5 grams of mossy zinc and 5 grams aluminum turnings. Water is 
circulated through the condenser, the light bulb is switched on, and air 
is admitted through the bubble counter and the delivery tube at a rate of 
approximately one bubble per second. After 72 hours of continuous 
refluxing, the contents of the flask are allowed to cool to room 
temperature. A 25 milliliter sample of the liquid is removed and tested 
according to the pH/titer tests described above.

EXAMPLE I 
A three-necked, three liter flask equipped with a mechanical stirrer, a 
temperature recorder, a solid carbon dioxide-acetone reflux condenser and 
a source of nitrogen is charged with 1184.3 grams (69.6 moles) liquid 
anhydrous ammonia. A small piece of metallic potassium and 1 gram ferric 
nitrate nonahydrate [Fe(NO.sub.3).sub.3.9H.sub.2 O] are added 
sequentially. Over a period of 3 hours, 59 grams (1.5 gram-atoms) metallic 
potassium is added. The resulting potassium amide/ammonia mixture is 
stirred for 30 minutes. While passing a slow stream of nitrogen through 
the addition funnel into the flask and out the condenser, 213.6 grams 
(1.74 moles) 2-chloromethyl-1,3-dioxolane is added dropwise. Upon 
completion of the addition, the reaction mixture is refluxed about 12 
hours. The ammonia is then allowed to escape. To the remaining material is 
added 3.3 milliliters of a 40 percent solution of acetaldehyde 
dimethylhydrazone in trichloroethylene. The product is separated by vacuum 
distillation through a short Vigreaux column at an absolute pressure of 43 
millimeters of mercury. Analysis by nuclear magnetic resonance 
spectroscopy shows the product to be 2-methylene-1,3-dioxolane of 80 to 90 
percent purity, with the main impurity being 2-chloromethyl-1,3-dioxolane. 
The product polymerizes quite rapidly upon exposure to the air, but it 
could be stored under nitrogen in a household freezer for short periods of 
time before polymerization is observed. 
EXAMPLE II 
A three-necked, three liter flask is equipped with a mechanical stirrer, a 
500 milliliter pressure equalizing addition funnel with a stopcock in the 
side arm and a Claisen adapter. One end of a stopcock is inserted in the 
straight tube of the Claisen adapter and a serum cap is affixed to the 
other end of the stopcock. A Friedrichs condenser is inserted in the 
parallel arm of the Claisen adapter. In the top joint of the Friedrichs 
condenser is inserted an adapter with a stopcock. This adapter is 
connected to a drying tube filled with calcium sulfate. The Friedrichs 
condenser is cooled by methanol circulating through a refrigerant loop. 
This loop runs, in the direction of the circulating methanol, from the 
outlet of the coolant side of the Friedrichs condenser to a tee in which 
is inserted a thermometer for measuring the temperature of the methanol, 
to a methanol reservoir, to a centrifugal pump, to a copper coil immersed 
in an insulated container filled with a mixture of solid carbon dioxide 
and acetone, and thence to the inlet of the coolant side of the Friedrichs 
condenser. 
The reaction system is purged with nitrogen and the circulating methanol is 
cooled to the minimum stable temperature allowed by the system. 
Approximately 1245 grams (73.1 moles) of liquid ammonia is added to the 
flask. A small piece of metallic potassium and 1 gram of ferric nitrate 
nonahydrate are added sequentially. Over a period of about 31/4 hours, 
small pieces of metallic potassium are intermittently added while the 
refrigerant temperature is in the range of from about -70.degree. C. to 
about -67.degree. C. The total amount of metallic potassium added is 72 
grams (1.84 gram-atoms). While passing a slow stream of nitrogen through 
the addition funnel into the flask and out the condenser, 225.7 grams 
(1.84 moles) 2-chloromethyl-1,3-dioxolane is added dropwise over a period 
of 83 minutes and is completed at 5:03 p.m. Stirring is continued. At 5:25 
p.m. and 6:10 p.m. the refrigerant temperature is -65.degree. C. At 9:15 
p.m. the solid carbon dioxide and acetone bath is replenished for the last 
time. At 8:10 a.m. the next morning there is no more solid carbon dioxide 
in the cooling bath and the refrigerant temperature is -49.degree. C. At 
8:53 a.m. the temperature of the refrigerant is -33.degree. C. At this 
time a very slow nitrogen purge is started through the addition funnel. At 
9:15 a.m. the refrigerant temperature is -23.degree. C. and the 
centrifugal pump for the refrigerant is turned off. At 10:20 to 10:25 
a.m., 3.5 milliliters of a 40% solution of acetaldehyde dimethylhydrazone 
in trichloroethylene is added using a syringe and a long needle inserted 
through the rubber serum cap. Venting of ammonia by the slow nitrogen 
purge without external warming of the flask is continued until the next 
morning, at which time a considerable amount of solid precipitate is 
observed. While maintaining a slow nitrogen purge, the Friedrichs 
condenser and the Claisen adapter are replaced with a nitrogen purge 
adapter. The addition funnel is replaced with an 11 inch Vigereaux 
distillation column, distillation head and thermometer, condenser, a 
vacuum distillation adapter, and a 300 milliliter 2-necked receiver flask. 
A rubber serum cap is attached to the remaining neck of the receiver, and 
the nitrogen purge adapter on the three-liter flask is replaced with a 
glass stopper. 
During distillation, the reaction flask is heated with an oil bath, the 
condenser is cooled with water circulated through an ice and water bath by 
a submersible pump, and the receiving flask is cooled by liquid nitrogen 
in a Dewar flask. Using a conventional vacuum system and associated 
hardware, distillation is conducted at an absolute pressure of 17 
millimeters of mercury for about 2 hours while the temperature at the 
distillation head is in the range of 23.degree. C. to 39.degree. C. The 
system is returned to atmospheric pressure with nitrogen. To the 33.6 
grams of frozen distillate which has been collected, is added 33.6 grams 
methylchloroform. The resulting first solution is stored in a freezer. 
Analysis by nuclear magnetic resonance spectroscopy shows the first 
solution to contain about 43 percent 2-methylene-1,3-dioxolane, about 51 
percent methylchloroform and about 6 percent 2-chloromethyl-1,3-dioxolane. 
In a similar manner, distillation of the remaining contents of the reaction 
flask is resumed, but during the distillation the absolute pressure is 
reduced from the initial 20 millimeters of mercury to 4 millimeters of 
mercury. To the frozen distillate collected is added 53.1 grams 
methylchloroform. The resulting second solution is stored in a freezer. 
Analysis by nuclear magnetic resonance spectroscopy shows the second 
solution to contain about 34 percent 2-methylene-1, 3-dioxolane, about 57 
percent methylchloroform and about 9 percent 2-chloromethyl-1,3-dioxolane. 
The appearance of the solutions after storage in a household freezer is 
shown in Table 2. 
TABLE 2 
______________________________________ 
Appearance After Storage 
Storage Time 
Solution 
(approximate) 
Appearances 
______________________________________ 
First 21/2 days Clear and colorless; contains only 
a few specks of white solid. 
Second 21/2 days Cloudy. 
First 5 weeks Cloudy; contains some finely divided 
white solid. 
______________________________________ 
EXAMPLE III 
A first composition is prepared by admixing 1001.1 grams methylchloroform, 
4.9 grams of an 80 percent 2-methylene-1,3-dioxolane composition wherein 
the chief impurity is 2-chloromethyl-1,3-dioxolane, 0.05 gram acetaldehyde 
dimethylhydrazone, 10.6 grams 1,3-dioxolane, 7.9 grams isobutanol, 7.9 
grams methyl ethyl ketone, 21.1 grams nitromethane and 8.5 grams toluene. 
An additive composition is prepared by admixing 21.9 grams of an 83 percent 
2-methylene-1,3-dioxolane composition wherein the chief impurity is 
2-chloromethyl-1,3-dioxolane and 22.4 grams methylchloroform. 
A second composition is prepared by admixing 996.9 grams methylchloroform, 
9.5 grams of the above additive composition, 0.05 gram acetaldehyde 
dimethylhydrazone, 10.6 grams 1,3-dioxolane, 8.0 grams isobutanol, 8.0 
grams methyl ethyl ketone, 21.2 grams nitromethane and 8.5 grams toluene. 
A conrol composition is prepared by admixing 1003.0 grams methylchloroform, 
0.05 gram acetaldehyde dimethylhydrazone, 10.6 grams 1,3-dioxolane, 7.9 
grams isobutanol, 7.9 grams methyl ethyl ketone, 21.2 grams nitromethane 
and 8.5 grams toluene. 
The first composition, the second composition and the control composition 
are tested according to the pH/titer test, the blade aluminum scratch test 
and the blender agitation test. The results are shown in Table 3. The same 
compositions are also tested according to the aluminum turnings-cutting 
oil reflux test. The results are shown in Table 4. 
TABLE 3 
__________________________________________________________________________ 
STABILITY TEST RESULTS 
BLENDER AGITATION TEST 
BLADE ALUMINUM SOLVENT APPEARANCE AFTER: 
pH/TITER 
SCRATCH TEST APHA STANDING 
COMPOSITION 
INITIAL 
(AVERAGE) pH/TITER 
COLOR BLENDING 
30 MIN. FILTERING 
__________________________________________________________________________ 
First 6.8/0.2 
4.2 4.2/2.8 
4200 Brown Dk. brown 
Amber 
Second 6.7/0.2 
4.5(10*) 4.7/2.9 
2550 Gray-green 
Dk. amber 
Amber 
Control 6.7/0.6 
4.5 3.2/10.2 
4380 Dk. brown 
Dk. brown 
Dk. 
__________________________________________________________________________ 
amber 
*1 out of 4 of the tests of this sample decomposed completely. 
TABLE 4 
______________________________________ 
RESULTS OF ALUMINUM 
TURNINGS-CUTTING OIL REFLUX TEST 
COMPO- pH/TITER AFTER 
SITION 0 HOURS 24 HOURS 48 HOURS 
168 HOURS 
______________________________________ 
First 6.1/1.0 6.5/0.5 6.7/0.3 6.6/0.4 
Second 6.4/0.8 6.6/0.4 6.7/0.3 6.7/0.4 
Control 5.4/1.5 3.9/3.0 3.3/7.8 2.9/15.4 
______________________________________ 
EXAMPLE IV 
A stabilized composition is prepared by admixing various additives with 
methylchloroform. The identity of the additives and their concentration 
expressed as percent by weight of the composition are: 
______________________________________ 
Nitromethane 1.5 percent 
1,3-Dioxolane 1.5 
2-Methylene-1,3-dioxolane 
0.31 
Methyl Ethyl Ketone 0.75 
Isobutanol 0.75 
Toluene 0.80 
Acetaldehyde Dimethylhydrazone 
0.005* 
______________________________________ 
*This concentration of acetaldehyde dimethylhydrazone does not include th 
amount of that material present in the 2methylene-1,3-dioxolane used to 
prepare the formulation. Titration of 20milliliter portions of the 
stabilized composition and the control composition with 0.1N HClO.sub.4 i 
glacial acetic acid shows that the total concentration of acetaldehyde 
dimethylhydrazone in the stabilized composition is 2.5 times that in the 
control composition. 
A first control composition is prepared in the same manner as above except 
that the 2-methylene-1,3-dioxolane is omitted. 
The stabilized composition and the first control composition are tested 
according to the pH/titer test and the blender agitation test. The results 
are shown in Table 5. The same compositions are also tested according to 
the aluminum turnings-cutting oil reflux test. The results are shown in 
Table 6. 
TABLE 5 
__________________________________________________________________________ 
STABILITY TEST RESULTS 
BLENDER AGITATION TEST 
pH/TITER APHA SOLVENT APPEARANCE 
COMPOSITION 
INITIAL 
pH/TITER 
COLOR AFTER FILTERING 
__________________________________________________________________________ 
Stabilized 
7.30/&lt;0.1 
3.8/2.9 
3000 medium amber with a very 
(pH drifts slight haze 
to 7.0) 
First Control 
6.7/0.3 
2.9/10.8 
3000 medium to dark amber with a 
(dk. brwn.) 
very slight haze 
__________________________________________________________________________ 
TABLE 6 
__________________________________________________________________________ 
RESULTS OF ALUMINUM TURNINGS-CUTTING OIL REFLUX TEST 
REFLUX APPEARANCE AFTER 168 HOURS 
TIME, STEEL ALUMINUM 
ALUMINUM 
COMPOSITION 
HOURS pH/TITER 
SOLVENT 
STRIPS 
CHIPS COUPON 
__________________________________________________________________________ 
Stabilized 
0 6.1/0.5 
amber slight 
clean clean 
24 6.5/0.4 stains 
48 6.2/0.4 (iridescent) 
168 6.4/0.5 
First Control 
0 4.6/1.3 
very dark 
heavy numerous 
heavy black 
24 3.3/5.2 
amber brown black spot 
and brown 
48 3.1/8.5 stains 
stains deposit on 
168 2.9/13.2 (rust) one side 
__________________________________________________________________________ 
To determine if the additional acetaldehyde dimethylhydrazone is 
responsible for the good performance of the stabilized composition as 
compared with the first control composition in the aluminum 
turnings-cutting oil reflux test, a second control composition is prepared 
which, except for the absence of the 2-methylene-1,3-dioxolane, has the 
same composition as the stabilized composition. The second control 
composition is then tested according to the aluminum turnings-cutting oil 
reflux test. The results are shown in Table 7. 
TABLE 7 
__________________________________________________________________________ 
RESULTS OF ALUMINUM TURNINGS-CUTTING OIL REFLUX TEST 
REFLUX APPEARANCE AFTER 168 HOURS 
TIME, STEEL 
ALUMINUM 
ALUMINUM 
COMPOSITION 
HOURS pH/TITER SOLVENT 
STRIPS 
CHIPS COUPON 
__________________________________________________________________________ 
Second Control 
0 5.6/0.9 very dark 
heavy 
a few small 
black 
(pH drifts to 6.0) 
amber brown 
black spot 
deposit 
24 3.2/6.9 stains 
stains in upper 
48 3.1/8.6 (rust) corner; 
168 3.1/8.8 remainder 
was clean 
__________________________________________________________________________ 
EXAMPLE V 
A control composition is prepared by admixing 2478.5 grams 
trichloroethylene containing 0.01 percent thymol, 0.25 gram acetaldehyde 
dimethylhydrazone, 3.1 grams n-propanol, 7.1 grams 1,2-butylene oxide and 
1.0 gram cyclohexene oxide. 
An additive composition is prepared by admixing 21.9 grams of an 83 percent 
2-methylene-1,3-dioxolane composition wherein the main impurity is 
2-chloromethyl-1,3-dioxolane, and 22.5 grams trichloroethylene. 
A stabilized composition is prepared by admixing 798.0 grams of the control 
composition and 1.9 grams of the above additive composition. 
The stabilized composition and the control composition are tested according 
to the pH/titer test, the Federal Accelerated Oxidation test and the mild 
steel reflux test. The results are shown in Table 8. 
TABLE 8 
______________________________________ 
STABILITY TEST RESULTS 
FEDERAL 
ACCEL- 
ERATED MILD STEEL 
OXIDATION REFLUX TEST 
COMPO- pH/TITER TEST APHA 
SITION INITIAL pH/TITER pH/TITER 
COLOR 
______________________________________ 
Control 6.9/&lt;0.1 3.1/15.4 6.9/&lt;0.1 
90 
Stabilized 
6.9/&lt;0.1 6.5/0.2 7.2/0.1 21 
______________________________________ 
EXAMPLE VI 
A first composition is prepared by admixing 954.1 grams of 
trichloroethylene containing 0.01 percent thymol with 3.9 grams of an 80 
percent 2-methylene-1,3-dioxolane composition wherein the chief impurity 
is 2-chloromethyl-1,3-dioxolane, 1.2 grams n-propanol and 0.24 gram of 40 
percent acetaldehyde dimethylhydrazone in trichloroethylene. 
A second composition is prepared by admixing 796.5 grams of 
trichloroethylene containing 0.01 percent thymol with 1.0 gram n-propanol, 
0.2 gram of 40 percent acetaldehyde dimethylhydrazone in trichloroethylene 
and 8.1 grams of the additive composition of Example V. 
The first composition and the second composition are tested according to 
the pH/titer test, the Federal Accelerated Oxidation test and the standard 
stability test. The results are shown in Table 9. 
TABLE 9 
______________________________________ 
STABILITY TEST RESULTS 
FEDERAL STANDARD 
ACCELERATED STABILITY 
COMPO- pH/TITER OXIDATION TEST TEST 
SITION INITIAL pH/TITER pH/TITER 
______________________________________ 
First 7.3/0.2 8.4/0.2 6.8/&lt;0.1 
Second 7.1/&lt;0.1 8.2/0.5 6.9/-- 
______________________________________ 
EXAMPLE VII 
A trichloroethylene control composition is prepared containing 0.01 percent 
thymol, 0.125 percent n-propanol and 0.01 percent acetaldehyde 
dimethylhydrazone. 
An additive composition is prepared containing about 21 percent 
2-methylene-1,3-dioxolane, about 5 percent 2-chloromethyl-1,3-dioxolane 
and about 74 percent trichloroethylene. 
A first composition is prepared by admixing 1319.4 grams trichloroethylene 
containing 0.01 percent thymol with 1.7 grams n-propanol and 26.9 grams of 
the above additive composition. 
A second composition is prepared by admixing 100 parts of the first 
composition and 0.01 part acetaldehyde dimethylhydrazone. 
The first composition, the second composition and the control composition 
are tested as shown in Table 10, which also shows the results obtained. 
TABLE 10 
______________________________________ 
STABILITY TEST RESULTS 
COMPOSITION 
TEST First Second Control 
______________________________________ 
Mild Steel Reflux 
pH/titer 6.8/0.1 7.0/-- 3.2/13.4 
Metal Condition 
Vapor Phase Clean Clean Rusty 
Interface Clean Clean Rusty 
Liquid Phase Slight Clean Rusty 
white 
film with 
iridescence 
Solvent Appearance (APHA) 
6 9 500 (very 
cloudy) 
Federal Accelerated Oxidation 
pH/titer 3.8/10.9 6.6/0.2 3.5/20.4 
Strip Condition 
Flask Clean Clean Tar- 
nished 
Condenser Very black 
Clean Clean 
and rusty 
Solvent Appearance (APHA) 
2650 200 &gt;500 
(dark (slightly 
(cloudy) 
red-orange) 
cloudy) 
Standard Stability Not run Not run 
pH/titer 6.8/&lt;0.1 
AgNO.sub.3 Trap Condition 
Clear 
Solvent Appearance 
Dark 
red-amber 
______________________________________ 
Although the recent invention has been described with reference to specific 
details of certain embodiments thereof, it is not intended that such 
detail should be regarded as limitations upon the scope of the invention 
except insofar as they are included in the accompanying claims.