CA1126299A

CA1126299A - Stabilisation of chlorinated hydrocarbons

Info

Publication number: CA1126299A
Application number: CA321,767A
Authority: CA
Inventors: Christopher S. Allen
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1978-02-20
Filing date: 1979-02-19
Publication date: 1982-06-22
Also published as: AU4435479A; NZ189640A; DE2906529A1; DE2906529C2; SE445212B; NL176935C; AT370071B; ATA129179A; NO153453B; IT1110204B; JPS6230175B2; FI65985B; DK67879A; JPS54125601A; FI65985C; FI790568A; SE7901448L; NO153453C; DK152356C; DK152356B

Abstract

ABSTRACT OF THE DISCLOSURE
1,1,1-trichloroethane is stabilised against de-composition due to presence of metals with an epoxy alkyl ester derived from a carboxylic acid and an alcohol, for example as contained in an epoxidised vegetable oil.

Description

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~ STA8ILISATION OF CHLORINATED HYD OCARBONS

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This invention relates to the stabilisation of l,l,l-trichloroethane.
In recent years there has been expanding use of 1,1,1- -trichloroethane in industrial cleaning processes, especially in degreasing of metals. However large scale use of l,l,l-trichloroethane particularly, in vapour degreasing, presents difficulties since in contact with ~-reactive metals such as iron, zinc, copper and aluminium there is attack on the solvent. This leads to tar formation and evolution of large amounts of acids.
- We have now found that certain epoxy esters or stabilising compositions which include said epoxy esters are highly effective in reducing metal induced decomposition of l,l,l-trichloroethane.
According to the present invention there is provided l,l,l-trichloroethane stabilised by an epoxy alkyl ester which ester is derived from a carboxylic acid containing 12to 20 carbon atoms and from an alcohol containing 3 to 12 carbon atoms.
The carboxylic acid from which the ester is deri~ed may contain, for example 18 carbon atoms.

The preferred alcohols fxom which the esters are derived are those containing 3 to 8 carbon atoms.

2~ By the term "epoxy alkyl ester" we mean those compounds wherein an epoxy group is introduced into -, ~

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~26299 -- 2. MD 30047 the alkyl group of the alcohol and/or into the alkyl group of the carboxylic acid from which the ester is derived.
The alkyl ester itself (into which the epoxy group is introduced) may be derived from a carboxylic acid con-taining a n-alkyl,iso-alkyl or cycloalkyl group and from `an aLcohol which contains a n-alkyl iso-alkyl, alkenyl, cycloalkyl group, or which is a polyol.
Examples of epoxy alkyl esters include for instance -, octyl epoxy stearate and butyl epoxy stearate. An example '' 10 of an epoxy'isoalkyl ester is epoxy 2-ethyl hexyl -stearate. An example of an epoxy cycloalkyl ester is epoxy cyclohexyl stearate. Mixturès of epoxy alkyl esters can be employed. ~ l ..
15- j ~ -s A'mixture of epoxy alkyl esters derived from long chain fatty acids and glycerol is very useful according to the invention as a stabiliser for l,l,l-trichloro-ethane. Particularly useful stabilisers are epoxidised vegetable oils, for example epoxidised soya bean~oil and epoxidised linseed oil, which contains such epoxy alkyl esters.
The epoxy alkyl esters may be made in known manner, " for example by epoxidation of the corresponding esters 25 containing ethylenic unsaturation in the acid and/or ~-alcohol components.
Quite small proportions by weight of the epoxy alkyl esters for example of the epoxidised vegetable oil are useful in the present invention. For example 0.025% by 30 'weight or less of said epoxy alkyl'esters with reference to the solvent has a stabilising effect on 1,1,1-trichloroethane. Usually the proportion of the epoxy alkyl ester is greater than 0.05% but not greater than 5%
with reference to the solvent. For example, very good results can be obtained when the proportion by weight of , - ,, - : ~, .:

3. MD.30047 the epoxy alkyl ester is in the range 0.1% to 2% by weight with reference to the solvent.
One or more conventional stabilisers for 1,1,1-trichloroethane may also be associated with the present novel stabiliser. For example useful results can be obtained when there is also incorporated in the 1,1,1-trichloroethane a stabilising amount of one or more of the following conventional stabilising compounds:-organic nitrates, nitriles, nitroalkanes, cyclic ethers having 3 to 6 membered rings, amines, alcohols, alkyl esters and ketones. Any one of these known stabilisers is usually present in an amount not greater than 4% by weight with reference to the solvent. Indeed con-siderably lower amounts of said conventional stabilisers can be used if desired.
There are also provided according to the present invention concentrated solutions of the epoxy alkyl ester in the l,;l,l-trichloroethane in which the proportions by weight of the epoxy alkyl ester are much greater than the aforesaid 5% by weight. These solutions may contain 20%
to 70% by weight of epoxy alkyl esters, for example, epoxy butyl stearate and epoxidised vegetable oil with reference to the solvent. By adding such concentrate to pure solvent or solvent depleted in said epoxy alkyl ester content there can be obtained a 1,1,1-trichloro-ethane containing desired smaller amounts of the epoxy alkyl ester which can then be used directly for cleaning of metals or for other purposes. Likewise concentrates may be utilised which contain not only a high proportion by weight of epoxy alkyl ester but also a high proportion of conventional stabiliser or stabilisers.
The present invention includes within its scope a method of inhibiting decomposition of l,l,l-trichloro-ethane due to presence of metals which comprises incorporating in the solvent said epoxy alkyl esters.

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4. MD 30047 The invention also includes a method of degreasing, particularly vapour degreasing, metal and other articles which comprises bringing the articles in~o contact with l,l,l-trichloroethane in the liquid or vapour state wherein the l,l,l-trichloroethane has been stabilised with an epoxy alkyl ester. In such a method the 1,1,1-trichloroethane may, if desired, also contain conventional stabilisers.
The following Example illustrates the invention.
Where percentages are mentioned they are by weight.
EXAMPLE
The apparatus comprised a pear-shaped glass flask (100 ccs capacity) surmounted by a vertical glass tube leading to a water-cooled reflux condenser. The tube was also provided with a horizontal glass side tube which abutted a second horizontal glass tube. The ends - of both horizontal tubes were so deformed that by application of a spring clip as will be evident herein-after a desired amount of solvent could be withdrawn from the end of the second glass tube. The latter abutted a third glass tube which was bent at right angles to connect with a mild steel tube (lS cms length, 0.64 cms diameter). Heat from a Meker burner was applied through a shroud tube to a middle (3 cms length) of the vertical mild steel tube. A glass tube connected the steel tube through two right angle turns to the glass flask.
50 ccs of l,l,l-trichloroethane were placed in the glass flask. By heating the mild steel tube, 1,1,1-trichloroethane pa~sed through the glass side arms andthe mild steel tube, thus acting as a thermosyphon. The circulating l,l,l-trichloroethane was thus subjected to an accelerated stability test in the presence of mild steel.

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5. MD 30047 Various proportions of epoxy alkyl esters with and without conventional stabilisers were incorporated in ` the l,l,l-trichloroethane and were subjected to the accelerated stability test for a period of 120 minutes.
Onset, if any, of acidity, measured to pH4, in the vapour (in condenser) and in the stabilised solvent was indicated by universal indicator paper. Similar tests were also carried out with an epoxy alkyl ester also containing conventional stabilisers.
- 10 The results are indicated in Table I.

Stabiliser Time for vapour Time for to become acidic liquid to become acidic 0.2% epoxidised no indication of no soya bean oil (I) acidity àfter indication known under the 120 mins. of acidity 20 Registered Trade after Mark 'Paraplex' G62 120 mins.
and available commercially from Rohm and Haas 25 0.5~ epoxidised soya bean oil (I) plus 2% iso-propyl nitrate ditto ditto 0.5% nitromethane 0.5% epoxidised soya bean 30 oil (I) plus ditto ditto 2% t-butanol 0.5% nitromethane _ _ ~, , , .~- , . . .

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Stabiliser Time for vapour Time for to become acidic liquid to become acidic__ 0.5% epoxidised soya bean no indication of no oil (I) acidity after indication plus 120 mins. of acidity 2% t-amyl alcohol after 0.5% nitromethane 120 mins.
10 0.5% epoxidised soya bean oil (I) plus ditto ditto 2% methyl ethyl ketone 0.5% nitromethane 15 0.5% epoxidised soya bean oil (I) pius ditto ditto 35% 1,4-dioxane 0.5% nitromethane 20 0.5% epoxidised soya bean oil (I) plus ditto ditto 2% isobutyl acetate 0.5% nitromethane 25 0.5% epoxidised soya bean oil (I) plus ditto ditto 2% 2-methyl-3-butyn-2-ol 0.5% nitromethane ...... .
30 0.5% epoxidised soya bean oil (I) plus 2% 1,3-dioxolane ditto ditto 0.5% nitromethane 0.05% acetaldehyde dimethyl hydrazone ~' . .

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7. MD 30047 Stabiliser Time for vapour Time for to become acidic liquid to become acidic 5 0.2% epoxidised linseed no indication of no oil (II) known under the acidity after indication Trade Mark 'Edenol' B316 120 mins. of acidity and available after . i commercially from 120 mins. .
10 Henkel and Co _ 0.5% epoxidised linseed oil (II) plus ditto ditto % isopropyl nitrate .
15 _.5% nitromethane . 0.5% epoxidised linseed oil (IIl .
plus ditto ditto 35% t-butanol 20 0.5% nitromethane 0.5% epoxidised linseed oil (II) plus ditto ditto 2% t-amyl alcohol 25 0.5% nitromethane 0.5% epoxidised linseed oil (II) plus 2% methyl ethyl ketone ditto ditto 30 0.5% nitromethane 0.5% epoxidised linseed .
oil (II) plus .
3.5% 1,4-dioxane ditto ditto 0.5% nitromethane .. _ _ .

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. _ Stabiliser Time for vapour Time for to become acidic liquid to become acidic 5 0.5% epoxidised linseed no indication of no oil (II) acidity after indication plus 120 mins. of acidity 2% isobutyl acetate after 0.5% nitromethane- `- 120 mins.
10 0.5% epoxidised linseed oil (II) plus ditto ditto 2% 2-methyl-3 butyn-2-ol 0.5% nitromethane 15 0.5% epoxidised linseed _ oil (II) -plus `
2% 1,3-dioxolane 0.5% nitromethane ditto ditto 20 0.05% acetaldehyde dimeth 1 h drazone X Y
0.25% epoxidised linseed oil (II) plus 25 3.5% 1,4-dioxane ditto ditto 0.5% nitromethane 0.25% 1,2-butene oxide . ~ .
0.25% epoxidised linseed oil (II) plus 2.0% methyl ethyl ketone ditto ditto 2.0% nitromethane 0.25% 1,2-butene oxide 0.2~ epoxy octyl stearate ditto ditto :~
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Stabiliser Time for vapour Time for to become acidic liquid to become acidic 5 0.2% epoxy octyl no indication no stearate of acidity indication plus after of acidity 3.5% 1,4-dioxane 120 mins. after 0.5% nitromethane 120 mins. ¦ - -10 0.5% epoxy 2-ethyl hexyl stearate (III) known under the Trade Mark 'Edenol' ditto ditto B74 and available 15 commercially from Henkel and Co 0.5% (III) plus 2% isopropyl nitrate ditto ditto 20 0.5% nitromethane 0.5% (III) plus ditto ditto 2% t-butanol 0.5% nitromethane _ 0.5% (III) plus 2% t-amyl alcohol ditto ditto 0.5% nitromethane _ 30 0.5% (III) plus 2% methyl ethyl ketone ditto ditto 0.5% nitromethane ,, ' ,, ':
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~ Stabiliser Time for vapour Time for ; to become acidic liquid to become acidic 5 0.5% (III) no indication of no plus acidity after indication 3.5% 1,4-dioxane 120 mins. of acidity ; 0.5% nitromethane after , ~ - 120 mins.
0.5% (III) ., plus 2% isobutyl acetate , ditto ditto 0.5% nitromethane _ 0.5% (III) , lS plu5 2% 2-methyl-3-butyn-2-ol ditto ditto0.5% nitromethane _ ~ 0.5% (III) `., plus 20 2% 1,3-dioxolane ;
0.5% nitromethane ditto ditto ' 0.5% acetaldehyde ,, 35 dimethyl hydrazone 0.5% epoxy cyclohexyl stearate (IV) known under the Trade Mark ditto . ditto 'Edenol' HS235 and available commercially from Henkel and Co 30 0.5% (IV) plus ditto ditto 2% isopropyl nitrate 0.5% nitromethane ,, : - . . .. . ;, ;. ,, ,~ .: .; .. '.;, : .. , : ~ , - ~ ~
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ll. MD 30047 . . . __ Stabiliser Time for vapour Time for to become acidic liquid to , become acidic 5 0.5% (IV) no indication of no plus acidity after indication 2% t-butanol 120 mins. of acidity o.s% nitromethane after .. . . . ................ .. . . . . 120 m_ns- ¦
lO 0.5% (IV) , ~ , plus 2% t-amyl alcohol ditto ditto : - 0.5% nitromethane _ _ . 0.5% (IV) ~ 15 plus ~
2% methyl ethyl ketone - ditto ditto 0~.5% nitromethane .
.
: 0.5% (IV) plus 20 3.5% 1,4-dioxane ditto ditto 0.5% nitromethane l I
0.5% (IV) plu8 ~:~ 2% isobutyl acetate ditto ditto :~ 25 0.5% nitromethane .s% (IV) .
plus , 2% 2-methyl-3-butyn-2-ol ditto ditto 0.5% nitromethane 30 0.5% (IV) plus 2% 1,3-dioxolane .
o.s% nitromethane ditto - ditto 0.05% acetaldehyde dimethyl hydrazone ... . . ..

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. There was ever~ indication from these Runs that onset of acidity did not occur in the vapour or in the liquid long after the period of 120 minutes even up to several hours. For instance with a stabilising mixture consisting of 0.5% 'Edenol' B316 plus 2% isopropyl nitrate and 0.5% nitromethane there was no onset of acidity in the vapour or in the liquid after 14 hours.
COMPARISON
By way of comparison said accelerated thermal stability test was carried out to determine the time to develop acidic conditions as indicated by universal indicator paper to pH4 with 1,1,1-trichloroethane stabilised with stabilising materials not according to the invention.
The results are indicated in Table II.

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. Stabiliser Time for vapour Time for liquid .~ to become acidic to become acidic 0.2% 1,2-butene oxidie 5 mins 25 mins .~ .
. 2% isopropyl- .
. nitrate . 0.5% nitromethane4 mins 4 mins ¦
~ 10 2~ t-amyl alcohol : . . .
: 0.5% nitromethane15 mins 19 mins ,~ .
. 2% methyl ethyl I . ~etone 5% nitro- :~
~` methane 20 mins 20 mins _ _ _ .__ .. . .... v .
~ 15 3.5% 1,4-dioxane i O.S% nitromethane15 mins ~ 6 mins 2% isobutyl acetate ~ .
0.5% nitromethane2 mins~ ~3 mins -:
_ .... _ . .
:~ 2% 2-methyl-3-butyn-20 2-ol 0.5% nitro- ~ .
~: ~ methane 3 mins 20 mins ~ ~ , . _ .... _ 2% 1,3-dioxolane .
. 0.5% nitromethane . .
. 0.05% acetaldehyde .
;1 25 dime~yl hydrazon-e _5 mins 40 mins . 2% isopropyl nitrate .
O.S% 1,2-butene oxide .
0.5% nitromethane5 mins 5 mins 2% 1,3-dioxolane .
30 0.5% 1,2-butene oxide 0.5% nitromethane5 mins 10 mins :~

Claims

What we claim is:-

1. l,l,l-trichloroethane stabilised by an epoxy alkyl ester which ester is derived from a carboxylic acid containing 12 to 20 carbon atoms and from an alcohol containing 3 to 12 carbon atoms.

2. 1,l,I-trichloroethane as claimed in Claim l wherein the alcohol component from which the ester is derived contains 3 to 8 carbon atoms.

3 l,l,l-trichloroethane as claimed in Claim 1 in which the epoxy ester is derived from a carboxylic acid containing a n-alkyl, iso-alkyl alkenyl or cycloalkyl group and an alcohol containing a n-alkyl, iso-alkyl, alkenyl, cycloalkyl group, or a polyol.

4. 1,1,1-trichloroethane as claimed in Claim 3 in which the epoxy alkyl ester is octyl epoxy stearate.

5. l,l,l-trichloroethane as claimed in Claim 3 in which the epoxy alkyl ester is butyl epoxy stearate.

6. l,l,l-trichloroethane as claimed in Claim 3 in which the epoxy iso-alkyl ester is an epoxy 2-ethyl hexyl stearate.

7. l,l,l-trichloroethane as claimed in Claim 3 in which the epoxy cycloalkyl ester is an epoxy cyclohexyl stearate.

8. l,l,l-trichloroethane as claimed in Claim 3 in which the stabiliser for l,l,l-trichloroethane is a mixture of epoxy alkyl esters derived from long chain fatty acids and glycerol.

9. 1,1,1-trichloroethane as claimed in Claim 8 in which the stabiliser for l,l,l-trichloroethane is an epoxidised vegetable oil.

10. 1,1,1-trichloroethane as claimed in Claim -8 in which the stabiliser for l,l,l-trichloroethane is an epoxidised soya bean oil.

11. 1,1,1-trichloroethane as claimed in Claim 8 in which the stabiliser for l,l,l-trichloroethane is an epoxidised linseed oil.

12. 1,1,1-trichloroethane as claimed in Claim 1 in which the proportion by weight of epoxy alkyl ester is at least 0.025% with reference to l,1,1-trichlorethane.

13. 1,1,1-trichloroethane as claimed in Claim 12 in which the proportion by weight of epoxy alkyl ester is greater than 0.05% but not greater than 5% with reference to l,l,l-trichloroethane.

14. trichloroethane as claimed in Claim 12 in which the proportion by weight of epoxy alkyl ester is in the range 0.1% to 2% with reference to 1,1,1-trichloroethane.

15. 1,1,l-trichloroethane as claimed in Claim 1 in which there is also incorporated a stabilising amount of one or more of the following conventional stabilisers:- organic nitrates, nitriles, nitroalkanes, cyclic ethers having 3 to 6 membered rings, amines, alcohols, alkyl esters and ketones.

16. 1,1,1-trichloroethane as claimed in Claim 14 in which any one of the stabilisers is present in amount not greater than 4% by weight with reference to the l,l,l-trichloroethane.

17. A concentrated solution containing 20% to 70% by weight with reference to 1,1,1-trichloroethane of an epoxy alkyl ester as described in Claim 1.

18. A concentrated solution as claimed in Claim 17 which also contains a conventional stabiliser selected from one or more of the conventional stabilisers as described in Claim 15.

19. A method of inhibiting decomposition of 1,1,1-trichloroethane due to the presence of metals, which comprises incorporating in said solvent an epoxy alkyl ester as described in Claim 1 and also if desired incorporating a conventional stabiliser as described in Claim 15.

20. A method of degreasing metal and other articles which comprises bringing the articles into contact with 1,1,1-trichloroethane in the liquid or vapour state, wherein the 1,1,1-trichloroethane has been stabilised with an epoxy alkyl ester as described in Claim 1 which solvent may also contain a conventional stabiliser as described in Claim 15.