CA1175220A

CA1175220A - Stabilized trichloroethene and agent for the stabilization of trichloroethene

Info

Publication number: CA1175220A
Application number: CA000415213A
Authority: CA
Inventors: Klaus Blum; Rudolf Strasser
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 1982-02-05
Filing date: 1982-11-09
Publication date: 1984-10-02
Also published as: JPS6121604B2; DE3203907A1; EP0085949A3; EP0085949B1; ATE53565T1; EP0085949A2; JPS58135827A; DE3381638D1

Abstract

ABSTRACT Stabilized trichloroethene and agent for the stabi-lization of tricholorethene, which contains as stabilizing components a) a member selected from the group conslstlng of N-methylpyrrole, 2-tert.-butylphenol, 2,4-ditert.-butylphenol, 4-hydroxyanisol, 2-tert.-butyl-4-hydroxyanisol, 3-tert.-butyl-4-hydroxyanisol, 2,6-dimethylphenol and a mixture of at least two of the above members; b) a member selected from the group consisting of 2-methyl-2,3-epoxybutane, 2,3-dimethyl-2,3-epoxybutane, 3,3-dimethyl-1,2-epoxybutane, 1,2-epoxypentane, cyclopentenoxide, and a mixture of at least two of the above members: c) dllsobutylene; d) a member selected from the group consisting of ethyl acetate and propyl acetate and a mixture thereof; and e) at least one amlne which boils between 70 and 110°C at 1 bar.

Description

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The present invention relates to stabilized trichlo-roethene and an agent for the stabilization of tricholoroethene.

It is known that trichloroethene has to be stabilized against the disintegrating effect of heat, light, moisture and metals. A frequently used additive for trichloroethene, which has high stabilizing properties, is butylene oxide. Other stabilizing agents are mixtures of nitrilesr e.g., propionitrile, acrylic nitrile, and the like, which are added to trichloroethene which is used as an auxiliary component for lacquers.

In recent times, it was found, by toxicologic in-vestigations, that the addition of nitriles and especially butylene oxide as stabilizing additives for trichloroethene, is unadvisable.

It is therefore an object of the invention to find stabilizing agents for trichloroethene which do not contain the above-mentioned substances.

:

It is also another object of the invention to provide stabi1izing agents for trichloroethene which will render it suitable, in appropriately composed formulations, as an auxiliary ingredient for lacquers, as well as for degreasing agents.

Other objects of the invention will become apparent from the following description.

The stabilizing agent for trichloroethene according to the invention is characterized by the combination o~
the following ingredients:

a) N-methylpyrrole and/or 2-tert.-butylphenol and/or 2,4-ditert.-butylphenol and/or 4-hydroxyanisol and/or 2-tert.-butyl-4-hydroxyanisol and/or 3-tert.-butyl-4-hydroxyanisol and/or 2,6-dimethylphenol;

b) 2-methyl-2,3-epoxybutane and/or 2,3-dimethyl-

2,3-epoxybutane and/or 3,3-dimethyl-1,2-epoxybutane and/or 1,2-epoxypentane and/or cyclopentenoxide;

c) Diisobutylene;

d) Ethyl acetate and/or propyl acetate; and e) Diisopropylamine.

The invention further relates to stabilized tri-chloroethene which contains the stabilizer mixture defined above. The amount of stabilizer lies, as a rule, between 3,200 and 25,000 ppm by weight, preferably 5,000-10,000 ppm by weight, calculated on the total amount of stabilized trichloroethene.

Preferably, stabilized trichloroethene according to the invention contains (by weight):

a) 0 - 500 ppm N-methylpyrrole;

b) 0 - 500 ppm 2-tert.-butylphenol and/or 2,4-ditert.-butylphenol and/or 4-hydroxyanisol and/
or 2-tert.-butyl-4-hydroxyanisol and/or 3-tert.-butyl-4-hydroxyanisol and/or 2,6-dimethylphenol with the proviso that the components according to a) and b) amount to at least 10 ppm by weight;

c) 1,000 - 8,000 ppm 2-methyl-2,3-epoxybutane and/or 2,3-dimethyl-2,3-epoxybutane and/or

3,3-dimethyl-1,2-epoxybutane and/or 1,2-epoxypentane and/or cyclopentenoxide;

d) 100 - 4,000 ppm diisobutylene;

e) 2,000 - 3,000 ppm ethyl acetate and/or propyl acetate; and f) 10 - 100 ppm diisopropylamine.

Amines which boil at one bar between 70 C and 110 C are equivalent to diisopropylamine for the purposes of the invention. Examples are triethylamine and dimethylisobutylamine.

The amounts of epoxides (according to c) ) is preferably 4,000 - 6,000 ppm by weight.

When trichloroethene according to the invention is to be used as additive foe lac~uers, the amount of N-methylpyrrole is preferably maximally 10 ppm by weight, especially 0 or 0 - 5 ppm by weight. It is advantageous to adjust the amount of diisobutylene to the amount and type of the phenol used.

With 1,000 to 3,000 ppm by weight diisobutylene the optimum concentration for 2-tert.-butylphenol and 2,4-ditert.-butylphenol is 200 - 500 ppm by weight and with

4-hydroxyanisol it is 50 - 100 ppm by weight.

When 2-tert.-butyl-4-hydroxyanisol is used, preferably only 10 - 50 ppm by weight in addition to 100-200 ppm by weight diisobutylene are used.

For testing the stability, the trichloroethene according to the invention was subjected to the following three tests:

1) The accelerated oxidation time according to MIL-T-81533 A was determined. The test apparatus consisted of a boiling vessel with flux cooler heated by means of a 150 watt bulb and filled with 200 ml trichloroethene stabilized according to the invention.

Into the test liquid, a continuous, steam-saturated oxygen current (10-12 bubbles per minute) was passed.

Furthermore, a metallic aluminum strip was so arranged that half of it dipped into the test liquid. A second aluminum strip was arranged on the bottom of the vessel.

The stability was measured by the time during which the stabilized trichloroethene had to be sub~ected to the 'D

above conditions in order to reach an HCl-content of 0.02 % by weight. The HCl-content was determined by regular withdrawal of specimens and subsequent titration with phenolphthalein as indicator.

2) DKH-test: The above test arrangement was used with the difference that steel strips were used instead of aluminum strips. After 48 hours, the pH-value and the colour of the test liquid were evaluated. Moreover, the standing time which it took to reach the acidity limit of 0.02 % by weight HCl-content, was determined.

3) Further testing of the quality was carried out by the testing method proposed by the Bundesanstalt fUr Materialprufung (National Institute for Materials Testing:
BAM-Test).

For that test, 100 ml trichloroethene stabilized according to the invention were mixed with 100 ml toluene and boiled under reflux for 18 hours together with 18 g of alumi-num flakes, particle size less than 0.5 mm, and 0.7 g anhy-drous aluminum chloride.

A second test specimen was made up of the same ingredients, but it additionally contained lg zinc stearate.

A third test specimen additionally contained 10 ml oleic acid.

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Finally, the three described tests were repeated with distillates of trichloroethene stabilized according to the invention. The testing was considered satisfactory, if in none of the individual tests exothermic reactions were observed.

The invention will now be more fully described by a number of examples and comparison examples, but it should be understood that these a~e given by way of illustration and not of limitation. The data refers to the three test methods described above. The minus (-) sign indicates that no reaction occurred during the BAM
tests.

To 3 kg trichloroethene were added. 0.9 g N-methyl-pyrrole, 15 g 2-methyl-2,3-epoxybutane, 8.3 g diisobutylene, 8.3 g ethyl acetate, and 0.08 9 diisopropylamine.

The BAM test occurred without reaction. The accele-rated oxidation-time test according to MIL-T-81533 A
resulted in a standing time of 1920 hours.

Other results of tests carried out in the manner as followed in Example 1 are tabulated below.

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To 3 kg trichloroethene were added: 0.66 y 2.4-ditert.-butylphenol, 13.5g 2-methyl-2.3-epoxybutane, 6 g diisobutylene, 8.4 g ethyl acetate, and 0.06 g diisobutylamine.

The so-stabilized trichloroethene was subjected to the DKH-test. After 48 hours, the pH-value was 9.5; the test liquid was colourless. The standing time until the acidity limit of 0.02 % by weight HCl was reached was 240 hours.

Other results of tests carried out in the manner followed in Exasnple 5 are tabulated below.

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x All the tests according to Examples 5-11 fulfill the criteria of the BAM-test.

The composition of Example 5 was subjected to the DKH-test with the difference that, instead of 220 ppm 2,4-ditert.-butylphenol, the following compounds were used.

a) 220 ppm 2,6-ditert.-butylphenol;

b) 220 ppm anisol;

c) 220 ppm 2,6-dimethyl-p-cresol;

d) 220 ppm 4-tert.-amylphenol;

e) 220 ppm 2,6-ditert.-butyl-p-cresol; and f) 220 ppm 4-tert.-butylphenol The results are summarized in the following table.

STANDING TIME UNTIL
ACHIEVING THE ACIDITY
COMPARISON DKH-TEST LIMIT OF 0.02% BY
WEIGHT IN HOURS
EXAMPLE pH-VALUECOLOR
:
la 7.9Yellow 90 lb 1.5Yellow 48 lc 3.6Yellow 60 2'1~

STANDING TIME UNTIL
A~IEVING THE ACIDITY
COMPARI~ON DKH-TEST LIMIT OF 0.02% BY
WEIGHT IN HOURS
EXAMPLEpH-VALUE COLOR

ld 3.5 Yellow 60 le 2.5 Yellow 50 lf 3.9 Light 62 Yellow The results of Examples 1-11 show the excellent stability of the trichloroethene stabilized according to the invention to light metals, e.g., aluminum, which ls exhibited by the extremely high standing times.
Moreover, the DKH tests prove that the trichloroethene stabilized according to the invention is not only suitable as degreasing agent, but will also fulfill the requirements asked of trichloroethene as an auxiliary material for lacquers.

Comparison Examples la-lf demonstrate that the object of the invention is not achieved, if instead of the phenolic components used according to the invention, other phenolic components of similar structure are used.

Thus, while only several examples of the present invention have been shown and described, it will be obvious that many changes and modifications may be made thereunto, without departing from the spirit and scope of the invention.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A stabilizing agent for trichloroethene comprising:

a) a member selected from the group consisting of N-methylpyrrole, 2-tert.-butylphenol, 2,4-ditert.-butylphenol,4-hydroxyanisol, 2-tert.-butyl-4-hydroxyanisol, 3-tert.-butyl-4-hydroxyanisol, 2,6-dimethylphenol and a mixture of at least two of the above members;

b) a member selected from the group consisting of 2-methyl-2,3-epoxybutane, 2,3-dimethyl-2,3-epoxybutane, 3,3-dimethyl-1,2-epoxybutane, 1,2-epoxypentane, cyclopentenoxide, and a mixture of at least two of the above members;

c) diisobutylene;

d) a member selected from the group consisting of ethyl acetate and propyl acetate and a mixture thereof;
and e) at least one amine which boils between 70 and 110°C at 1 bar.

2. Stabilized trichloroethene comprising trichloroethane and a stabilizing agent comprising:

a) a member selected from the group consisting of N-methylpyrrole, 2-tert.-butylphenol, 2,4-ditert.-butylphenol,4-hydroxyanisol, 2-tert.-butyl-4-hydroxyanisol, 3-tert.-butyl-4-hydroxyanisol, 2,6-dimethylphenol and a mixture of at least two of the above members;

b) a member selected from the group consisting of 2-methyl-2,3-epoxybutane, 2,3-dimethyl-2,3-epoxybutane, 3,3-dimethyl-1,2-epoxybutane, 1,2-epoxypentane, cyclopentenoxide, and a mixture of at least two of the above members;

c) diisobutylene;

d) a member selected from the group consisting of ethyl acetate and propyl acetate and a mixture thereof;
and e) at least one amine which boils between 70 and 110°C at 1 bar.

3. The stabilized trichloroethene of claim 2 which contains 3,200 to 25,000 ppm by weight of said stabilizing agent.

4. The stabilized trichloroethene of claim 2, wherein said stabilizing agent comprises:

a) 0-500 ppm by weight N-methylpyrrole, b) 0-500 ppm by weight of a member selected from the group consisting of 2-tert.-butylphenol, 2,4-ditert.-butylphenol, 4-hydroxyanisol, 2-tert.-butyl-4-hydroxyanisol, 3-tert.-butyl-4-hydroxyanisol, 2,6-dimethylphenol and a mixture of at least two of the above members, with the proviso that the components according to a) and b) are at least present in an amount of 10 ppm by weight;

c) 1,000 - 8,000 ppm by weight of a member selected from the group 2-methyl-2,3-epoxybutane, 2,3-dimethyl-2,3-epoxybutane, 3,3-dimethyl-1,2-epoxybutane, 1,2-epoxypentane, cyclopentenoxide, and a mixture of at least two of the above members;

d) 100 - 4,000 ppm by weight diisobutylene;

e) 2,000-3,000 ppm by weight of a member of the group consisting of ethyl acetate, propyl acetate and a mixture thereof; and f) 10-100 ppm by weight of a member selected from the group consisting of diisopropylamine, triethylamine, dimethylisobutylamine and a mixture thereof.