JPH04221324A - Production of perfluoro organic compound - Google Patents

Abstract

PURPOSE:To obtain a perfluoro organic compound excellent in liquid separation without any malodor in use as a heating medium for vapor-phase soldering. CONSTITUTION:A perfluoro organic compound is obtained by bringing a fluorination product of an organic compound into contact with at least one base selected from the group consisting of alkali metallic hydroxides, alkaline earth metallic hydroxides, secondary amines and tertiary amines and then with a molecular fluorine.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a perfluorinated organic compound which is stable even when used as a heat medium in vapor phase soldering and exhibits good liquid drainage.

0002

[Prior Art] Conventionally, electric field fluorination and methods using high-valent metal fluorides such as cobalt trifluoride have been known as methods for obtaining perfluorinated organic compounds from organic compounds having carbon-hydrogen bonds. It is being When producing perfluoro organic compounds by these methods,
In the resulting fluorinated product, in addition to the target perfluoroorganic compound and other perfluoroorganic compounds, there is generally an incompletely fluorinated product in which some of the hydrogen atoms in the raw material remain.

[0003] It is extremely difficult to selectively separate incompletely fluorinated compounds by distillation from perfluorinated organic compounds obtained by the above-mentioned fluorination method. On the other hand, when perfluorinated organic compounds are used for various purposes, even trace amounts of incompletely fluorinated compounds often cause serious problems. To this end, various methods have been attempted to remove incomplete fluorine compounds contained in perfluorinated organic compounds obtained by fluorination. As a result, methods are currently preferred in which the fluorinated product is contacted with a solution of an alkali metal or alkaline earth metal hydroxide, or with a secondary or tertiary amine.

0004

The perfluorinated organic compounds obtained by such a method are chemically stable and do not contain any incompletely fluorinated compounds, and can be used in various applications without problems. However, when such perfluorinated organic compounds are used in a heated state for a long period of time, they are used as a heating medium for vapor phase soldering (hereinafter abbreviated as VPS), in which soldering is performed in the vapor phase in a boiling state. Although the cause is unknown, the electronic components may gradually emit a strange odor, and even if the electronic components, which are the objects of VPS, are pulled out of the perfluoro organic compound vapor bath after VPS and held vertically, the electronic components Perfluorinated organic compounds are attached to the surfaces of electronic components, etc., and electronic components remain wet with the perfluorinated organic compounds for a relatively long period of time, resulting in the need for special processes such as drying. there were.

Although it is not clear why the separation of perfluorinated organic compounds from the surfaces of electronic parts and the like is exacerbated when perfluorinated organic compounds are used as heat carriers in VPS, it is clear that organic compounds with high boiling points are removed by VPS. generation of,
Alternatively, it can be considered that this is the production of an organic compound that has a high affinity with the surface of the VPS target.

[0006]

[Means for Solving the Problem] In order to provide a perfluoro organic compound that does not undergo such changes even when used as a heat medium for VPS over a long period of time, the present inventors have conducted various studies regarding its production method. I've done it. As a result, the desired stable perfluoroorganic compound can be obtained by a simple method of contacting the perfluoroorganic compound that does not contain hydrogen atoms obtained by the conventional production method described above with molecular fluorine. They discovered this and completed the present invention.

[0007] That is, the present invention uses a product obtained by fluorinating an organic compound having a carbon-hydrogen bond, which is composed of an alkali metal hydroxide, an alkaline earth metal oxide, a secondary amine, and a tertiary amine. This is a method for producing a perfluoroorganic compound, which comprises contacting with at least one base selected from the group and then contacting with molecular fluorine.

In the present invention, organic compounds having carbon-hydrogen bonds used as raw materials for fluorination include:
When performing fluorination, the number of carbon atoms is 4 to 32, and even 6 to 32.
24 organic compounds are preferred, including halogen,
It may also contain atoms such as nitrogen, oxygen, and sulfur. These organic compounds include hydrocarbons such as saturated or unsaturated aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons;
Included are ethers, amines, alcohols, amides, carboxylic acids, sulfonic acids, acid halides, esters, ketones, and the like. Specifically, octane, octene, benzene, phenanthrene, decalin, caproic acid chloride, caproic acid fluoride, octane sulfonyl chloride, tetrasdropyran, octyl alcohol, hexyl alcohol, octanoic acid, hexanoic acid, octanesulfonic acid, octanoic acid Methyl, tetrahydrofurfuryl amyl ether, benzamide, 2-octanone, monohexylamine, dihexylamine, tripentylamine, tributylamine, tripropylamine, trihexylamine, dipentylamine, dibutylpropylamine, 4-methyloctahydroquinolidine , dimethylaniline, octanethiol, etc.

In the present invention, in order to obtain a highly stable perfluorinated organic compound, it is preferable to use as a raw material an organic compound that does not contain any halogen atoms other than fluorine in its molecule.

When electrolytic fluorination is employed as a method for fluorinating the above-mentioned organic compound having a carbon-hydrogen bond, ethers having 4 to 32 carbon atoms, preferably 6 to 24 carbon atoms among the above-mentioned organic compounds are used. , polyethers, amines, carboxylic acid halides, and sulfonic acids are preferably used. Among these, particularly preferred organic compounds are amines having 4 to 32 carbon atoms, preferably 6 to 24 carbon atoms, especially tertiary amines, which include, in addition to trialkylamines, carbon chains bonded to the nitrogen atom that are free of carbon atoms. Tertiary amines having saturated bonds or cyclic structures are also included. When fluorination with a high-atomic metal fluoride is employed, among the organic compounds, aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, and aromatic hydrocarbons having 4 to 32 carbon atoms, preferably 6 to 24 carbon atoms are used. , alicyclic hydrocarbons, and ethers are preferably used.

[0011] As a method for fluorinating the above-mentioned organic compound having a carbon-hydrogen bond, known methods such as electrolytic fluorination, fluorination using a high-valent metal fluoride, and fluorination using molecular fluorine can be employed. ,,The method of the present invention is applicable when a relatively mild fluorination method is used, such as electrolytic fluorination method or fluorination using a high-valent metal fluoride, in which a fluorinated product containing an incompletely fluorinated product is obtained. The effect is remarkable.

The procedure and conditions for the above fluorination method may be the same as those of known methods. The product obtained by fluorination contains the target perfluorinated organic compound as well as an incompletely fluorinated product in which some hydrogen atoms remain. In order to remove incompletely fluorinated products, the present invention converts the fluorinated products into alkali metal hydroxides, alkaline earth metal hydroxides,
After being brought into contact with at least one base selected from the group consisting of secondary amines and tertiary amines, it is brought into contact with molecular fluorine. Before carrying out this treatment, in order to remove hydrogen fluoride mixed in the product, neutralization with a dilute aqueous solution of sodium hydroxide, potassium hydroxide, etc., and blowing of an inert gas such as nitrogen gas are carried out. Alternatively, distillation or other operations may be carried out in order to preliminarily separate some components other than the desired perfluoroorganic compound. Sodium hydroxide, potassium hydroxide, and calcium hydroxide are used as the alkali metal hydroxide and alkaline earth metal hydroxide used to remove incompletely fluorinated compounds. These are usually used as a solution dissolved in water, alcohol such as methanol or ethanol, phenol, or the like. Preferred among these are aqueous solutions of sodium hydroxide, potassium hydroxide, and alcoholic solutions of potassium hydroxide. In this case, the concentration is usually selected from a range of 20% by weight or more.

The secondary amine and tertiary amine are not particularly limited, and include, for example, dibutylamine, diisobutylamine, dipropylamine, dibentylamine, tripropylamine, tributylamine, trioctylamine, piperidine, pyridine, Quinoline and the like are preferably used. Even better effects can be obtained when the alkali metal hydroxide or alkaline earth metal hydroxide is used in combination with a secondary amine or tertiary amine. In this case, the mixing ratio of the alkali metal hydroxide or alkaline earth metal hydroxide and the secondary amine or tertiary amine is selected from a wide range, but is usually 1/4 to 4/1 (weight ratio). It is.

[0014] The fluorinated product and the above-mentioned base are brought into contact with each other at a temperature of 50°C or higher under stirring, more preferably at a temperature of 50°C under reflux.
It is carried out in the range of ~250 hours. After that, let it stand and collect the liquid consisting of the perfluoro organic compound in the lower layer.
Perform purification treatment if necessary.

The greatest feature of the present invention is that the perfluoroorganic compound obtained by the above method is brought into contact with molecular fluorine. The perfluorinated organic compound can be brought into contact with molecular fluorine in a gaseous or liquid state, but is usually brought into contact with molecular fluorine in a liquid state by the following method. (1) A perfluorinated organic compound is brought into contact with molecular fluorine while stirring. (2) Injecting molecular fluorine into a perfluorinated organic compound. (3) Bringing the perfluorinated organic compound and molecular fluorine into contact in countercurrent flow. (4) Bringing the perfluorinated organic compound into contact with molecular fluorine in the form of droplets.

In this case, in order to improve the efficiency of contact, it is preferable to use particles of nickel, nickel alloy, other metals, Raschig rings, wire mesh, etc. as fillers.

The amount of molecular fluorine to be supplied varies depending on the contact efficiency between the two, but 1 kg of perfluoro organic compound
It is usually sufficient if the amount is 0.1 to 2.0 mol or more. In this case, molecular fluorine discharged from the system without being consumed can be recovered and recycled. Molecular fluorine can be used as it is or diluted to about several percent with an inert gas such as nitrogen, helium, or neon. The temperature during contact is -30 to 110°C, preferably 10 to 80°C. The contact is usually carried out under normal pressure, but may also be under pressure. The contact time is not particularly limited, but is usually 1~
Selected from a range of 90 hours. Nickel, Monel, stainless steel, etc. are used as the material of the device for making contact.

After the perfluoroorganic compound and molecular fluorine are brought into contact, operations such as distillation may be performed as necessary to increase the purity of the desired perfluoroorganic compound.

[0019]

[Effect] The perfluorinated organic compound obtained by carrying out the present invention can be used for long periods of time in a heated state, especially for vapor phase soldering (VPS) in which soldering is performed in the vapor phase in a boiling state. Also when used as a heat medium,
It does not give off any strange odor, and since the liquid quickly separates from electronic parts, etc., it becomes easy to dry electronic parts, etc. after VPS is completed.

In most cases, no significant changes in the composition or various physical properties of perfluoroorganic compounds are found before and after contact with fluorine gas according to the present invention. Despite this, it is unclear why such a large effect is obtained, but the present inventors discovered that a small amount of a compound with an unstable chemical structure present in the perfluoro organic compound was removed before contacting with fluorine gas. It is speculated that this is due to stabilization caused by contact with fluorine gas.

[0021]

[Examples] Examples are shown below to explain the present invention in more detail, but the present invention is not limited to these examples.

Example 1 Electrolytic fluorination of tributylamine was carried out using a reflux condenser (
-40℃) made of fluororesin electrolytic cell (inner diameter 11cm)
m, height 30 cm). The anode and cathode consisted of 14 nickel plates (65 mm x 105 mm) arranged alternately with a distance between the electrodes of 1.1 mm. After 1,550 g of anhydrous hydrogen fluoride and 160 g of tributylamine were supplied to the electrolytic cell, electricity was applied at a constant current value of 27 A (voltage was approximately 5.8 V) until the raw material amine was exhausted and the cell voltage rose sharply. Note that the electrolysis temperature was maintained at -9°C by adjusting the temperature of the refrigerant cooling the electrolytic cell. Thereafter, the fluorinated purified product accumulated at the bottom of the electrolytic cell was extracted. The same operation was repeated to obtain sufficient amount of fluorinated product to perform the following experiments. The percentage of incompletely fluorinated substances contained in this was approximately 38% according to gas chromatography analysis.

Next, equal volumes of a 65% aqueous sodium hydroxide solution and diisobutylamine were added to the fluorinated product and heated under reflux for 110 hours. Thereafter, the mixture was allowed to stand still, and the liquid in the lower layer was collected, washed with water, and then distilled to obtain perfluorotributylamine containing no incompletely fluorinated substances. Furthermore, this was treated with fluorine gas as follows. 2.5 kg of perfluorotributylamine was charged into a nickel container (inner diameter 10 cm, height 30 cm) equipped with a stirrer and a reflux condenser (-50°C) at the top, and the temperature was maintained at 35°C with an oil bath from the bottom. Mixed gas of fluorine gas and nitrogen gas (volume ratio 1:1) at 300ml/hr
(25° C.) for 80 hours. Subsequently, only nitrogen gas was blown into the film for 3 hours, followed by washing with water and drying. The same operation was repeated to obtain a sufficient amount of fluorine-treated perfluorotributylamine to perform the following test as a heating medium for vapor phase soldering.

The perfluorotributylamine thus obtained is put into a vapor phase soldering device, and a cream solder for low boiling point solder is applied to the vapor layer at about 177° C. formed on the top of the liquid, and the board on which the soldered parts are mounted is applied. I supplied it and soldered it. As a vapor phase soldering device, perfluorotributylamine is filled up to 3 cm above the electric heater, and a copper cooling coil is installed 10 cm above the liquid level.
Further, another cooling coil was used at a distance of 50 cm above the cooling coil. The vapor phase soldering apparatus was operated for 1000 hours while replenishing the decreased liquid amount of perfluorotributylamine. At this point, the liquid was removed from the device and examined, and there was no odor, and there was almost no dirt found inside the device. In order to determine the degree of separation of the extracted liquid, 0.02 ml was dropped onto a KBr plate for infrared absorption spectrum measurement using a microsyringe.
), then this liquid is set vertically at 20℃.
1200 is burnt off from the Br surface, indicating the presence of C-F bonds.
The time until absorption at cm-1 was no longer observed was measured. The measurement result was 10 minutes and 15 seconds. For comparison, the same liquid that was not used for vapor phase soldering was also measured in the same manner, and the time was 10 minutes and 20 seconds.

Comparative Example An experiment using perfluorotributylamine as a heating medium for vapor phase soldering was carried out in the same manner as in Example 1, except that perfluorotributylamine was not treated with fluorine gas.

After operating the vapor phase soldering device for 1000 hours, the liquid was drained and examined, and it had a pungent odor and the inside surface of the device was found to be quite dirty. The time taken for the liquid dropped on the KBr plate to disappear for both the extracted liquid and the liquid not used for vapor phase soldering was 20 minutes 5 seconds and 10 minutes 50 seconds, respectively.

Example 2 The same procedure was followed except that equal volumes of 85% aqueous potassium hydroxide and tributylamine were added to the electrolytically fluorinated product and heated under reflux for 40 hours in order to remove incompletely fluorinated products. The experiment was carried out as in Example 1. In this case, the time required for the liquid dropped on the KBr board to disappear for both the perfluorinated organic compound used for vapor phase soldering and the unused one was 10 minutes 45 seconds and 10 minutes 30 seconds, respectively.

Example 3 Perfluorotributylamine was treated with fluorine gas at a temperature of 80°C, a flow rate of 400ml/hour (25°C) of a mixed gas of fluorine gas and nitrogen gas (3:1 by volume), and a treatment time of 30°C. The experiment was conducted in exactly the same manner as in Example 1, except that the experiment was conducted using time. In this case, the time required for the liquid dropped on the KBr board to disappear during vapor phase soldering was 10 minutes 25 seconds and 10 minutes 20 seconds for both the used and unused perfluorinated organic compounds.

Example 4 Fluorination of phenanthrene with cobalt trifluoride was
The experiment was carried out using a nickel reactor with a length of 50 cm and an inner diameter of 9 cm, equipped with a stirrer and filled with 1.8 kg of cobalt trifluoride powder. 40g of phenanthrene is vaporized, 7g/
2 with nitrogen gas (80ml/min) at a rate of hr.
It was fed to a reactor maintained at 80°C. As a result, 128.5 g of a fluorinated product consisting of perfluorophenanthrene and an incompletely fluorinated product was obtained. To this, equal amounts of 65% potassium hydroxide and diisobutylamine were added, and the mixture was heated under reflux for 90 hours. Thereafter, the liquid was allowed to stand still and the lower layer was collected, washed with water, and then distilled to obtain perfluoroperhydrophenanthrene containing no incompletely fluorinated substances. 2.5 kg of perfluoroperhydrophenanthrene obtained by repeating the same operation was treated with fluorine gas in exactly the same manner as in Example 1. Using the obtained liquid, conduct vapor phase soldering once in the same manner as in Example 1.
I went for 000 hours. At this point, the liquid was removed from the device and examined, and there was no odor, and there was almost no dirt found inside the device. The time taken for the liquid dropped on the KBr plate to disappear was measured in the same manner as in Example 1 for the extracted liquid and the liquid not used in vapor phase soldering for comparison. They were minutes 55 seconds and 28 minutes 40 seconds.

Claims (1)

[Claims] Claim 1: A product obtained by fluorinating an organic compound having a carbon-hydrogen bond, selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, secondary amines and tertiary amines. 1. A method for producing a perfluoroorganic compound, which comprises contacting the perfluorinated organic compound with at least one base and then contacting it with molecular fluorine.