JP2834586B2 - Method for producing perfluoro organic compound - Google Patents

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 perfluoro organic compound which is stable even when used as a heating medium for vapor-phase soldering and has good drainage.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a corresponding perfluoro organic compound from an organic compound having a carbon-hydrogen bond, an electrolytic fluorination method and a method using a high-valent metal fluoride such as cobalt trifluoride are known. Have been. When producing a perfluoro organic compound by these methods,
In general, the obtained fluorinated product includes an incomplete fluorinated product in which a hydrogen atom in the raw material partially remains in addition to the target perfluoro organic compound and other perfluoro organic compounds.

It is extremely difficult to selectively separate incomplete fluorinated compounds from the perfluoro organic compound obtained by the above-mentioned fluorination method by distillation. On the other hand, when a perfluoro organic compound is used for various purposes, even a small amount of incomplete fluorinated compound often causes serious trouble. For this reason, various attempts have been made to remove incomplete fluorine compounds contained in perfluoro organic compounds obtained by fluorination. As a result, a method in which the fluorinated product is brought into contact with a solution of an alkali metal or alkaline earth metal hydroxide, or a secondary or tertiary amine is currently preferably employed.

[0004]

The perfluoro organic compound obtained by such a method is substantially free of incomplete fluorinated compounds, is chemically stable, and can be used in various applications without any problem. However, when such a perfluoro organic compound is used in a heated state for a long period of time, particularly, a heat medium for vapor phase soldering (hereinafter abbreviated as VPS) for performing soldering in a gas phase portion in a boiling state. When used as an electronic component, the cause is unknown, but it gradually emits an unpleasant odor, or even after the VPS is completed, the electronic component or the like, which is the object of the VPS, is pulled up from the vapor bath of the perfluoro organic compound and held vertically. Since the perfluoro organic compound adheres to the surface of the electronic component and the like, and the electronic components and the like continue to be wet by the perfluoro organic compound for a relatively long time, a special process such as drying is required separately. there were.

It is not clear why the permeation of the perfluoro organic compound from the surface of the electronic component or the like becomes worse when the perfluoro organic compound is used as a heat medium for the VPS, but the organic compound having a high boiling point due to the VPS is not clear. Generation of
Alternatively, it can be considered that the organic compound has high affinity with the surface of the object of the VPS.

[0006]

Means for Solving the Problems In order to supply a perfluoro organic compound which does not cause such a change even when it is used for a long time as a heating medium for a VPS or the like, the present inventors have made various studies on its production method. I've been going. As a result, the desired stable perfluoro organic compound can be obtained by a simple method of bringing the hydrogen-free perfluoro organic compound obtained by the above-mentioned conventional production method into contact with molecular fluorine. And completed the present invention.

That is, the present invention relates to hydrocarbons having 4 to 32 carbon atoms, ethers, amines, alcohols, amides, carboxylic acids, sulfonic acids, acid halides,
Corresponding fluorinated product obtained by fluorinating at least one organic compound having a carbon-hydrogen bond selected from esters and ketones (hereinafter, also simply referred to as an organic compound having a carbon-hydrogen bond) Is contacted with at least one base selected from the group consisting of alkali metal hydroxides, alkaline earth metal oxides, secondary amines and tertiary amines, and then with molecular fluorine. A method for producing a perfluoro organic compound corresponding to the above organic compound.

In the present invention, the organic compound having a carbon-hydrogen bond used as a raw material for fluorination includes:
In performing fluorination, it is an organic compound having 4 to 32 carbon atoms, and more preferably an organic compound having 6 to 24 carbon atoms. The molecule may contain atoms such as halogen, nitrogen, oxygen, and sulfur. As these organic compounds, saturated or unsaturated aliphatic hydrocarbons, alicyclic hydrocarbons,
It is at least one selected from hydrocarbons such as aromatic hydrocarbons, ethers, amines, alcohols, amides, carboxylic acids, sulfonic acids, acid halides, esters, and ketones. Specifically, octane, octene, benzene, phenanthrene, decalin, caproic acid chloride, caproic acid fluoride,
Octanesulfonyl chloride, tetrasdropyran,
Octyl alcohol, hexyl alcohol, octanoic acid, hexanoic acid, octane sulfonic acid, methyl octanoate, tetrahydrofurfuryl amyl ether, benzamide, 2-octanone, monohexylamine, dihexylamine, tripentylamine, tributylamine, tripropylamine, Examples include trihexylamine, dipentylamine, dibutylpropylamine, 4-methyloctahydroquinolidine, dimethylaniline, octanethiol, and the like.

In the present invention, in order to obtain a highly stable perfluoro organic compound, it is preferable to use an organic compound containing no halogen atom other than fluorine in the molecule as a raw material.

When electrolytic fluorination is employed as the method for fluorinating an organic compound having a carbon-hydrogen bond, ethers having 4 to 32 carbon atoms, preferably 6 to 24 carbon atoms, of the organic compound 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, more preferably 6 to 24 carbon atoms, particularly tertiary amines. Tertiary amines having a saturated bond or a cyclic structure are also included. When fluorination with a high-atom metal fluoride is employed, among the organic compounds, particularly, aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, and aromatic hydrocarbons having 4 to 32, preferably 6 to 24 carbon atoms , Alicyclic hydrocarbons and ethers are preferably used.

As a method for fluorinating the organic compound having a carbon-hydrogen bond, known methods such as electrolytic fluorination, fluorination with high valent metal fluoride, and fluorination with molecular fluorine can be employed. The method of the present invention employs a relatively mild fluorination method that produces a fluorinated product containing incomplete fluorinated compounds such as electrolytic fluorination or fluorination with a high-valent metal fluoride. , Its effect is remarkable.

The procedure and conditions of the above fluorination method may be performed in the same manner as known methods. The corresponding fluorinated product obtained by the fluorination includes an incomplete fluorinated product in which some hydrogen atoms remain together with the desired perfluoro organic compound. In order to remove incomplete fluorinated compounds, the present invention provides that the fluorinated product is at least one selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, secondary amines and tertiary amines. And then contact with molecular fluorine. Before performing this treatment, neutralization with a dilute aqueous solution of sodium hydroxide, potassium hydroxide, etc., or blowing of an inert gas such as nitrogen gas is performed to remove hydrogen fluoride mixed in the fluorinated product. Or other operations such as distillation to separate in advance some components other than the desired perfluoro organic compound. As the alkali metal hydroxide and alkaline earth metal hydroxide used for removing incomplete fluorinated compounds, sodium hydroxide, potassium hydroxide and calcium hydroxide are used. These are usually used as solutions dissolved in water, alcohols such as methanol and ethanol, phenol and the like. Of these, preferred are aqueous solutions of sodium hydroxide and potassium hydroxide in an alcoholic solution of potassium hydroxide. in this case,
The concentration is usually selected from a range of 20% by weight or more.

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

The contact between the fluorinated product and the above-mentioned base is carried out at a temperature of 50 ° C. or higher with stirring, more preferably at a reflux temperature of 5 to 5 ° C.
Performed for a period of 250 hours. Thereafter, the mixture is allowed to stand, and a liquid substantially composed of a perfluoro organic compound in the lower layer is collected, and a purification treatment is performed as necessary.

The most important feature of the present invention resides in that a mixture substantially consisting of a perfluoro organic compound, which is a fluorination product obtained by the above-mentioned method, is brought into contact with molecular fluorine. The mixture of the perfluoro organic compound can be brought into contact with molecular fluorine in a gas or liquid state, but is usually brought into contact with molecular fluorine in a liquid state by the following method. (1) The perfluoro organic compound is brought into contact with molecular fluorine while stirring. (2) Molecular fluorine is blown into the perfluoro organic compound. (3) The perfluoro organic compound and molecular fluorine are brought into contact in countercurrent. (4) The perfluoro organic compound is brought into contact with molecular fluorine as droplets.

In this case, it is preferable to use nickel, nickel alloy, other metal particles, Raschig ring, wire mesh, or the like as the filler in order to increase the contact efficiency.

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

After the perfluoro organic compound is brought into contact with the molecular fluorine, if necessary, an operation such as distillation can be performed to increase the purity of the target perfluoro organic compound.

[0019]

The perfluoro organic compound obtained by practicing the present invention can be used for a vapor phase soldering (VPS) in which the perfluoro organic compound is used in a heated state for a long period of time, and particularly in a boiling state and soldered in a vapor phase. When used as a heat carrier,
Since the liquid does not give off-flavors and the liquid separates quickly from the electronic components and the like, the drying of the electronic components and the like after the end of the VPS becomes easy.

Before and after the contact with fluorine gas of the present invention, in many cases, no remarkable change has been found in the composition and various physical properties of the perfluoro organic compound. Nevertheless, it is not clear why such a large effect can be obtained, but the present inventors have found that a compound having some unstable chemical structure present in a trace amount in a perfluoro organic compound before contacting fluorine gas. It is presumed that the stabilization is caused by contact with fluorine gas.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 Electrolytic fluorination of tributylamine A fluororesin electrolytic cell (with an inner diameter of 11) having a reflux condenser (-40 ° C.) at the top.
cm, height 30 cm). The negative anode was composed of 14 nickel plates (6
5 mm x 105 mm). 1 anhydrous hydrogen fluoride in the electrolytic cell
After 550 g and 160 g of tributylamine were supplied, current was supplied at a constant current of 27 A (voltage: about 5.8 V) until the raw material amine disappeared and the cell voltage sharply increased. In addition, the electrolysis temperature was kept at -9 ° C by adjusting the temperature of the refrigerant cooling the electrolysis tank. Thereafter, the fluorinated purified product accumulated at the bottom of the electrolytic cell was extracted. The same operation was repeated to obtain a sufficient amount of the fluorinated product to carry out the following experiment. The ratio of the incomplete fluorinated product contained therein was about 38% according to gas chromatography analysis.

Next, an equal volume of a 65% aqueous sodium hydroxide solution and diisobutylamine were added to the fluorinated product, and the mixture was refluxed for 110 hours. Thereafter, the mixture was allowed to stand, the lower layer liquid was collected, washed with water, and distilled to obtain perfluorotributylamine containing no incomplete fluorinated product. Further, this was treated with fluorine gas as follows. 2.5 kg of perfluorotributylamine was charged into a nickel container (with an inner diameter of 10) having a stirrer and a reflux condenser (−50 ° C.) at the top.
cm, height 30cm), and set the temperature to 3 by oil bath.
While maintaining the temperature at 5 ° C., a mixed gas of fluorine gas and nitrogen gas (1: 1 by volume) was supplied from the lower portion at a rate of 300 ml / hr (25 ° C.) for 80 hours. Subsequently, only nitrogen gas was blown for 3 hours, followed by washing with water and drying. The same operation was repeated to obtain a fluorine-treated perfluorotributylamine in an amount sufficient to carry out the following test as a heating medium for vapor phase soldering.

The thus obtained perfluorotributylamine is put into a gas-phase soldering apparatus, and cream solder for low-boiling solder is applied to a vapor layer at about 177 ° C. formed above the liquid, and the substrate on which the soldering parts are mounted is mounted. It was supplied and soldered. As a vapor phase soldering device, a device in which perfluorotributylamine is filled up to a position 3 cm above an electric heater, a copper cooling coil is provided 10 cm above the liquid surface, and another cooling coil is provided 50 cm above the same. Using. The gas-phase soldering apparatus was operated for 1000 hours while replenishing the reduced amount of perfluorotributylamine. At this time, when the liquid was extracted from the apparatus and examined, it was found that there was no smell, and on the other hand, there was almost no dirt inside the apparatus. In order to know the degree of separation of the extracted liquid, 0.02 ml was dropped on a KBr plate for infrared absorption spectrum measurement using a microsyringe, and this KBr plate was transferred to an infrared absorption spectrum measuring apparatus (IR-440 manufactured by Shimadzu Corporation). ), The time was measured until the liquid was burned off the KBr surface at 20 ° C. and no absorption at 1200 cm ⁻¹ indicating the presence of CF bonds was observed.
The measurement result was 10 minutes and 15 seconds. For comparison, the same measurement was performed on the same liquid that was not used for vapor-phase soldering, and it was 10 minutes and 20 seconds.

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

After operating the vapor-phase soldering apparatus for 1000 hours, the liquid was extracted and examined. The liquid showed an irritating odor, and the inner surface of the apparatus was considerably contaminated. The time required for the liquid dropped on the KBr plate to disappear for both the extracted liquid and the liquid not used for the vapor phase soldering was 20 minutes 5 seconds and 10 minutes 50 seconds, respectively.

Example 2 In order to remove the incomplete fluorinated product, the same procedure was carried out except that an equal volume of an 85% aqueous potassium hydroxide solution and tributylamine were added to the electrolytic fluorinated product, and the mixture was heated under reflux for 40 hours. An experiment was performed as in Example 1. In this case, the time required for the liquid dropped on the KBr plate to disappear for both the perfluoro organic compound used for the vapor phase soldering and the unused compound 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 a mixed gas of fluorine gas and nitrogen gas (3: 1 by volume) at a flow rate of 400 ml / hour (25 ° C.), and a processing time of 30 minutes. The experiment was performed in exactly the same manner as in Example 1 except that the experiment was performed for a time. In this case, the time required for the liquid dropped on the KBr plate to disappear for both the used perfluoro organic compound and the unused perfluoro organic compound in the vapor phase soldering is 1 hour.
0 minutes 25 seconds and 10 minutes 20 seconds.

Example 4 The fluorination of phenanthrene with cobalt trifluoride
The reaction was carried out using a nickel reactor having a length of 50 cm and an inner diameter of 9 cm equipped with a stirrer filled with 1.8 kg of cobalt trifluoride powder. 40 g of phenanthrene were vaporized and supplied to a reactor maintained at 280 ° C. together with nitrogen gas (80 ml / min) at a rate of 7 g / hr. As a result, 128.5 g of a fluorinated product consisting of perfluorophenanthrene and incomplete fluorinated product was obtained. Equal amounts of 65% potassium hydroxide and diisobutylamine were added thereto, and the mixture was heated under reflux for 90 hours. Thereafter, the liquid was allowed to stand, and the lower layer liquid was collected, washed with water and distilled to obtain perfluoroperhydrophenanthrene containing no incomplete fluorinated product. Treatment of 2.5 kg of perfluoroperhydrophenanthrene obtained by repeating the same operation with fluorine gas was performed in exactly the same manner as in Example 1. Using the obtained liquid, vapor phase soldering was performed for 1000 hours in the same manner as in Example 1. At this time, when the liquid was extracted from the apparatus and examined, it was found that there was no smell, and on the other hand, there was almost no dirt inside the apparatus.
For each of the extracted liquid and the liquid not used for vapor phase soldering for comparison, the time taken for the liquid dropped on the KBr plate to be measured in the same manner as in Example 1 was 28. Minutes 55 seconds and 28 minutes 40 seconds.

Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07B 39/00 C07C 209/74 C07C 17/00

Claims (1)

(57) [Claims] 1. At least one member selected from hydrocarbons having 4 to 32 carbon atoms, ethers, amines, alcohols, amides, carboxylic acids, sulfonic acids, acid halides, esters and ketones. A corresponding fluorinated product obtained by fluorinating an organic compound having a carbon-hydrogen bond is selected from the group consisting of an alkali metal hydroxide, an alkaline earth metal hydroxide, a secondary amine and a tertiary amine. A method for producing a perfluoroorganic compound corresponding to the above organic compound, which comprises contacting with at least one base and then contacting with molecular fluorine.