JPS6389690A - Production of perfluorotripentylamine - Google Patents

Abstract

PURPOSE:To produce perfluorotripentylamine capable of suppressing the generation of perfluoroisobutylene (PFIB) by restricting the concn. of an isomer having isopentyl and 2-methylbutyl groups in tripentylamine as starting material. CONSTITUTION:The concn. of an isomer having isopentyl and 2-methylbutyl groups in tripentylamine as starting material is restricted to <=8mol%. The tripentylamine is electrolytically fluorinated to produce perfluorotripentylamine. This product has perfluoroisopentyl and perfluoro-2-methylbutyl groups which account for <=about 13% of all of perfluoropentyl groups in the product. When the perfluorotripentylamine is used as a heat medium for vapor soldering, the generation of poisonous PFIB can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing perfluorotripentylamine by electrolytic fluorination using tripentylamine as a raw material.

[Description of prior art and problems to be solved by the invention]

Par7A/Olotribentylamine is chemically stable, inert to various materials, high dielectric strength, excellent thermal conductivity, low surface tension, non-flammable, non-toxic.・It has various excellent properties such as being odorless. Utilizing these properties, fluorotriquatinylamine is used as a heating medium in test baths and vapor phase soldering methods in the field of electronic materials.

In particular, recently, with the miniaturization of electronic devices, the vapor phase soldering method has begun to attract attention due to the demand for mounting electronic components on a board with high density. However, commercially available A
- Fluorotripentylamine “70 Linato F”
"C-70" (product name: 3M) uses 9-fluoroisobutylene (hereinafter referred to as PFI) during vapor phase soldering.
B), and acidic substances such as hydrogen fluoride, although in very small quantities, have the problem of repelling insects. PFIB
is a highly toxic substance.

As a result of repeated research aimed at reducing the amount of PFIB produced, the present inventors discovered that perfluorotripentylamine contains various isomers and that these isomers grow perfluoroisomer. We have discovered that when the proportion of pentyl groups and perfluoro-2-methylbutyl groups to all perfluoropentyl groups (ratio of the number of groups, the same applies hereinafter) is below a certain value, the amount of PFIB produced can be suppressed to an extremely low level, Already suggested. (Patent application (2) filed on September 16, 1986) In order to reduce the amount of PFZE produced, the 74-fluoroisopentyl group and the f-fluoro-2-methylbutyl group in the 4-fluorotriitylamine It is possible to reduce the proportion of these groups, but it is extremely difficult to selectively separate isomers bearing each of these groups. Accordingly, the present inventors have conducted various studies on methods of creating fluorotriben f-fluoramine with a small proportion of each of the above groups in a method of electrolytically fluorinating tripentylamine.

[Means for solving the problem] As a result, if the amount of the isomer possessing at least one of the isopentyl group and the 2-methylbutyl group contained in tripentylamine used as a raw material is below a certain value, It was discovered that the ratio of i4-fluoroisopentyl groups and 9-fluoro-2-methylbutyl groups to the total barfluoropentyl groups in the obtained .f-fluorotripentylamine was significantly reduced, and the present invention was completed. Ta.

That is, the present invention provides a method for electrolytically fluorinating tripentylamine to create perfluorotripentylamine. This is a method for creating perfluorotripentylamine, which is characterized by using tripentylamine whose isomer having at least one of the following has a degree of a of 8 molar or less.

Among the various isomers in tri4-ethylamine, which is a raw material for electrolytic fluorination, when the concentration of the isomer containing at least one of isopentyl group and 2-methylbutyl group becomes 8 molar or less, this tripentylamine The proportion of perfluoroisohentyl groups and perfluoro-2-methylbutyl groups to the total perfluoropentyl groups in perfluorotripentylamine obtained by electrolytic fluorination of fluorinated perfluorotripentylamine rapidly decreases (Figure 1). Then, the concentration of the isomer having at least one of an isopentyl group and a 2-methylbutyl group is reduced to 5 molar or less.
The proportion of the perfluoroisopentyl group and the i9-fluoro-2-methylbutyl group in the total perfluoro-tetra groups in the fluorotripentylamine can be 10% or less. On the other hand, when using Tsuku-fluorotripentylamine as a heating medium for vapor phase soldering,
For the purpose of reducing the generation of PFIB, it is preferable that the proportion of the nosefluoroisopentyl group and the perfluoro-2-)methylgutyl group to the total perfluoropentyl groups is 10% or less. Therefore, in the tripentylamine used as a raw material in the present invention, it is preferable that the proportion of isomers having at least one of an isopentyl group and a 2-methylbutyl group is 5 molar or less.

When the concentration of the isomer containing at least one of the iso-4-ethyl group and the 2-methylbutyl group contained in the tripentylamine starting material is reduced to 8 molar or less, the product 9-fluoro-IJ Perfluoroisopentyl group in hentylamine and .f-fluoro-2-
The present inventors discovered for the first time the phenomenon that the total amount of methylbutyl groups--the proportion of fluoroityl groups in the total amount decreases rapidly. Incidentally, in the above-mentioned commercially available perfluorotrihenthylamine, the ratios of the glossy fluoroisopentyl group and the perfluoro-2-methylbutyl group to the total perfluorotetra groups are about 8% and 10%, respectively. Therefore, in the creation of commercially available fluorotritylamine, the concentration of isomers having at least one of isopentyl group and 2-methylbutyl group is very high, according to the above-mentioned Figure 1. , for example 4
It is presumed that a compound with a molar coefficient of 0 or more is used.

5 In the present invention, the degree a of the isomer in which at least one of the isopentyl group and the 2-methylbutyl group in tripentylamine is M can separate these isomers from tri-n-pentylamine, etc. It was determined based on a calibration curve for each isomer prepared in advance by gas chromatography using a column.

The method for obtaining tripentylamine in which the concentration of the isomer having at least one of an isopentyl group and a 2-methylbutyl group contained in tripentylamine as a raw material is within the range specified in the present invention is based on the production of such an isomer. Either a production method that suppresses the above isomers is selected, or a method is adopted in which tripentylamine containing such isomers is produced and then the above isomers are removed from N production.

As the electrolytic fluorination method, any known method can be employed without any restriction. That is, fluorination can be carried out by charging anhydrous hydrogen fluoride in which tripentylamine is dissolved in an electrolytic cell having an anode and a cathode, and applying current between the anode and the cathode. Anhydrous hydrogen fluoride can be used by using commercially available anhydrous hydrogen fluoride as it is, or by dehydrating a trace amount of water by a known method, for example, electrolysis using a microcurrent. It is generally preferred that the amount of tripentylamine dissolved in anhydrous hydrogen heptadide ranges from 3 to 40M. The anode in the electrolytic cell is usually made of nickel, and the cathode is made of iron, stainless steel, nickel, a nickel alloy, etc. As for the electrolytic conditions, known conditions may be employed without particular limitation. Current density is 0.5-5 A/
dm2s voltage is 4.5~S, OV, electrolysis temperature is -10
It is preferable to conduct electrolysis while stirring or circulating the electrolytic solution, which may be selected from the range of 20° C. to 20° C., and can be carried out by either a patch method or a continuous method.

Perfluorotripentylamine separates into layers below the electrolyte along with other fluorinated compounds. Therefore, after extracting the separated fluoride either continuously or intermittently, some of the anhydrous hydrogen fluoride mixed in is removed, and 74? - Distill components other than fluorotripentylamine as necessary;
Perfluorotripentylamine is obtained by separation by known methods such as amine treatment.

〔effect〕

When /4'fluorotripentylamine is prepared by the method of the present invention, the concentration of the isomer having at least one of an isopentyl group and a 2-methylbutyl group in tripentyl as a raw material and amine is 8 molar or less. Furthermore, the molar ratio should be 5 or less, preferably 3 or less, so that the total perfluorohythyl groups of the obtained perfluorotripentylamine, the perfluoroisopentyl groups, and the 3-fluoro - The proportion occupied by the 2-methylbutyl group is 13% or less, further 10% or less,
Most preferably, it can be 6 or less. Therefore, even when this strong fluorotripentylamine is used as a heating medium in vapor phase soldering, P
The amount of FIB generated can be suppressed to an extremely low level.

〔Example〕

Seven types of tripentylamine having the composition ratios shown in Table 1 obtained by mixing tri-n-pentylamine, tripentylamine having an isopentyl group, and tripentylamine having a 2-methylbutyl group were electrolytically fluorinated. It was used as a raw material.

The composition ratio was measured by gas chromatography under the following conditions.

Apparatus: Takafusa GC-7A Chromatodulum (manufactured by Takafusa Seisakusho) Column: Length 3 m
Metshu) (Ji-nz Manpil Company!!!l) K-/Ricoh y S E-30 (
Column temperature: 180°C Column temperature: 180°C For electrolytic fluorination, the diameter was 10cy, the height was 20°C.
An electrolytic cell made of M fluororesin and equipped with a reflux condenser (-40°C) at the top was used. In addition, as cathodes and anodes, a total of 14 nickel plates (6
5tptm x 100wa, H-sa 1,5m
) I used a good one.

Anhydrous hydrogen fluoride 1.61 is passed through the raw material supply pipe to the electrolytic tank.
After supplying 200 g of tripentylamine, a constant current of 28 amperes (C'fL pressure was around 6.5 V) was applied for about 60 hours until the raw material ran out and the stain pressure suddenly increased. The temperature of the electrolytic bath was maintained at about 0° C. by flowing a refrigerant through a nickel tube inside the electrolytic bath.

After the electrolysis was completed, the fluorinated product accumulated at the bottom of the electrolytic cell was taken out by opening the cock at the bottom of the electrolytic cell. - Neutralize the desired anhydrous hydrogen fluoride with a caustic potash solution and then wash with water,
Subsequently, alkali-amine treatment and vacuum distillation were performed/4'-
Obtain a liquid with a purity of fluorotripentylamine of 901 or higher. It was confirmed from the results of mass spectrometry that the impurities were completely fluorinated.

/4'No' in fluorotri-4-ethylamine? - The proportion of fluoro n-pentyl group, perfluoroisopentyl group and U/4-fluoro-2-methylbutyl group is F 1
The results are shown in Table 1.

Next, these various isomeric compositions of 4'-fluorotripentylamine were placed in a vapor phase soldering device.

Insert soldered parts. As a vapor phase soldering device,
An electric heater was used that was filled with perfluorotri(methylamine) to a depth of 3 cm above the liquid level, provided with a copper cooling coil 10 m above the liquid level, and further provided with another cooling coil 50 m above the liquid level.

/4-Fluoroisobutylene was analyzed as follows. The gas at a position 5 degrees above the boiling perfluorotripentylamine liquid level was sucked into the sampling reservoir through the sump 2-, and quantified using a gas chromatograph. The analytical column used was a 5 m x 3 m stainless steel column packed with diatomaceous earth supporting polyethylene glycol.

Vapor phase soldering was successful.

Also, please note that the amount of perfluoroin butylene produced is shown in Table 1.

[Brief explanation of the drawing]

Figure 1 shows the ratio (molti) of isomers that carry at least one of the iso-4-antyl group and 2-methylbutyl group contained in tripentylamine, the raw material, and the 9-fluorocarbon product. ) IJ Bear f / l / amine is a graph showing the relationship between total perfluoropear fA' groups, barfluoroisopentyl groups, doper7 / I / oro 2-methylbutyl groups and the total ratio (l). .

Claims (1)

[Claims] (1) In the method of producing perfluorotripentylamine by electrolytic fluorination of tripentylamine, at least one of the isopentyl group and 2-methylbutyl group among the various isomers contained in the tripentylamine is used. A method for producing perfluorotripentylamine, which comprises using tripentylamine in which the concentration of one of the isomers is 8 mol% or less.