JPS62226932A - Production of perfluorohexylmethylbenzene derivative - Google Patents

Abstract

PURPOSE:To economically improve the yield of the titled compound useful as a starting raw material for surfactant, etc., by reacting perfluoro-2- methylpent-2-ene with a benzyl bromide derivative in a specific solvent in the presence of potassium fluoride. CONSTITUTION:The objective compound of formula II can be produced by reacting (A) 1mol of perfluoro-2-methylpent-2-ene with (B) preferably about 0.5-2mol, especially about 0.5-1mol of a benzyl bromide derivative of formula I (R is H, p-CN, m-CN, o-CN, p-NO2, m-NO2, o-NO2, p-CH2Br, m-CH2Br) in dimethylformamide solvent in the presence of potassium fluoride preferably at about 80-130 deg.C. The amount of potassium fluoride is preferably about 1-2mol per 1mol of perfluoro-2-methylpent-2-ene.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the production of perfluorohexylmethylbenzene derivatives useful as starting materials for surfactants, insulating oils in electrical equipment, and inert hydraulic fluids used in precision instruments. Regarding the law.

PRIOR ART AND THE PROBLEM TO BE SOLVED BY THE INVENTION A process for producing perfluorohexylmedelbenzene from perfluoro-2-methylbent-2-ene and benzyl bromide is known [Makarov et al.
AKAROV et”al; Journal of Fluorine Chemistry
Luorine Chemistry) Volume 1O, Volume 1
See pages 57 to 158 (1977)]. According to this synthesis method, perfluorohexylmethylbenzene can be obtained in high yield at room temperature and in a short time by using dirim as a reaction solvent and cesium fluoride as a basic catalyst.

This reaction is thought to proceed via perfluoro-jet-carbanion as an intermediate state as shown in the following formula.

However, cesium fluoride is an expensive and highly hygroscopic compound, so it is not practical. Even if this reaction is carried out under the same conditions as above using KP or NaF instead of cesium fluoride, the target compound can only be obtained in an extremely low yield. This is thought to be because it is difficult for the reaction to proceed with sodium fluoride or potassium fluoride because it is difficult to generate stable carbanions.

This is due to the fact that conventionally, the fluorinating agent for low molecular weight oligomers (dimers, trimers) of hexafluoroolefins or tetrafluoroolefins has been limited to cesium fluoride. Corresponding [for example, Japanese Patent Application Laid-Open No. 57-150625 and Jacobson et al.
, G,YAKOBSONet,at,);
Synthesis page 169 (
1983)].

The present inventors have discovered that perfluorohexylmethylbenzene derivatives can be obtained in high yield by using KF instead of expensive CsF and using dimethylformamide (DMF') instead of diglyme as a reaction solvent. The present invention was completed.

Means for solving the problem, namely, the present invention provides perfluoro-2-methylbent-2
-ene and general formula [I]: (wherein R is H, p-CN, m-CN, o-ON.

p-Nov, mNO2, oNO3, p-CHtBr or m-CHtBr) is reacted with the general formula [IT] in the presence of potassium fluoride in a dimethylformamide solvent. :(wherein, R' is H
, p-CN, m-CN, o-CN.

p -N O,, mN0t, oNOt, p CHtRf
or m cr-r2rtf group, and F3 Rf represents a CF3CF2CFtC- group. ) A method for producing a perfluorohexylmethylbenzene derivative represented by F3.

Perfluoro-2-methylbent-2-ene can be easily obtained, for example, by dimerization reaction of hexafluoropropene.

The benzyl bromide derivatives used in the present invention include:
In the general formula [1], the substituent R is Hlp CN, m
CN, o CN, p NO2, m -N O7
, o-No2, p-CHtBr or m-CH2Br.

The reaction molar ratio of perfluoro-2-methylbent-2-ene and benzyl bromide derivative is not particularly limited, but is usually about 0.5 to 2 moles of the latter, preferably about 0.5 to 2 moles of the former. It is 1 mole.

The amount of KF used is also not particularly limited, but it is usually about 1 to 1 mole per fluoro-2-methylbent-2-ene.
3 moles, preferably about 1-2 moles.

The above reaction components are mixed in DMF, usually at about 50-150°C.
Preferably about 2-70 at a temperature of about 80-130°C
By reacting for a period of time, the perfluorohexylmethylbenzene derivative represented by the general formula []T] can be obtained in high yield.

Hereinafter, the present invention will be explained by examples.

, perfluoro-2-methylpent-2-ene (4, 5
09, +5 mmol), potassium fluoride (1,16 g,
20 mmol), α-bromo-p-tolnitrile (1
, 96 g, IO mmol) and N,N-dimethylformamide (10 leaves) were added to the reaction vessel, and while stirring well,
The reaction is carried out at 100°C for 10 hours. After the reaction was completed, the reaction solution was transferred to an ether solvent, and water, 5% NaHCO3 aqueous solution,
Wash thoroughly with water. The ether is then removed to obtain a yellow oily liquid.

In order to remove unreacted benzyl bromide, the yellow mixture was added to the ether/pyridine mixed solution and stirred well at room temperature for 3 hours. Subsequently, it is washed with water, 5% HCQ aqueous solution, and water in this order. Thereafter, the organic solvent phase was taken out, dried over anhydrous magnesium sulfate, the solvent was removed, and the title compound C4, 26 g was obtained as a colorless transparent liquid, yield 9.
8%). Table 3 shows the physical properties of this compound.

Examples 2-9 Compounds ■ were prepared according to the procedure of Example I and under the reaction conditions of Table 1.
A was synthesized. The yield is shown in Table 1.

Comparative Examples 1 to 5 According to the procedure of Example 1, compounds
A was synthesized. The yield is shown in Table 1.

=7- Table 1 2 DMF KF 1.5:1:2 50 20
663 DMF KF 1.5+1:5 50
20 694 DMF KF 1.5:l:1
050. 20 725 DMF KF 1.5
:1:2 50 40 806 DMF KFl
, 5・1:2 50 70 987 DMF K
F L, 5+1. :2100 5 93 Comparative Example I Diglyme CsF 1.5: 1: 2 50
2 982 Digrim KP 1.5:l:2 50
20 43 DMF NaFl, 5:]
:2 50 70 44 DMF NaF
l, 5:1:2]0010 45 DMSOKF
1.5+l:3 50 20 23a) I a
5 mo1% of Gizanoh 18-crown-6 was added to dicyclo.

c) A. Perfluoro-2-methylbent-2-ene-8 = 10 lb 1.5:L:2 100
1011 Ic 1.5:1:2
100 +012 1d 1.5:
1. :2 100 1013 [e
1.5:1:2 100 1014 If
1.5:1+2 100 1015
1g 1.5+1:2 100 1016
1j 3:1:2 too 10
17 Ik 3:1:2 100
10a) A+perfluoro-2-methylbent-2-ene b) a R=p-CN b R=m-CHc
R=o CN d R=p Note R=
m-NO2fR=o-N02 g R=HJR-p-cr(pRr k R= m CH2Rf Example 1〇217 Compounds IIa-g, j, The yields and physical properties of these compounds are shown in Table 3.

Claims (1)

[Claims] 1. Perfluoro-2-methylpent-2-ene and general formula [I]: ▲ Numerical formulas, chemical formulas, tables, etc. ▼ [1] (In the formula, R is H, p-CN, m -CN, o-CN, p-
NO_2, m-NO_2, O-NO_2, p-CH_2
General formula [II], which is characterized by reacting a benzyl bromide derivative represented by Br or m-CH_2Br in the presence of potassium fluoride in a dimethylformamide solvent: ▲There are mathematical formulas, chemical formulas, tables, etc. ▼[II] (In the formula, R' is H, p-CN, m-CN, o-CN) p
-NO_2, m-NO_2, O-NO_2, p-CH_
Represents 2Rf or m-CH_2Rf group, and Rf represents ▲ which has numerical formula, chemical formula, table, etc. ▼ group. ) A method for producing a perfluorohexylmethylbenzene derivative represented by 2. The method according to item 1, wherein the reaction temperature is about 50 to 150°C.