JPS6212728A - Production of diiodobiphenyl compound - Google Patents

Abstract

PURPOSE:To obtain the titled substance useful as a synthetic intermediate for benzidine compound which is an organic photoconductive substance useful as a photosensitive material for electrophotography, economically, by reacting a dimethylbiphenyl compound with periodic acid and iodine in an aqueous solution containing a specific amount of acetic acid under heating. CONSTITUTION:The objective compound of formula II can be produced by reacting the biphenyl compound of formula I with periodic acid and iodine in a mixture of acetic acid and water containing 60-100vol%, preferably 70-95vol% acetic acid, at 80-95 deg.C, preferably 90-95 deg.C. The amounts of periodic acid and iodine are preferably 0.30-0.32 equivalent and 0.90-1.01 equivalent per 1 equivalent of the compound of formula I, respectively. The amount of the mixture of acetic acid and water is >=6ml, preferably >=10ml per 1g of the compound of formula I. The above reaction may be carried out in the presence of a catalyst (preferably sulfuric acid).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the production of short biphenyl compounds, which are necessary intermediates for obtaining benzidine compounds useful as organic photoconductive substances used in electrophotographic photoreceptors, etc. Regarding the manufacturing method.

[Prior art] As a conventional method for obtaining short biphenyl compounds, B
Erichte der Deutschen Cha
mie 21, 1099 (I88B), and also by Annalen aer Deutschan.
Chemie 634. 84 (I960) is known, but the Sandmeyer reaction yields a short biphenyl compound obtained in a low yield and the purification operation is troublesome. In addition, in the method of iodination of biphenyl compounds, short biphenyl compounds can be obtained in a fairly good yield when biphenyl compounds without substituents are iodized.
[In the north case, the resulting short biphenyl compound is
(The yield is very low, and it is very difficult to separate and purify the monoiodo form and the short form after the reaction.)
1. (There was a drawback.

In addition, as a method for obtaining a short biphenyl compound, methods other than the above, such as Bu'11etin de la Elociete
Chimique de France 7.

654 (I940).

Journa1 of engineering C! chemical
5ociety 14, 156 (I937).

Journal of Chemical 5ocie
ty, Perkin Trans 1.

180 (I972), and Japan Chemical Journal 92. 1021 (I971) is also known, but these methods also yield a low yield of jotobi-7 ale compound.
Moreover, it has the disadvantage that separation and purification is difficult.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a manufacturing method that can obtain a di-iodobiphenyl compound represented by the following formula (II) in a high yield and that allows easy separation and purification operations.

[Means and effects for solving the problem] As a result of extensive research, the present inventors have solved the above problem by causing a heating reaction between a dimethylbiphenyl compound, periodic acid, and iodine in an aqueous solution with a relatively high acetic acid content. The present invention has been completed based on the discovery that the above objects can be achieved.

That is, the present invention combines a biphenyl compound represented by the following formula (I) with periodine and iodine into an acetic acid compound having an acetic acid content of 60 to less than 100 parts by volume.
This is a method for producing a short biphenyl compound represented by the following formula (I1), in which the reaction is carried out by heating in a water mixed solvent.

In the production method of the present invention, a biphenyl compound represented by formula (I) and iodine and left iodic acid are heated to react in an acetic acid-water mixed solvent to produce a target substance, which is a short film represented by general formula (II). A biphenyl compound is obtained, and this reaction is thought to proceed according to the reaction formula below.

The ratio of periodic acid and iodine to 1 equivalent of the biphenyl compound represented by formula (I) in the above reaction is determined stoichiometrically. It is best to use a stoichiometric amount or an excess amount relative to 1 equivalent of the biphenyl compound,
Periodic acid is added to 8 equivalents of CLZ to a35 equivalents, preferably α
30 equivalents to o, 32 equivalents are used. From the same point of view, iodine also has cL85 equivalents fi to 1.01 equivalents, preferably α90
An equivalent to 1.01 equivalent is used.

The amount of acetic acid in the acetic acid-water mixed solvent used as a solvent is from 60 percent to less than 100 percent by volume, preferably from 70 percent to 95 percent.

The ratio of the biphenyl compound represented by general formula (I) to the acetic acid-water mixed solvent is 12 for the compound represented by general formula (I).
Each time, 6 or more acetic acid-water mixed solvents are used. It is preferable to use 10- or more.

In the above reaction, a catalyst can be used for the purpose of promoting the reaction. Sulfuric acid is preferably used as the catalyst. Catalyst 1 varies depending on the catalyst used, but when sulfuric acid is used as a catalyst, a biphenyl compound 1fI%0.2- to α5-1 represented by the general formula (...)
Preferably α3- to 4, [14m are used. i′ In the production method of the present invention, the bifu expressed by formula 0)
1= A nil compound, iodine, and periodic acid are dissolved in an acetic acid-water mixed solvent, and the solution to which a catalyst is added is heated to react.

The reaction conditions include a reaction temperature of 80°C to 95°C, preferably 9°C.
The temperature is 0°C to 95°C, and the reaction time is 2 hours to 8 hours, preferably about 4 hours, and it is preferable to confirm the completion of the reaction by conventionally known confirmation means.

Regarding the acetic acid concentration in the acetic acid-water mixed solvent, we examined the reaction conditions by changing only the acetic acid concentration in the reaction system, and found that the acetic acid concentration was around 60% by volume, and when the acetic acid concentration was 60% or more, the raw material was well processed. was consumed, whereas if it was less than 60%, the raw material iodine sublimated, making it impossible to react effectively, and the formation of monoiodine was observed. The acetic acid volume concentration in the acetic acid-water mixed solvent used as a solvent in the present invention is 60% or more.
It is preferable to use 70% to 95%, especially less than 00%.

After completion of the reaction, the product, the short biphenyl compound represented by formula (I1), can be separated and purified by simple operations as exemplified below.

That is, after the reaction mixture is cooled after the reaction is completed, water is added to the reaction mixture, then methylene chloride is added to extract the product, the extract is washed with hydrogen sulfite rum, and then dried with sulfuric acid. Then, after methylene chloride is distilled off under reduced pressure, the product is dissolved in n-hexane, treated with activated clay, and then n-hexane is distilled off. Recrystallization of the residue from ethyl acetate gives the formula (If
) is obtained.

The separation and purification of short biphenyl compounds is not limited to the above-mentioned methods, and means well known to those skilled in the art can be applied as appropriate.

The short biphenyl compound represented by the formula (...) has the following general formula (I1) which is useful as an organic photoconductive substance, particularly as a charge transport material to be dispersed in a charge transport layer when used as a functionally separated organic photoconductor. In the formula, R1 and R
2 are independent of each other, - an alkyl group,
It represents an aralkyl group, a heterocyclic group, or a substituent represented by the general formula (t) (wherein R3 is a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom). ] It is used as an important intermediate in the process of obtaining the benzidine compound shown below.

〔Example〕

Examples and comparative examples of the method for producing the short biphenyl compound represented by formula (n) of the present invention are listed below.

In addition, in the following examples, infrared absorption spectrum (Engine R) F
Measured by iKBr tablet method, nuclear magnetic resonance spectrum (NM
R) is measured as an OD Ois solution.

Example 1 45'-dimetherbyyx=(Ia) 1 f (5
-49 mmol), iodine t x t (5,56 m
mol) H engineering 04/2H, O126t (I, 58m
mol), concentrated sulfuric acid Q, 56- to 95% acetic acid aqueous solution 5
〇- Under air atmosphere, react for ~95'Cf'' time 1
After heating to 8 degrees and cooling for 1 time (add 80 degrees of water, extract with methylene chloride, wash with an aqueous solution of sodium bisulfite, dry over 1 degree of sodium sulfate, distill off the methylene chloride under reduced pressure, and then extract with methylene chloride. ,L4
18. 3. The residue was recrystallized from 100% chill to give 1.99 (79.8%) of 4.4'-short-3'-dimethylbiphenyl (2a).

Elemental analysis' Cl4H1! Calculated value as engineered snow C3a74% H2, 79% actual value
Ct 3a 62% R2, 81% NMR: Fig. 1 R: Fig. 2 Example 21 1a 1f, (5,49 mmol), iodine 1.2
t' (4,77 mmol), )l
IO4-2) 1,0 α4 t (I,y 6Mol
), 0.36 td of concentrated sulfuric acid was reacted and treated in 12 d of 953 euacetic acid in the same manner as in Example 1, and 2a was converted to 1.94 td.
f (81.5%) was obtained.
1 (self-comparison example 1 a1t (5,49 mmol), iodine 1.4f (5,56 mmol), HIO, -2H20
α36f (7,58 mmol) and concentrated sulfuric acid α36- were reacted and treated in 100% acetic acid (glacial acetic acid) in the same manner as in Example 1, and 2a was obtained at 1.18 F (42,7 qb).
)Obtained.

Example 3 1 a 1 f/ (5,49 mmol), iodine 1.4 t (5,56 mmol), HIO4-2H,O
α36F (I, 58 mmol), concentrated sulfuric acid 0.36 w
d was reacted in 30 d of water-acetic acid mixed solvents with various acetic acid concentrations at 90 to 95° under an air atmosphere for a predetermined period of time, and after cooling to room temperature was separated and produced in the same manner as in Example 1.
4゜a'-shotos, 3'-dimethylbiphenyl was obtained.

The relationship between the acetic acid-water mixed solvent and the unit yield of 4,4'-dimethylbiphenyl in this case is shown in FIG. Acetic acid concentration 60%
Below, the reaction time exceeded 4 hours, and above that, the reaction was completed within 4 hours. Further, at 60% or less, sublimation of the raw material iodine was observed, and mono-iodine was produced.

〔Effect of the invention〕

According to the method for producing short biphenyl compounds of the present invention, short biphenyl compounds having methyl groups at ortho and meta positions as substituents can be produced at extremely high yields on substituted biphenyl bases, which could only be obtained in extremely low yields in the past. It can be obtained in high yield. In addition, according to the method for producing a short biphenyl compound of the present invention, impurities other than the short biphenyl compound produced as a reaction product are produced in extremely small amounts, so that it is difficult to produce a short biphenyl compound as a reaction product. Simple means can be used and purified short biphenyl compounds can be easily obtained. Short biphenyl compounds are effectively used as intermediates necessary for synthesizing benzidine compounds, which are photoconductive substances.

[Brief explanation of drawings]

Figures 1 and 2 are nuclear magnetic resonance spectra or infrared absorption spectra of Examples of 4,4'-short-43'-dimethylbiphenyl obtained by the production method of the present invention, and Figure 5 is acetic acid absorption spectra. Temperature and 4,4'-short-3,
This is a graph showing the relationship between the isolation yield of 3'-dimethylbiphenyl. Continued from page 1. 1) Hiroshi Naka 1 Takematsu, Minamiashigara City
60 Hata Estate Foil, Akira Frame 1) Katsumi, Takematsu 1, Minamiashigara City
6001 Fuji Xerox Co., Ltd. Takematsu Business within the property: ■, Yo. Wow, 8 constructions. , Ka, A - Ma [ Uto 艮 [

Claims (1)

[Scope of Claims] A biphenyl compound represented by the following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I), periodic acid and iodine, with an acetic acid content of 60% by volume to less than 100% by volume. A method for producing a jordobiphenyl compound represented by the following formula (II) ▲Mathematical formula, chemical formula, table, etc. available▼(II), which is characterized by heating and reacting in an acetic acid-water mixed solvent.