JP2006233182A - Nematic liquid crystal composition and liquid crystal display element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition having negative dielectric anisotropy large in its absolute value and having low viscosity, and to provide a liquid crystal display element such as a VA-type, using the composition. <P>SOLUTION: The liquid crystal composition contains a compound represented by general formula (I) and an alkenyl compound represented by general formula (II). A liquid crystal composition having a low viscosity and a negative dielectric anisotropy is obtained by combining the above liquid crystal compounds, while almost keeping physical properties such as refractive index anisotropy. The liquid crystal display element capable of keeping voltage retention rate high up to a high-temperature region and excellent in reliability is provided by using the composition, and the display is much practical as a liquid crystal display for VA (vertical alignment)-type, ECB (electrically controlled birefringence)-type, IPS (in-plane switching)-type, etc. and is especially effective for achieving rapid response without adopting a specially thin cell gap. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nematic liquid crystal composition having a negative dielectric anisotropy Δε useful as an electro-optical liquid crystal display material, and a liquid crystal display device using the same.

The liquid crystal display element is used in various electric appliances for home use, measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions, etc., including clocks and calculators. Typical liquid crystal display methods include TN (twisted nematic), STN (super twisted nematic), DS (dynamic light scattering), GH (guest / host), and IPS (in-plane switching). Type, OCB (optical compensation birefringence) type, ECB (voltage controlled birefringence) type, VA (vertical alignment) type, CSH (color super homeotropic) type, FLC (ferroelectric liquid crystal), etc. . As a driving method, multiplex driving is generally used instead of conventional static driving, and the active matrix (AM) method driven by a TFT (thin film transistor), TFD (thin film diode) or the like has become mainstream recently. ing.
In these display systems, the IPS type, ECB type, VA type, CSH type, and the like have a feature that a liquid crystal material having a negative dielectric anisotropy (Δε) is used, unlike currently used TN type and STN type. . Among these, VA type display by AM driving is currently most expected in application to a display element that requires a high speed and a wide viewing angle, such as a television.

A liquid crystal material used in a display method such as a VA type is required to have low voltage driving, high speed response, and a wide operating temperature range. That is, the dielectric anisotropy is negative, the absolute value is large, the viscosity is low, and a high nematic phase-isotropic liquid phase transition temperature (Tni) is required. In addition, it is necessary to adjust the refractive index anisotropy of the liquid crystal material to an appropriate range according to the cell gap from the setting of Δn × d, which is the product of the refractive index anisotropy (Δn) and the cell gap (d). is there. In order to realize a high-speed response, the cell gap of the display element is reduced, but there is a limit to narrowing the cell gap due to the above-described restrictions. In order to improve the response speed without changing the cell gap, it is effective to use a liquid crystal composition having a low viscosity. In the case of applying a liquid crystal display element to a television or the like, since high-speed response is important, development of a liquid crystal composition having particularly low viscosity has been demanded.
As a liquid crystal material having a negative dielectric anisotropy, the following liquid crystal compound having a 2,3-difluorophenylene skeleton (see Patent Documents 1 and 2) is disclosed.

（式中、R及びR’は炭素数１から１０のアルキル基又はアルコキシ基を表す。）
更に、これらの引用文献には、本願発明を構成する液晶化合物の基本骨格である1-ヒドロキシ-2,3-ジフルオロ-4-置換ベンゼン骨格を有する化合物を含むものである。しかし、当該引用文献に記載される化合物は広範であり、側鎖にアルケニル基を有する化合物に関する具体的な開示は無く、記載された化合物を用いた誘電率異方性が負の液晶組成物は、液晶テレビ等の高速応答が要求される液晶組成物においては十分に低い粘性を実現するに至っていない。

(In the formula, R and R ′ represent an alkyl group having 1 to 10 carbon atoms or an alkoxy group.)
Furthermore, these references include compounds having a 1-hydroxy-2,3-difluoro-4-substituted benzene skeleton, which is the basic skeleton of the liquid crystal compound constituting the present invention. However, the compounds described in the cited document are wide, and there is no specific disclosure regarding compounds having an alkenyl group in the side chain, and liquid crystal compositions having a negative dielectric anisotropy using the described compounds are In a liquid crystal composition that requires a high-speed response such as a liquid crystal television, a sufficiently low viscosity has not been realized.

  On the other hand, there is also a disclosure of a liquid crystal composition using a compound having a 1-hydroxy-2,3-difluoro-4-substituted benzene skeleton, which is a basic skeleton of a liquid crystal compound constituting the present invention (Patent Document 3, Patent Document 3). 4 and Patent Document 5), there is no specific description of a liquid crystal composition using a compound having an alkenyl group in the side chain, and the viscosity of the liquid crystal composition is reduced by using the compound and any other compound. There is no specific disclosure about what can be done.

In addition, a liquid crystal compound having a 2,3-difluorohydroquinone skeleton has already been disclosed (see Patent Documents 6 and 7), and a liquid crystal composition using the compound is also disclosed. However, since the compound has a hydroquinone skeleton, it is considered that it cannot be used for an active matrix in terms of voltage holding ratio (see Non-Patent Document 1). A low-viscosity liquid crystal composition for VA using the compound. The development of things was delayed.
Accordingly, development of a liquid crystal composition having a negative dielectric anisotropy and a low viscosity has been desired.

JP-A-60-199840 JP-A-2-4725 JP-A-8-104869 JP 2000-96055 A European Patent Application No. 04744062 (page 14) Special table 2-503568 German Patent Application Publication No. 3,906,058 Numata Hiroshi, Monthly Display, Vol. 4, no. 3 pp. 1-7, (1998) (table 4 on page 5)

  The problem to be solved by the present invention is to provide a liquid crystal composition having a negative dielectric anisotropy having a large absolute value, and having a low viscosity without reducing or increasing the refractive index anisotropy. Another object is to provide a VA type liquid crystal display element using the above.

The present invention, as a result of intensive studies to solve the above problems,
As the first component, the general formula (I)

（式中、R¹は炭素数2から10のアルケニル基を表し、これらの基中に存在する1個のCH₂基又は隣接していない2個以上のCH₂基はO及び/又はSに置換されてもよく、またこれらの基中に存在する1個又は2個以上の水素原子はF又はClに置換されてもよく、R²は炭素数1から10のアルキル基、又は炭素数1から10のアルコキシル基を表し、
mは0、１又は2を表す。）
で表される化合物を１種又は２種以上含有しその含有率が１０から８０質量％であり、
第二成分として、一般式（II）

(In the formula, R ¹ represents an alkenyl group having 2 to 10 carbon atoms, and one CH ₂ group present in these groups or two or more CH ₂ groups not adjacent to each other represent O and / or S. One or two or more hydrogen atoms present in these groups may be substituted with F or Cl, and R ² is an alkyl group having 1 to 10 carbon atoms, or 1 carbon atom. Represents 10 to 10 alkoxyl groups,
m represents 0, 1 or 2. )
1 or 2 or more types of the compound represented by this, and the content rate is 10 to 80 mass%,
As the second component, the general formula (II)

(式中、R³及びR⁴はそれぞれ独立的に炭素数1から10のアルキル基、炭素数2から10のアルケニル基、炭素数1から10のアルコキシル基又は炭素数3から10のアルケニルオキシ基を表し、

(Wherein R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or an alkenyloxy group having 3 to 10 carbon atoms) Represents

B ¹ and B ² are each independently
(a) trans-1,4-cyclohexylene group (two CH ₂ groups not one CH ₂ group or adjacent present in this group may be substituted with an oxygen atom or a sulfur atom)
(b) 1,4-phenylene group (one or more CH groups present in this group may be substituted with a nitrogen atom)
(c) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6 Represents a group selected from the group consisting of a -diyl group and a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and the group (a), the group (b) or the group (c) is CN or May be substituted with halogen,
Y ¹ and Y ² are independently
-CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF ₂ CF _2- , -CF = CF-, -CH ₂ O-, -OCH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) _{3 O -, - O (CH} 2) 3 -, - C≡C -, - CF 2 O -, - OCF 2 -, - COO -, - OCO -, - COS -, - SCO- or a single bond ,
When there are a plurality of Y ² and B ² , they may be the same or different,
p represents 0, 1 or 2. )
1 type or 2 types or more of the compound represented by these, The content rate is 20 to 70 mass%,
A nematic liquid crystal composition having a negative dielectric anisotropy and a liquid crystal display device using the liquid crystal composition are provided.
Furthermore, the general formula (1)

（式中、R^aは水素原子または炭素原子数1〜3の直鎖状アルキル基を表し、R^bは炭素原子数1〜7の直鎖状アルキル基を表し、p1は0、1または2を表す。）で表されるジフルオロベンゼン誘導体を提供する。

(In the formula, R ^a represents a hydrogen atom or ^a linear alkyl group having 1 to 3 carbon atoms, R ^b represents a linear alkyl group having 1 to 7 carbon atoms, and p1 is 0, 1 or 2) A difluorobenzene derivative represented by:

  By the combination of the liquid crystal compounds of the present invention, a liquid crystal composition having a low viscosity and a negative dielectric anisotropy was obtained while substantially maintaining the refractive index anisotropy. By using this composition, a highly reliable liquid crystal display element capable of maintaining a high voltage holding ratio up to a high temperature range is provided, and this display is very practical as a liquid crystal display of VA mode, ECB mode, IPS mode, etc. In particular, it is effective for high-speed response without reducing the cell gap.

  In the liquid crystal composition of the present invention, the first component contains one or more compounds represented by the general formula (I), preferably 1 to 20 types, more preferably 1 to 15 types. 1 to 10 types are more preferable, and 1 to 8 types are particularly preferable.

The compound represented by the general formula (I) has a negative dielectric anisotropy having a large absolute value, but if the content is large, the compound tends to increase the viscosity, or increase the smectic-nematic phase transition temperature. Therefore, when low viscosity is important or when low smectic-nematic phase transition temperature is important, it is preferable that these contents are small, and negative dielectric anisotropy with a large absolute value is important. When doing so, it is preferable that these content rates are large.
In the general formula (I), R ¹ preferably represents an alkenyl group having 2 to 10 carbon atoms or an alkenyl group having 2 to 7 carbon atoms substituted by an alkoxyl group having 1 to 5 carbon atoms. The alkenyl group of 7 is more preferable, and the following structures (1) to (5) are particularly preferable.

(The structural formula shall be connected to the ring at the right end.)
R ² preferably represents an alkyl group having 1 to 7 carbon atoms or an alkoxyl group having 1 to 7 carbon atoms.
More specifically, the general formula (I) is preferably a compound represented by the following general formula (IA) or general formula (IB) as a specific structure.

（式中、R⁵及びR⁷はそれぞれ独立して一般式（I）におけるR¹と同じ意味を表し、R⁶及びR⁸はそれぞれ独立して炭素数1から10のアルキル基を表す。）
一般式（I-A）及び（I-B）は、具体的な構造として、以下の一般式（I-A-I）から（I-A-IV）及び一般式（I-B-I）から（I-B-IV）からなる群で表される化合物がより好ましい。

(In the formula, R ⁵ and R ⁷ each independently represent the same meaning as R ¹ in the general formula (I), and R ⁶ and R ⁸ each independently represent an alkyl group having 1 to 10 carbon atoms.)
General formulas (IA) and (IB) are compounds represented by the following general formulas (IAI) to (IA-IV) and general formulas (IBI) to (IB-IV) as specific structures: Is more preferable.

（式中、R⁶及びR⁸はそれぞれ独立して炭素数1から7のアルキル基を表す。）
第二成分として、一般式（II）で表される化合物を１種又は２種以上を含有するが、１種から１２種が好ましく、１種から８種がより好ましく、１種から６種がさらに好ましい。

(Wherein R ⁶ and R ⁸ each independently represents an alkyl group having 1 to 7 carbon atoms.)
As the second component, one or more compounds represented by the general formula (II) are contained, preferably 1 to 12 types, more preferably 1 to 8 types, and more preferably 1 to 6 types. Further preferred.

The compound represented by the general formula (II) has the effect of lowering the viscosity although there is almost no effect of increasing the absolute value of the dielectric anisotropy, and when the low viscosity is regarded as important, these contents are large. In the case where importance is placed on increasing the absolute value of the dielectric anisotropy, it is preferable that the content is small.
In general formula (II), R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or 3 to 10 carbon atoms. R ³ represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, R ⁴ represents an alkyl group having 1 to 10 carbon atoms, an alkoxyl having 1 to 10 carbon atoms More preferably, R ³ represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and R ⁴ represents an alkyl having 1 to 5 carbon atoms. It is more preferable that the group represents an alkoxyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, and it is more preferable that at least one of R ^{3 and} R ⁴ represents an alkenyl group.

Specifically, as R ³ , —CH ₃ , —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ , — (CH ₂ ) ₄ CH ₃ , — (CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -CH = CH ₂ , -CH = CHCH ₃ (E form),-(CH ₂ ) ₂ CH = CH ₂ ,-( CH ₂ ) ₂ CH = CHCH ₃ (E form),-(CH ₂ ) ₄ CH = CH ₂ ,-(CH ₂ ) ₄ CH = CHCH ₃ (E form) or-(CH ₂ ) ₆ CH = CH ₂ Named,
Specifically, as R ⁴ , —CH ₃ , —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ , — (CH ₂ ) ₄ CH ₃ , — (CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , -O (CH ₂ ) ₄ CH ₃ , -O (CH ₂ ) ₅ CH ₃ , -O (CH ₂ ) ₆ CH ₃ , -O (CH ₂ ) ₇ CH _3, -CH = CH ₂ , -CH = CHCH ₃ (E-form),-(CH ₂ ) ₂ CH = CH ₂ ,-(CH ₂ ) ₂ CH = CHCH ₃ (E-form),-(CH ₂ ) ₄ CH = CH ₂ ,-(CH ₂ ) ₄ CH═CHCH ₃ (E form) or — (CH ₂ ) ₆ CH═CH ₂ is mentioned.

B ¹ and B ² are each independently a trans-1,4-cyclohexylene group (one CH ₂ group present in this group or _two non-adjacent CH ₂ groups are substituted with oxygen atoms). 1,4-phenylene group (including one or more CH groups substituted by nitrogen atoms), 1,4-cyclohexenylene group 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, or 1,2,3,4 -It preferably represents a tetrahydronaphthalene-2,6-diyl group or a substituent in which these hydrogen atoms are substituted with fluorine atoms, trans-1,4-cyclohexylene group, 1,4-phenylene group, fluorine-substituted More preferably 1,4-phenylene group or 1,4-bicyclo [2.2.2] octylene group, trans-1,4-cyclohexylene group or And particularly preferably a 1,4-phenylene group.

Y ¹ and Y ² are each independently -CH ₂ CH _2- , -CH = CH- (E form), -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF ₂ CF _2- , -CF = CF- (E form), -CH ₂ O-, -OCH _2- , -OCH (CH ₃ )-, -CH ( CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF ₂ -,- COO-, -OCO-, -COS-, -SCO- or a single bond is preferred, but -CH ₂ CH _2- , -CH = CH- (E form), -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CF ₂ CF _2- , -CF = CF- (E form), -CH ₂ O-, -OCH _2- , -OCH (CH ₃ )-, -CH ( CH ₃ ) O—, —C≡C—, —CF ₂ O—, —OCF ₂ — or a single bond is more preferable, and —CH ₂ CH ₂ —, —CH═CH— (E form) or a single bond is further preferable.
More specifically, the general formula (II) is preferably a compound represented by the following general formula (II-A) to general formula (II-G) as a specific structure.

(In the formula, R ^3a , R ^3b , R ^3c , R ^3d , R ^3e , R ^3f , R ^3g , R ^4a , R ^4b , R ^4c , R ^4d , R ^4e , R ^4f , and R ^4g are independent of each other. And represents the same meaning as R ³ and R ⁴ in formula (II).)
R ^3a , R ^3b , R ^3c , R ^3d , R ^3e , R ^3f and R ^3g are -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,- (CH ₂ ) ₄ CH ₃ -CH = CH ₂ , -CH = CHCH ₃ (E form),-(CH ₂ ) ₂ CH = CH ₂ ,-(CH ₂ ) ₂ CH = CHCH ₃ (E form), R ^4a , R ^4b , R ^4c , R ^4d , R ^4e , R ^4f , and R ^4g are —CH ₃ , —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ ,-(CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , -O (CH ₂ ) ₄ CH ₃ , -CH = CH ₂ , -CH = CHCH ₃ (E form),-(CH ₂ ) ₂ It is preferable to represent CH═CH ₂ , — (CH ₂ ) ₂ CH═CHCH ₃ (E-form).

In addition, as a compound in which at least one of R ³ or R ⁴ in the general formula (II) represents an alkenyl group, the following (II-A-1) to (II-A-8), (II-B-1) The compound groups shown in (II-B-7), (II-C-1) to (II-C-6), and (II-D-1) to (II-D-5) are preferred.

  From general formula (II-A-1) to general formula (II-A-8)

(Wherein R ⁹ , R ¹⁰ and R ¹¹ each independently represents an alkyl group having 1 to 10 carbon atoms, one CH ₂ group present in these groups or two or more not adjacent to each other) The CH ₂ group may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl.)
R ⁹ , R ¹⁰ and R ¹¹ are -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,-(CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , —O (CH ₂ ) ₄ CH ₃ , —O (CH ₂ ) ₅ CH ₃ , —O (CH ₂ ) ₆ CH ₃ or —O (CH ₂ ) ₇ CH ₃ is preferably represented, − More preferably, CH ₃ , —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ , — (CH ₂ ) ₄ CH ₃ are represented.

Among the compounds represented by general formula (II-A-1) to general formula (II-A-8), general formula (II-A-1), general formula (II-A-2) or general formula (II The compound represented by -A-3) is particularly preferable.
From general formula (II-B-1) to general formula (II-B-7)

(In the formula, R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , and R ¹⁷ each independently represents an alkyl group having 1 to 10 carbon atoms, and one CH present in these groups. _Two groups or two or more non-adjacent CH ₂ groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups are substituted with F or Cl May be.)
R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , and R ¹⁷ are -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,-( CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , -O (CH ₂ ) ₄ CH ₃ , -O (CH ₂ ) ₅ CH ₃ , -O (CH ₂ ) ₆ CH ₃ or -O (CH ₂ ) it is preferable to represent the _{7 CH 3, -CH 3, -CH} 2 CH 3, - (CH 2) 2 CH 3, - (CH 2) 3 CH 3, - (CH 2) more may represent ₄ CH ₃ preferable.
From general formula (II-C-1) to general formula (II-C-6)

(Wherein, R ²¹ and R ²² are each independently represent an alkyl group having 1 to 10 carbon atoms in which one CH ₂ group or not adjoining present in the group two or more CH ₂ The groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl.)
R ²¹ and R ²² are -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,-(CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , -O (CH ₂ ) ₄ CH ₃ , -O (CH ₂ ) ₅ CH ₃ , -O (CH ₂ ) ₆ CH ₃ or -O (CH ₂ ) ₇ CH ₃ are preferred, -CH ₃ , It is more preferable to represent —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ , — (CH ₂ ) ₄ CH ₃ .

Among the compounds represented by general formula (II-C-1) to general formula (II-C-6), general formula (II-C-1), general formula (II-C-2) or general formula (II) -C-4) is particularly preferred.
From general formula (II-D-1) to general formula (II-D-5)

(Wherein, R ²⁷ and R ²⁸ each independently represent an alkyl group having 1 to 10 carbon atoms in which one CH ₂ group or not adjoining present in the group two or more CH ₂ The groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl.)
R ²⁷ and R ²⁸ are -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,-(CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -OCH ₃ , -OCH ₂ CH ₃ , -O (CH ₂ ) ₂ CH ₃ , -O (CH ₂ ) ₃ CH ₃ , -O (CH ₂ ) ₄ CH ₃ , -O (CH ₂ ) ₅ CH ₃ , -O (CH ₂ ) ₆ CH ₃ or -O (CH ₂ ) ₇ CH ₃ are preferred, -CH ₃ , It is more preferable to represent —CH ₂ CH ₃ , — (CH ₂ ) ₂ CH ₃ , — (CH ₂ ) ₃ CH ₃ , — (CH ₂ ) ₄ CH ₃ .

  The nematic liquid crystal composition of the present invention contains one or more compounds selected from the compound group consisting of general formula (IA) and general formula (IB), and has the general formula (II-A), It is preferable to contain a compound represented by the formula (II-B), the general formula (II-C) or the general formula (II-F), and from the compound group consisting of the general formula (IA) and the general formula (IB) It is preferable to contain one or more selected compounds and a compound represented by general formula (II-A) or general formula (II-F). Further, it contains one or more compounds selected from the compound group consisting of general formula (IA) and general formula (IB), and has the general formula (II-A-1), general formula (II-A) -2) or a compound represented by the general formula (II-A-3) is also preferable. Further, it contains one or more compounds selected from the compound group consisting of general formula (IA) and general formula (IB), and includes general formula (II-C-1) and general formula (II-C) -2) or a compound represented by formula (II-C-4) is also preferable. The nematic liquid crystal composition of the present invention contains 10 to 80% by mass of one or more compounds selected from the compound group consisting of the general formula (IA) and the general formula (IB), and the general formula (II -A-1) to one or more compounds selected from the compound group consisting of general formula (II-A-8), and / or general formula (II-B-1) to general formula (II- B-7) selected from the compound group consisting of one or more compounds selected from the group consisting of compounds, and / or the compound group consisting of formulas (II-C-1) to (II-C-6) 1 or 2 or more compounds, and / or 1 or 2 or more compounds selected from the compound group consisting of general formula (II-D-1) to general formula (II-D-5) from 20 It is preferable to contain 70 mass%.

  Contains 10 to 80% by mass of one or more compounds selected from the group consisting of general formula (IAI) to general formula (IA-IV) and general formula (IBI) to general formula (IB-IV) And one or more compounds selected from the group consisting of compounds of general formula (II-A-1) to general formula (II-A-8), and / or general formula (II-B-1 ) To one or more compounds selected from the compound group consisting of general formula (II-B-7), and / or general formula (II-C-1) to general formula (II-C-6) One or two or more compounds selected from the compound group consisting of: and / or one or two compounds selected from the compound group consisting of general formula (II-D-1) to general formula (II-D-5) It is more preferable to contain 20 to 70% by mass of the compound of the seed or more.

  20 to 70% by mass of one or more compounds selected from the group consisting of compounds of general formula (IAI) to general formula (IA-IV) and general formula (IBI) to general formula (IB-IV) More preferably, the content is more preferably 30 to 60% by mass.

One or more compounds selected from the group consisting of general formula (II-A-1) to general formula (II-A-8), or / and general formula (II-B-1) to general One or more compounds selected from the group consisting of compounds of formula (II-B-7) or / and compounds of formulas (II-C-1) to (II-C-6) One or more compounds selected from the group, or / and one or more compounds selected from the compound group consisting of the general formula (II-D-1) to the general formula (II-D-5) The content of the compound is more preferably 30 to 60% by mass, and further preferably 40 to 50% by mass.
As an additional component, it is also preferable to contain one or more compounds selected from the group consisting of the following general formulas (III-A) to (III-J).

(Wherein R ²⁹ and R ³⁰ each independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one CH ₂ group present in these groups or adjacent thereto. Two or more non-CH ₂ groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl, R ³¹ represents an alkyl group having 1 to 10 carbon atoms, even the one CH ₂ group or not adjoining two or more CH ₂ groups present in the group is replaced with O and / or S And one or more hydrogen atoms present in these groups may be replaced by F or Cl.)
In the formula, R ²⁹ is -CH ₃ , -CH ₂ CH ₃ ,-(CH ₂ ) ₂ CH ₃ ,-(CH ₂ ) ₃ CH ₃ ,-(CH ₂ ) ₄ CH ₃ ,-(CH ₂ ) ₅ CH ₃ ,-(CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ , -CH = CH ₂ , -CH = CHCH ₃ (E form),-(CH ₂ ) ₂ CH = CH ₂ ,-(CH ₂ ) ₂ CH = CHCH ₃ (E form),-(CH ₂ ) ₄ CH = CH ₂ ,-(CH ₂ ) ₄ CH = CHCH ₃ (E form) or-(CH ₂ ) ₆ CH = CH ₂ Preferably
R ³⁰ is _{-CH 3, -CH 2 CH 3,} - (CH 2) 2 CH 3, - (CH 2) 3 CH 3, - (CH 2) 4 CH 3, - (CH 2) 5 CH 3, - (CH ₂ ) ₆ CH ₃ ,-(CH ₂ ) ₇ CH ₃ ,-(CH ₂ ) ₂ CH = CH ₂ ,-(CH ₂ ) ₂ CH = CHCH ₃ (E form),-(CH ₂ ) ₄ CH = CH ₂ , — (CH ₂ ) ₄ CH═CHCH ₃ (E-form) or — (CH ₂ ) ₆ CH═CH ₂ is preferably represented.

  Of the compounds represented by general formula (III-A) to general formula (III-J), compounds represented by general formula (III-E) or general formula (III-F) are more preferred.

In the liquid crystal composition of the present invention, the nematic phase-isotropic liquid phase transition temperature (Tni) is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, and further preferably 80 ° C. or higher. . The dielectric anisotropy (Δε) at 25 ° C. is preferably −2 or less, more preferably −2.5 or less, and further preferably −3.0 or less. The refractive index anisotropy (Δn) at 25 ° C. is more preferably 0.10 or more and even more preferably 0.12 or more when it corresponds to a thin cell gap. In the case of dealing with a thick cell gap, it is more preferably 0.095 or less, and further preferably 0.085 or less. The viscosity is preferably 30 mPa · s or less, more preferably 25 mPa · s or less, and further preferably 20 mPa · s or less.
From the above, the dielectric anisotropy Δε at 25 ° C. is in the range of −2.0 to −8.0, the refractive index anisotropy Δn at 25 ° C. is in the range of 0.06 to 0.16, and the viscosity at 20 ° C. is 10 to 30 mPa · A liquid crystal composition having a range of s and a nematic phase-isotropic liquid phase transition temperature Tni in the range of 70 ° C. to 130 ° C. is preferable.

  The nematic liquid crystal composition is useful for a liquid crystal display element, particularly useful for an active matrix driving liquid crystal display element, and can be used for a VA mode, IPS mode or ECB mode liquid crystal display element.

The nematic liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal and the like in addition to the above compounds.
Production examples of the compound represented by the general formula (1) constituting the present invention will be given below.

(Production method 1)
Formula (9)

で表されるジケトン化合物に対し、メトキシメチルトリフェニルホスホニウムクロリドより調製されるイリドを反応させて式(10)

Is reacted with an ylide prepared from methoxymethyltriphenylphosphonium chloride to form a diketone compound represented by formula (10):

で表される化合物を得る。得られた式(10)の化合物を酸触媒加水分解し、さらに塩基性条件下でシス−トランス異性化することにより式(11)

To obtain a compound represented by: The resulting compound of formula (10) is subjected to acid-catalyzed hydrolysis and further cis-trans isomerization under basic conditions to give a compound of formula (11)

で表される化合物を得る。得られた式(11)の化合物に対し、メチルトリフェニルホスホニウムブロミドより調製されるイリドを反応させて式(12)

To obtain a compound represented by: The resulting compound of formula (11) is reacted with an ylide prepared from methyltriphenylphosphonium bromide to give a compound of formula (12)

で表される化合物を得る。得られた式(12)の化合物を水素化ほう素ナトリウム等の還元剤を用いて還元して式(13)

To obtain a compound represented by: The resulting compound of formula (12) is reduced using a reducing agent such as sodium borohydride to obtain the formula (13)

で表される化合物を得る。得られた式(13)の化合物を一般式(14)

To obtain a compound represented by: The obtained compound of the formula (13) is represented by the general formula (14)

（式中、X¹は塩素、臭素、よう素、ベンゼンスルホニル機、p-トルエンスルホニル基、メタンスルホニル基またはトリフルオロメタンスルホニル基を表す。）で表される化合物へ変換し、一般式(15)

(Wherein X ¹ represents chlorine, bromine, iodine, a benzenesulfonyl group, a p-toluenesulfonyl group, a methanesulfonyl group or a trifluoromethanesulfonyl group), and is converted to a compound represented by the general formula (15)

（式中、R^bは一般式(1)と同じ意味を表す。）で表されるフェノール化合物から調製されるフェノラートと反応させることにより一般式(16)

(Wherein R ^b represents the same meaning as in general formula (1)), and is reacted with a phenolate prepared from a phenol compound represented by general formula (16)

（R^bは一般式(1)と同じ意味を表す。）で表される化合物を得ることができる。

A compound represented by the formula ( ^Rb represents the same meaning as in the general formula (1)) can be obtained.

(Production method 2)
Formula (17)

で表される化合物に対し、式(9)から式(11)への変換と同様の反応を行うことにより式(18)

The compound represented by formula (18) is subjected to a reaction similar to the conversion from formula (9) to formula (11).

で表される化合物を得る。得られた式(18)の化合物を水素化ほう素ナトリウム等の還元剤を用いて還元して式(19)

To obtain a compound represented by: The obtained compound of the formula (18) is reduced using a reducing agent such as sodium borohydride to obtain the formula (19).

で表される化合物を得る。得られた式(19)で表される化合物を一般式(20)

To obtain a compound represented by: The resulting compound represented by the formula (19) is represented by the general formula (20)

（式中、X²は一般式(14)におけるX¹と同じ意味を表す。）で表される化合物へと変換し、酸性条件下で脱保護することにより一般式(21)

(In the formula, X ² represents the same meaning as X ¹ in the general formula (14)), and is converted to a compound represented by the general formula (21) by deprotection under acidic conditions.

（式中、X²は一般式(14)におけるX¹と同じ意味を表す。）で表される化合物を得る。得られた一般式(21)で表される化合物に対し、式(9)から式(11)への変換と同様の反応を行うことにより式(22)

(Wherein X ² represents the same meaning as X ¹ in formula (14)). The compound represented by the general formula (21) thus obtained is subjected to a reaction similar to the conversion from the formula (9) to the formula (11) to obtain the formula (22).

（式中、X²は一般式(14)におけるX¹と同じ意味を表す。）で表される化合物を得る。得られた一般式(22)で表される化合物を水素化ほう素ナトリウム等の還元剤を用いて還元して一般式(23)

(Wherein X ² represents the same meaning as X ¹ in formula (14)). The resulting compound represented by the general formula (22) is reduced using a reducing agent such as sodium borohydride to obtain the general formula (23).

（式中、X²は一般式(14)におけるX¹と同じ意味を表す。）で表される化合物を得る。得られた一般式(23)で表される化合物を一般式(15)で表されるフェノール化合物から調製されるフェノラートと反応させることにより一般式(16)で表される化合物を得ることができる。

(Wherein X ² represents the same meaning as X ¹ in formula (14)). The compound represented by the general formula (16) can be obtained by reacting the obtained compound represented by the general formula (23) with a phenolate prepared from the phenol compound represented by the general formula (15). .

(Manufacturing method 3)
Formula (24)

で表される化合物に対し、式(9)から式(12)への変換と同様の反応を行うことにより式(25)

The compound represented by formula (25) is subjected to a reaction similar to the conversion from formula (9) to formula (12).

で表される化合物を得る。得られた式(25)で表される化合物を水素化リチウムアルミニウム、水素化ビス(2-メトキシエトキシ)アルミニウムナトリウム等の還元剤により還元して式(26)

To obtain a compound represented by: The resulting compound represented by the formula (25) is reduced by a reducing agent such as lithium aluminum hydride, sodium bis (2-methoxyethoxy) aluminum hydride,

で表される化合物を得る。得られた式(26)で表される化合物を一般式(27)

To obtain a compound represented by: The resulting compound represented by the formula (26) is represented by the general formula (27)

（式中、X³は一般式(14)におけるX¹と同じ意味を表す。）で表される化合物へと変換し、
一般式(15)で表されるフェノール化合物から調製されるフェノラートと反応させることにより一般式(28)

(Wherein X ³ represents the same meaning as X ¹ in the general formula (14)),
By reacting with a phenolate prepared from a phenol compound represented by the general formula (15), the general formula (28)

（式中、R^bは一般式(1)と同じ意味を表す。）で表される化合物を得ることができる。

(Wherein R ^b represents the same meaning as in the general formula (1)) can be obtained.

EXAMPLES The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. The structure of the compound was confirmed by nuclear magnetic resonance spectrum (NMR), mass spectrum (MS) and the like. Further, “%” in the compositions of the following Examples and Comparative Examples means “mass%”.
In the examples, the measured characteristics are as follows.
T _ni : Nematic phase-isotropic liquid phase transition temperature (° C)
Δn: Birefringence at 25 ° C. Δε: Dielectric anisotropy at 25 ° C. η: Viscosity (mPa · s) (20 ° C.)
The following abbreviations are used in compound descriptions.

THF: tetrahydrofuran
DMF: N, N-dimethylformamide
Me: methyl group
Et: ethyl group
Bu: Butyl group
Pen: pentyl group
Pr: Propyl group
Ph: phenyl group
Ms: Methanesulfonyl group (Example 1) Synthesis of 1-ethoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (Ia) (1-1) 2,3-difluoro-4- Synthesis of ethoxyphenol

（１−１−１） 2,3-ジフルオロエトキシベンゼンの合成
2,3-ジフルオロフェノールの130.1gとヨウ化エチルの234.0gをアセトン650mLに溶解し、無水炭酸カリウム207.3gを加え2時間還流した後、室温まで冷却した。濾過し、濾液を濃縮した後、残渣にヘキサン600mLを加え、有機層を水、飽和食塩水の順に洗浄した。無水硫酸ナトリウムで乾燥後、濃縮し、190gの反応混合物を得た。減圧蒸留により、油状物として2,3-ジフルオロエトキシベンゼンの134.1gを得た。沸点95〜96℃/57hPa。

(1-1-1) Synthesis of 2,3-difluoroethoxybenzene
130.1 g of 2,3-difluorophenol and 234.0 g of ethyl iodide were dissolved in 650 mL of acetone, 207.3 g of anhydrous potassium carbonate was added and refluxed for 2 hours, and then cooled to room temperature. After filtration and concentration of the filtrate, 600 mL of hexane was added to the residue, and the organic layer was washed with water and saturated brine in this order. The extract was dried over anhydrous sodium sulfate and concentrated to obtain 190 g of a reaction mixture. Distillation under reduced pressure gave 134.1 g of 2,3-difluoroethoxybenzene as an oil. Boiling point 95-96 ° C / 57hPa.

(1-1-2) Synthesis of 2,3-difluoro-4-ethoxyphenol
122.2 g of 2,3-difluoroethoxybenzene was dissolved in 1200 mL of THF, and 313.2 mL of butyl lithium (2.59 M hexane solution) was added dropwise at -60 to -56 ° C. over 60 minutes. Further, after stirring at −56 to −60 ° C. for 2 hours, 88.3 g of trimethyl borate was dissolved in 160 mL of THF and added dropwise at −50 ° C. over 45 minutes. Furthermore, after stirring at -60 ° C for 1 hour, the temperature was raised to -5 ° C and 120 mL of acetic acid was added. 240 mL of 15% aqueous hydrogen peroxide was added dropwise over 25 minutes so that the temperature of the system was kept at 30 ° C. or lower on a water bath. After further stirring at room temperature for 2 hours, the organic layer and the aqueous layer were separated, and the aqueous layer was extracted with ethyl acetate. The organic layers were combined and washed with water, a saturated aqueous sodium hydrogensulfite solution, water, saturated aqueous sodium hydrogen carbonate, water, and saturated brine in this order. The extract was dried over anhydrous magnesium sulfate and concentrated to obtain 220 g of a reaction mixture. Recrystallization from silica gel column chromatography (hexane-ethyl acetate mixed solvent) and hexane-ethyl acetate mixed solvent gave 116.0 g of 2,3-difluoro-4-ethoxyphenol.
(1-2) Synthesis of 1-ethoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (Ia)

(1-2-1) Synthesis of methyl 4-methoxymethylidenecyclohexanecarboxylate 263.4 g of methoxymethyltriphenylphosphonium chloride was dispersed in 750 mL of tetrahydrofuran (THF), and 86.2 g of potassium t-butoxide was added to -9. Added at -4 ° C over 5 minutes. Further, after stirring at −4 to −11 ° C. for 30 minutes, 100.0 g of methyl 4-oxocyclohexanecarboxylate was dissolved in 300 mL of THF and added dropwise at −10 to 4 ° C. over 80 minutes. After further stirring for 60 minutes at 0 to 4 ° C., 7.0 g of ammonium chloride and 20 mL of water were added. After the solvent of the reaction mixture was distilled off under reduced pressure, 600 mL of hexane was added and stirred at room temperature for 30 minutes. After the precipitate was filtered off, the precipitate was suspended and washed again with 600 mL of hexane, and the hexane filtrate was combined and washed with a methanol-water (1: 1) mixture, water, and saturated brine in this order. After drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain 103 g of methyl 4-methoxymethylidenecyclohexanecarboxylate as an oil.

(1-2-2) Synthesis of methyl 4-formylcyclohexanecarboxylate
103 g of methyl 4-methoxymethylidenecyclohexanecarboxylate was dissolved in 350 mL of THF, and 100 mL of 10% hydrochloric acid was added dropwise thereto at 11-13 ° C. over 10 minutes. After further stirring for 3 hours at room temperature, 80 mL of hexane was added. The aqueous layer was extracted with ethyl acetate, and the organic layers were combined and washed sequentially with water and saturated brine. After drying over anhydrous magnesium sulfate and concentrating, 92.4 g of methyl 4-formylcyclohexanecarboxylate was obtained as an oil. As a result of analysis by gas chromatography, the obtained product was a 64:36 mixture of cis and trans isomers.

(1-2-3) Synthesis of methyl 4-vinylcyclohexanecarboxylate Disperse 297.4 g of methyltriphenylphosphonium bromide in 900 mL of THF, and add 95.6 g of potassium-t-butoxide at -8 ° C over 3 minutes. It was. After stirring for another 30 minutes, the entire amount of methyl 4-formylcyclohexanecarboxylate was dissolved in 270 mL of THF and added dropwise at −6 to 4 ° C. over 50 minutes. After further stirring at 0-4 ° C. for 30 minutes, 15 mL of water was added. The solvent of the reaction mixture was distilled off under reduced pressure, 500 mL of hexane was added, and the mixture was stirred at room temperature for 30 minutes. After the precipitate was filtered off, the precipitate was suspended and washed again with 500 mL of hexane, and the hexane filtrate was combined and washed with a methanol-water (1: 1) mixture, water, and saturated brine in this order. After drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain 81.2 g of an oil. Distillation under reduced pressure gave 57.3 g of methyl 4-vinylcyclohexanecarboxylate. Boiling point 122-127 ° C / 48hPa. As a result of gas chromatography analysis, the obtained product was a 26:74 mixture of cis- and trans-isomers.

(1-2-4) Synthesis of trans-4-vinylcyclohexanecarboxylic acid
After dissolving 55.3 g of methyl 4-vinylcyclohexanecarboxylate in 60 mL of methanol and cooling to 15 ° C., 100 g of a 20% aqueous sodium hydroxide solution was added thereto. After further stirring at room temperature for 2 hours, concentrated hydrochloric acid was added to acidify the system. After extraction with hexane, the organic layer was washed with saturated brine. The extract was dried over anhydrous sodium sulfate and concentrated to obtain 52.4 g of a reaction mixture. Recrystallization from hexane gave 23.0 g of trans-4-vinylcyclohexanecarboxylic acid.

(1-2-5) Synthesis of methyl trans-4-vinylcyclohexanecarboxylate Dissolve the total amount of trans-4-vinylcyclohexanecarboxylic acid in 120 mL of methanol, add 0.1 g of trimethylsilyl chloride, reflux for 6 hours, and cool to room temperature. And concentrated under reduced pressure. After adding 150 mL of hexane and separating the methanol layer, the methanol layer was extracted with hexane, and the organic layers were combined and washed with saturated brine. The extract was dried over anhydrous sodium sulfate and concentrated to obtain 29.5 g of methyl trans-4-vinylcyclohexanecarboxylate as an oily substance.

(1-2-6) Synthesis of (trans-4-vinylcyclohexyl) methanol 5.7 g of lithium aluminum hydride was dispersed in 50 mL of THF, and the total amount of methyl trans-4-vinylcyclohexanecarboxylate was dissolved in 75 mL of THF. The solution was added dropwise at 16 ° C. over 40 minutes. Furthermore, after stirring at 10-20 degreeC for 30 minutes, water was added slowly. About 70 mL of 10% hydrochloric acid was added, and sludge-like insoluble matter was removed with a decanter while rinsing with hexane, and the obtained organic layer was washed with 10% hydrochloric acid, saturated aqueous sodium hydrogen carbonate, and saturated brine in this order. The extract was dried over anhydrous sodium sulfate and concentrated to obtain 26 g of (trans-4-vinylcyclohexyl) methanol.

(1-2-7) Synthesis of methyl methanesulfonate (trans-4-vinylcyclohexyl)
The total amount of (trans-4-vinylcyclohexyl) methanol was dissolved in 100 mL of dichloromethane, and 23.6 g of pyridine and 0.9 g of 4-dimethylaminopyridine were added. To this, 18.8 g of methanesulfonyl chloride was dissolved in 36 mL of dichloromethane and added dropwise at 14 to 20 ° C. over 25 minutes. The mixture was further stirred at room temperature for 7 hours and allowed to stand overnight. After adding 40 mL of water and separating the organic layer, the organic layer was washed sequentially with 10% hydrochloric acid, water, saturated aqueous sodium hydrogen carbonate, and saturated aqueous ammonium chloride. The extract was dried over anhydrous magnesium sulfate and concentrated to obtain 32.7 g of a solid. Recrystallization from hexane gave 30.8 g of methyl methanesulfonate (trans-4-vinylcyclohexyl).

(1-2-8) Synthesis of 1-ethoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (Ia) 16.1 g of methyl methanesulfonate (trans-4-vinylcyclohexyl) Then, 14.2 g of 2,3-difluoro-4-ethoxyphenol was dissolved in 100 mL of DMF, 42.4 g of potassium phosphate was added, and the mixture was stirred at 70 ° C. for 8 hours. After cooling to room temperature and adding 300 mL of water and 150 mL of toluene, the organic layer and the aqueous layer were separated. The aqueous layer was extracted with toluene, and the organic layers were combined and washed sequentially with 10% hydrochloric acid, saturated aqueous sodium hydrogen carbonate, saturated brine, and saturated aqueous ammonium chloride. The extract was dried over anhydrous sodium sulfate and concentrated to obtain 30.8 g of a reaction mixture. Silica gel column chromatography (toluene), vacuum distillation (boiling point 142-144 ° C./40 Pa), followed by recrystallization from ethanol, 1-ethoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene ( 15.2 g of Ia) was obtained.
Melting point 35.3 ℃
MS m / z: 296 (M ⁺ ), 146 (100)
¹ H-NMR (400 MHz, CDCl ₃ )
δ: 1.00 1.25 (m, 4 H), 1.30 1.45 (m, 3 H), 1.70 2.00 (m, 6 H), 3.77 (d, J = 6.0 Hz, 2 H), 4.04 (q, J = 7.2 Hz , 2 H), 4.88 5.02 (m, 2 H), 5.78 (ddd, J = 17.2 Hz, J = 10.0 Hz, J = 6.4 Hz, 1 H), 6.57 6.64 (m, 2 H)

Example 2 Synthesis of 1-butoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (IIa) (2-1) Synthesis of 2,3-difluoro-4-butoxyphenol

ヨウ化エチルに替えてヨウ化ブチルを用いる以外は実施例１記載の2,3-ジフルオロ-4-エトキシフェノールの合成と同様な方法で2,3-ジフルオロ-4-ブトキシフェノールを合成した。
（２−２） 1-ブトキシ-2,3-ジフルオロ-4-(トランス-4-ビニルシクロヘキシル)メトキシベンゼン(IIa)の合成

2,3-Difluoro-4-butoxyphenol was synthesized in the same manner as the synthesis of 2,3-difluoro-4-ethoxyphenol described in Example 1, except that butyl iodide was used instead of ethyl iodide.
(2-2) Synthesis of 1-butoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (IIa)

1-エトキシ-2,3-ジフルオロ-4-(トランス-4-ビニルシクロヘキシル)メトキシベンゼン(Ia)の合成において、2,3-ジフルオロ-4-エトキシフェノールの代わりに2,3-ジフルオロ-4-ブトキシフェノールを用い、同様の反応を行うことで無色油状物質として1-ブトキシ-2,3-ジフルオロ-4-(トランス-4-ビニルシクロヘキシル)メトキシベンゼン(IIa)を得た。
MS m/z : 324 (M⁺), 146 (100)
¹H-NMR (400 MHz, CDCl₃)
δ: 0.97 (t, J = 7.2 Hz, 3 H), 1.00 1.25 (m, 4 H), 1.40 1.55 (m, 2 H), 1.70 2.00 (m, 8 H), 3.78 (d, J = 6.4 Hz, 2 H), 3.98 (t, J = 6.4 Hz, 2 H), 4.88 5.02 (m, 2 H), 5.79 (ddd, J = 17.6 Hz, J = 10.4 Hz, J = 6.4 Hz, 1 H), 6.55 6.65 (m, 2 H)

In the synthesis of 1-ethoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (Ia), instead of 2,3-difluoro-4-ethoxyphenol, 2,3-difluoro-4- The same reaction was carried out using butoxyphenol to obtain 1-butoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (IIa) as a colorless oily substance.
MS m / z: 324 (M ⁺ ), 146 (100)
¹ H-NMR (400 MHz, CDCl ₃ )
δ: 0.97 (t, J = 7.2 Hz, 3 H), 1.00 1.25 (m, 4 H), 1.40 1.55 (m, 2 H), 1.70 2.00 (m, 8 H), 3.78 (d, J = 6.4 Hz , 2 H), 3.98 (t, J = 6.4 Hz, 2 H), 4.88 5.02 (m, 2 H), 5.79 (ddd, J = 17.6 Hz, J = 10.4 Hz, J = 6.4 Hz, 1 H), 6.55 6.65 (m, 2 H)

Example 3 Synthesis of 4-ethoxy-2,3-difluoro-1- (trans-4- (trans-4-vinylcyclohexyl) cyclohexyl) methoxybenzene (IIIa)

(3-1) Synthesis of 4,4′-bismethoxymethylidenebicyclohexyl 882.3 g of methoxymethyltriphenylphosphonium chloride was dispersed in 2600 mL of THF and cooled to −10 ° C. While maintaining the internal temperature, 313.2 g of potassium-t-butoxide was added. After stirring for 1 hour while maintaining the internal temperature, a solution of bicyclohexyl-4,4′-dione 200.0 g in THF (800 mL) was added dropwise. After stirring for 1 hour while maintaining the internal temperature, water was added to stop the reaction. After the solvent was distilled off under reduced pressure, hexane was added and stirred vigorously, followed by filtration (twice). The filtrates were combined, washed with 50% aqueous methanol and saturated brine in that order, and dried over anhydrous magnesium sulfate. The solvent was distilled off to obtain 231.8 g of a white solid.

(3-2) Synthesis of trans, trans-bicyclohexyl-4,4′-dicarbaldehyde To a solution of 231.8 g of the solid obtained in (3-1) in THF (930 mL) was added 700 mL of 10% hydrochloric acid, Heated to reflux for 1 hour. After allowing the reaction solution to cool, the organic layer was separated and extracted from the aqueous layer with toluene (4 times). The combined organic layers were washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure to obtain 204.5 g of a reddish brown liquid. This was dissolved in 800 mL of methanol, and 80 mL of 10% aqueous sodium hydroxide solution was added dropwise while maintaining the internal temperature while stirring vigorously at −10 ° C. The mixture was stirred for 2 hours while maintaining the internal temperature. Water was added, and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and methanol in this order and dried to obtain 189.4 g of a white solid.

(3-3) Synthesis of 4'-Vinylbicyclohexyl-4-carbaldehyde Methyltriphenylphosphonium bromide (192.5 g) was dispersed in THF (580 mL) and vigorously stirred at -10 ° C while maintaining the internal temperature. Potassium-t-butoxide 66.6 g was added. The mixture was stirred for 1 hour while maintaining the internal temperature, and added dropwise to a solution of 120.0 g of the solid obtained in (3-2) in THF (1800 mL) at an internal temperature of 5 ° C. After stirring for 1 hour while maintaining the internal temperature, water was added to stop the reaction. The reaction solution was washed with 5% aqueous ammonium chloride solution. The solvent of the organic layer was distilled off, hexane and toluene were added, and the mixture was washed with 50% aqueous methanol. After drying over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure to obtain 60.1 g of an almost colorless solid.

(3-4) Synthesis of trans-4- (trans-4-vinylcyclohexyl) cyclohexylmethanol While stirring a solution of sodium borohydride 1.65 g in ethanol (120 mL) at -10 ° C, the internal temperature was maintained. Then, a solution of 60.1 g of the almost colorless solid obtained in (3-3) in THF (180 mL) was added dropwise. After warming to room temperature, the mixture was stirred for 2 hours, and water, ethyl acetate, and an aqueous ammonium chloride solution were added to stop the reaction. Saturated brine was added to the reaction solution, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (twice). The combined organic layers were washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and purified by column chromatography to obtain 15.4 g of trans-4- (trans-4-vinylcyclohexyl) cyclohexylmethanol as a white solid.

(3-5) Methanesulfonic acid Synthesis of trans-4- (trans-4-vinylcyclohexyl) cyclohexylmethyl Trans-4- (trans-4-vinylcyclohexyl) cyclohexylmethanol 15.1 g, pyridine 8.2 mL and 4-dimethylaminopyridine 0.41 g was dissolved in 50 mL of dichloromethane. Under ice-cooling, a solution of 6.3 mL of methanesulfonyl chloride in 6 mL of dichloromethane was added dropwise over 30 minutes, the temperature was raised to room temperature, stirred for 6 hours, and left overnight. The reaction solution was poured into 10% hydrochloric acid, the organic layer was separated, and the aqueous layer was extracted with dichloromethane. The organic layers were combined, washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography (silica gel / toluene) and recrystallization (hexane / toluene) three times to obtain methanesulfonic acid trans-4- (trans-4-vinylcyclohexyl) cyclohexyl as colorless crystals. Methyl 9.8 g was obtained.

(3-6) Synthesis of 4-ethoxy-2,3-difluoro-1- (trans-4- (trans-4-vinylcyclohexyl) cyclohexyl) methoxybenzene (IIIa) Methanesulfonic acid trans-4- (trans-4 -Vinylcyclohexyl) cyclohexylmethyl 9.8 g and 2,3-difluoro-4-ethoxyphenol 5.96 g were dissolved in DMF 90 mL. Thereto was added 10.4 g of tripotassium phosphate, and the mixture was stirred at 90.degree. C. for 3 hours. The reaction mixture was poured into water, extracted with toluene, washed successively with water, 10% hydrochloric acid, water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was subjected to column chromatography (silica gel / toluene), recrystallization (methanol / acetone), column chromatography (alumina and silica gel / hexane), ion-exchanged water washing, silica treatment, recrystallization (methanol / Acetone) was purified in this order to obtain 8.5 g of 4-ethoxy-2,3-difluoro-1- (trans-4- (trans-4-vinylcyclohexyl) cyclohexyl) methoxybenzene (IIIa) as colorless crystals.
Phase transition temperature C 61 N 141 I
MS m / z: 378 (M ⁺ ), 174 (100)
¹ H-NMR (400 MHz, CDCl ₃ )
δ: 0.95 1.15 (m, 10 H), 1.41 (t, J = 6.8 Hz, 3 H), 1.65 2.00 (m, 10 H), 3.76 (d, J = 6.3 Hz, 2 H), 4.05 (q, J = 6.8 Hz, 2 H), 4.80 5.00 (m, 2 H), 5.77 (ddd, J = 17.3 Hz, J = 10.2 Hz, J = 6.3 Hz, 1 H), 6.60 (d, J = 4.9 Hz, 2 H)

Example 4 Synthesis of 4-butoxy-2,3-difluoro-1- (trans-4- (trans-4-vinylcyclohexyl) cyclohexyl) methoxybenzene (IVa)

In the synthesis of 4-ethoxy-2,3-difluoro-1- (trans-4- (trans-4-vinylcyclohexyl) cyclohexylmethoxy) benzene (IIIa), 2 instead of 2,3-difluoro-4-ethoxyphenol 1-butoxy-2,3-difluoro-4- (trans-4-vinylcyclohexyl) methoxybenzene (IVa) was obtained by the same reaction using 1,3-difluoro-4-butoxyphenol.
Phase transition temperature C 65.4 N 129.9 I
MS m / z: 406 (M ⁺ ), 146 (100)
¹ H-NMR (400 MHz, CDCl ₃ )
δ: 0.90 1.15 (m, 10 H), 0.97 (t, J = 7.6 Hz, 3 H), 1.40 1.55 (m, 2 H), 1.65 2.00 (m, 12 H), 3.76 (d, J = 6.4 Hz , 2 H), 3.98 (t, J = 6.8 Hz, 2 H), 4.80 5.00 (m, 2 H), 5.77 (ddd, J = 17.6 Hz, J = 10.0 Hz, J = 6.4 Hz, 1 H), 6.26 6.66 (m, 2 H)
(Example 5)
As Example 5, a liquid crystal composition (No. 1) represented by the following structure was prepared using the compounds produced in Examples 1 and 2, and the physical properties thereof were measured.

Example 5 is characterized in that only a compound having an alkyl group as a side chain in the general formula (II) is used, and the characteristics are Tni: 79.8 ° C., Δn: 0.073, Δε: −4.7, η : 20.3 mPa · s.
(Comparative Example 1)
As Comparative Example 1, a liquid crystal composition (R-1) represented by the following structure having a composition similar to that of Example 1 and not containing the compound represented by the general formula (I) was prepared, and the physical property values thereof were adjusted. It was measured.

Ｒ−１の特性は、Tni：80.0℃、Δn：0.073、Δε：-4.8、η：23.0 mPa・sであった。
これらの特性を表１にまとめる。

The characteristics of R-1 were Tni: 80.0 ° C., Δn: 0.073, Δε: −4.8, η: 23.0 mPa · s.
These characteristics are summarized in Table 1.

From Table 1, R-1 is No. It can be seen that Tni, Δn and dielectric anisotropy are almost equal to 1, but the viscosity is quite high.
In the table, (III) represents a compound represented by general formulas (III-A) to (III-J). The same applies to the following table.
(Example 6)
A liquid crystal composition (No. 2) represented by the following structure was prepared and measured for physical properties.

No. 2 is No. 2 described in Example 5. 1, the liquid crystal composition had a slightly larger Δn, and the characteristics were Tni: 90.8 ° C., Δn: 0.096, Δε: −3.0, η: 17.0 mPa · s.
(Comparative Example 2)
As Comparative Example 2, the compound represented by the general formula (II) has a similar composition, but does not include the compound represented by the general formula (I), and the liquid crystal composition represented by the following structure (R-2) ) And the physical properties thereof were measured.

The characteristics of R-2 were Tni: 91.2 ° C., Δn: 0.095, Δε: −2.6, and η: 18.0 mPa · s.
These characteristics are summarized in Table 2.

From Table 2, no. It can be seen that 2 is an excellent liquid crystal composition having Tni and Δn equivalent to R-2, but having a negative Δε having a larger absolute value than R-2 and having a low viscosity.
(Examples 7 and 8)
A liquid crystal composition (No. 3) represented by the following structure was prepared and measured for physical properties.

No. The characteristics of No. 3 were Tni: 78.9 ° C., Δn: 0.074, Δε: −4.7, η: 18.5 mPa · s.
A liquid crystal composition (No. 4) represented by the following structure was prepared and measured for physical properties.

No. The characteristics of No. 4 were Tni: 76.4 ° C., Δn: 0.076, Δε: −4.6, η: 17.6 mPa · s.
No. 3 and no. No. 4 uses a compound having an alkenyl side chain in the compound represented by the general formula (II), and particularly has both a high absolute value of Δε and a low viscosity.
(Comparative Examples 3, 4, 5 and 6)
As Comparative Example 3, a liquid crystal composition (R-3) represented by the following structure not containing the compound represented by the general formula (I) was prepared, and the physical properties thereof were measured.

The characteristics of R-3 were Tni: 76.3 ° C., Δn: 0.074, Δε: −4.8, and η: 20.0 mPa · s.

  As Comparative Example 4, a liquid crystal composition (R-4) represented by the following structure having a small content of the compound represented by the general formula (I) was prepared, and the physical properties thereof were measured.

The characteristics of R-4 were Tni: 76.5 ° C., Δn: 0.074, Δε: −4.8, and η: 20.2 mPa · s.
As Comparative Example 5, a liquid crystal composition (R-5) represented by the following structure containing no compound represented by the general formula (I) was prepared, and the physical properties thereof were measured.

The characteristics of R-4 were Tni: 82.0 ° C., Δn: 0.082, Δε: -2.5, and η: 22.3 mPa · s.
As Comparative Example 6, a liquid crystal composition (R-6) represented by the following structure containing no compound represented by the general formula (I) was prepared, and the physical properties thereof were measured.

The characteristics of R-6 were Tni: 49.5 ° C., Δn: 0.076, Δε: -3.0, and η: 23.1 mPa · s.
These characteristics are summarized in Table 3.

From Table 3, No. Comparing 3 and R-3, it can be seen that the viscosity is high and Tni is slightly low. R-3 is No. 3 is characterized in that a compound in which the general formula (I) is substituted on the alkyl side chain is used. R-4 has a composition in which the compound having an alkyl side chain in R-3 is partially substituted with the general formula (I) having an alkenyl side chain. However, the amount of substitution is as small as 6% and is outside the scope of the present invention. R-4 generally has the same characteristics as R-3. When compared with 3, the viscosity is high and Tni is slightly low.
On the other hand, R-5 is a liquid crystal composition mainly composed of a compound having a negative Δε that does not have a linking group and is widely used in liquid crystal display devices. R-5 has a small absolute value of Δε and high viscosity. R-6 is a liquid crystal composition composed mainly of a compound having a negative Δε having no linking group and a general formula (II) having an alkyl group. In addition to the drawbacks of R-5, Tni is also greatly reduced. is doing.
Example 9
A liquid crystal composition (No. 5) represented by the following structure was prepared and measured for physical properties.

No. 5 is a liquid crystal composition having a large Δn, and its characteristics were Tni: 91.2 ° C., Δn: 0.122, Δε: −3.0, η: 19.0 mPa · s.
(Comparative Example 7)
As Comparative Example 7, a liquid crystal composition represented by the following structure not containing the general formula (I) was prepared, and the physical properties thereof were measured.

The characteristics of R-7 were Tni: 91.2 ° C., Δn: 0.123, Δε: −2.6, and η: 23.6 mPa · s.
These characteristics are summarized in Table 4.

From Table 4, these liquid crystal compositions are characterized by having a large Δn and a relatively high Tni. 5 and R-7 have equivalent Tni and Δn. However, in R-7, as a result of equalizing Tni and Δn, the absolute value of Δε decreases and the viscosity increases significantly.
(Examples 10, 11 and 12)
A liquid crystal composition (No. 6), a liquid crystal composition (No. 7) and a liquid crystal composition (No. 8) represented by the following structures were prepared and their physical properties were measured.

No. The characteristics of No. 6 were Tni: 77.7 ° C., Δn: 0.075, Δε: −4.6, η: 18.8 mPa · s.

No. The characteristics of No. 7 were Tni: 80.9 ° C., Δn: 0.077, Δε: −4.5, η: 18.6 mPa · s.

No. The characteristics of No. 8 were Tni: 84.2 ° C., Δn: 0.079, Δε: −4.4, and η: 19.3 mPa · s.

  These characteristics are summarized in Table 5.

These liquid crystal compositions are mainly composed of compounds having alkenyl side chains, and it can be seen that both a large Δε and a low viscosity are compatible.
Using these liquid crystal compositions, a VA liquid crystal display device having excellent display quality could be produced.

The liquid crystal composition of the present invention is very practical as a constituent member of liquid crystal displays such as VA mode, ECB mode, and IPS mode.

Claims (18)

As the first component, the general formula (I)

(In the formula, R ¹ represents an alkenyl group having 2 to 10 carbon atoms, and one CH ₂ group present in these groups or two or more CH ₂ groups not adjacent to each other represent O and / or S. One or two or more hydrogen atoms present in these groups may be substituted with F or Cl, and R ² is an alkyl group having 1 to 10 carbon atoms, or 1 carbon atom. Represents 10 to 10 alkoxyl groups,
m represents 0, 1 or 2. )
1 or 2 or more types of the compound represented by this, and the content rate is 10 to 80 mass%,
As the second component, the general formula (II)

(Wherein R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or an alkenyloxy group having 3 to 10 carbon atoms) Represents
B ¹ and B ² are each independently
(a) trans-1,4-cyclohexylene group (two CH ₂ groups not one CH ₂ group or adjacent present in this group may be substituted with an oxygen atom or a sulfur atom)
(b) 1,4-phenylene group (one or more CH groups present in this group may be substituted with a nitrogen atom)
(c) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6 Represents a group selected from the group consisting of a -diyl group and a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, and the group (a), the group (b) or the group (c) is CN or May be substituted with halogen,
Y ¹ and Y ² are independently
-CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF ₂ CF _2- , -CF = CF-, -CH ₂ O-, -OCH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) _{3 O -, - O (CH} 2) 3 -, - C≡C -, - CF 2 O -, - OCF 2 -, - COO -, - OCO -, - COS -, - SCO- or a single bond ,
When there are a plurality of Y ² and B ² , they may be the same or different,
p represents 0, 1 or 2. )
1 type or 2 types or more of the compound represented by these, The content rate is 20 to 70 mass%,
A nematic liquid crystal composition having a negative dielectric anisotropy. The nematic liquid crystal composition according to claim 1, wherein in general formula (II), at least one of R ^{3 and} R ⁴ represents an alkenyl group having 2 to 10 carbon atoms. General formula (IA) and general formula (IB)

(Wherein R ⁵ and R ⁷ each independently represent the same meaning as R ¹ in formula (I), R ⁶ and R ⁸ each independently represent an alkyl group having 1 to 10 carbon atoms, carbon Represents an alkenyl group of formula 2 to 10.)
The nematic liquid crystal composition of Claim 1 or 2 containing the 1 type, or 2 or more types of compound chosen from the compound group represented by these. From general formula (II-A) to general formula (II-G)

(In the formula, R ^3a , R ^3b , R ^3c , R ^3d , R ^3e , R ^3f , R ^3g , R ^4a , R ^4b , R ^4c , R ^4d , R ^4e , R ^4f , and R ^4g are independent of each other. And the same meaning as R ³ and R ⁴ in formula (II).) The nematic liquid crystal composition according to claim 1, comprising one or more compounds selected from the group of compounds represented by formula (II). Contains one or more compounds selected from the group consisting of general formula (IA) and general formula (IB), and includes general formula (II-A), general formula (II-B), and general formula The nematic liquid crystal composition according to claim 4, comprising a compound represented by (II-C) or the general formula (II-F). From general formula (II-A-1) to general formula (II-A-8)

(Wherein R ⁹ , R ¹⁰ and R ¹¹ each independently represents an alkyl group having 1 to 10 carbon atoms, one CH ₂ group present in these groups or two or more not adjacent to each other) The CH ₂ group in the above may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl. The nematic liquid crystal composition according to claim 2, comprising one or more compounds selected from the group of compounds. From general formula (II-B-1) to general formula (II-B-7)

(In the formula, R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , and R ¹⁷ each independently represents an alkyl group having 1 to 10 carbon atoms, and one CH present in these groups. _Two groups or two or more non-adjacent CH ₂ groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups are substituted with F or Cl The nematic liquid crystal composition according to claim 2, comprising one or more compounds selected from the group of compounds represented by: From general formula (II-C-1) to general formula (II-C-6)

(Wherein, R ²¹ and R ²² are each independently represent an alkyl group having 1 to 10 carbon atoms in which one CH ₂ group or not adjoining present in the group two or more CH ₂ A group may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl.) The nematic liquid crystal composition according to claim 2 or 3, which contains one or more selected compounds. From general formula (II-D-1) to general formula (II-D-5)

(Wherein, R ²⁷ and R ²⁸ each independently represent an alkyl group having 1 to 10 carbon atoms in which one CH ₂ group or not adjoining present in the group two or more CH ₂ A group may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl.) The nematic liquid crystal composition according to claim 2, comprising one or more selected compounds. General formula (IA) and general formula (IB)

(Wherein R ⁵ and R ⁷ each independently represent the same meaning as R ¹ in formula (I), R ⁶ and R ⁸ each independently represent an alkyl group having 1 to 10 carbon atoms, carbon Represents an alkenyl group of formula 2 to 10.)
Containing one or more compounds selected from the group of compounds represented by formula (II-A-1), general formula (II-A-2) or general formula (II-A- The nematic liquid crystal composition according to claim 6, comprising a compound represented by 3). General formula (IA) and general formula (IB)

(Wherein R ⁵ and R ⁷ each independently represent the same meaning as R ¹ in formula (I), R ⁶ and R ⁸ each independently represent an alkyl group having 1 to 10 carbon atoms, carbon Represents an alkenyl group of formula 2 to 10.)
Containing one or more compounds selected from the group of compounds represented by formula (II-C-1), general formula (II-C-2) or general formula (II-C- The nematic liquid crystal composition according to claim 8, which contains the compound represented by 4). From general formula (III-A) to general formula (III-J)

(Wherein R ²⁹ and R ³⁰ each independently represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and one CH ₂ group present in these groups or adjacent thereto. Two or more non-CH ₂ groups may be substituted with O and / or S, and one or more hydrogen atoms present in these groups may be substituted with F or Cl, R ³¹ represents an alkyl group having 1 to 10 carbon atoms, even the one CH ₂ group or not adjoining two or more CH ₂ groups present in the group is replaced with O and / or S And one or more hydrogen atoms present in these groups may be replaced by F or Cl.)
The nematic liquid crystal composition according to claim 1, 2, 4, 10, or 11, further comprising one or more compounds selected from the group consisting of: Dielectric anisotropy Δε at 25 ° C. is in the range of −2.0 to −8.0, refractive index anisotropy Δn at 25 ° C. is in the range of 0.06 to 0.16, and viscosity at 20 ° C. is in the range of 10 to 30 mPa · s. The nematic liquid crystal composition according to claim 1, wherein the nematic phase-isotropic liquid phase transition temperature Tni is in the range of 70 ° C to 130 ° C. General formula (1)

(In the formula, R ^a represents a hydrogen atom or ^a linear alkyl group having 1 to 3 carbon atoms, R ^b represents a linear alkyl group having 1 to 7 carbon atoms, and p1 is 0, 1 or 2) A difluorobenzene derivative represented by: The compound according to claim 14, wherein R ^a in formula (1) represents ^a hydrogen atom. A liquid crystal display element using the nematic liquid crystal composition according to claim 1. A liquid crystal display element for driving an active matrix, using the nematic liquid crystal composition according to claim 1. A liquid crystal display element for VA mode, IPS mode, or ECB mode, using the nematic liquid crystal composition according to claim 1.