Liquid crystal compound containing terminal alkenyl group, and preparation method and application thereof

Abstract

This invention provides a terminal alkenyl-containing liquid crystal compound, its preparation method, and its applications. The terminal alkenyl-containing liquid crystal compound has the structure shown in general formula P. Liquid crystal compositions containing the terminal alkenyl-containing liquid crystal compound of this invention exhibit a fast response speed, a large refractive index and clearing point, and a wide phase transition temperature. The synthesis method of the compound of this invention has high yield, simple post-processing, and is suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of compound preparation technology, and relates to a liquid crystal compound containing terminal alkenyl groups, its preparation method and application. Background Technology

[0002] Liquid crystal display (LCD) elements can be used in various household appliances such as clocks and calculators, measuring machines, automotive panels, word processors, computers, printers, and televisions. Based on display mode, they are classified into PC (phase change), TN (twist nematic), STN (super-twist nematic), ECB (electrically controlled birefringence), OCB (optically compensated bend), IPS (in-plane switching), and VA (vertical alignment). Based on the driving method, they are classified into PM (passive matrix) and AM (active matrix). PM is further divided into static and multiplex types. AM is divided into TFT (thin film transistor) and MIM (metal-insulator-metal). TFT types include amorphous silicon and polycrystalline silicon. The latter is divided into high-temperature type and low-temperature type according to the manufacturing process. Liquid crystal display elements are divided into reflective type using natural light, transmissive type using backlight, and transmissive type using both natural light and backlight according to the type of light source.

[0003] Liquid crystal compositions with low viscosity can improve the response speed of liquid crystal display elements (LCDs). A fast response speed makes LCDs suitable for animation display. Furthermore, injecting the liquid crystal composition into the liquid crystal cell of the LCD can shorten the injection time, improving workability.

[0004] Existing technologies disclose liquid crystal compositions with low power consumption and fast response, such as patent document CN102858918A. However, existing liquid crystal compositions have environmental problems (such as the use of chlorine-containing compounds), short lifespan (such as poor stability against UV or heat), low contrast (such as screen whitening under sunlight), and cannot simultaneously meet the performance balance requirements of appropriate optical anisotropy, appropriate dielectric anisotropy, high voltage retention rate, good UV resistance and high temperature stability in LCD TVs, tablet computers, etc.

[0005] From the perspective of liquid crystal material preparation, the various properties of liquid crystal materials are interdependent and mutually influential; improving one performance indicator may alter other properties. Therefore, preparing liquid crystal materials with suitable properties in all aspects often requires creative effort.

[0006] Liquid crystal materials are a crucial component of liquid crystal displays (LCDs), which currently enjoy significant global market demand and are widely used in electronic products. However, their lifespan is relatively short. This short lifespan naturally leads to problems such as waste pollution. Given the increasing emphasis on environmental protection, controlling the issue at its source—selecting environmentally friendly materials during the liquid crystal material manufacturing process—can significantly reduce the environmental costs of disposing of waste LCDs. Therefore, developing liquid crystal materials that are suitable in all aspects, economical, and environmentally friendly often requires creative effort. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a liquid crystal compound containing terminal alkenyl groups, its preparation method and application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] On one hand, the present invention provides a liquid crystal compound containing terminal alkenyl groups, wherein the liquid crystal compound containing terminal alkenyl groups has a structure represented by the general formula P:

[0010]

[0011] Wherein, R1 represents hydrogen, halogen, alkyl group with 1 to 6 (e.g., 1, 2, 3, 4, 5 or 6) carbon atoms that are fluorinated or unfluorinated, alkoxy group with 1 to 6 (e.g., 1, 2, 3, 4, 5 or 6) carbon atoms that are fluorinated or unfluorinated, alkenyl group with 2 to 6 (e.g., 2, 3, 4, 5 or 6) carbon atoms that are fluorinated or unfluorinated, and alkenoxy group with 2 to 6 (e.g., 2, 3, 4, 5 or 6) carbon atoms that are fluorinated or unfluorinated.

[0012] R2 represents hydrogen, an alkyl group with 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12), an alkoxy group with 1 to 12 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12), an alkenyl group with 2 to 12 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12), or an alkenyl group with 2 to 12 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12). The alkyl group of the alkyl group of the 1 to 12 carbon atoms, the alkoxy group of the 1 to 12 carbon atoms, the alkenyl group of the 2 to 12 carbon atoms, the alkenyl group of the 2 to 12 carbon atoms, or the alkenyl group of the 2 to 12 carbon atoms, one or more of the -CH2- groups can be replaced by -CH=CH-, -C≡C-, -O-, -S-, -CO-, -CO-O- or -O-CO-;

[0013] ring Independently representing cyclohexene, cyclohexenyl, cyclopentyl, cyclopentenyl, cyclobutyl, propylene oxide, or an unsubstituted or substituted benzene ring group, wherein one or more of the -CH2- groups in cyclohexene, cyclohexenyl, cyclopentenyl, cyclobutyl, and propylene oxide can be replaced by -O-, wherein substitution refers to one or more hydrogen atoms on the benzene ring being replaced by a halogen, a fluorinated or unfluorinated alkyl group of 1-3 (e.g., 1, 2, or 3) carbon atoms, or a fluorinated or unfluorinated alkoxy group of 1-3 (e.g., 1, 2, or 3) carbon atoms, or one or more -CH= groups on the benzene ring being replaced by -N= groups.

[0014] m represents an integer from 0 to 2 (e.g., 0, 1, or 2), n represents an integer from 1 to 6 (e.g., 1, 2, 3, 4, 5, or 6), and n1 and n2 represent integers from 1 to 4 (e.g., 1, 2, 3, or 4).

[0015] X1 and X2 may be the same or different, and each independently represents H, halogen, alkyl group with 1-3 (e.g., 1, 2 or 3) carbon atoms that is fluorinated or unfluorinated, or alkoxy group with 1-3 (e.g., 1, 2 or 3) carbon atoms that is fluorinated or unfluorinated. When n1 or n2 is not 1, multiple X1s may be the same or different, and multiple X2s may be the same or different.

[0016] In this invention, "one or more" refers to one or at least two.

[0017] Preferably, ring A represents

[0018] Preferably, The group can be selected from

[0019] Preferably, The group can be selected from

[0020] Preferably, the liquid crystal compound containing terminal alkenyl groups is any one of the compounds having the following structure:

[0021]

[0022] Preferably, R1 represents hydrogen, -F, -F2, alkyl group with 1 to 3 carbon atoms that is fluorinated or unfluorinated, alkoxy group with 1 to 3 carbon atoms that is fluorinated or unfluorinated, alkenyl group with 2 to 4 carbon atoms that is fluorinated or unfluorinated, and alkenyloxy group with 2 to 4 carbon atoms that is fluorinated or unfluorinated.

[0023] R2 represents hydrogen, an alkyl group with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkenyloxy group with 2 to 6 carbon atoms, or an alkynyl group with 2 to 6 carbon atoms, wherein one or more of the alkyl group with 1 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkenyl group with 2 to 6 carbon atoms, alkenyloxy group with 2 to 6 carbon atoms, or alkynyl group with 2 to 6 carbon atoms, -CH2- can be replaced by -CH=CH-, -C≡C-, -O-, -S-, -CO-, -CO-O-, or -O-CO-.

[0024] More preferably, R2 is selected from hydrogen, methyl, trifluoromethyl, ethyl, propyl, methoxy, trifluoromethoxy, ethoxy, vinyl, propenyl, or difluoroalkenyl with 2-4 carbon atoms.

[0025] More preferably, R2 is selected from methyl, ethyl, or propyl.

[0026] Preferably, n is 2.

[0027] Preferably, the liquid crystal compound containing terminal alkenyl groups is any one of the following compounds:

[0028]

[0029] On the other hand, the present invention provides a method for preparing the terminal alkenyl-containing liquid crystal compound as described above, the method comprising the following steps:

[0030] (1) Compound A and compound B react in the presence of metallic magnesium to give compound C, as shown in the following reaction formula:

[0031]

[0032] (2) Compound C reacts with compound D to give compound E, as shown in the following reaction formula:

[0033]

[0034] (3) Compound E undergoes a dehydration reaction in the presence of a catalyst to obtain the liquid crystal compound with terminal alkenyl groups shown in Formula P, as follows:

[0035]

[0036] Where X represents Cl, Br, I, p-toluenesulfonyl (Ots) or methanesulfonyl (OMs), and Hal represents Cl, Br or I.

[0037] Preferably, the molar ratio of compound A to compound B in step (1) is 1:0.9 to 1:3, for example, 1:0.9, 1:1.0, 1:1.5, 1:2.0, 1:2.5, 1:3.0, etc., and preferably 1:0.9 to 1:1.2.

[0038] Preferably, the molar ratio of metallic magnesium to compound B in step (1) is 1:1 to 1.5:1, for example 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, preferably 1:1 to 1.2:1.

[0039] Preferably, the reaction temperature in step (1) is -30 to 100°C, for example, -30°C, -20°C, -10°C, 0°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C, and the reaction time is 0.5 to 24 hours, for example, 0.5 hours, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, or 24 hours.

[0040] Preferably, the reaction in step (1) is carried out under nitrogen protection.

[0041] Preferably, the reaction in step (1) is carried out in an organic solvent selected from one or a combination of at least two of tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether or methyl tert-butyl ether, preferably tetrahydrofuran and / or 2-methyltetrahydrofuran.

[0042] Preferably, after the reaction in step (1) is completed, the mixture is separated, washed with water, concentrated, and crystallized to obtain the compound of formula C.

[0043] Preferably, the molar ratio of compound C to compound D in step (2) is 1:0.9 to 1:1.5, for example, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc., preferably 1:0.9 to 1:1.1.

[0044] Preferably, the reaction in step (2) is carried out in the presence of an alkaline substance.

[0045] Preferably, the alkaline substance is selected from any one of lithium methyl, lithium n-butyl, lithium sec-butyl, or lithium tert-butyl, with lithium n-butyl or lithium sec-butyl being more preferred.

[0046] Preferably, the reaction in step (2) is a reaction of compound C in the presence of a base at a temperature of -100 to -20°C (e.g., -100°C, -90°C, -80°C, -70°C, -60°C, -50°C, -40°C, -30°C, or -20°C) for a time of 0.5 to 24 hours (e.g., 0.5 hours, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, or 24 hours). h), and then add compound D, and react at -100 to 20°C (e.g. -100°C, -90°C, -80°C, -70°C, -60°C, -50°C, -40°C, -30°C, -20°C, -10°C, 0°C, 10°C or 20°C) for 0.5 to 24 h (e.g. 0.5 h, 1 h, 3 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h or 24 h).

[0047] Preferably, the reaction in step (2) is carried out in an organic solvent selected from one or a combination of at least two of toluene, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, methyl tert-butyl ether or ethylene glycol dimethyl ether, preferably one or a combination of at least two of tetrahydrofuran, 2-methyltetrahydrofuran or diethyl ether.

[0048] Preferably, the reaction in step (2) is carried out under nitrogen protection.

[0049] Preferably, after the reaction in step (2) is completed, the product is separated, washed with water, concentrated, and crystallized to obtain compound E.

[0050] Preferably, the catalyst in step (3) is selected from one or a combination of at least two of p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid or solid acid catalysts, with p-toluenesulfonic acid being the most preferred.

[0051] Preferably, the dehydration reaction in step (3) is carried out in an organic solvent selected from one or a combination of at least two of toluene, tetrahydrofuran, petroleum ether, acetonitrile, dioxane, ethanol or isopropanol, and preferably one or a combination of at least two of benzene, tetrahydrofuran or petroleum ether.

[0052] Preferably, the temperature of the dehydration reaction in step (3) is 20 to 110°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or 110°C, and the reaction time is 0.5 to 24 hours, for example, 0.5 hours, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours.

[0053] Preferably, after the dehydration reaction in step (3) is completed, the product is separated, washed with water, concentrated, and crystallized to obtain compound P.

[0054] On the other hand, the present invention provides a liquid crystal composition comprising the terminal alkenyl liquid crystal compound as described above.

[0055] In some embodiments of the present invention, the terminal alkenyl-containing liquid crystal compound accounts for 0.1-30% by weight of the liquid crystal composition (inclusive of any value or subrange within this range), for example, 0.1%, 0.3%, 0.5%, 0.7%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or a range between any two of these values.

[0056] The terminal alkenyl group-containing liquid crystal compound accounts for 0.1%-30% of the weight of the liquid crystal composition, for example, 0.1%, 0.5%, 1%, 5%, 10%, 20%, 25% or 30%.

[0057] The liquid crystal composition of the present invention further comprises: one or more compounds of general formula M:

[0058]

[0059] One or more compounds of general formula A-1

[0060] as well as

[0061] One or more compounds of general formula A-2

[0062]

[0063] R M1 and R M2 Each can independently represent -H, a straight-chain or branched alkyl group containing 1-12 carbon atoms, One or more non-adjacent -CH2- atoms in the straight-chain or branched alkyl group containing 1-12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O-, or -O-CO-.

[0064] R A1 and R A2 Each independently represents a straight-chain or branched alkyl group containing 1-12 carbon atoms. One or more non-adjacent -CH2- atoms in the straight-chain or branched alkyl group containing 1-12 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O-, or -O-CO-, and the straight-chain or branched alkyl group containing 1-12 carbon atoms... One or more -H can be independently replaced by -F or -Cl;

[0065] Z M1 and Z M2 Each can independently represent a single bond, -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH=CH-, -C≡C-, -CH2CH2-, or -(CH2)4-;

[0066] Z A11 Z A21 and Z A22 Each can independently represent a single bond, -CH2CH2-, -CF2CF2-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH-, -CF=CF-, -CH2O-, or -OCH2-;

[0067] L A11 L A12 L A13 L A21 and L A22 Each can independently represent -H, an alkyl group containing 1-3 carbon atoms, or a halogen;

[0068] X A1 and X A2 Each can independently represent a halogen, a haloalkyl or haloalkoxy group containing 1-5 carbon atoms, or a haloalkenyl or haloalkenoxy group containing 2-5 carbon atoms.

[0069] ring ring and ring Each represents independently

[0070] in, One or more of the -CH2- can be replaced by -O-. At most one -H in the halogen can be replaced by a halogen;

[0071] ring ring ring and ring Each represents independently in, One or more -CH2- bonds can be replaced by -O- bonds, and one or more single bonds in a ring can be replaced by double bonds. One or more -H can be replaced by -CN, -F or -Cl, and -CH= in one or more rings can be replaced by -N=;

[0072] n M1 n A11 and n A2 Each can independently represent 0, 1, 2, or 3, and when n M1 When = 2 or 3, the ring They can be the same or different, Z M2 They can be the same or different; when n A11 When = 2 or 3, the ring They can be the same or different, Z A11 They can be the same or different; when n A2 When = 2 or 3, the ring They can be the same or different, Z A21 They can be the same or different;

[0073] n A12 Represents 1 or 2, and when n A12 When = 2, ring They can be the same or different.

[0074] In some embodiments of the present invention, the compound of general formula M is selected from the group consisting of the following compounds:

[0075]

[0076]

[0077] as well as

[0078]

[0079] In some embodiments of the present invention, the compound of general formula M accounts for 0.1%-90% of the weight percentage of the liquid crystal composition, for example 0.1%, 0.5%, 1%, 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%.

[0080] In some embodiments of the present invention, the content of the compound of general formula M must be appropriately adjusted according to the required properties such as solubility at low temperature, transition temperature, electrical reliability, birefringence, process adaptability, drip marks, burn-in, and dielectric anisotropy.

[0081] Regarding the weight percentage of the compound of general formula M in the liquid crystal composition of the present invention, the preferred lower limit is 0.1%, 1%, 10%, 20%, 30%, 40%, or 50% relative to the total weight of the liquid crystal composition of the present invention; the preferred upper limit is 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 35%, or 25% relative to the total weight of the liquid crystal composition of the present invention.

[0082] Regarding the content of compounds of general formula M, when it is necessary to maintain a low viscosity and a short response time in the liquid crystal composition of the present invention, it is preferable to have a higher lower limit and a higher upper limit; further, when it is necessary to maintain a high clearing point and good temperature stability in the liquid crystal composition of the present invention, it is preferable to have a higher lower limit and a higher upper limit; in order to keep the driving voltage low and increase the absolute value of dielectric anisotropy, it is preferable to have a lower lower limit and a lower upper limit.

[0083] In some embodiments of the present invention, where reliability is a priority, R is preferred. M1 and R M2 All are alkyl groups; when reducing the volatility of the compound is of priority, R is preferred. M1 and R M2 All are alkoxy groups; when viscosity reduction is a priority, R is preferred. M1 and R M2 At least one of them is an alkenyl group.

[0084] In some embodiments of the invention, the compound of general formula M is preferably free from the group consisting of compounds of general formulas M1, M2, M3, M4, M5, M7, M8, M9, M10, M11, M13, M15, M16, M17, M18, M19, M20, M21, M22, M23 and M24.

[0085] In some embodiments of the invention, compounds of general formula M are further preferably the group consisting of compounds of general formulas M1, M2, M4, M5, M9, M11, M13, M20 and M22.

[0086] In some embodiments of the present invention, in compounds of general formula M1, R M1 It refers to a straight-chain or branched alkyl or alkoxy group containing 1 to 7 carbon atoms; more preferably, it refers to a straight-chain or branched alkyl or alkoxy group containing 1 to 5 carbon atoms.

[0087] Preferred weight percentages of the compound of general formula M1 in the liquid crystal composition of the present invention: the preferred lower limit of the weight percentage of the compound of general formula M1 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 3%, 5%, 7%, 10%, 13%, 15%, 17%, 20%, 23%, 25%, or 30%; the preferred upper limit of the weight percentage of the compound of general formula M1 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 60%, 55%, 50%, 45%, 40%, 37%, 35%, 33%, 30%, 27%, 25%, 23%, 20%, 17%, 15%, 13%, or 10%.

[0088] To particularly improve the response time of the liquid crystal composition of the present invention, it is preferable that R in the compound of general formula M1 is... M1 It is ethyl, n-propyl, butyl, or pentyl, and R M2 Compounds that are methyl or methoxy, in which R is a methyl or methoxy compound, are compounds of general formula M1. M1 It is ethyl, n-propyl, butyl, or pentyl, and R M2 Compounds that are ethyl or ethoxylated, or compounds of general formula M1 in which R M1 It is n-propyl, butyl, or pentyl, and R M2 Compounds that are n-propyl or propoxy.

[0089] Relative to the total weight of the liquid crystal composition of the present invention, R in the compound of general formula M1 M1 It is n-propyl and R M2The preferred lower limit for the weight percentage of the ethyl compound in the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 13%, 15%, 18%, or 20%; relative to the total weight of the liquid crystal composition of the present invention, R in general formula M1 M1 It is n-propyl and R M2 The preferred upper limit for the weight percentage of the ethyl compound in the liquid crystal composition of the present invention is 20%, 17%, 15%, 13%, 10%, 8%, 7%, or 6%.

[0090] The preferred weight percentage of the compound of general formula M2 in the liquid crystal composition of the present invention is as follows: the lower limit of the weight percentage of the compound of general formula M2 in the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7% or 10% relative to the total weight of the liquid crystal composition of the present invention; the upper limit of the weight percentage of the compound of general formula M2 in the liquid crystal composition of the present invention is 20%, 15%, 13%, 10%, 8%, 7%, 6%, 5% or 3% relative to the total weight of the liquid crystal composition of the present invention.

[0091] The preferred weight percentage of the compound of general formula M4 in the liquid crystal composition of the present invention is as follows: the lower limit of the weight percentage of the compound of general formula M4 in the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7% or 10% relative to the total weight of the liquid crystal composition of the present invention; the upper limit of the weight percentage of the compound of general formula M4 in the liquid crystal composition of the present invention is 20%, 15%, 13%, 10%, 8%, 7%, 6%, 5% or 3% relative to the total weight of the liquid crystal composition of the present invention.

[0092] Regarding the preferred weight percentage of the compound of general formula M9 in the liquid crystal composition of the present invention: the preferred lower limit of the weight percentage of the compound of general formula M9 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 14%, 16%, 20%, 23%, 26%, 30%, 35%, or 40%; the preferred upper limit of the weight percentage of the compound of general formula M9 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 50%, 40%, 35%, 30%, 20%, 15%, 10%, or 5%.

[0093] In some embodiments of the present invention, depending on the required properties such as solubility at low temperatures, transition temperature, electrical reliability, and birefringence, R in a compound containing the general formula M9 is preferred. M1 It is a straight-chain or branched alkenyl group containing 2-4 carbon atoms, and R M2 The compound is CH3-, and the alkenyl group containing 2-4 carbon atoms, either straight-chain or branched, is further preferred.

[0094] Relative to the total weight of the liquid crystal composition of the present invention, the compound of general formula M9 contains R M1 for And R M2 The preferred lower limit for the weight percentage of the CH3- compound in the liquid crystal composition of the present invention is 1%, 3%, 5%, 7%, 9%, 11%, 12%, 13%, 18%, or 21%, and the preferred upper limit is 45%, 40%, 35%, 30%, 25%, 23%, 20%, 18%, 15%, 13%, 10%, or 8%. When both compounds are present, the preferred lower limit for the weight percentage of the two compounds in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 3%, 5%, 7%, 9%, 11%, 13%, 15%, 19%, 24%, or 30%, and the preferred upper limit is 45%, 40%, 35%, 30%, 25%, 23%, 20%, 18%, 15%, 13%, 11%, or 9%.

[0095] The preferred weight percentage of the compound of general formula M10 in the liquid crystal composition of the present invention is as follows: the lower limit of the weight percentage of the compound of general formula M10 in the liquid crystal composition of the present invention is 1%, 2%, 3%, 4%, 5%, 7%, 10%, 14%, 16% or 20% relative to the total weight of the liquid crystal composition of the present invention; the upper limit of the weight percentage of the compound of general formula M10 in the liquid crystal composition of the present invention is 45%, 40%, 35%, 30%, 20%, 15%, 10% or 5% relative to the total weight of the liquid crystal composition of the present invention.

[0096] In some embodiments of the present invention, depending on the required properties such as solubility at low temperatures, transition temperature, electrical reliability, and birefringence, R in a compound containing the general formula M10 is preferred. M1 It is a straight-chain or branched alkenyl group containing 2-4 carbon atoms, and R M2 The compound is CH3-, and the alkenyl group containing 2-4 carbon atoms, either straight-chain or branched, is further preferred.

[0097] Relative to the total weight of the liquid crystal composition of the present invention, the compound of general formula M10 contains R M1 for And R M2The preferred lower limit for the weight percentage of the CH3- compound in the liquid crystal composition of the present invention is 1%, 3%, 4%, 5%, 7%, 9%, 11%, 12%, 13%, 18%, or 20%, and the preferred upper limit is 40%, 35%, 30%, 25%, 23%, 20%, 18%, 15%, 13%, 10%, or 8%. When both compounds are present, the preferred lower limit for the weight percentage of the two compounds in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 3%, 5%, 7%, 9%, 11%, 13%, 15%, 19%, 24%, or 30%, and the preferred upper limit is 45%, 40%, 35%, 30%, 25%, 23%, 20%, 18%, 15%, or 13%.

[0098] Regarding the preferred weight percentage of the compound of general formula M11 in the liquid crystal composition of the present invention: the preferred lower limit of the weight percentage of the compound of general formula M11 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 14%, 16%, 20%, 23%, 26%, 30%, 35%, or 40%; the preferred upper limit of the weight percentage of the compound of general formula M11 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 50%, 40%, 35%, 30%, 20%, 15%, 10%, or 5%.

[0099] In some embodiments of the invention, the compound of general formula M11 is preferably R. M1 It is n-propyl or n-pentyl, and R M2 Compounds that are C2H5-, or preferably R M1 for And R M2 Compounds that are n-propyl, or preferably R M1 It is n-propyl, n-butyl, or n-pentyl, and R M2 Compounds that are CH3O-; R is particularly preferred. M1 It is n-propyl, and R M2 It is a compound with C2H5-.

[0100] Regarding the preferred weight percentage of the compound of general formula M13 in the liquid crystal composition of the present invention: the preferred lower limit of the weight percentage of the compound of general formula M13 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 14%, 16%, 20%, 23%, 26%, 30%, 35%, or 40%; the preferred upper limit of the weight percentage of the compound of general formula M13 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 50%, 40%, 35%, 30%, 20%, 15%, 10%, or 5%.

[0101] In some embodiments of the invention, the compound of general formula M13 is preferably R. M1 and R M2 Each independently represents a straight-chain or branched alkyl compound containing 2-5 carbon atoms, or preferably R M1 and R M2 One of them is The other is a compound of CH3- or C2H5-.

[0102] Regarding the preferred weight percentage of the compound of general formula M15 in the liquid crystal composition of the present invention: the preferred lower limit value of the weight percentage of the compound of general formula M15 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 12%, 14%, 16%, 18%, 20%, 23%, 26%, 30%, 35%, or 40%; the preferred upper limit value of the weight percentage of the compound of general formula M15 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 50%, 40%, 35%, 30%, 25%, 22%, 20%, 18%, 15%, 12%, 10%, 8%, or 5%.

[0103] Regarding the preferred weight percentage of the compound of general formula M16 in the liquid crystal composition of the present invention: the preferred lower limit of the weight percentage of the compound of general formula M16 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 1%, 2%, 3%, 5%, 7%, 10%, 12%, 14%, 16%, 18%, 20%, 23%, 26%, 30%, 35%, or 40%; the preferred upper limit of the weight percentage of the compound of general formula M16 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 50%, 40%, 35%, 30%, 25%, 22%, 20%, 18%, 15%, 12%, 10%, 8%, or 5%.

[0104] Regarding the weight percentage of compounds of general formulas M20 to M24 in the liquid crystal composition of the present invention, the preferred lower limit values ​​are 1%, 2%, 3%, 5%, 7%, 10%, 14%, 16%, or 20% relative to the total weight of the liquid crystal composition of the present invention; and the preferred upper limit values ​​are 30%, 25%, 23%, 20%, 18%, 15%, 12%, 10%, or 5% relative to the total weight of the liquid crystal composition of the present invention.

[0105] In some embodiments of the present invention, the compound of general formula A-1 is selected from the group consisting of the following compounds:

[0106]

[0107]

[0108]

[0109] as well as

[0110]

[0111] in,

[0112] R A1 Indicates a straight-chain or branched alkyl group containing 1-8 carbon atoms. One or more non-adjacent -CH2- groups in the straight-chain or branched alkyl groups containing 1-8 carbon atoms may be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H groups present in these groups may be independently replaced by -F or -Cl.

[0113] R v and R w Each can be represented independently as -CH2- or -O-;

[0114] L A11 L A12 L A11 ’ L A12 ’ L A14 L A15 and L A16 Each can be represented independently as -H or -F;

[0115] L A13 and L A13 ’ Each can be independently represented as -H or -CH3;

[0116] X A1 It indicates -F, -CF3, or -OCF3; and

[0117] v and w each independently represent 0 or 1.

[0118] In some embodiments of the present invention, the compound of general formula A-1 accounts for 0.1%-80% by weight of the liquid crystal composition, for example 0.1%, 0.5%, 1%, 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%.

[0119] Regarding the preferred weight percentage of the compound of general formula A-1 in the liquid crystal composition of the present invention: the preferred lower limit value of the weight percentage of the compound of general formula A-1 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 17%, 18% or 20%; the preferred upper limit value of the weight percentage of the compound of general formula A-1 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30% or 25%.

[0120] Regarding the preferred content of the compound of general formula A-1, in order to keep the viscosity of the liquid crystal composition of the present invention low and the response speed fast, it is preferable to keep the lower limit value slightly low and the upper limit value slightly low; furthermore, in order to keep the clearing point of the liquid crystal composition of the present invention high and the temperature stability good, it is preferable to keep the lower limit value slightly low and the upper limit value slightly low; in addition, in order to keep the driving voltage low and to increase the absolute value of dielectric anisotropy, it is preferable to keep the lower limit value slightly high and the upper limit value slightly high.

[0121] In some embodiments of the present invention, the compound of general formula A-1 is preferably selected from the group consisting of compounds of general formula A-1-1, general formula A-1-4, general formula A-1-7, general formula A-1-13, general formula A-1-14, general formula A-1-15, general formula A-1-16 and general formula A-1-17.

[0122] In some embodiments of the invention, the compound of general formula A-1 is further preferably the group consisting of compounds of general formulas A-1-4, A-1-7, A-1-13, A-1-14 and A-1-15.

[0123] In some embodiments of the present invention, the compound of general formula A-2 is selected from the group consisting of the following compounds:

[0124]

[0125]

[0126] as well as

[0127]

[0128] in,

[0129] R A2 This refers to a straight-chain or branched alkyl group containing 1-8 carbon atoms, wherein one or more non-adjacent -CH2- groups in the straight-chain or branched alkyl group containing 1-8 carbon atoms can be independently replaced by -CH=CH-, -C≡C-, -O-, -CO-, -CO-O- or -O-CO-, and one or more -H groups present in these groups can be independently replaced by -F or -Cl;

[0130] L A21 L A22 L A23 L A24 and L A25 Each can be represented independently as -H or -F; and

[0131] X A2 It represents -F, -CF3, -OCF3, or -CH2CH2CH=CF2.

[0132] In some embodiments of the present invention, the compound of general formula A-2 accounts for 0.1%-80% by weight of the liquid crystal composition, for example, 0.1%, 0.5%, 1%, 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%.

[0133] Regarding the preferred weight percentage of the compound of general formula A-2 in the liquid crystal composition of the present invention: the preferred lower limit value of the weight percentage of the compound of general formula A-2 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 17%, 18% or 20%; the preferred upper limit value of the weight percentage of the compound of general formula A-2 in the liquid crystal composition of the present invention relative to the total weight of the liquid crystal composition of the present invention is 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30% or 25%.

[0134] Regarding the preferred content of the compound of general formula A-2, in order to keep the viscosity of the liquid crystal composition of the present invention low and the response speed fast, it is preferable to keep the lower limit value slightly low and the upper limit value slightly low; furthermore, in order to keep the clearing point of the liquid crystal composition of the present invention high and the temperature stability good, it is preferable to keep the lower limit value slightly low and the upper limit value slightly low; in addition, in order to keep the driving voltage low and to increase the absolute value of dielectric anisotropy, it is preferable to keep the lower limit value slightly high and the upper limit value slightly high.

[0135] In some embodiments of the present invention, the compound of general formula A-2 is preferably selected from the group consisting of compounds of general formula A-2-4, general formula A-2-8, general formula A-2-11 and general formula A-2-12.

[0136] In addition to the compounds mentioned above, the liquid crystal compositions of the present invention may also contain conventional nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, antioxidants, ultraviolet absorbers, infrared absorbers, polymerizable monomers, or light stabilizers.

[0137] The following shows possible dopants that are preferably added to the liquid crystal composition according to the invention.

[0138]

[0139]

[0140] as well as

[0141]

[0142] In some embodiments of the present invention, preferably, the dopant accounts for 0-5% of the weight percentage of the liquid crystal composition, for example, 0%, 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%; more preferably, the dopant accounts for 0-1% of the weight percentage of the liquid crystal composition.

[0143] Furthermore, the antioxidants, light stabilizers, and other additives used in the liquid crystal composition of the present invention are preferably the following substances:

[0144]

[0145]

[0146]

[0147]

[0148] Where n represents a positive integer from 1 to 12.

[0149] Preferably, the light stabilizer is selected from the light stabilizers shown below:

[0150]

[0151] In some embodiments of the present invention, preferably, the light stabilizer accounts for 0-5% of the total weight percentage of the liquid crystal composition, for example, 0%, 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%; more preferably, the light stabilizer accounts for 0-1% of the total weight percentage of the liquid crystal composition; particularly preferably, the light stabilizer accounts for 0.01-0.1% of the total weight percentage of the liquid crystal composition.

[0152] On the other hand, the present invention provides a liquid crystal display element comprising the liquid crystal composition described above.

[0153] Compared with the prior art, the present invention has the following beneficial effects:

[0154] The liquid crystal compounds containing terminal alkenyl groups of the present invention have a fast response speed, a large refractive index and clearing point, and a wide phase transition temperature. Their synthesis method has a high yield and simple post-processing, making them suitable for industrial production. Detailed Implementation

[0155] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0156] Example 1

[0157] Preparation of compound P-1

[0158]

[0159] In a 500 ml three-necked flask, 3 g (125 mmol) of magnesium shavings and one iodine grain were added, followed by 50 ml of dry tetrahydrofuran. Under nitrogen protection and with the temperature controlled at 0–10 °C, 10.8 g (120 mmol) of a tetrahydrofuran solution of compound B-1 (B-1 dissolved in 150 ml of tetrahydrofuran) was slowly added dropwise. After initiation, the remaining B-1 solution was slowly added dropwise at 0–10 °C. After stirring for 30 min, 34.4 g (100 mmol) of a tetrahydrofuran solution of A-1 (A-1 dissolved in 50 ml of tetrahydrofuran) was slowly added dropwise. After the addition was complete, the reaction was carried out at 0–10 °C for 2 h. The mixture was allowed to cool naturally to room temperature, and 200 ml of water was added for lysis. The aqueous phase was extracted with 2 × 100 ml of ethyl acetate, and the organic phases were combined. The mixture was washed with 3 × 80 ml of water, and the solvent was evaporated to dryness at 50 °C under negative pressure to obtain 30 g of a pale yellow solid. 26.5g of light yellow solid C-1 was obtained by pulping and drying with petroleum ether.

[0160] The gas phase purity (Agilent 7820 gas chromatograph) of compound C-1 was 98.5%, and the yield was 87%.

[0161] In a 500 ml three-necked flask, add 200 ml of tetrahydrofuran and 26.5 g (87 mmol) of compound C-1, purge with nitrogen at least three times, cool to -60 to -70 °C, and add 36 ml (90 mmol, 2.5 M) of n-butyllithium dropwise while maintaining the temperature at -60 to -70 °C. Keep warm for 1 h, then add 12.6 g (90 mmol) of tetrahydrofuran solution of compound D-1 (12.6 g D-1 dissolved in 30 ml tetrahydrofuran), and keep warm at -60 to -70 °C for 2 h.

[0162] Dehydration: Naturally heat to -40℃, add 150ml of saturated ammonium chloride solution, stir and naturally heat to room temperature, extract with 3×100ml of toluene, combine the organic phases and wash with 3×100ml of water until neutral, add 1.6g (8.7mmol) of p-toluenesulfonic acid, and react at 85~90℃ for 3h.

[0163] Post-processing: After cooling to room temperature, transfer to a separatory funnel, add 3 × 100 ml of water and wash until neutral. Concentrate toluene at 70℃ under negative pressure (-0.095 MPa), spread with 15 g of 200-300 mesh silica gel, dissolve the concentrated product in petroleum ether and pass through a column. Evaporate the solvent at 50℃ to obtain 28 g of viscous solid. Recrystallize by adding toluene:ethanol = 2:4, freeze at -30℃ for 3 h, filter through a Buchner funnel and dry to obtain 22.5 g of white solid.

[0164] Compound P-1 purity: 99.91%; yield: 74%.

[0165] GCMS data M+(348): 41(23%), 55(14%), 69(18%), 237(21%), 250(46%), 264(26%), 307(100%), 308(48%), 348(56%).

[0166] Example 2:

[0167] Preparation of compound P-1

[0168]

[0169] In a 500 ml three-necked flask, 3 g (125 mmol) of magnesium shavings and one iodine grain were added, followed by 50 ml of dry tetrahydrofuran. Under nitrogen protection and with the temperature controlled at 0–10 °C, 10.8 g (120 mmol) of a tetrahydrofuran solution of compound B-1 (B-1 dissolved in 150 ml of tetrahydrofuran) was slowly added dropwise. After initiation, the remaining B-1 solution was slowly added dropwise at 0–10 °C. After stirring for 30 min, 30 g (100 mmol) of a tetrahydrofuran solution of A-2 (A-2 dissolved in 50 ml of tetrahydrofuran) was slowly added dropwise. After the addition was complete, the reaction was carried out at 50–60 °C for 2 h. After cooling to room temperature, 200 ml of water was added for lysis. The aqueous phase was extracted with 2 x 100 ml ethyl acetate, and the organic phases were combined. The mixture was washed with 3 x 80 ml of water, and the solvent was evaporated at 50 °C under negative pressure to obtain 30 g of a pale yellow solid. The solid was then slurried with petroleum ether and dried to obtain 26 g of a pale yellow solid C-1.

[0170] Compound C-1 has a purity of 97.8% and a yield of 85.2%.

[0171] In a 500 ml three-necked flask, add 200 ml of tetrahydrofuran and 26 g (85 mmol) of compound C-1, purge with nitrogen at least three times, cool to -60 to -70 °C, and dropwise add 35 ml (88 mmol, 2.5 M) of n-butyllithium while maintaining the temperature at -60 to -70 °C. Keep the temperature for 1 h, then dropwise add 12.3 g (88 mmol) of tetrahydrofuran solution of compound D-1 (12.3 g D-1 dissolved in 30 ml of tetrahydrofuran), and keep the temperature at -60 to -70 °C for 2 h.

[0172] Dehydration: Naturally heat to -40℃, add 150ml of saturated ammonium chloride solution, stir and naturally heat to room temperature, extract with 3 x 100ml petroleum ether, combine the organic phases and wash with 3 x 100ml water until neutral, add 1.6g (8.5mmol) of p-toluenesulfonic acid, and react at 70-80℃ for 3h.

[0173] Post-treatment: Cool to room temperature, transfer to a separatory funnel, add 3 x 100 ml of water and wash until neutral, then dry with anhydrous sodium sulfate for 2 h. Spread 15 g of 200-300 mesh silica gel, pass through a column in petroleum ether solution, evaporate the solvent at 50 °C to obtain 28.5 g of viscous solid. Recrystallize with petroleum ether / ethanol, freeze at -30 °C for 3 h, filter through a Buchner funnel and dry to obtain 23 g of white solid.

[0174] Compound P-1 purity: 99.9%; yield: 77.8%.

[0175] M+(348): 41 (23%), 55 (14%), 69 (18%), 237 (21%), 250 (46%), 264 (26%), 307 (100%), 308 (48%), 348 (56%).

[0176] Example 3:

[0177] Preparation of compound P-2

[0178]

[0179] P-2 was obtained by referring to the method in Example 1.

[0180] Compound P-2 purity: 99.9%; yield: 74.1%.

[0181] M+(362): 55 (26%), 69 (18%), 237 (22%), 250 (48%), 264 (25%), 307 (100%), 308 (44%), 362 (52%).

[0182] Example 4:

[0183] Preparation of compound P-3

[0184]

[0185] P-3 was obtained by referring to the method in Example 2.

[0186] Compound P-2 purity: 99.9%; yield: 75.1%.

[0187] M+(416): 41 (16%), 55 (22%), 111 (18%), 237 (23%), 250 (47%), 264 (26%), 346 (13%), 375 (100%), 376 (43%), 416 (47%).

[0188] Example 5:

[0189] Preparation of compound P-4

[0190]

[0191] P-3 was obtained by referring to the method in Example 2.

[0192] Compound P-2 purity: 99.91%; yield: 75.2%.

[0193] M+(384): 41 (16%), 55 (26%), 69 (18%), 273 (23%), 286 (47%), 300 (26%), 329 (100%), 330 (47%), 384 (52%).

[0194] Examples of LCD applications:

[0195] Table 1. Structure codes of compound groups in liquid crystal compositions.

[0196]

[0197]

[0198] Take the following compound with the following structural formula as an example:

[0199]

[0200] If the structural formula is represented by the codes listed in Table 1, it can be expressed as: nCCGF, where n in the code represents the number of C atoms in the alkyl group at the left end. For example, if n is "3", it means that the alkyl group is -C3H7. In the code, C represents 1,4-cyclohexylene, G represents 2-fluoro-1,4-phenyleneene, and F represents fluorine.

[0201] In the following embodiments, the abbreviated codes for performance test items are shown in Table 2.

[0202] Table 2 Abbreviated Codes for Performance Test Items

[0203] Test Project Code meaning Δn Optical anisotropy (589nm, 25℃) Cp Clearing point (nematic-isotropic phase transition temperature, °C) Δε Dielectric anisotropy (1kHz, 25℃) γ1 Rotational viscosity (25℃, mPa·s) t(-30℃) Duration without precipitation after storage at -30℃ (h)

[0204] in,

[0205] Δn: Measured using an Abbe refractometer under a sodium lamp (589nm) light source at 25℃.

[0206] Cp: ​​Measured using an MP70 melting point apparatus.

[0207] Δε: Δε = ε ∥ -ε ⊥ , where ε ∥ ε is the dielectric constant parallel to the molecular axis. ⊥ The dielectric constant is perpendicular to the molecular axis. Test conditions: 25℃, 1KHz, VA type test box, box thickness 5.8μm.

[0208] γ1: Measured using the LCM-2 type liquid crystal property evaluation system; test conditions: 25℃, 160-240V, test cell thickness 20μm.

[0209] t(-30℃): Duration of storage at -30℃ without precipitation (h).

[0210] All other components used in the liquid crystal compositions of the following application examples can be synthesized by known methods or are commercially available.

[0211] The liquid crystal compositions in the following examples are prepared by mixing according to the proportions of each component (the parentheses at the end of each component in each example are the general formulas for the components) and by conventional preparation methods such as heating, ultrasonication, suspension, etc.

[0212] Application Example 1

[0213] In this application example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0214]

[0215]

[0216] Application Example 2

[0217] In this application example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0218]

[0219] Application Example 3

[0220] In this application example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0221]

[0222] Application Example 4

[0223] In this application example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0224]

[0225] Comparative Example 1

[0226] In this comparative example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0227]

[0228] Comparative Example 2

[0229] In this comparative example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0230]

[0231]

[0232] Comparative Example 3

[0233] In this comparative example, the liquid crystal composition comprises the components in the following table by mass percentage, and its performance test results are listed in the table below:

[0234]

[0235] The positive liquid crystal composition of the present invention has high dielectric constant Δε and refractive index Δn, while having low viscosity γ1 and high clearing point.

[0236] Compared to Comparative Examples 1-3, Example 1 has a higher refractive index Δn and a higher clearing point, while having a lower viscosity γ1.

[0237] Compared to Comparative Example 1, the monomers in this example have a larger dielectric Δε due to their fluorine content, as well as a lower viscosity γ1, resulting in higher solubility and stability in mixed crystals.

[0238] The applicant declares that the above embodiments illustrate the compounds, their preparation methods, and applications of this invention, but the invention is not limited to the above embodiments, i.e., it does not mean that the invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. An end-alkenyl group-containing liquid crystal compound, characterized by, The liquid crystal compound containing terminal alkenyl groups has a structure represented by the general formula P: in, R1 represents hydrogen, halogen, alkyl group with 1 to 6 carbon atoms that is fluorinated or unfluorinated, alkoxy group with 1 to 6 carbon atoms that is fluorinated or unfluorinated, alkenyl group with 2 to 6 carbon atoms that is fluorinated or unfluorinated, and alkenyl group with 2 to 6 carbon atoms that is fluorinated or unfluorinated. R2 represents hydrogen, an alkyl group with 1 to 12 carbon atoms, an alkoxy group with 1 to 12 carbon atoms, an alkenyl group with 2 to 12 carbon atoms, an alkenyloxy group with 2 to 12 carbon atoms, or an alkynyl group with 2 to 12 carbon atoms, wherein one or more of the alkyl group with 1 to 12 carbon atoms, an alkoxy group with 1 to 12 carbon atoms, an alkenyl group with 2 to 12 carbon atoms, an alkenyloxy group with 2 to 12 carbon atoms, or an alkynyl group with 2 to 12 carbon atoms may be replaced by -CH=CH-, -C≡C-, -O-, -S-, -CO-, -CO-O-, or -O-CO-; ring independently represents cyclohexanediyl, cyclohexenyl, cyclopentanediyl, cyclopentenyl, cyclobutanediyl, cyclopropanediyl or unsubstituted or substituted phenyl, wherein one or more -CH2- in cyclohexanediyl, cyclohexenyl, cyclopentanediyl, cyclopentenyl, cyclobutanediyl, cyclopropanediyl can be replaced by -O-, said substitution means that one or more hydrogens on the phenyl ring can be replaced by halogen, fluoro- or non-fluoro-alkyl of 1-3 carbon atoms or fluoro- or non-fluoro-alkoxy of 1-3 carbon atoms, one or more -CH= on the phenyl ring can be replaced by -N=, m represents an integer from 0 to 2, n represents an integer from 1 to 6, and n1 and n2 represent integers from 1 to 4; X1 and X2 may be the same or different, and each independently represents H, halogen, alkyl group with 1-3 carbon atoms that is fluorinated or unfluorinated, or alkoxy group with 1-3 carbon atoms that is fluorinated or unfluorinated. When n1 or n2 is not 1, multiple X1 may be the same or different, and multiple X2 may be the same or different.

2. The liquid crystal compound containing terminal alkenyl groups according to claim 1, characterized in that, Ring A represents 3. The liquid crystal compound containing terminal alkenyl groups according to claim 1, characterized in that, Groups are selected from Preferably, Groups are selected from 4. The liquid crystal compound containing terminal alkenyl groups according to any one of claims 1-3, characterized in that, The liquid crystal compound containing terminal alkenyl groups is any one of the compounds having the following structures:

5. The liquid crystal compound containing a terminal alkenyl group according to any one of claims 1-4, characterized in that, R1 represents hydrogen, -F, -F2, alkyl groups with 1 to 3 carbon atoms that are fluorinated or unfluorinated, alkoxy groups with 1 to 3 carbon atoms that are fluorinated or unfluorinated, alkenyl groups with 2 to 4 carbon atoms that are fluorinated or unfluorinated, and alkenyloxy groups with 2 to 4 carbon atoms that are fluorinated or unfluorinated. R2 represents hydrogen, an alkyl group with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkenyloxy group with 2 to 6 carbon atoms, or an alkynyl group with 2 to 6 carbon atoms, wherein one or more of the alkyl group with 1 to 6 carbon atoms, the alkoxy group with 1 to 6 carbon atoms, the alkenyl group with 2 to 6 carbon atoms, the alkenyloxy group with 2 to 6 carbon atoms, or the alkynyl group with 2 to 6 carbon atoms may be replaced by -CH=CH-, -C≡C-, -O-, -S-, -CO-, -CO-O-, or -O-CO-; More preferably, R2 is selected from hydrogen, methyl, trifluoromethyl, ethyl, propyl, methoxy, trifluoromethoxy, ethoxy, vinyl, propenyl or difluoroalkenyl with 2-4 carbon atoms; More preferably, R2 is selected from methyl, ethyl, or propyl; Preferably, n is 2.

6. The liquid crystal compound containing a terminal alkenyl group according to any one of claims 1-5, characterized in that, The liquid crystal compound containing terminal alkenyl groups is any one of the following compounds:

7. The method for preparing the liquid crystal compound containing terminal alkenyl groups according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Compound A and compound B react in the presence of metallic magnesium to give compound C, as shown in the following reaction formula: (2) Compound C reacts with compound D to give compound E, as shown in the following reaction formula: (3) Compound E undergoes a dehydration reaction in the presence of a catalyst to obtain the liquid crystal compound with terminal alkenyl groups shown in Formula P, as follows: Where X represents Cl, Br, I, p-toluenesulfonyl or methylsulfonyl, and Hal represents Cl, Br or I.

8. The preparation method according to claim 7, characterized in that, The molar ratio of compound A to compound B in step (1) is 1:0.9 to 1:3, preferably 1:0.9 to 1:1.2; Preferably, the molar ratio of metallic magnesium to compound B in step (1) is 1:1 to 1.5:1, more preferably 1:1 to 1.2:1; Preferably, the reaction temperature in step (1) is -30 to 100°C, and the reaction time is 0.5 to 24 hours; Preferably, the reaction in step (1) is carried out under nitrogen protection; Preferably, the reaction in step (1) is carried out in an organic solvent selected from one or a combination of at least two of tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether or methyl tert-butyl ether, preferably tetrahydrofuran and / or 2-methyltetrahydrofuran; Preferably, after the reaction in step (1) is completed, the mixture is separated, washed with water, concentrated, and crystallized to obtain the compound of formula C; Preferably, the molar ratio of compound C to compound D in step (2) is 1:0.9 to 1:1.5, more preferably 1:0.9 to 1:1.1; Preferably, the reaction in step (2) is carried out in the presence of an alkaline substance; Preferably, the alkaline substance is selected from any one of lithium methyl, lithium n-butyl, lithium sec-butyl, or lithium tert-butyl, with lithium n-butyl or lithium sec-butyl being preferred. Preferably, the reaction in step (2) is to react compound C in the presence of a base at a temperature of -100 to -20°C for 0.5 to 24 hours, and then add compound D and react at -100 to 20°C for 0.5 to 24 hours. Preferably, the reaction in step (2) is carried out in an organic solvent selected from one or a combination of at least two of toluene, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, methyl tert-butyl ether or ethylene glycol dimethyl ether, preferably one or a combination of at least two of tetrahydrofuran, 2-methyltetrahydrofuran or diethyl ether; Preferably, the reaction in step (2) is carried out under nitrogen protection; Preferably, after the reaction in step (2) is completed, the mixture is separated, washed with water, concentrated, and crystallized to obtain compound E; Preferably, the catalyst in step (3) is selected from one or a combination of at least two of p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid or solid acid catalysts, with p-toluenesulfonic acid being the most preferred; Preferably, the dehydration reaction in step (3) is carried out in an organic solvent, which is selected from one or a combination of at least two of toluene, tetrahydrofuran, petroleum ether, acetonitrile, dioxane, ethanol or isopropanol, and preferably one or a combination of at least two of benzene, tetrahydrofuran or petroleum ether. Preferably, the temperature of the dehydration reaction in step (3) is 20–110°C, and the reaction time is 0.5–24 h; Preferably, after the dehydration reaction in step (3) is completed, the product is separated, washed with water, concentrated, and crystallized to obtain compound P.

9. A liquid crystal composition, characterized in that, The liquid crystal composition includes a liquid crystal compound containing a terminal alkenyl group as described in any one of claims 1-6.

10. A liquid crystal display element, characterized in that, The liquid crystal display element includes the liquid crystal composition as described in claim 9.

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