Preparation method of linear alkylbenzene mixture, obtained linear alkylbenzene mixture and application

Abstract

The invention discloses a preparation method of a linear alkylbenzene mixture, the obtained linear alkylbenzene mixture and application, the method is carried out in a front reactor and a rear reactor which are connected in series, the feeding of the front reactor comprises a first strand of long-chain olefin and a benzene raw material, and the feeding of the rear reactor comprises a second strand of long-chain olefin and a benzene raw material; the feeding of the rear reactor comprises a second strand of long-chain olefin and the discharging of the front reactor, the conversion rate of the long-chain olefin in the front reactor is 40-90%, and the conversion rate of the long-chain olefin in the rear reactor is 95-100%. By utilizing the method disclosed by the invention, a product linear alkylbenzene mixture with the 2-LAB proportion of 30-40wt% can be obtained, and the linear alkylbenzene mixture is used as a liquid detergent.

Description

Technical Field

[0001] The invention belongs to the field of linear alkylbenzene preparation, and in particular relates to a method for preparing a linear alkylbenzene mixture, the obtained linear alkylbenzene mixture and application. Background Art

[0002] Linear alkylbenzene (LAB) is an important raw material for synthetic detergents. It is produced by the alkylation reaction of benzene and long-chain olefins under the action of an acidic catalyst. Detergents synthesized using LAB have the characteristics of high surface activity and good biodegradability. Benzene is alkylated with long-chain olefins to obtain linear alkylbenzene, which is a mixture of multiple isomers. Important considerations for commercial alkylbenzene products include the 2-phenyl isomer content and the linearity of the alkyl substituent. Alkylbenzenes with higher 2-phenyl contents are expected to provide surfactants with better detergency when sulfonated. However, the solubility of 2-LAB is poor, so a suitable proportion of 2-LAB is more needed. Products with a 2-LAB ratio of 30 to 40wt% in the product are more suitable as liquid detergents.

[0003] At present, although the industrial synthesis method of linear alkylbenzene can produce high conversion rate, after the alkylation reaction lasts for 24 hours, the catalyst needs to be washed and regenerated with benzene, and continuous production cannot be achieved. Moreover, the selectivity of 2-phenyl isomer is usually 30wt% or less. Although existing literature reports that catalysts such as mordenite and potassium zeolite have high selectivity for 2-phenyl isomers, they are difficult to industrialize due to their unstable catalytic performance and easy deactivation. Summary of the invention

[0004] In order to overcome the technical problems existing in the prior art, the present invention provides a method for preparing a linear alkylbenzene mixture, the obtained linear alkylbenzene mixture and application. The method is carried out in a front reactor and a rear reactor connected in series, wherein the front reactor has the characteristics of low conversion rate and long-term high activity, and the rear reactor has the characteristics of high conversion rate. In this way, not only a linear alkylbenzene mixture for synthetic detergent can be obtained, but also the obtained linear alkylbenzene mixture has a low bromine index. At the same time, the catalysts in the two reactors do not need to be regenerated, and the method can be carried out continuously to realize industrial production.

[0005] On one hand, the present invention provides a method for preparing a linear alkylbenzene mixture, comprising: carrying out the preparation in a front reactor and a rear reactor connected in series, wherein the feed of the front reactor comprises a first strand of long-chain olefins and a benzene raw material, and the feed of the rear reactor comprises a second strand of long-chain olefins and the discharge of the front reactor, wherein the conversion rate of the long-chain olefins in the front reactor is 40-90%, and the conversion rate of the long-chain olefins in the rear reactor is 95%-100%.

[0006] The long-chain olefin is selected from linear olefins having 8 to 28 carbon atoms, preferably from linear olefins having 9 to 15 carbon atoms.

[0007] The front reactor is filled with a catalyst A, and the catalyst A is selected from at least one of USY, AlCl3, and ZSM-38 zeolite.

[0008] The post-reactor is filled with a catalyst B, and the catalyst B is selected from a modified zeolite having an MWW structure, and is preferably an organosilicon-modified zeolite having an MWW structure.

[0009] The temperature of the front reactor was controlled at 140-190°C.

[0010] The temperature of the post-reactor is controlled at 160-220°C.

[0011] The pressures of the front reactor and the rear reactor are independently controlled to be 0.2 to 4.5 MPa, preferably 1 to 3 MPa.

[0012] The benzene-olefin ratio of the feed in the front reactor is 5-30.

[0013] The total weight space velocity of benzene and long-chain olefins in the front reactor is 0.1 to 4 h -1 , preferably 0.2 to 2 hours -1 .

[0014] The weight space velocity of the long-chain olefin in the post-reactor is 0.4 to 15 h -1 , preferably 0.8 to 5h -1 .

[0015] The output from the post-reactor is separated, and benzene is removed therefrom to obtain a linear alkylbenzene mixture with a 2-LAB ratio of 30 to 40 wt%.

[0016] The second aspect of the present invention is to provide a linear alkylbenzene mixture obtained by the preparation method described in the first aspect of the present invention.

[0017] The proportion of 2-LAB in the linear alkylbenzene mixture is 30-40 wt%.

[0018] The linear alkylbenzene mixture has a bromine index of less than 30.

[0019] The third aspect of the present invention is to provide the use of the linear alkylbenzene mixture obtained by the preparation method described in the first aspect of the present invention in liquid detergents.

[0020] The endpoints and any values ​​of the scope disclosed in the present invention are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, the endpoint values ​​of each scope, the endpoint values ​​of each scope and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The method of the present invention can be used to obtain a linear alkylbenzene mixture with a 2-LAB ratio of 30 to 40 wt%, which is used as a liquid detergent;

[0023] (2) The linear alkylbenzene mixture obtained by the method of the present invention has a very low bromine index, and a high-quality product is obtained;

[0024] (3) The front reactor and the rear reactor in the method of the present invention are not easily deactivated, and can be operated for a long period of time and can be used for industrial applications. DETAILED DESCRIPTION

[0025] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0026] One of the purposes of the present invention is to provide a method for preparing a linear alkylbenzene mixture, comprising: carrying out the preparation in a front reactor and a rear reactor connected in series, wherein the feed of the front reactor comprises a first strand of long-chain olefins and a benzene raw material, and the feed of the rear reactor comprises a second strand of long-chain olefins and a discharge from the front reactor, wherein the conversion rate of the long-chain olefins in the front reactor is 40-90%, and the conversion rate of the long-chain olefins in the rear reactor is 95%-100% (preferably 98%-100%, more preferably 100%).

[0027] In a preferred embodiment, the long chain olefin is selected from linear olefins having 8 to 28 carbon atoms, preferably linear olefins having 9 to 15 carbon atoms, for example, a mixture of one or more linear olefins having 8, 10, 12, 15, 20, 25 or 28 carbon atoms.

[0028] In a preferred embodiment, the pre-reactor is filled with a catalyst A, and the catalyst A is selected from at least one of USY, AlCl3, and ZSM-38 zeolite.

[0029] In a further preferred embodiment, the silicon-to-aluminum ratio of catalyst A is 5 to 50, for example, any value among 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or a range consisting of any two values.

[0030] Among them, the reactivity of catalyst A is worse than that of catalyst B. The conversion rate of catalyst A to long-chain olefins is incomplete, only 40% to 90% (for example, 40%, 50%, 60%, 70%, 80% or 90%). The present invention utilizes its low reactivity because it gives it the characteristics of not being easily deactivated and being able to react for a long time (specifically, the front reactor is more tolerant to impurities in benzene raw materials, can operate for a long time and is not easily deactivated), and the long-chain olefins that are not converted in catalyst A can be completely converted in catalyst B, ensuring a low bromine index of the product.

[0031] In the present invention, the effect of low conversion rate of the pre-reactor can be achieved by combining the catalyst selection of the pre-reactor and the control of various conditions of the pre-reactor (including temperature, feed space velocity, feed molar ratio, etc.).

[0032] In a preferred embodiment, the post-reactor is filled with a catalyst B, and the catalyst B is selected from at least one of the organosilicon zeolites with a long-chain olefin conversion rate of 95% to 100% (preferably 98% to 100%, more preferably 100%), preferably a self-modified zeolite with an MWW structure, and more preferably an organosilicon-modified zeolite with an MWW structure, such as the organosilicon zeolite catalyst disclosed in CN108569945A.

[0033] The catalyst B can achieve a long-chain olefin conversion rate of almost 100%.

[0034] Preferably, the organosilicon zeolite comprises the following molar composition: (1 / n)Al2O3:SiO2:(m / n)R, wherein n=5-250, m=0.01-50, and R is at least one of an alkyl group, an alkene group, or a phenyl group; 29 The NMR solid nuclear magnetic spectrum contains at least one Si between 80 and +50 ppm 29 Nuclear magnetic resonance peaks; the X-ray diffraction spectrum of the zeolite has d spacing maximum values ​​at 12.4±0.2, 10.5±0.3, 9.3±0.3, 6.8±0.2, 6.1±0.2, 5.5±0.2, 4.4±0.2, 4.0±0.2, 3.5±0.1, 3.4±0.1 and 3.3±0.1 angstroms; preferably, n=10-100, m=0.05-20, the alkyl group is an alkyl group having 1 to 8 carbon atoms (such as methyl or ethyl), and the alkenyl group is an alkenyl group having 2 to 10 carbon atoms (such as vinyl).

[0035] In the present invention, all the contents about organosilicon zeolite in Patent ZL201710147816.0 (CN108569945A) are introduced into the present invention as a limitation of Catalyst B.

[0036] In a preferred embodiment, the temperature of the front reactor is controlled to be 140-190°C, preferably 150-180°C, for example 140°C, 150°C, 160°C, 170°C, 180°C or 190°C; and / or, the temperature of the rear reactor is controlled to be 160-220°C, preferably 170-210°C, for example 160°C, 170°C, 180°C, 190°C, 200°C, 210°C or 220°C.

[0037] In a further preferred embodiment, the temperature of the front reactor is controlled to be lower than the temperature of the rear reactor.

[0038] Among them, the present invention needs to control the incomplete conversion of long-chain olefins in the front reactor and the catalyst A is not easy to deactivate. After a lot of experimental research, the inventor found that in addition to the selection of catalyst A, it is easier to solve the above technical problems of the present invention by combining the low-temperature reaction of the front reactor.

[0039] In a further preferred embodiment, the temperature of the front reactor is controlled to be 10-80°C lower than the temperature of the rear reactor, for example, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C lower.

[0040] In a preferred embodiment, the pressure of the front reactor and the rear reactor are independently controlled to be 0.2-4.5 MPa, preferably 1-3 MPa, for example, 0.2 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa or 4.5 MPa.

[0041] In a preferred embodiment, the benzene-olefin ratio of the feed in the front reactor is 5 to 30, for example, any point value among 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30 or a range consisting of any two points.

[0042] The benzene-olefin ratio refers to the molar ratio of benzene to long-chain olefins.

[0043] In a further preferred embodiment, the total weight space velocity of benzene and long-chain olefins in the front reactor is 0.1 to 4 h -1 , preferably 0.2 to 2 hours -1 , for example 0.1h -1 、0.5h -1 , 1h -1 , 1.5h -1, 2h -1 , 2.5h -1 , 3h -1 , 3.5h -1 or 4h -1 .

[0044] The total weight space velocity of the front reactor refers to the total weight space velocity of benzene and long-chain olefins in the feed of the front reactor.

[0045] In the present invention, the conversion rate of long-chain olefins in the pre-reactor is 40-90%, the catalyst A therein is not easily deactivated and can operate for a long period of time, and the proportion of 2-LAB obtained in the pre-reactor is between 25 and 35wt% (for example, 25wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt% or 35wt%), and unreacted benzene and incompletely reacted long-chain olefins are still present in the discharge of the pre-reactor.

[0046] In a preferred embodiment, the weight space velocity of the long-chain olefin in the post-reactor is 0.4 to 15 h -1 , preferably 0.8 to 5h -1 , for example 0.4h -1 , 1h -1 , 2h -1 , 4h -1 , 6h -1 , 8h -1 , 10h -1 , 12h -1 or 15h -1 .

[0047] In the present invention, the post-reactor can completely convert the long-chain olefins from the front reactor and the long-chain olefins fed to the post-reactor, and the olefin conversion rate reaches 100%, so that the obtained product has a very low bromine index.

[0048] In a preferred embodiment, the total weight space velocity of benzene and long-chain olefins in the front reactor is lower than the weight space velocity of the long-chain olefins in the rear reactor.

[0049] The front reactor reacts at low temperature and low space velocity to prevent the catalyst A from being deactivated and ensure the long-term operation of the entire method, while the unreacted olefins and benzene in the front reactor can enter the highly active catalyst B for complete reaction.

[0050] In a preferred embodiment, the discharge from the post-reactor is separated, and after removing benzene therefrom, a linear alkylbenzene mixture having a 2-LAB ratio of 30 to 40 wt% (e.g., 30 wt%, 32 wt%, 34 wt%, 36 wt%, 38 wt% or 40 wt%) is obtained.

[0051] In a further preferred embodiment, the separation is carried out by distillation to obtain components having a boiling point greater than 280 degrees at normal pressure.

[0052] In the present invention, a catalyst A which is not easy to deactivate, has high tolerance to raw material impurities but low conversion rate is used to react first. At this time, although the conversion rate is low, the unconverted olefins will be completely converted in the catalyst B with high conversion rate, which also ensures the low bromine index of the product. The reason why the catalyst B uses a high-activity and high-conversion catalyst is not easy to deactivate is that the impurities of the benzene raw material are basically absorbed or decomposed in the catalyst A, so the benzene entering the catalyst B is purified benzene, so the catalyst B can choose a catalyst with high activity and 100% conversion rate. The present invention not only achieves a low bromine index of the product, but also the method can be operated for a long period of time, and the 2-LAB ratio in the obtained product is 30-40%, which can be used for liquid detergents.

[0053] The second object of the present invention is to provide a linear alkylbenzene mixture obtained by the preparation method described in the first object of the present invention.

[0054] In a preferred embodiment, the proportion of 2-LAB in the linear alkylbenzene mixture is 30-40wt%, for example, any point value among 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt% or a range consisting of any two points.

[0055] In a further preferred embodiment, the bromine index of the linear alkylbenzene mixture is less than 30, for example, 29, 25, 20, 15, 10, 5 or 2.

[0056] The third object of the present invention is to provide the use of the linear alkylbenzene mixture obtained by the preparation method described in one of the objects of the present invention in liquid detergents.

[0057] Example

[0058] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0059] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0060] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0061] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0062] [Example 1]

[0063] A front reactor and a rear reactor are connected in series, wherein the feed of the front reactor includes a mixed material of benzene raw material and a first stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%), and the feed of the rear reactor includes the discharge of the front reactor and a mixed material of a second stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%).

[0064] The front reactor is filled with a USY catalyst (silicon to aluminum ratio of 10), and the rear reactor is filled with an organosilicon zeolite, which is selected from the organosilicon zeolite prepared in Example 1 of Patent ZL201710147816.0 (CN108569945A).

[0065] The benzene-olefin ratio in the feed of the front reactor was controlled to be 15:1, the temperature of the front reactor was controlled to be 160°C, and the total weight space velocity of the feed of the front reactor was controlled to be 0.5h -1 Through product analysis, the conversion rate of the first long-chain olefin was calculated to be 85%; the temperature of the rear reactor was 190°C, and the second long-chain olefin was combined with the product of the front reactor and entered the rear reactor. The weight space velocity of the second long-chain olefin was controlled to be 1.0h -1 In the rear reactor, all long-chain olefins are completely converted, and the pressure of the front reactor and the rear reactor is controlled to be 2.5 MPa. The output of the rear reactor is subjected to rectification and separation, and the 2-LAB ratio in the final product after benzene removal is 32wt%, and the bromine index is 9.5. The product obtained in Example 1 can be used as a liquid detergent.

[0066] In addition, the front reactor and the rear reactor of Example 1 can both be operated for a long period of time. After 1000 hours of reaction, the bromine index of the product is 25.6.

[0067] [Example 2]

[0068] A front reactor and a rear reactor are connected in series, wherein the feed of the front reactor includes a mixed material of benzene raw material and a first stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%), and the feed of the rear reactor includes the discharge of the front reactor and a mixed material of a second stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%).

[0069] The front reactor is filled with Y catalyst (silicon to aluminum ratio 6), and the rear reactor is filled with organosilicon zeolite, and the organosilicon zeolite is selected from Example 2 in Patent ZL201710147816.0.

[0070] The benzene-olefin ratio in the feed of the front reactor was controlled to be 25:1, the temperature of the front reactor was controlled to be 160°C, and the total weight space velocity of the feed of the front reactor was controlled to be 0.3h -1 Through product analysis, the conversion rate of the first long-chain olefin was calculated to be 72%; the temperature of the rear reactor was 180°C, and the second long-chain olefin was combined with the product of the front reactor and entered the rear reactor, and the weight space velocity of the second long-chain olefin was controlled to be 1.5h -1 All long-chain olefins are completely converted in the post-reactor, and the pressure of the front reactor and the post-reactor is controlled to be 2.5 MPa. The output of the post-reactor is subjected to rectification and separation, and the 2-LAB ratio in the final product after benzene removal is 38wt%, and the bromine index is 5.5.

[0071] The product obtained in Example 1 can be used as a liquid detergent.

[0072] In addition, the front reactor and the rear reactor of Example 1 can both be operated for a long period of time. After 1000 hours of reaction, the bromine index of the product is 21.8.

[0073] [Example 3]

[0074] A front reactor and a rear reactor are connected in series, wherein the feed of the front reactor includes a mixed material of benzene raw material and a first stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%), and the feed of the rear reactor includes the discharge of the front reactor and a mixed material of a second stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%).

[0075] The front reactor is filled with USY catalyst (silicon to aluminum ratio 8), and the rear reactor is filled with organosilicon zeolite, and the organosilicon zeolite is selected from the organosilicon zeolite prepared in Example 2 in Patent ZL201710147816.0.

[0076] The benzene-olefin ratio was 20:1, the temperature of the front reactor was controlled at 170°C, and the total weight space velocity of the feed in the front reactor was controlled at 1.5h -1Through product analysis, the conversion rate of the first long-chain olefin was calculated to be 66%; the temperature of the rear reactor was 180°C, and the second long-chain olefin was combined with the product of the front reactor and entered the rear reactor, and the weight space velocity of the second long-chain olefin was controlled to be 2.5h -1 In the rear reactor, all long-chain olefins are completely converted, and the pressure of the front reactor and the rear reactor is controlled to be 3.0 MPa. The output of the rear reactor is subjected to rectification and separation, and the 2-LAB ratio in the final product after benzene removal is 35wt%, and the bromine index is 11.8. The product obtained in Example 1 can be used as a liquid detergent.

[0077] In addition, the front reactor and the rear reactor of Example 1 can both be operated for a long period of time. After 1000 hours of reaction, the bromine index of the product is 28.4.

[0078] [Example 4]

[0079] A front reactor and a rear reactor are connected in series, wherein the feed of the front reactor includes a mixed material of benzene raw material and a first stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%), and the feed of the rear reactor includes the discharge of the front reactor and a mixed material of a second stream of long-chain olefins (C9-C14, wherein the proportion of straight-chain olefins is not less than 90%).

[0080] The front reactor is filled with USY catalyst (silicon to aluminum ratio of 10), and the rear reactor is filled with organosilicon zeolite, and the organosilicon zeolite is selected from the organosilicon zeolite prepared in Example 2 in Patent ZL201710147816.0.

[0081] The benzene-olefin ratio in the feed of the front reactor was controlled to be 10:1, the temperature of the front reactor was controlled to be 170°C, and the total weight space velocity of the feed of the front reactor was controlled to be 1.5h -1 Through product analysis, the conversion rate of the first long-chain olefin was calculated to be 52%; the temperature of the rear reactor was 200°C, and the second long-chain olefin was combined with the product of the front reactor and entered the rear reactor. The weight space velocity of the second long-chain olefin was controlled to be 1.5h -1 In the rear reactor, all long-chain olefins are completely converted, and the pressure of the front reactor and the rear reactor is controlled to be 3.0 MPa. The output of the rear reactor is subjected to rectification and separation, and the 2-LAB ratio in the final product after benzene removal is 38wt%, and the bromine index is 10.5.

[0082] The product obtained in Example 1 can be used as a liquid detergent.

[0083] In addition, the front reactor and the rear reactor of Example 1 can both be operated for a long period of time. After 1000 hours of reaction, the bromine index of the product is 28.3.

[0084] [Comparative Example 1]

[0085] The process of Example 1 was repeated, except that: (1) the front reactor and the rear reactor were arranged in parallel; (2) the benzene-olefin ratio of the front reactor was 15:1; and (3) the rear reactor was fed with a benzene feedstock in addition to the long-chain olefins, wherein the benzene-olefin ratio of the rear reactor was 15:1.

[0086] The final product has a 2-LAB ratio of 31% and a bromine index greater than 500, and cannot be used in liquid detergents.

[0087] [Comparative Example 2]

[0088] The process of Example 1 was repeated, except that the temperature of the front reactor was the same as that of the rear reactor, both of which were 160° C. The final product had a 2-LAB ratio of 34% and a bromine index of 9.0. After 1000 h of reaction, the bromine index of the product was 114.5.

[0089] [Comparative Example 3]

[0090] The process of Example 1 was repeated, except that the catalyst in the front reactor used the same organosilicon zeolite as that in the rear reactor. The final product had a 2-LAB ratio of 53%. Although the olefin conversion rate was high, the 2-LAB was too high and could not be adjusted.

[0091] [Comparative Example 4]

[0092] The process of Example 1 was repeated, except that the catalyst in the rear reactor was the same as that in the front reactor. The final product had a 2-LAB ratio of 25% and a bromine index of 185.2. In this comparative example 4, not only was the 2-LAB ratio in the obtained product too low, but the bromine index in the product was too high, and a high-quality product could not be obtained.

[0093] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a linear alkylbenzene mixture, comprising: The method is carried out in a front reactor and a rear reactor connected in series, wherein the feed of the front reactor includes a first stream of long-chain olefins and a benzene raw material, and the feed of the rear reactor includes a second stream of long-chain olefins and the discharge of the front reactor, wherein the conversion rate of the long-chain olefins in the front reactor is 40% to 90%, and the conversion rate of the long-chain olefins in the rear reactor is 95% to 100%.

2. The preparation method according to claim 1, characterized in that: The long-chain olefin is selected from linear olefins having 8 to 28 carbon atoms, preferably from linear olefins having 9 to 15 carbon atoms.

3. The preparation method according to claim 1, characterized in that: The front reactor is filled with a catalyst A, and the catalyst A is selected from at least one of USY, AlCl3, and ZSM-38 zeolite.

4. The preparation method according to claim 1, characterized in that: The post-reactor is filled with a catalyst B, and the catalyst B is selected from a modified zeolite having an MWW structure, and is preferably an organosilicon-modified zeolite having an MWW structure.

5. The preparation method according to claim 1, characterized in that: The temperature of the front reactor is controlled to be 140-190°C; and / or the temperature of the rear reactor is controlled to be 160-220°C.

6. The preparation method according to claim 1, characterized in that: The pressures of the front reactor and the rear reactor are independently controlled to be 0.2 to 4.5 MPa, preferably 1 to 3 MPa.

7. The preparation method according to claim 1, characterized in that: The feed benzene-olefin ratio in the pre-reactor is 5 to 30; and / or the total weight space velocity of benzene and long-chain olefins in the pre-reactor is 0.1 to 4 h -1 , preferably 0.2 to 2 hours -1 ; and / or, the weight space velocity of the long-chain olefin in the post-reactor is 0.4 to 15 h -1 , preferably 0.8 to 5h -1 .

8. The preparation method according to any one of claims 1 to 7, characterized in that: The output from the post-reactor is separated, and benzene is removed therefrom to obtain a linear alkylbenzene mixture with a 2-LAB ratio of 30 to 40 wt%.

9. A linear alkylbenzene mixture obtained by the preparation method according to any one of claims 1 to 8.

10. The linear alkylbenzene mixture according to claim 9, characterized in that The proportion of 2-LAB in the linear alkylbenzene mixture is 30-40 wt%.

11. The linear alkylbenzene mixture according to claim 9 or 10, characterized in that The linear alkylbenzene mixture has a bromine index of less than 30.

12. Use of the linear alkylbenzene mixture obtained by the preparation method according to any one of claims 1 to 8 in liquid detergents.