Multistage series-parallel microchannel continuous flow ethoxylation process for nonylcyclohexanol and products

Abstract

The application discloses a multistage series-parallel microchannel continuous flow ethoxylation method of nonylcyclohexanol and a product, the method utilizes a multistage series-parallel microchannel reactor, and through separation design, the ethoxylation reaction process is continuous; under the action of a ternary composite catalyst system (V2Mo2O 11 , SrMoO4 and a phosphorus-containing heteropoly acid), the reaction selectivity is accurately controlled through feed ratio; a three-component mixed solvent system composed of n-hexadecane, ethanol and N,N-dimethylformamide is adopted to form a polarity gradient microenvironment in the reaction channel, and precise regulation and control of product molecular distribution are realized. The product obtained by the method has a purity of greater than or equal to 98.3%, a molecular weight distribution index PDI of 1.08 to 1.12, and a reaction time of 20 to 30 min. Through integrated optimization of the reactor architecture, catalyst synergy and solvent environment, the application realizes efficient and controllable production of mono / diethoxylation of nonylcyclohexanol.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical synthesis and fine chemical technology, specifically relating to a multi-stage series-parallel microchannel continuous flow ethoxylation method and product of nonylcyclohexanol. Background Technology

[0002] Nonylcyclohexanol ethoxy ether is an important intermediate for nonionic surfactants, widely used in textile printing and dyeing auxiliaries, personal care products, and pesticide emulsifiers. Its application properties, especially its hydrophilic-lipophilic balance (HLB), surface tension, and foaming characteristics, are highly dependent on the length and distribution of the ethoxy chain in the molecule. Therefore, achieving highly selective and controllable mono / diethoxylation preparation is of great significance for meeting diverse application needs.

[0003] Regarding raw material preparation, patent CN 103435449 A reports a method for preparing nonylcyclohexanol from nonylphenol via catalytic hydrogenation, which can obtain nonylcyclohexanol with high purity. However, this method only focuses on the synthesis of raw materials and does not address the selective control of the subsequent ethoxylation reaction. Furthermore, the traditional batch autoclave ethoxylation process has serious drawbacks: due to the intense exothermic reaction of ethylene oxide within the reactor, the large-volume reactor has a low heat transfer coefficient, making temperature control difficult and prone to runaway temperatures and tar byproducts. More critically, backmixing is severe—newly introduced nonylcyclohexanol mixes with the already reacted mono / diethoxy ether products and continues to react, resulting in mono / diethoxy ether purity of only 85%–92%, requiring multi-step separation and purification. The reaction cycle typically lasts 2–6 hours, resulting in low production efficiency and significant safety risks.

[0004] Although existing literature proposes improvements to the continuous flow approach, such as patent CN 120005170 A disclosing a continuous flow process for isooctanol polyoxyethylene ether, using a modified activated carbon-supported palladium catalyst and continuously introducing ethylene oxide under segmented heating; and patent CN 103709396 A involving a two-step continuous flow synthesis process for dihydromyrcenol polyoxyethylene ether, achieving a narrow distribution of PDI products of 1.10~1.15, these existing continuous flow schemes still have significant shortcomings: the reactor structure is simple, mostly a single microchannel or simple series connection, making it impossible to precisely control the product distribution; the catalyst lacks a systematic design for mono / diethoxy selectivity, mostly being a single or simple binary system; and the solvent selection is unsystematic, failing to create a "microenvironment" to guide selective reactions.

[0005] For the ethoxylation reaction of nonylcyclohexanol, there is an urgent need to achieve highly selective, efficient, and controllable continuous flow mono / diethoxylation production through the refined structural design of multi-stage series and parallel reactors, the synergistic mechanism of ternary composite catalyst systems, and the construction of a microenvironment for multi-component solvent systems. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a continuous flow mono / diethoxylation method for nonylcyclohexanol based on a multi-stage series-parallel microchannel reactor, a ternary synergistic composite catalyst system, and a three-component mixed solvent microenvironment. This method, through the organic coupling of reactor structure, catalyst selection, and solvent design, improves product selectivity and purity while achieving precise control of product molecular weight distribution, significant improvement in reaction efficiency, and flexible adjustment of process parameters.

[0007] The specific technical solution is as follows:

[0008] A multi-stage series-parallel microchannel continuous flow ethoxylation method for nonylcyclohexanol includes the following steps:

[0009] (1) The composite catalyst is dissolved in nonylcyclohexanol and mixed evenly in an inert solvent to form material 1; ethylene oxide is mixed with a multi-component mixed solvent and a co-solvent at 2~8℃ to form material 2; wherein, the composite catalyst includes a main catalyst 1, a main catalyst 2 and a co-catalyst;

[0010] (2) Material 1 and Material 2 are respectively transported to the mixing zone of the multi-stage series-parallel microchannel reactor by precision metering pumps and mixed under the control of external heat transfer oil heat exchanger. The mixed materials enter each parallel microchannel reactor module in equal throughput.

[0011] (3) By adjusting the flow rate of the metering pump, the material ratio, reaction temperature and residence time are controlled, and the mixed material enters the multi-stage series and parallel microchannel reactor in equal flow to carry out catalytic reaction.

[0012] (4) The reaction liquid flowing out of the reactor outlet passes through a cooling coil ice-water bath, and is then degassed and purified under reduced pressure to obtain nonylcyclohexanol monoethoxy ether and / or diethoxy ether.

[0013] Preferably, the main catalyst 1 is a metal oxide with redox activity, selected from V₂Mo₂O. 11 The catalyst 2 is a metal oxide with basic sites, selected from at least one of magnesium oxide, barium oxide, zinc oxide, cerium oxide, and lanthanum oxide; the co-catalyst is a phase transfer catalyst or complexing agent, selected from at least one of polyethylene glycol-400, N,N-dimethylformamide, CsI, and KI.

[0014] Preferably, the mass ratio of the main catalyst 1, the main catalyst 2 and the co-catalyst is 1:0.8~1.0:0.2~0.5, and the total mass of the composite catalyst relative to nonylcyclohexanol is 5%~10%.

[0015] Preferably, the multi-component mixed solvent is an equal mass mixture of methylnaphthalene and methylbiphenyl, or an equal mass mixture of methylbiphenyl and acetone, or an equal mass mixture of toluene and phenylcyclohexane; the co-solvent is selected from at least one of xylene, ethylbenzene, cyclohexane, and methylcyclohexane; wherein the mass ratio of the multi-component mixed solvent to the co-solvent is 1:0.1~0.3.

[0016] Preferably, the reaction temperature is 90℃~120℃, the reaction pressure is 1.0 MPa~3.0 MPa, and the residence time in the microchannel reactor is 20~30 min.

[0017] Preferably, the molar ratio of nonylcyclohexanol to ethylene oxide is 1:1.2~2.2.

[0018] Preferably, the multi-stage series-parallel microchannel reactor includes different functional areas such as a feeding zone, a mixing zone, a reaction zone, and a discharging zone; wherein, the mixing zone and the reaction zone are each composed of n microchannel reactor modules arranged in series, parallel, or a combination thereof, wherein n is an integer from 2 to 10.

[0019] Preferably, the internal flow channel structure of the microchannel reactor module is selected from chain channels, fish-shaped channels, or a combination of chain channels and fish-shaped channels, and the inner diameter of the microchannel is 2.5~3.0mm.

[0020] Preferably, the separation and purification step includes at least one of short-path molecular distillation, adsorption filtration, or extraction.

[0021] The present invention also provides a product obtained by the method described in any one of the above-mentioned methods, wherein the main content of nonylcyclohexanol monoethoxy ether and / or diethoxy ether is ≥98%, the free nonylcyclohexanol content is ≤2.5%, the color (Pt-Co) is ≤50, and the molecular weight distribution index (PDI) is ≤1.15.

[0022] The above technical solution has the following advantages or beneficial effects:

[0023] 1. The multi-stage series-parallel reactor design of this invention avoids material backmixing. The composite catalyst system isolates the activity of newly generated secondary alcohols through a phase transfer mechanism, and the multi-component solvent forms a polar gradient environment for microscopic separation. Compared with conventional industrial batch reactor processes, this invention, through precise spatiotemporal control of the multi-stage series-parallel reactor architecture and the construction of the solvent microenvironment, significantly suppresses excessive ethoxylation side reactions, enabling the purity of the obtained product to be stably increased to over 98%, and significantly reducing the content of free nonylcyclohexanol.

[0024] 2. This invention achieves extremely narrow residence time distribution of fluid micro-elements and concentrated ethoxy chain length distribution of products through precise temperature control, standardized residence time, and equal-flux liquid distribution, with PDI stabilizing at 1.08~1.12, which is significantly narrower than the 1.20~1.30 of the traditional process.

[0025] 3. This invention utilizes the synergistic effect of high specific surface area of ​​microchannels and multiple active centers of a ternary composite catalyst to simultaneously improve heat and mass transfer and reaction rate. Reaction time is reduced from 2-6 hours to 20-30 minutes, and conversion rate is increased to 99.8%. The continuous flow design keeps the instantaneous concentration of ethylene oxide at a consistently low level, completely avoiding the risks of accumulation and explosive polymerization, significantly improving intrinsic safety and increasing production efficiency by 3-5 times.

[0026] 4. This invention achieves precise control of the mono / diethoxy ether ratio through process optimization of temperature regulation, EO molar ratio adjustment, catalyst combination, and solvent ratio. The embodiments of this invention also verify that the main product content is ≥98.3% and PDI is ≤1.12 under various parameter combinations, demonstrating strong process robustness. A single unit can quickly switch between different product specifications, improving production flexibility and asset utilization efficiency. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention, wherein:

[0028] Figure 1 These are the two main pathways for the ethoxylation reaction of nonylcyclohexanol (NCH) in this invention;

[0029] Figure 2 This is a flow chart of a multi-stage series-parallel nonylcyclohexanol microchannel continuous flow mono / diethoxylation catalytic reaction process according to the present invention;

[0030] Figure 3 This is a flowchart of the microreactor system used in this invention; in the figure: 1, 11, 12 - feed pumps; 2, 21, 22, 23, 24 - microreactor structure; 3 - feed channel; 4 - product receiving device; 5, 51, 52, 53, 54, 55, 56 - pressure gauges; 6, 61, 62, 63, 64 - temperature gauges; 7, 71, 72, 73, 74, 75, 76 - flow meters; 8 - flow divider;

[0031] Figure 4 This is a schematic diagram of the shunt structure used in the method of the present invention;

[0032] Figure 5 This is the chain structure used in the process of this invention;

[0033] Figure 6It is the fish-shaped structure used in the process of this invention. Detailed Implementation

[0034] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0036] In this invention, a multi-stage series-parallel microchannel reactor continuous flow system is used for the reaction. The system mainly includes:

[0037] (1) Feeding area: Three precision metering pumps respectively deliver feed liquid A (nonylcyclohexanol + composite catalyst), feed liquid B (ethylene oxide + mixed solvent) and auxiliary liquid. For example... Figure 4 As shown, this system uses a symmetrical flow divider for feed distribution. The flow divider has an internal equal-length distribution structure. Through the symmetrical branch flow channel design, it ensures that the material entering from the feed pumps (1, 11, 12) achieves a uniform pressure drop and flow rate before entering each parallel microchannel reactor module (2, 21...), effectively avoiding local flow fluctuations caused by uneven flow resistance, thus ensuring the consistency of reaction conditions within each reaction module.

[0038] (2) Mixing zone: It consists of n microchannel mixing modules (inner diameter 2~3mm) connected in series. The mixing time is <1 second, so that the two raw materials can be quickly and uniformly mixed at the mixing temperature (usually 85℃).

[0039] (3) Reaction zone: It consists of multiple parallel microchannel reactor modules (inner diameter 2.5~3mm) and adopts a chain or fish-shaped channel structure. The reaction temperature (±1℃) is precisely controlled by an external heat transfer oil heat exchanger, and the back pressure valve maintains the system pressure within the specified range, so that the reaction products flow out continuously.

[0040] (4) Cooling and separation: The product is rapidly cooled to below 10°C through a cooling coil (ice-water bath) to stop the reaction. Subsequent degassing, separation and purification are carried out under reduced pressure.

[0041] Working principle of microchannel reactor continuous flow system: After the feed liquid is completely and uniformly mixed in the mixing zone, it is distributed into each parallel reactor channel in equal flow rate. Under precise temperature and pressure control, the continuous flow ethoxylation reaction is carried out to ensure the narrow distribution characteristics of the product.

[0042] In this embodiment of the invention, the microchannel reactor continuous flow system uses a precision metering pump and a symmetrical distributor, which are conventional in the art, for feed distribution. By maintaining the same flow resistance in each parallel channel, the material is ensured to enter each micro-reaction module at an equal throughput, thereby providing a stable reaction environment for the synergistic reaction of the composite catalytic system and the solvent microenvironment.

[0043] The heteropolyacid (or its salt) catalytic systems described in the various embodiments of this invention have all undergone loading pretreatment to adapt to the continuous flow channel requirements of the microchannel reactor. The specific loading process follows the conventional art of equal-volume impregnation and high-temperature calcination anchoring route, aiming to fix the heteropolyacid active components in a highly dispersed state within the pores of the support, effectively suppressing the aggregation and loss of active components within the microchannels, and ensuring the homogeneous performance and catalytic stability of the reaction system under continuous flow conditions.

[0044] Example 1

[0045] This embodiment 1 provides V2Mo2O 11 This method utilizes a multi-stage, parallel-chain, nonylcyclohexanol microchannel continuous flow mono / diethoxylation catalysis reaction with the main catalyst and a chain-channel-based, parallel-chain structure.

[0046] Device setup: Refer to Figure 3 and Figure 4 The multi-stage series-parallel microreactor system adopts a pipeline configuration of chain channel + chain channel with an inner diameter of 3mm. The liquid holdup is determined according to the flow rate and reaction residence time, and the heat exchange medium is heat transfer oil.

[0047] The preparation method includes the following steps:

[0048] (1) Take 2.5 g of V2Mo2O 11 2.0 g of magnesium oxide and 0.5 g of polyethylene glycol-400 are mixed to form a composite catalyst. The composite catalyst is dissolved in 100 g of nonylcyclohexanol and 20 g of methylnaphthalene, and heated to 70°C to fully dissolve and homogenize the catalyst, forming material 1.

[0049] (2) Mix 37g of ethylene oxide, 37g of methylnaphthalene, methylbiphenyl solvent (mass ratio 1:1), and xylene co-solvent at 5°C to form material 2, wherein the mass ratio of solvent to co-solvent is 1:0.1.

[0050] (3) Control the molar ratio of nonylcyclohexanol to ethylene oxide to be 1:1.2. Material 1 and material 2 are fed into the mixing zone of the multi-stage series-parallel microreactors by independent precision feed pumps at a total flow rate of 15 mL / min. The mixing temperature is controlled at 85℃. The mixed materials are distributed into the channels of each parallel microreactor in equal flow rates. The reaction temperature is 90℃, the pressure is 1.0 MPa and the reaction is carried out in a continuous flow reaction with a residence time of 20 min.

[0051] (4) The reaction product flows out of the reactor outlet in a continuous flow. After being depressurized by a back pressure valve, it enters a cooling coil equipped with an ice-water bath, rapidly reducing the product temperature to below 10°C, thus stopping the reaction. The cooled product is then degassed under reduced pressure to remove trace amounts of ethylene oxide and other volatile components, and purified by short-path molecular distillation to finally obtain the target product: narrow-distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). Product analysis showed a main content of 98.3%, free nonylcyclohexanol of 1.9%, color (Pt-Co) of 15, and PDI of 1.12.

[0052] Example 2

[0053] This embodiment 2 provides a method for the continuous flow mono / diethoxylation catalysis of nonylcyclohexanol microchannels with SrMoO4 ​​as the main catalyst and a chain-channel + fish-shaped channel tandem parallel structure.

[0054] Device setup: Refer to Figure 3 and Figure 4 The multi-stage series-parallel microreactor system adopts a pipeline configuration of chain channel + fish-shaped channel. The inner diameter of the chain channel is 3mm and the inner diameter of the fish-shaped channel is 2.5mm. The liquid holdup is determined according to the flow rate and reaction residence time. The heat exchange medium is heat transfer oil.

[0055] The preparation method includes the following steps:

[0056] (1) Mix 4 g SrMoO4, 4 g barium oxide and 2.0 g N,N-dimethylformamide to form a composite catalyst. Dissolve the composite catalyst in 100 g nonylcyclohexanol and 40 g methylbiphenyl, and heat to 75°C to fully dissolve and homogenize the catalyst to form material 1.

[0057] (2) Mix 70g of ethylene oxide, 70g of methyl biphenyl, acetone solvent (mass ratio 1:1), and co-solvent ethylbenzene at 5°C to form material 2, wherein the mass ratio of solvent to co-solvent is 1:0.3.

[0058] (3) The molar ratio of nonylcyclohexanol to ethylene oxide is controlled to be 1:2.2. Material 1 and material 2 are fed into the mixing zone of the multi-stage series-parallel microreactors by independent precision feed pumps at a total flow rate of 15 mL / min. The mixing temperature is controlled to be 85℃. The mixed materials are distributed into the channels of each parallel microreactor in equal flow rates. The reaction temperature is 120℃, the pressure is 3.0 MPa and the reaction is carried out in a continuous flow reaction with a residence time of 30 min.

[0059] (4) The reaction product flows out of the reactor outlet in a continuous flow. After being depressurized by the back pressure valve, it enters a cooling coil equipped with an ice-water bath, so that the product temperature drops rapidly to below 10°C to terminate the catalytic activity and lock the product distribution, thus stopping the reaction. The cooled material is introduced into a preheating degassing tank or a vacuum distillation kettle, and the temperature is slowly increased under vacuum conditions to effectively remove unreacted ethylene oxide and low-boiling-point residual solvents. The product is purified by short-path molecular distillation, and the target product is finally obtained: narrow-distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether, with a relatively high proportion of diethoxy ether). The product analysis shows that the main content is 99.1%, free nonylcyclohexanol is 0.7%, color (Pt-Co) is 14, and PDI is 1.10.

[0060] Example 3

[0061] This embodiment 3 provides a method for the continuous flow mono / diethoxylation catalysis of nonylcyclohexanol microchannels with a fish-shaped channel + chain channel tandem structure, using phosphomolybdic acid as the main catalyst.

[0062] Device setup: Refer to Figure 3 and Figure 4 The multi-stage series-parallel microreactor system adopts a pipeline configuration of fish-shaped channel + chain channel. The inner diameter of the chain channel is 3mm and the inner diameter of the fish-shaped channel is 2.5mm. The liquid holdup is determined according to the flow rate and reaction residence time. The heat exchange medium is heat transfer oil.

[0063] The preparation method includes the following steps:

[0064] (1) Mix 4 g of phosphomolybdic acid, 3.2 g of zinc oxide and 1.0 g of CsI to form a composite catalyst. Dissolve the composite catalyst in 100 g of nonylcyclohexanol and 30 g of phenylcyclohexane, and heat to 70°C to fully dissolve and homogenize the catalyst to form material 1.

[0065] (2) Mix 55g of ethylene oxide, 55g of toluene and phenylcyclohexane solvent (mass ratio 1:1) and co-solvent cyclohexane at 5°C to form material 2, wherein the mass ratio of solvent to co-solvent is 1:0.2.

[0066] (3) The molar ratio of nonylcyclohexanol to ethylene oxide is controlled at 1:1.5. Materials 1 and 2 are fed into the mixing zone of the multi-stage series-parallel microreactors at a total flow rate of 15 mL / min via independent precision feed pumps. The mixing temperature is controlled at 85℃. The mixed materials are distributed into the channels of each parallel microreactor in equal flow rates. The reaction temperature is 100℃, the pressure is 2.0 MPa, and the residence time is 25 min. The fish-shaped channel (with strong disturbance mixing characteristics) is used for mixing and preliminary reaction first, while the chain channel is used for deep reaction. Under the mild and high pressure conditions of 100℃ and 2.0 MPa, ethylene oxide and nonylcyclohexanol undergo ethoxylation reaction under the catalysis of the composite catalyst.

[0067] (4) The reaction product flows out of the reactor outlet in a continuous flow. After being depressurized by a back pressure valve, it enters a cooling coil equipped with an ice-water bath, causing the product temperature to drop rapidly to below 10°C, thus stopping the reaction. The cooled product is then degassed under reduced pressure to remove trace amounts of ethylene oxide and other volatile components, and purified by short-path molecular distillation to finally obtain the target product: narrow-distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). Product analysis showed a main content of 99.4%, free nonylcyclohexanol of 0.3%, color (Pt-Co) of 12, and PDI of 1.08.

[0068] Example 4

[0069] This embodiment 4 provides a method for the continuous flow mono / diethoxylation catalysis of nonylcyclohexanol microchannels with phosphotungstic acid as the main catalyst and a fish-shaped channel + fish-shaped channel series-parallel structure.

[0070] Device setup: Refer to Figure 3 and Figure 4 The multi-stage series-parallel microreactor system adopts a fish-shaped channel + fish-shaped channel pipeline configuration, with the inner diameter of each fish-shaped channel being 2.5mm. The liquid holdup is determined based on the flow rate and reaction residence time, and the heat exchange medium is heat transfer oil.

[0071] The preparation method includes the following steps:

[0072] (1) Mix 4 g phosphotungstic acid, 3.5 g cerium oxide and 1.0 g KI to form a composite catalyst. Dissolve the composite catalyst in 100 g nonylcyclohexanol and 30 g heavy aromatic solvent oil. Heat to 75°C to fully dissolve and homogenize the catalyst to form material 1.

[0073] (2) Mix 66g of ethylene oxide, 66g of toluene and phenylcyclohexane solvent (mass ratio 1:1) and co-solvent methylcyclohexane at 5°C to form material 2, wherein the mass ratio of solvent to co-solvent is 1:0.2.

[0074] (3) The molar ratio of nonylcyclohexanol to ethylene oxide is controlled to be 1:1.8. Material 1 and material 2 are fed into the mixing zone of the multi-stage series-parallel microreactors by independent precision feed pumps at a total flow rate of 15 mL / min. The mixing temperature is controlled to be 85℃. The mixed materials are distributed into the channels of each parallel microreactor in equal flow rates. The reaction temperature is 110℃, the pressure is 2.0 MPa and the reaction is carried out in a continuous flow reaction with a residence time of 25 min.

[0075] (4) The reaction product flows out of the reactor outlet in a continuous flow. After being depressurized by a back pressure valve, it enters a cooling coil equipped with an ice-water bath, rapidly reducing the product temperature to below 10°C, thus stopping the reaction. The cooled product is then degassed under reduced pressure to remove trace amounts of ethylene oxide and other volatile components, and purified by short-path molecular distillation to finally obtain the target product: narrow-distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). Product analysis showed a main content of 99.3%, free nonylcyclohexanol of 0.5%, color (Pt-Co) of 12, and PDI of 1.08.

[0076] Example 5

[0077] This embodiment 5 provides V2Mo2O 11 As the main catalyst, optimize the catalyst dosage and solvent ratio.

[0078] A method for the continuous flow mono / diethoxylation catalysis of nonylcyclohexanol via multi-stage tandem and parallel microchannels.

[0079] Device setup: Refer to Figure 3 and Figure 4 The multi-stage series-parallel microreactor system adopts a pipeline configuration of chain channels + chain channels, with the inner diameter of each chain channel being 3mm. The liquid holdup is determined based on the flow rate and reaction residence time, and the heat exchange medium is heat transfer oil.

[0080] The preparation method includes the following steps:

[0081] (1) Take 4 g of V2Mo2O 11 A composite catalyst was prepared by mixing 3.5 g of lanthanum oxide and 1.0 g of CsI. The composite catalyst was dissolved in 100 g of nonylcyclohexanol and 30 g of methylbiphenyl, and heated to 70°C to ensure that the catalyst was fully dissolved and homogeneous, forming material 1.

[0082] (2) Mix 66g of ethylene oxide, 66g of methylnaphthalene, methylbiphenyl solvent (mass ratio 1:1), and co-solvent methylcyclohexane at 5°C to form material 2, wherein the mass ratio of solvent to co-solvent is 1:0.2.

[0083] (3) The molar ratio of nonylcyclohexanol to ethylene oxide is controlled to be 1:1.8. Material 1 and material 2 are fed into the mixing zone of the multi-stage series-parallel microreactors by independent precision feed pumps at a total flow rate of 15 mL / min. The mixing temperature is controlled to be 85℃. The mixed materials are distributed into the channels of each parallel microreactor in equal flow rates. The reaction temperature is 110℃, the pressure is 2.0 MPa and the reaction is carried out in a continuous flow reaction with a residence time of 25 min.

[0084] (4) The reaction product flows out of the reactor outlet in a continuous flow. After being depressurized by a back pressure valve, it enters a cooling coil equipped with an ice-water bath, causing the product temperature to drop rapidly to below 10°C, thus stopping the reaction. The cooled product is then degassed under reduced pressure to remove trace amounts of ethylene oxide and other volatile components, and purified by short-path molecular distillation to finally obtain the target product: narrow-distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). Product analysis showed a main content of 99.5%, free nonylcyclohexanol of 0.2%, color (Pt-Co) of 13, and PDI of 1.09.

[0085] Example 6

[0086] This Example 6 is basically the same as Example 5, except that: ① This Example 6 uses a chain channel + fish-shaped channel configuration, with the inner diameter of the chain channel being 3 mm and the inner diameter of the fish-shaped channel being 2.5 mm. ② In the preparation method, in step (3) of this Example 6, the molar ratio of nonylcyclohexanol to ethylene oxide is controlled at 1:2.0, the reaction temperature is 110℃, the pressure is 2.0 MPa for continuous flow reaction, and the residence time is 28 min. The rest are the same as in Example 5, and the final product obtained is: narrow distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). The product analysis shows that the main content is 99.0%, free nonylcyclohexanol is 0.7%, color (Pt-Co) is 13, and PDI=1.09.

[0087] Example 7

[0088] This embodiment 7 is basically the same as embodiment 5, except that: ① This embodiment 7 uses a fish-shaped channel + chain channel configuration, with the inner diameter of the chain channel being 3 mm and the inner diameter of the fish-shaped channel being 2.5 mm. ② In step (3) of this embodiment 7, the continuous flow reaction is carried out at 100°C and 2.0 MPa, with a residence time of 25 min. The rest is the same as in embodiment 5, and the final product obtained is: narrow distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). The product analysis showed that the main content was 99.2%, the free nonylcyclohexanol was 0.6%, the color (Pt-Co) was 12, and the PDI was 1.08.

[0089] Example 8

[0090] This embodiment 8 is basically the same as embodiment 5, except that: ① This embodiment 8 uses a fish-shaped channel + fish-shaped channel pipeline configuration, with the inner diameter of the fish-shaped channels being 2.5 mm. ② In step (3) of this embodiment 8, the continuous flow reaction is carried out at 100°C and 2.0 MPa, with a residence time of 25 min. The rest is the same as in embodiment 5, and the final product obtained is: narrow distribution nonylcyclohexanol polyoxyethylene ether (mainly mono / diethoxy ether). The product analysis shows 99.1% purity, 0.7% free nonylcyclohexanol, color (Pt-Co) 13, and PDI = 1.08.

[0091] Based on the comparative study of the above eight embodiments, the conclusions are as follows:

[0092] (1) Screening of catalyst systems

[0093] Examples 1-4 respectively used V2Mo2O 11 Four composite catalyst systems—SrMoO4, phosphomolybdic acid, and phosphotungstic acid—were compared. The results showed that different catalysts achieved good performance under the corresponding process conditions, with the main product content ranging from 98.3% to 99.4%. Among them, the phosphomolybdic acid and phosphotungstic acid catalysts exhibited the best product PDI value (1.08) under moderate temperature conditions (100–110 °C), indicating that phosphorus-containing heteropolyacid catalysts have better product distribution control capabilities.

[0094] (2) Optimization of catalyst dosage and solvent

[0095] Example 5: Optimization of V2Mo2O 11 Adjusting the dosage, composition of the co-catalyst (lanthanum oxide + CsI), and ratio of the multi-component solvent further improved product performance. Compared with Example 1, the content of the main product increased from 98.3% to 99.5%, and the free nonylcyclohexanol decreased from 1.9% to 0.2%, indicating that the synergistic effect of the composite catalyst system can significantly improve the feed conversion rate and product purity.

[0096] (3) Influence of microchannel structure

[0097] Examples 6-8, while maintaining the catalyst system of Example 5, investigated the effect of different channel structures on product performance. The results showed that: ① the chain + chain structure of Example 5 achieved the best performance under standard conditions; ② the chain + fish-shaped structure of Example 6 could handle higher EO molar ratios, and the proportion of diethoxy ether in the product relatively increased; ③ the fish-shaped + chain structure of Example 7 maintained high product performance (99.2% main content, PDI = 1.08) even when the reaction temperature was reduced to 100°C. The fish-shaped + fish-shaped structure in Example 8 achieves the narrowest product molecular weight distribution (PDI = 1.08). The flexible application of various channel structure combinations provides process selection options for different application needs.

[0098] (4) Controllable range of process parameters

[0099] Based on a comprehensive analysis of eight embodiments, the present invention establishes the following controllable process parameter ranges:

[0100] The ethylene oxide molar ratio was 1:1.2~2.2; the reaction temperature was 90~120℃; the system pressure was 1.0~3.0 MPa; and the residence time was 20~30 min. Within this parameter range, the main product content was stable at 98.3%~99.5%, the free nonylcyclohexanol content was 0.2%~1.9%, and the PDI value was 1.08~1.12, all of which showed significant advantages compared with the traditional batch reactor method.

[0101] (5) Product quality indicators

[0102] The key quality indicators of the product obtained by this invention are as follows:

[0103] Main product content: ≥98%; Free nonylcyclohexanol: ≤2% (optimal up to 0.2%); Color (Pt-Co): 12~15; PDI value: 1.08~1.12, achieving true narrow distribution characteristics.

[0104] (6) Scalability of the technical solution

[0105] Through systematic optimization of the catalyst system, microchannel structure, and process parameters, the process provided by this invention has high flexibility and can be customized according to different application needs (textile auxiliaries, emulsifiers, cleaning agents, etc.), providing a complete continuous production solution.

[0106] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multi-stage series-parallel microchannel continuous flow ethoxylation method for nonylcyclohexanol, characterized in that, Includes the following steps: (1) The composite catalyst is dissolved in nonylcyclohexanol and mixed evenly in an inert solvent to form material 1; ethylene oxide is mixed with a multi-component mixed solvent and a co-solvent at 2~8℃ to form material 2; wherein, the composite catalyst includes a main catalyst 1, a main catalyst 2 and a co-catalyst; (2) Material 1 and Material 2 are respectively transported to the mixing zone of the multi-stage series-parallel microchannel reactor by precision metering pumps and mixed under the control of external heat transfer oil heat exchanger. The mixed materials enter each parallel microchannel reactor module in equal throughput. (3) By adjusting the flow rate of the metering pump, the material ratio, reaction temperature and residence time are controlled, and the mixed material enters the multi-stage series and parallel microchannel reactor in equal flow rate for catalytic reaction; (4) The reaction liquid flowing out of the reactor outlet passes through a cooling coil ice-water bath, and is then degassed and purified under reduced pressure to obtain nonylcyclohexanol monoethoxy ether and / or diethoxy ether.

2. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The main catalyst 1 is a metal oxide with redox activity, selected from V₂Mo₂O. 11 The catalyst 2 is a metal oxide with basic sites, selected from at least one of magnesium oxide, barium oxide, zinc oxide, cerium oxide, and lanthanum oxide; the co-catalyst is a phase transfer catalyst or complexing agent, selected from at least one of polyethylene glycol-400, N,N-dimethylformamide, CsI, and KI.

3. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The mass ratio of the main catalyst 1, the main catalyst 2, and the co-catalyst is 1:0.8~1.0:0.2~0.5, and the total mass of the composite catalyst relative to nonylcyclohexanol is 5%~10%.

4. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The multi-component mixed solvent is an equal mass mixture of methylnaphthalene and methylbiphenyl, or an equal mass mixture of methylbiphenyl and acetone, or an equal mass mixture of toluene and phenylcyclohexane; the co-solvent is selected from at least one of xylene, ethylbenzene, cyclohexane, and methylcyclohexane; wherein the mass ratio of the multi-component mixed solvent to the co-solvent is 1:0.1~0.

3.

5. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The reaction temperature is 90℃~120℃, the reaction pressure is 1.0 MPa~3.0 MPa, and the residence time in the microchannel reactor is 20~30 min.

6. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The molar ratio of nonylcyclohexanol to ethylene oxide is 1:1.2~2.

2.

7. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 1, characterized in that, The multi-stage series-parallel microchannel reactor includes different functional areas such as a feeding zone, a mixing zone, a reaction zone, and a discharging zone; wherein, the mixing zone and the reaction zone are each composed of n microchannel reactor modules arranged in series, parallel, or a combination thereof, where n is an integer from 2 to 10.

8. The multi-stage series-parallel microchannel continuous flow ethoxylation method according to claim 7, characterized in that, The internal flow channel structure of the microchannel reactor module is selected from chain channels, fish-shaped channels, or a combination of chain channels and fish-shaped channels, and the inner diameter of the microchannel is 2.5~3.0mm.

9. The method according to claim 1, characterized in that, The separation and purification steps include at least one of short-path molecular distillation, adsorption filtration, or extraction.

10. The product obtained by the multi-stage series-parallel microchannel continuous flow ethoxylation method according to any one of claims 1 to 9, characterized in that, The product contains ≥98% nonylcyclohexanol monoethoxy ether and / or diethoxy ether, ≤2.5% free nonylcyclohexanol content, ≤50 color (Pt-Co), and ≤1.15 molecular weight distribution index (PDI).

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