Production system and manufacturing method for producing salt-free amino acid surfactants by continuous flow.

Abstract

The present application discloses a production system and a method for producing salt-free amino acid surfactants by continuous flow, comprising: an amidation reaction module arranged to carry out an amidation reaction, the module including at least one reactor unit with an input port arranged to input amino acid salt, acid chloride, liquid alkali and mother liquor processing liquid, and an output port arranged to output an amidation product; a post-treatment module connected to the output port of the reactor unit, the post-treatment module conveying the amidation product into the post-treatment module for separation and concentration treatment, the output line A of the post-treatment module being connected to a finished product tank, and the output line B of the post-treatment module discharging the mother liquor; and a mother liquor separation module including at least one separation unit, the output port of the separation unit discharging the separated salt, and the reflux port of the separation unit being connected to the input port of the reactor unit to reflux the mother liquor processing liquid. The present application can produce salt-free amino acid surfactants by full continuous flow, with low energy consumption, green and no wastewater discharge.

Description

Technical Field

[0001] [Cross-reference to Related Applications] This application claims the priority of a Chinese patent application with the application number 202210348694.2, filed with the China National Intellectual Property Administration on April 1, 2022, and the invention title "Production System and Manufacturing Method for Producing Salt-Free Amino Acid Surfactants by Continuous Flow", and its entire content is incorporated herein by reference.

[0002] This application relates to the technical field of chemical engineering, and particularly to a production system and a manufacturing method for producing salt-free amino acid surfactants by continuous flow.

Background Art

[0003] Amino acid surfactants are surfactants with mild anions. Due to their structural characteristics of having an amide group and an amino acid structure, in addition to the basic properties of surfactants such as emulsification, washing, dispersion, foaming, penetration, and solubilization, they also have advantages such as better low irritation, low toxicity, good biodegradability, and good biocompatibility, and are widely used in fields such as detergents, cosmetics, pharmaceuticals, foods, biology, materials, and environmental protection. As people's concerns about the safety and mildness of surfactant products and the requirements for environmental protection are increasing, such surfactants are being increasingly emphasized and the application fields are becoming increasingly wide.

[0004] There are several methods for synthesizing amino acid-based surfactants, including the Schotten-Baumann reaction, acid chloride method, fatty acid anhydride method, aliphatic nitrile hydrolysis method, and enzymatic method. Currently, the acid chloride method is the one used industrially. The general process involves employing the Schotten-Baumann reaction, followed by amidation, then acidification with a large amount of inorganic acid to separate the product into multiple layers. The oil layer is then obtained as an aliphatic acyl amino acid, and finally neutralization with a base to form a salt. This process is generally carried out using a batch-type single reactor. Conventional batch production has many production steps, is complex, results in unstable product quality, and generates large amounts of waste acid water, highlighting its obvious drawbacks. Chinese patent application CN106748871A proposes an amino acid recycling technology to solve the problem of acid water discharge, but this technology is still based on batch production. While continuous production is used in Chinese patent applications CN201310366274 and CN108003050A, fully continuous production of low-salt products has not been achieved. In contrast, low-salt amino acid surfactants are commonly used in the high-end cleaning raw materials market. [Overview of the project] [Problems that the invention aims to solve]

[0005] In response to the shortcomings of conventional technology, this application provides a production system and manufacturing method for producing salt-free amino acid surfactants by continuous flow. This production system enables fully continuous flow production of salt-free amino acid surfactants. The process is simple and efficient to operate, produces no waste acid, has a low free acid index in the produced amino acid surfactant product, is salt-free, has stable quality, facilitates large-scale production, significantly reduces production costs, and realizes a green, environmentally friendly production process with no waste acid water discharge. [Means for solving the problem]

[0006] To achieve the above objectives, this application employs the following technical solution. In the first aspect, the present application relates to a production system for producing salt-free amino acid surfactants by continuous flow, an amidation reaction module configured to carry out an amidation reaction, comprising at least one reactor unit having an input port configured for introducing an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution, and an output port configured for discharging the amidation product, A post-treatment module, wherein the input port of the post-treatment module is connected to the discharge port of the reactor unit, the amidation product is transported into the post-treatment module for separation and concentration, the discharge path A of the post-treatment module is connected to the finished product tank, and the discharge path B of the post-treatment module discharges the mother liquor. A mother liquor separation module comprising at least one separation unit, wherein the input port of the separation unit is connected to the discharge path B of a post-treatment module, the discharge port of the separation unit discharges the separated salt, the reflux port of the separation unit is connected to the input port of a reactor unit, and the mother liquor separation module discharges the treated mother liquor and separated salt after the mother liquor has been treated by the separation unit, We provide a production system that includes [this].

[0007] Furthermore, the reactor unit is selected from one or more combinations of a microchannel reactor, a series coil pipe reactor, and a tubular reactor.

[0008] Preferably, two reactor units are installed, one being a microchannel reactor and the other a tubular reactor.

[0009] Furthermore, the amidation reaction module includes temperature interval T1 and temperature interval T2, and the temperature range of temperature interval T1 and temperature interval T2 is 0 to 90°C.

[0010] Preferably, the temperature range of temperature interval T1 is 0 to 40°C, and the temperature range of temperature interval T2 is 60 to 90°C.

[0011] More preferably, the temperature range of temperature interval T1 is 0 to 15°C, and the temperature range of temperature interval T2 is 70 to 85°C.

[0012] Furthermore, the post-processing module includes a membrane separation device and a substance concentration device. The membrane separation device is selected from one or more combinations of microfiltration membranes, ultrafiltration membranes, and nanofiltration membranes, and the substance concentration device is selected from one or more combinations of microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and RO membranes (reverse osmosis membranes).

[0013] Preferably, the membrane separation device and the substance concentration device are selected from an ultrafiltration membrane and a nanofiltration membrane, the filtration pressure of the ultrafiltration membrane or nanofiltration membrane is 0.1 to 5 MPa, and the filtration temperature is 10 to 80°C.

[0014] More preferably, the filtration pressure of the ultrafiltration membrane or nanofiltration membrane is 1 to 2 MPa, and the filtration temperature is 40 to 60°C.

[0015] Furthermore, the material concentrator is connected to an online solid content / pH monitoring device.

[0016] Furthermore, the separation unit is selected from an electrodialysis machine and an ion exchange resin machine.

[0017] Preferably, the separation unit is an electrodialysis machine, and the separation voltage is controlled to be 100-500V and the current to be 2-10A.

[0018] More preferably, the electrodialysis apparatus is controlled so that the separation voltage is 100-200V and the current is 2-2.5A.

[0019] In a second aspect, the present application relates to a manufacturing method for producing salt-free amino acid surfactants by continuous flow using the above-described production system, Step S1 involves introducing an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution into an amidation reaction module containing at least one reactor unit to carry out the amidation reaction, and then discharging the amidation product from the amidation reaction module. Step S2 involves transporting the amidation product into a post-treatment module, separating and concentrating it in discharge channel A of the post-treatment module to discharge the finished product into a finished product tank, separating it in discharge channel B of the post-treatment module to discharge the mother liquor, Step S3 involves transporting the mother liquor into a mother liquor separation module containing at least one separation unit, separating and discharging the mother liquor treatment liquid and the separated salt in the mother liquor separation module, and refluxing and transporting the mother liquor treatment liquid back into the amidation reaction module in step S1 for reuse. The present invention provides a manufacturing method that includes the following:

[0020] Furthermore, in step S1, the amino acid salt is one or more combinations of sarcosine salt, glutamate salt, alanine salt, glycine salt, aspartate salt, serine salt, taurine salt, and methyltaurine salt.

[0021] Preferably, the amino acid salt is one or more of the following: sodium sarcosinate, potassium glycine, sodium alanine, sodium glutamate, sodium methyltaurate, and sodium taurate.

[0022] Furthermore, in step S1, the acid chloride is either an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms.

[0023] Preferably, the acid chloride is any one or a combination of two or more of octanoic acid chloride, isooctanoic acid chloride, nonanoic acid chloride, isononanoic acid chloride, decanoic acid chloride, isodecanoic acid chloride, undecanoic acid chloride, dodecanoic acid chloride, tridecanoic acid chloride, tetradecanoic acid chloride, pentadecanoic acid chloride, hexadecanoic acid chloride, heptadecanoic acid chloride, octadecanoic acid chloride, nonadecanoic acid chloride, and eicosanoic acid chloride.

[0024] More preferably, the acid chloride is any one of dodecanoic acid chloride, coconut oil fatty acid chloride, and lauric acid chloride.

[0025] Furthermore, in step S1, the liquid alkali is a sodium hydroxide solution or a potassium hydroxide solution.

[0026] Furthermore, in step S1, the mass content of the amino acid salt is 5% - 50%.

[0027] Preferably, the mass content of the amino acid salt is 25% - 35%.

[0028] Furthermore, in step S1, the flow rates of the amino acid salt and the mother liquor treatment liquid are 0.04 - 100 kg / min.

[0029] Furthermore, in step S1, the flow rate of the acid chloride is 0.01 - 25 kg / min.

[0030] Furthermore, in step S1, the flow rate of the liquid alkali is 0.005 - 20 kg / min.

[0031] Furthermore, in step S1, the reaction and residence time of the amino acid salt, the mother liquor treatment liquid, the acid chloride, and the liquid alkali in the amidation reaction module is 180 - 360 s.

[0032] Preferably, the reaction and residence time of the amino acid salt, mother liquor treatment solution, acid chloride, and liquid alkali in the amidation reaction module is 190 to 230 seconds.

[0033] Compared to prior art, this application provides a production system and manufacturing method for producing salt-free amino acid surfactants by continuous flow, which have the following beneficial effects.

[0034] According to this application, salt-free amino acid surfactants can be produced in a continuous flow throughout the process, which is easy to operate and efficient, has no waste acid discharge, produces amino acid surfactant products with a low free acid index, is salt-free and of stable quality, is easy to mass-produce, significantly reduces production costs, and realizes a green and environmentally friendly production process with no discharge of waste acid water. [Brief explanation of the drawing]

[0035] To more clearly illustrate the embodiments of this application or the technical means in the prior art, the drawings used in the description of the embodiments or the prior art are briefly described below. However, the drawings in the following description represent only some embodiments of this application, and those skilled in the art can obtain other drawings from these drawings without any creative effort. [Figure 1] This is a schematic diagram of the production system for this application. [Modes for carrying out the invention]

[0036] The technical solutions of this application will be described clearly and completely below, but it is clear that the embodiments described are only a selection of embodiments of this application, not all embodiments. All other embodiments that can be obtained by a person skilled in the art without creative work based on the embodiments of this application are within the scope of protection of this application.

[0037] As shown in Figure 1, the production system for producing salt-free amino acid surfactants by continuous flow according to this application is: an amidation reaction module configured to carry out an amidation reaction, comprising at least one reactor unit having an input port configured for introducing an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution, and an output port configured for discharging the amidation product, A post-treatment module, wherein its input port is connected to the discharge port of the reactor unit, the amidation product is transported into the post-treatment module for separation and concentration, the discharge path A of the post-treatment module is connected to the finished product tank, and the discharge path B of the post-treatment module discharges the mother liquor. A mother liquor separation module comprising at least one separation unit, wherein the input port of the separation unit is connected to the discharge path B of a post-treatment module, the discharge port of the separation unit discharges the separated salt, and the reflux port of the separation unit is connected to the input port of a reactor unit, and the mother liquor is treated by the separation unit and then discharges the treated mother liquor liquid and the separated salt.

[0038] Here, the reactor unit is equipped with two reactors: a microchannel reactor and a tubular reactor. The amidation reaction module includes a temperature interval T1 corresponding to the microchannel reactor and a temperature interval T2 corresponding to the tubular reactor, with the temperature range of temperature intervals T1 and T2 being 0 to 90°C. During the amidation reaction, the raw materials first enter the microchannel reactor and then the tubular reactor.

[0039] The post-processing module comprises a membrane separator and a material concentrator, and an online solid content / pH monitor is connected to the material concentrator to facilitate online monitoring of desalination. The membrane separator is selected from one or more combinations of microfiltration membranes, ultrafiltration membranes, and nanofiltration membranes. The material concentrator is selected from one or more combinations of microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and RO membranes (reverse osmosis membranes). In some specific embodiments, the membrane separator and material concentrator are selected from ultrafiltration membranes and nanofiltration membranes, with a filtration pressure of 0.1 to 5 MPa and a filtration temperature of 10 to 80°C.

[0040] The separation unit is selected from an electrodialysis machine and an ion exchange resin machine. In some specific embodiments, the separation unit is preferably an electrodialysis machine, and is controlled so that the separation voltage is 100-500V and the current is 2-10A.

[0041] Furthermore, this application provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow using the above-described production system, the manufacturing method comprising the following steps S1 to S3. In step S1, an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution are introduced into an amidation reaction module containing at least one reactor unit, and the amidation reaction is carried out, after which the amidation product is discharged from the amidation reaction module. In step S2, the amidation product is transported to the post-treatment module, separated and concentrated in discharge channel A of the post-treatment module to discharge the finished product into the finished product tank, and separated again in discharge channel B of the post-treatment module to discharge the mother liquor. In step S3, the mother liquor is transported into a mother liquor separation module containing at least one separation unit, where the mother liquor treatment liquid and the separated salt are separated and discharged, and the mother liquor treatment liquid is refluxed into the amidation reaction module in step S1 and transported for reuse.

[0042] Here, in step S1, the amino acid salt is a combination of one or more of sarcosine salt, glutamate, alanine salt, glycine salt, aspartate, serine salt, taurine salt, and methyltaurine salt. Preferably, the amino acid salt is a combination of one or more of sodium sarcosinate, potassium glycine, sodium alanine, sodium glutamate, sodium methyltaurine, and sodium taurine.

[0043] In step S1, the acid chloride is an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms. Preferably, the acid chloride is one or more of the following: octanoic acid chloride, isooctanoic acid chloride, nonanoic acid chloride, isononanoic acid chloride, decanoic acid chloride, isodecanic acid chloride, undecanoic acid chloride, dodecanoic acid chloride, tridecanoic acid chloride, tetradecanoic acid chloride, pentadecanoic acid chloride, hexadecanic acid chloride, heptadecanic acid chloride, octadecanoic acid chloride, nonadecanic acid chloride, and eicosanoic acid chloride. More preferably, the acid chloride is one of the following: dodecanoic acid chloride, coconut oil fatty acid chloride, and lauric acid chloride.

[0044] In step S1, the liquid alkali is either a sodium hydroxide solution or a potassium hydroxide solution.

[0045] In step S1, the mass content of the amino acid salt is 5% to 50%, the flow rate of the amino acid salt and mother liquor treatment solution is 0.04 to 100 kg / min, the flow rate of the acid chloride is 0.01 to 25 kg / min, and the flow rate of the liquid alkali is 0.005 to 20 kg / min. The reaction and residence time in the amidation reaction module of the amino acid salt, mother liquor treatment solution, acid chloride, and liquid alkali is 180 to 360 s. The control of the input of these four raw materials can be adjusted or expanded as appropriate depending on the actual production scale.

[0046] The present application will be described in more detail below with reference to Figure 1 and using detailed embodiments.

[0047] All of the raw materials used in the following examples are commercially available.

[0048] Example 1 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, sodium sarcosinate (35% by mass), dodecanoic acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump to carry out the amidation reaction. Here, the temperature range T1 corresponding to the microchannel reactor was set to 2-5°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of sodium sarcosinate and mother liquor treatment solution was 40.2 g / min, the flow rate of dodecanoic acid chloride was 12.3 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 7.3 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 200 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 1 MPa and the filtration temperature to 60°C. In discharge channel A, the product sodium lauroyl sarcosinate was obtained and transported to the finished product tank, while in discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 100V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. For the sodium lauroyl sarcosinate produced in this example, the product indicators were free acid <1% and sodium chloride <0.1%.

[0049] Example 2 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, potassium glycine (25% by mass), dodecanoic acid chloride, liquid alkali (potassium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump to carry out the amidation reaction. Here, the temperature range T1 corresponding to the microchannel reactor was set to 5-15°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of potassium glycine and mother liquor treatment solution was 49.2 g / min, the flow rate of dodecanoic acid chloride was 12.3 g / min, and the flow rate of liquid alkali (potassium hydroxide solution, 30% by mass) was 7.3 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 220 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 1.5 MPa and the filtration temperature to 50°C. In discharge channel A, the product, potassium lauroylglycine, was obtained and transported to the finished product tank, while in discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 200V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. In this example, the product indicators for potassium lauroylglycine produced were free acid <1.8% and sodium chloride <0.2%.

[0050] Example 3 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, sodium alanine (30% by mass), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump, and the amidation reaction was carried out. Here, the temperature range T1 corresponding to the microchannel reactor was set to 0-5°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of sodium alanine and mother liquor treatment solution was 46.2 g / min, the flow rate of coconut oil fatty acid chloride was 13.3 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 7.9 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 190 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 1 MPa and the filtration temperature to 40°C. Through discharge channel A, the product, coconut oil fatty acid acylalanine sodium, was obtained and transported to the finished product tank, while through discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 100V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. For the coconut oil fatty acid acylalanine sodium produced in this example, the product indicators were free acid <1% and sodium chloride <0.2%.

[0051] Example 4 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, sodium glutamate (30% by mass), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump, and the amidation reaction was carried out. Here, the temperature range T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of sodium glutamate and mother liquor treatment solution was 56 g / min, the flow rate of coconut oil fatty acid chloride was 13 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 8 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 230 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 1.5 MPa and the filtration temperature to 60°C. In discharge channel A, the product, sodium coconut oil fatty acid acyl glutamate, was obtained and transported to the finished product tank, while in discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 100V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. For the sodium coconut oil fatty acid acyl glutamate produced in this example, the product indicators were free acid <1.8% and sodium chloride <0.2%.

[0052] Example 5 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, sodium glutamate (30% by mass), lauric acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump to carry out the amidation reaction. Here, the temperature range T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of sodium glutamate and mother liquor treatment solution was 56 g / min, the flow rate of lauric acid chloride was 1.3 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 7.3 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 230 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 1.5 MPa and the filtration temperature to 60°C. In discharge channel A, the product sodium lauroyl glutamate was obtained and transported to the finished product tank, while in discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 100V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. The product indicators for sodium lauroyl glutamate produced in this example were free acid <1.8% and sodium chloride <0.2%.

[0053] Example 6 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. The raw materials, sodium methyl taurate (30% by mass), lauric acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution, were each introduced into the amidation reaction module via a constant-flow pump to carry out the amidation reaction. Here, the temperature range T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of sodium methyl taurate and mother liquor treatment solution was 60 g / min, the flow rate of lauric acid chloride was 12.5 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 7.8 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 210 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 2 MPa and the filtration temperature to 60°C. In discharge channel A, the product, sodium lauroyl methyl taurate, was obtained and transported to the finished product tank, while in discharge channel B, the mother liquor was separated and discharged and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. By controlling the separation voltage to 200V and the current to 2A, the mother liquor was separated, and the mother liquor treatment liquid and separated salts were discharged. The mother liquor treatment liquid was then transported by reflux to the amidation reaction module for reuse. For the sodium lauroyl methyl taurate produced in this example, the product indicators were free acid <1.8% and sodium chloride <0.2%.

[0054] Example 7 This embodiment provides a manufacturing method for producing salt-free amino acid surfactants by continuous flow, and this manufacturing method was specifically as follows. A mixture of sodium methyltaurate and sodium taurine (30% by mass), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution), and mother liquor treatment solution were each introduced into the amidation reaction module via a constant-flow pump to carry out the amidation reaction. Here, the temperature range T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature range T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the introduced raw materials were set as follows: the flow rate of the mixture of sodium methyltaurate and sodium taurine and the mother liquor treatment solution was 60 g / min, the flow rate of coconut oil fatty acid chloride was 13.5 g / min, and the flow rate of liquid alkali (sodium hydroxide solution, 30% by mass) was 7.5 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then the tubular reactor, and the residence time was controlled to 200 s to allow for complete reaction. Subsequently, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrate, and the material concentrate was connected to an online solid content / pH monitor to facilitate online monitoring of desalting. Here, the membrane separator and material concentrate were selected from ultrafiltration membranes and nanofiltration membranes, and the filtration pressure was controlled to 2 MPa and the filtration temperature to 60°C. Discharge channel A yielded the product, sodium coconut oil fatty acid acylmethyl taurate / sodium coconut oil fatty acid acyl taurate, which was transported to the finished product tank, while discharge channel B separated and discharged the mother liquor, which entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis machine. The separation was controlled to have a voltage of 200V and a current of 2.5A, thereby separating the mother liquor. The mother liquor treatment liquid and separated salts were then discharged, and the mother liquor treatment liquid was transferred to the amidation reaction module by reflux for reuse. For the coconut oil fatty acid acylmethyltaurate sodium / coconut oil fatty acid acyltaurate sodium produced in this example, the product indicators were free acid <1% and sodium chloride <0.2%.

[0055] The foregoing description represents only preferred embodiments of this application and is not intended to limit it. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are also included within the scope of protection.

[0056] Although this specification has been described based on embodiments, each embodiment does not necessarily contain only one independent technical solution. This method of description in this specification is merely for clarity, and those skilled in the art should consider the specification as a whole and understand that the technical solutions in each embodiment may be combined as appropriate to form other embodiments that will be understood by those skilled in the art.

Claims

1. A production system for producing salt-free amino acid surfactants by continuous flow, an amidation reaction module configured to carry out an amidation reaction, comprising at least one reactor unit having an input port configured for introducing an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution, and an output port configured for discharging the amidation product, A post-treatment module, wherein the input port of the post-treatment module is connected to the discharge port of the reactor unit, the amidation product is transported into the post-treatment module for separation and concentration, the discharge path A of the post-treatment module is connected to the finished product tank, and the discharge path B of the post-treatment module discharges the mother liquor. A mother liquor separation module comprising at least one separation unit, wherein the input port of the separation unit is connected to the discharge path B of the post-treatment module, the discharge port of the separation unit discharges the separated salt, the reflux port of the separation unit is connected to the input port of the reactor unit, and the mother liquor is treated by the separation unit and then the treated mother liquor liquid and separated salt are discharged. Includes, The reactor unit consists of a sequentially connected microchannel reactor and a tubular reactor, wherein the temperature range of temperature interval T1 corresponding to the microchannel reactor is 0 to 15°C, and the temperature range of temperature interval T2 corresponding to the tubular reactor is 70 to 85°C. The post-processing module comprises a sequentially connected membrane separation device and a material concentration device, the amidation product being transported into the membrane separation device, both of which are nanofiltration membranes, the discharge channel A connecting the material concentration device and the finished product tank, the discharge channel B connecting to the membrane separation device and discharging the mother liquor, and the material concentration device being connected to an online solid content / pH monitoring device. The separation unit is an electrodialysis machine. A production system characterized by the following features.

2. A manufacturing method for producing a salt-free amino acid surfactant by continuous flow using the production system described in claim 1, Step S1 involves introducing an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment solution into an amidation reaction module containing at least one reactor unit to carry out the amidation reaction, and then discharging the amidation product from the amidation reaction module. Step S2 involves transporting the amidation product into a post-treatment module, separating and concentrating it in discharge channel A of the post-treatment module to discharge the finished product into a finished product tank, separating it in discharge channel B of the post-treatment module to discharge the mother liquor, Step S3 involves transporting the mother liquor into a mother liquor separation module containing at least one separation unit, separating and discharging the mother liquor treatment liquid and the separated salt in the mother liquor separation module, and refluxing and transporting the mother liquor treatment liquid back into the amidation reaction module in step S1 for reuse. A manufacturing method characterized by including the following.

3. The method for producing an amino acid in step S1 is characterized in that the amino acid salt is one or more combinations of sarcosine salt, glutamate salt, alanine salt, glycine salt, aspartate salt, serine salt, taurine salt, and methyltaurine salt, the acid chloride is an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms, and the liquid alkali is a sodium hydroxide solution or a potassium hydroxide solution.

4. The manufacturing method according to claim 2, characterized in that in step S1, the mass content of the amino acid salt is 5% to 50%.

5. The manufacturing method according to claim 2, characterized in that, in step S1, the flow rate of the amino acid salt and mother liquor treatment solution is 0.04 to 100 kg / min, the flow rate of the acid chloride is 0.01 to 25 kg / min, the flow rate of the liquid alkali is 0.005 to 20 kg / min, and the time during which the amino acid salt, mother liquor treatment solution, acid chloride and liquid alkali react and reside in the amidation reaction module is 180 to 360 s.

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