A bio-based ligand for chromium-free metal tanning agents

Abstract

The application discloses a kind of biological ligand for chromium-free metal tanning agent, it is formed by the following steps reaction: step one: taking the biological compound containing hydroxyl group, dissolved in solvent, adding catalyst step two: the solution is carried out ice bath, and the halogenated hydrocarbon containing epoxy group and the halogenated hydrocarbon containing aldehyde group are reacted;Step three: after the reaction product is washed, organic phase is collected, solvent is spun dry, and biological ligand is obtained by chromatographic column.In the application, mainly castor oil is used as biological carrier, (2-chloroethoxy) cyclopropane, 6-chloropyridine-3-formaldehyde is reacted with castor oil, (2-chloroethoxy) cyclopropane, 6-chloropyridine-3-formaldehyde has halogenated group, and castor oil has a large number of hydroxyl groups, so that the reaction occurs, so that castor oil molecules have a large number of epoxy groups and aldehyde groups, so as to be used as pre-kneading agent for pre-kneading leather.

Description

Technical Field

[0001] This invention relates to the field of leather tanning, and more specifically to a bio-based ligand for chromium-free metal tanning agents. Background Technology

[0002] Tanning is a crucial step in leather production. Currently, tanning primarily uses chromium-containing tanning agents. However, chromium tanning agents cause significant pollution after use, leading to the gradual replacement with chromium-free tanning agents and other metal tanning agents. However, the performance of other metal tanning agents is not as good as that of chromium tanning agents, thus requiring the addition of other ligands. Bio-based ligands have excellent advantages in the environmental protection field, but their ligand effects are relatively poor. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a bio-based ligand for chromium-free metal tanning agents.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A bio-based ligand for chromium-free metal tanning agents,

[0006] It is produced by the following steps:

[0007] Step 1: Take a hydroxyl-containing bio-based compound, dissolve it in a solvent, and add a catalyst;

[0008] Step 2: Place the above solution in an ice bath, and add halogenated hydrocarbons containing epoxy groups and halogenated hydrocarbons containing aldehyde groups to react;

[0009] Step 3: After washing the reaction product, collect the organic phase, evaporate the solvent, and pass it through a chromatographic column to obtain the bio-based ligand.

[0010] As a further improvement of the present invention

[0011] The hydroxyl-containing bio-based compound is castor oil.

[0012] As a further improvement of the present invention

[0013] The epoxy-containing halogenated hydrocarbon is (2-chloroethoxy)cyclopropane.

[0014] As a further improvement of the present invention

[0015] The aldehyde-containing haloalkane is 6-chloropyridine-3-carboxaldehyde.

[0016] As a further improvement of the present invention

[0017] The catalyst is triethylamine.

[0018] As a further improvement of the present invention

[0019] The solvent is dichloromethane.

[0020] As a further improvement of the present invention

[0021] It is produced by reacting the following parts by mass:

[0022] Castor oil: 100-200 parts

[0023] (2-Chloroethoxy)cyclopropane: 10–25 parts

[0024] 6-Chloropyridine-3-carboxaldehyde: 5-15 parts

[0025] Triethylamine: 10-20 parts.

[0026] As a further improvement of the present invention

[0027] The reaction time for step two is 20–30 hours.

[0028] As a further improvement of the present invention

[0029] Step three specifically involves:

[0030] The prepared solution was washed with deionized water, saturated sodium bicarbonate solution, and hydrochloric acid solution. The organic phase was collected, the solvent was evaporated, and then the solution was passed through a chromatographic column with ethyl acetate / petroleum ether at a ratio of 1:4 to 8 to obtain the bio-based ligand.

[0031] The beneficial effects of this invention are that it mainly uses castor oil as a bio-based carrier. Through the reaction of (2-chloroethoxy)cyclopropane and 6-chloropyridine-3-carboxaldehyde with castor oil, (2-chloroethoxy)cyclopropane and 6-chloropyridine-3-carboxaldehyde contain halogenated groups, and castor oil has a large number of hydroxyl groups, thus the reaction occurs, resulting in a large number of epoxy groups and aldehyde groups on the castor oil molecule, which can be used as a pre-rubbing agent to pre-rub leather.

[0032] Furthermore, the addition of aluminum sulfate as a tanning agent during the subsequent tanning process achieved good results. Both mechanical strength and heat shrinkage temperature were significantly improved. Detailed Implementation

[0033] Example 1: Preparation of bio-based ligands

[0034] Step 1: Take 100g of castor oil, dissolve it in 200ml of dichloromethane, and add 20g of triethylamine;

[0035] Step 2: Place the above solution in an ice bath, add 20g of de(2-chloroethoxy)cyclopropane and 10g of de6-chloropyridine-3-carboxaldehyde to react;

[0036] Step 3: Wash the above-reacted solution with deionized water, saturated sodium bicarbonate solution, and hydrochloric acid solution, collect the organic phase, evaporate the solvent, and then pass it through a chromatographic column with an ethyl acetate / petroleum ether solution of 1:5 to obtain the bio-based ligand.

[0037] Example 2: Leather Preparation

[0038] Bio-based ligand pretanning

[0039] 100 parts by weight of acid-treated sheepskin were deacidified as follows: 200 parts by weight of water were added to a drum machine, followed by 7 parts of sodium chloride for 10 minutes, then the acid-treated sheepskin was added, followed by 5 parts of sodium bicarbonate, and the drum was turned for 45 minutes.

[0040] Remove the deacidified wool, add 300 parts by weight of water to the drum machine, then put the wool in and wash it in the drum for 40 minutes.

[0041] Take out the washed wool, add 0.5 parts of hexamethylenetetramine and 100 parts of water to the drum machine, put in the wool, and drum for 30 minutes. Then add 8 parts of the bio-based ligand prepared in Example 1 to the drum machine and perform initial tanning for 240 minutes.

[0042] Add 10% sodium bicarbonate by mass, adjust the pH value to around 8, raise the temperature to 35°C, rotate the drum for 4 hours, then stop the drum and let it stand for 10 hours to obtain pre-tanned leather;

[0043] Example 3:

[0044] Aluminum tanning:

[0045] Take 200 parts by weight of water, 1 part of concentrated sulfuric acid, and 1 part of formic acid, mix them, cool to room temperature, add them to a drum machine, put in the pre-tanned leather obtained in Example 2, and soak in acid for 2 hours;

[0046] Add 8 parts aluminum sulfate and tan for 3 hours;

[0047] Add 10% sodium bicarbonate to adjust the pH to around 4, heat to 35°C, rotate the drum for 2 hours, stop the drum and let it stand for 10 hours, then air dry to obtain tanned leather.

[0048] Comparative Example 1:

[0049] The acid-treated sheepskins are deacidified as follows: 200 parts by weight of water are added to a drum machine, followed by 7 parts of sodium chloride for 10 minutes, then the acid-treated sheepskins are added, followed by 5 parts of sodium bicarbonate, and the drum is turned for 45 minutes.

[0050] Remove the deacidified wool hides, add 300 parts by weight of water to the drum machine, then put the wool hides in and wash them in the drum for 40 minutes. Remove the wool hides to obtain the washed hides.

[0051] Take 200 parts by weight of water, 1 part of concentrated sulfuric acid, and 1 part of formic acid, mix them, cool to room temperature, add them to the drum machine, put in water to wash the skin, and soak in acid for 2 hours;

[0052] Add 8 parts aluminum sulfate and tan for 3 hours;

[0053] Add 10% sodium bicarbonate to adjust the pH to around 4, heat to 35°C, rotate the drum for 2 hours, stop the drum and let it stand for 10 hours, then air dry to obtain tanned leather.

[0054] Raw material list:

[0055]

[0056]

[0057] test:

[0058] 1. In accordance with QB / T2713-2005, the heat shrinkage temperature shall be determined using a digital leather shrinkage rate thermometer.

[0059] 2. Sampling shall be carried out in accordance with the requirements of QB / T2710-2005 and QB / T2711-2005, and experiments shall be conducted on a tensile testing machine to determine the tensile strength and tear strength of the raw leather.

[0060] 3. Measure the thickness according to the requirements of QB / T2709-2005 standard and calculate the thickness increase rate:

[0061] W = (d2 - d1) / (d1) * 100%

[0062] W-thickness increase rate

[0063] d1 - Thickness before tanning

[0064] d2 - Thickness after tanning

[0065] Example 2 Example 3 Comparative Example Heat shrinkage temperature (°C) 76 72 60 Tensile strength (MPa) 28 32 22 Tear strength (N / mm) 33 37 27 Thickness increase rate (%) 35 45 2

[0066] In this invention, castor oil is mainly used as a bio-based carrier. The reaction between (2-chloroethoxy)cyclopropane, 6-chloropyridine-3-carboxaldehyde and castor oil is carried out. (2-chloroethoxy)cyclopropane and 6-chloropyridine-3-carboxaldehyde contain halogenated groups, and castor oil has a large number of hydroxyl groups. The reaction results in a large number of epoxy groups and aldehyde groups on the castor oil molecule, which can be used as a pre-rubbing agent to pre-rub leather.

[0067] Furthermore, the addition of aluminum sulfate as a tanning agent during the subsequent tanning process achieved good results. Both mechanical strength and heat shrinkage temperature were significantly improved.

[0068] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A bio-based ligand for chromium-free metal tanning agents, characterized in that: Step 1: Take 100g of castor oil, dissolve it in 200ml of dichloromethane, and add 20g of triethylamine; Step 2: Place the above solution in an ice bath, add 20g of (2-chloroethoxy)cyclopropane and 10g of 6-chloropyridine-3-carboxaldehyde to react; Step 3: Wash the above-reacted solution with deionized water, saturated sodium bicarbonate solution, and hydrochloric acid solution, collect the organic phase, evaporate the solvent, and then pass it through a chromatographic column with an ethyl acetate / petroleum ether solution of 1:5 to obtain the bio-based ligand.

2. A bio-based ligand for chromium-free metal tanning agents according to claim 1, characterized in that: The reaction time for step two is 20–30 hours.

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