A softener and preparation method thereof

Abstract

The invention discloses a softener, comprising an alkyl glycoside compound, a polyethylene glycol monoether and / or a nitrogen-containing compound; in terms of mass percentage, the alkyl glycoside compound accounts for 1-85% of the softener, and the remainder is polyethylene glycol monoether and / or a nitrogen-containing compound. The softener for soft polyurethane foam in the present invention participates in the reaction in the polyurethane soft foam system to form a part of the polyurethane foam structure, and the polyurethane soft foam material prepared under the condition of reducing or not using dichloromethane has excellent softness and excellent physical properties, solves the safety and environmental protection problems caused by dichloromethane, and the raw materials used have good biodegradability, good biodegradability, and is a green and environmentally friendly softener.

Description

[0001] This application is a divisional application of an invention patent application with an application date of February 4, 2021, application number 2021101699028, and invention name “A softener for soft polyurethane foam and its application”. Technical Field

[0002] The invention relates to the technical field of polyurethane materials and softeners, and in particular to a softener suitable for soft polyurethane foam and a preparation method of the softener. Background Art

[0003] Polyurethane is a general term for polymer compounds containing repeated carbamate groups on the main chain. Soft polyurethane foam is a particularly important type of polyurethane material. It has good resilience and load-bearing capacity and is widely used as furniture, sound insulation, filtration and lining materials.

[0004] Soft polyurethane foam is a polyurethane porous material that mainly relies on the combination of chemical foaming agents and physical foaming agents to obtain excellent hand feel. Water is used as a chemical foaming agent to react with isocyanate to release CO2. The generated amino group continues to react with isocyanate to obtain urea groups. The increase in urea groups increases the hardness of the foam. Dichloromethane is used in large quantities as a physical foaming agent in the preparation of soft polyurethane foam. Dichloromethane has a large heat of vaporization and can take away enough heat during the preparation of soft polyurethane foam and dilute the heat released during the reaction. When dichloromethane is used under the same density, the amount of chemical foaming agent water is reduced, so the amount of urea groups in the reaction process is reduced, and a softer and more comfortable soft polyurethane foam can be obtained. While the use of dichloromethane can bring comfortable soft polyurethane foam and reduce the risk of yellow heart of polyurethane foam, there are also environmental and safety issues. Dichloromethane itself is highly toxic. When the human body comes into contact with dichloromethane, it generally has the following symptoms: dichloromethane vapor is highly anesthetic, and large amounts of inhalation can cause acute poisoning, with symptoms such as nasal pain, headache, and vomiting; chronic poisoning can cause dizziness, fatigue, loss of appetite, impaired hematopoietic function, and a decrease in red blood cells. It is considered a possible carcinogen by the U.S. Environmental Protection Agency USEPA and the International Agency for Research on Cancer; dichloromethane is a transitional physical foaming agent with an ozone depletion potential greater than zero, and it still consumes a certain amount of ozone. At the end of 2017, the Ministry of Environmental Protection issued the "List of Priority Controlled Chemicals (First Batch)", and dichloromethane was included in the list. For the chemicals included in the list, the relevant departments will take risk control measures for the main links that generate environmental and health risks to minimize the significant impact of chemical production and use on human health and the environment.

[0005] To this end, patent document US4544678 discloses the use of polyethylene glycol in combination with a plasticizer as a softener in soft polyurethane foam, which can obtain soft polyurethane foam without using a physical foaming agent. The use of polyethylene glycol increases the flexible chain segment of the soft foam, which significantly reduces the supporting performance of the soft foam and affects the rebound and tear strength of the foam; patent US5539011 discloses a method for preparing soft polyurethane foam using a trimerization catalyst, but the trimerization catalyst has a strong odor and has a certain catalytic activity. The preparation process of the soft polyurethane foam needs to be changed, which affects the operating tolerance, thereby limiting their use.

[0006] At present, most softeners for soft polyurethane foams use special polyethers or special polyols in combination with cross-linking agents and trimerization catalysts to make the foam soft. The soft polyurethane foam must be prepared at a lower isocyanate index. At this time, the prepared soft polyurethane foam has excessive hydroxyl groups, which increases the affinity for water and affects the wet heat aging performance and physical properties of the foam. In addition, the exposed hydroxyl groups will be oxidized by oxygen free radicals to generate aldehyde compounds during the degradation process, resulting in an increase in the aldehyde content of the foam after aging. The soft polyurethane foam prepared at a higher index has the problem of poor open porosity. Summary of the invention

[0007] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide an environmentally friendly softener for soft polyurethane foam, which has low odor and good biodegradability, and can prepare soft polyurethane foam with good open-cell performance under the condition of 95 to 115 isocyanate index by replacing part of or not using dichloromethane.

[0008] A softener for soft polyurethane foam comprises an alkyl glycoside compound, wherein the alkyl glycoside compound accounts for 1-85% of the softener in terms of mass percentage.

[0009] According to some preferred embodiments of the present invention, the alkyl glucoside contains 50 wt % of distilled water.

[0010] According to some preferred embodiments of the present invention, the alkyl glycoside compound is methyl glucoside, n-octyl glucoside, decyl glucoside, lauryl glucoside, C 8-10 Alkyl glucoside, C 8-14 Alkyl glucoside, C 12-14 One or more of alkyl glucoside, tetradecyl glucoside, polyol glucoside, N-dodecyl glucoside lauramide, N-hydroxyethyl lauryl glucoside, n-octyl-β-pyranoglucoside, nonyl-β-D-pyranoglucoside, glucosamine lauramide, fatty alcohol lactose monoglycoside, and fatty alcohol lactose diglycoside.

[0011] According to some preferred embodiments of the present invention, the polyethylene glycol monoether is included, and the polyethylene glycol monoether accounts for 1-25% of the softener for flexible polyurethane foam by mass percentage. The polyethylene glycol monoether can increase the foam opening, ensuring that the softener can obtain open-cell soft foam when used at an index of 95 to 115.

[0012] According to some preferred embodiments of the present invention, the polyethylene glycol monoether has a structure shown in the following formula (1):

[0013] RO(CH2CH2O) m H(1)

[0014] In the formula, R is C 1～5 Alkyl, m=2-23.

[0015] According to some preferred embodiments of the present invention, the nonionic surfactant of secondary alcohol polyoxyethylene ether is included, and the nonionic surfactant of secondary alcohol polyoxyethylene ether accounts for 1-25% of the softener by mass percentage. The secondary alcohol polyoxyethylene ether can increase the compatibility of the alkyl glycoside nonionic surfactant and the polyethylene glycol monoether to obtain a stable clear and transparent solution.

[0016] According to some preferred embodiments of the present invention, the secondary alcohol polyoxyethylene ether nonionic surfactant has a structure shown in the following formula (2):

[0017]

[0018] Wherein, n=8-90.

[0019] According to some preferred implementation aspects of the present invention, distilled water is included, and the distilled water accounts for 1-50% of the softener in terms of mass percentage.

[0020] According to some preferred implementation aspects of the present invention, the nitrogen-containing compound is included, and the nitrogen-containing compound accounts for 0.01-5% of the softener in terms of mass percentage.

[0021] According to some preferred embodiments of the present invention, the nitrogen-containing compound is triethylenediamine, pentamethylenetriamine, dimethylaminopropylamine diisopropyl alcohol, pentamethyldiethylenetriamine, tetramethyldipropylenetriamine, N,N-dimethyl-1,3-diaminopropane, 3-dimethylaminopropyl urea, (dimethylaminoethyl) ether, N,N-di[3-(dimethylamino)propyl]-N',N'-dimethyl-1,3-propanediamine, hexadecylamine, 2-[[3-(dimethylamino)propyl]methylamino]ethanol, 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, N,N-dimethylethanolamine, N,N-dimethylbenzylamine, triethanolamine, diethanolamine amine, 1,8-diazabicyclo[5,4,0]undec-7-ene, 6-dimethylamino-1-hexanol, N-methyldicyclohexylamine, hexadecylamine, tetramethylguanidine, 1-isobutyl-2-methylimidazole, 2-amino-α-[[2-(1,1-dimethylethoxy)-2-oxoethoxy]imino]-4-thiazoleacetic acid, O,O-diethylthiophosphate anhydride, N-ethylmorpholine, N-methylmorpholine, benzylamine, diethylaminoethanol, N,N'-diisopropylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1,2-dimethylimidazole, N-methylimidazole, 2,2-dimorpholinodiethyl ether, dimethylamino Ethoxyethanol, 2-dimethylaminopyridine, 2,4-diaminopyrimidine, 4,5-diaminopyrimidine, 2-methylaminopyridine, 4-dimethylaminopyridine, 2,4-bis(dimethylamino)pyrimidine-6-carboxylic acid, 1-(methylamino)-3-(4-methylpiperazin-1-yl)-2-propanol, aminopiperazine hydrochloride, 2,2,4-trimethyl-2-silamorpholine, 1-(2-dimethylaminoethyl)piperazine, 1-(3-dimethylaminopropyl)piperazine, (2-morpholinopyridin-4-yl)methylamine, 4-chloro-6-dimethylaminopyrimidine, N,N-dimethyl(morpholin-2-yl)formamide, N,N-dimethyl(R-morpholin-2-yl)formamide, 4- One or more of methylmorpholine-2-methylamine, N,N-dimethyl(4-methyl-1-piperazinyl)ethylamine, hexahydro-1,3,5-trimethyl-S-triazine, 1,3,5-triethylhexahydro-S-triazine, N,N'-carbonyldiimidazole, dicyclohexylcarbodiimide, 3-(diethoxyphosphoryloxy), 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, N-hydroxy-7-azobenzotriazole, tripyrrolidinylphosphonium bromide hexafluorophosphate, O-benzotriazole-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(N-succinimide)-1,1,3,3-tetramethyluronium tetrafluoroborate.

[0022] The present invention also provides a method for preparing the softener, comprising the following steps: uniformly mixing an alkyl glycoside compound, polyethylene glycol monoether and / or a nitrogen-containing compound to obtain the softener.

[0023] The present invention also provides a use of the softener for soft polyurethane foam as described above in the preparation of polyurethane bra cotton, polyurethane furniture cotton and special polyurethane foam.

[0024] Due to the adoption of the above technical scheme, compared with the prior art, the present invention has the following beneficial effects: the softener for soft polyurethane foam of the present invention adopts an alkyl glycoside compound, and the alkyl glycoside nonionic surfactant contains 4 primary alcohols, which preferentially react with isocyanate during the reaction process, thereby reducing the foam stiffness problem caused by the formation of urea groups; the softener participates in the reaction in the polyurethane soft foam system to form a part of the polyurethane foam structure, and the polyurethane soft foam material prepared under the condition of reducing or not using dichloromethane has excellent softness and excellent physical properties, thereby solving the safety and environmental protection problems caused by dichloromethane; the raw materials used have good biodegradability, and the biodegradability is good, so it is a green and environmentally friendly softener. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 Microscopic photograph of the cell structure of the soft polyurethane foam prepared in Comparative Test 2 using the softener of Example 1 according to the formula of Table 3;

[0027] Figure 2 The micrograph of the cell structure of the soft polyurethane foam prepared by using the softener of Example 2 according to the formula of Table 3 in Comparative Test 2;

[0028] Figure 3 Microscopic photograph of the cell structure of the soft polyurethane foam prepared by using the softener of Example 3 according to the formula of Table 3 in Comparative Test 2;

[0029] Figure 4 The following is a micrograph of the cell structure of the soft polyurethane foam prepared according to the formula in Table 3 in Comparative Example 2 (without adding softener) in Comparative Test 2. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] Example 1

[0032] The softener for soft polyurethane foam provided in this embodiment is prepared as follows: at room temperature, 80 g C 8-10 Alkyl glucoside 0810, 10g polyethylene glycol monomethyl ether 350 and 10g secondary alcohol polyoxyethylene ether Softanol-30 are mixed evenly to obtain the product. 8-10 Alkyl glucoside 0810 contains 50 wt% of double distilled water.

[0033] Example 2

[0034] The softener for soft polyurethane foam provided in this embodiment is prepared as follows: at room temperature, 90 g C 8-10 Alkyl glucoside 0810 and 10g 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine were mixed evenly to obtain the product. 8-10 Alkyl glucoside 0810 contains 50 wt% of double distilled water.

[0035] Example 3

[0036] The softener for soft polyurethane foam provided in this embodiment is prepared as follows: at room temperature, 70 g C 8-10 Alkyl glucoside 0810, 15g diethanolamine, 10g polyethylene glycol monomethyl ether 350 and 5g secondary alcohol polyoxyethylene ether Softanol-90 are mixed evenly to obtain the product. 8-10 Alkyl glucoside 0810 contains 50 wt% of double distilled water.

[0037] Comparison test 1

[0038] The polyurethane soft foam formulas were compared by adding 1 part of the softener of the above Examples 1-3 and without adding softener (Comparative Example 1). The polyurethane soft foam formulas are shown in Table 1:

[0039] Table 1 Polyurethane soft foam formula

[0040]

[0041]

[0042] When preparing polyurethane foam plastics, weigh the materials as shown in Table 1 into a stirring tank, stir them at 25°C at a stirring speed of 2100 rpm / min for 5 seconds, pour them into a foaming box until the reaction is completed, and record the bubble jumping time to obtain polyurethane foam plastics.

[0043] It should be noted that the polyether polyol 5603 in Table 1 comes from Jiangsu Changhua Polyurethane Co., Ltd., UF-5840 (silicone oil), A-33 (amine catalyst) and T-9 (tin catalyst) come from Jiangsu Aoshijia Material Technology Co., Ltd., and toluene diisocyanate TDI comes from Huntsman Polyurethane Co., Ltd. The softeners prepared in Examples 1, 2 and 3 contain 40wt%, 45wt% and 35wt% of water, respectively, which needs to be deducted when calculating the formula addition.

[0044] The density of the samples was tested according to the national standard GB6343-1995; the elongation and tear strength of the samples were tested according to the national standard GB / T6344-1996 for soft polyurethane foam plastics; the rebound rate of the samples was tested according to the national standard GB / T6770-2008 for soft polyurethane foam plastics; the indentation hardness of the samples was tested according to the method B of the national standard GB / T10807-2006 for soft polyurethane foam plastics. The results are shown in Table 2:

[0045] Table 2 Performance test results of soft polyurethane foam

[0046] D25 Comparative Example 1 Example 1 Example 2 Example 3 Jump bubble time / s 112 110 110 122 <![CDATA[Density / (Kg / m 3 )]]> 27.84 27.33 26.9 26.24 Rebound / % 41 41 43 44 25% indentation hardness / N 88.02 74.58 71.88 70.61 40% indentation hardness / N 104.96 88.49 88.37 85.56 65% indentation hardness / N 176.61 145.91 141.04 141.07 Comfort Factor 2.00 1.96 1.96 2.00

[0047] The data in Table 2 show that the bubble jumping time and density of the comparative example and the example are close, indicating that the softener has little effect on the foaming of the formula; the rebound data shows that the elasticity of the example is better than that of the comparative example; in terms of hardness, the pressure line hardness of the example at 25%, 40%, and 65% is lower than that of the comparative example, proving that the softener has a significant effect. At the same time, it has little effect on the comfort factor of the sponge.

[0048] Comparison test 2

[0049] 1) The polyurethane soft foam formulas to which 1.5 parts of the softeners of Examples 1 to 3 above are added and the polyurethane soft foam formulas to which no softener is added (Comparative Example 2) are added are compared. The polyurethane soft foam formulas are shown in Table 2:

[0050] Table 3 Polyurethane soft foam formula

[0051] D32 Comparative Example 2 Example 1 Example 2 Example 3 Polyether polyol 5603 100 100 100 100 water 2.25 1.32 1.245 1.395 UF-5840 1 1 1 1 A-33 0.15 0.15 0.15 0.15 A-1 0.04 0.04 0.04 0.04 T-9 0.16 0.16 0.16 0.16 MC 27 12 12 12 TDI 32.2 32.2 32.2 32.2

[0052] When preparing polyurethane foam plastics, weigh the materials as shown in Table 3 into a stirring tank, stir them at 25°C at a stirring speed of 2100 rpm / min for 5 seconds, pour them into a foaming box until the reaction is completed, and record the bubble jumping time to obtain polyurethane foam plastics.

[0053] It should be noted that the polyether polyol 5603 in Table 3 comes from Jiangsu Changhua Polyurethane Co., Ltd., UF-5840 (silicone oil), A-33 (amine catalyst), A-1 (foaming amine catalyst) and T-9 (tin catalyst) come from Jiangsu Aoshijia Material Technology Co., Ltd., and toluene diisocyanate TDI comes from Huntsman Polyurethane Co., Ltd. The softeners prepared in Examples 1, 2 and 3 contain 40wt%, 45wt% and 35wt% of water, respectively, which needs to be deducted when calculating the formula addition.

[0054] The density of the samples was tested according to the national standard GB6343-1995; the elongation and tear strength of the samples were tested according to the national standard GB / T6344-1996 for soft polyurethane foam plastics; the resilience of the samples was tested according to the national standard GB / T6770-2008 for soft polyurethane foam plastics; the indentation hardness of the samples was tested according to the method B of the national standard GB / T10807-2006 for soft polyurethane foam plastics. The results are shown in Table 4:

[0055] Table 4 Performance test results of soft polyurethane foam

[0056] D25 Comparative Example 2 Example 1 Example 2 Example 3 Jump bubble time / s 204 233 231 175 <![CDATA[Density / (Kg / m 3 )]]> 31.99 31.78 32.48 32.05 Rebound / % 50 47 51 49 25% indentation hardness / N 55.43 58.18 63.03 54.66 40% indentation hardness / N 63.78 68.24 71.35 62.87 65% indentation hardness / N 105.37 117.44 116.35 111.33 Comfort Factor 1.90 2.01 1.85 2.04

[0057] The data in Table 4 show that if you want to achieve the same softness without adding softener, you need to add a large amount of methylene chloride (MC) to achieve a similar effect. In the polyurethane material with a small amount of softener added in the embodiment, the softness of the material is better than that of the comparative example 2 when the use of MC is reduced by at least half. Reducing the use of MC is in line with the national green chemistry trend and the needs of human health.

[0058] 2) The foams prepared in Table 3 were photographed using a microscope. The cell structures of the polyurethane foams prepared in Comparative Examples 1, 2, 3 and Comparative Example 2 were as follows: Figure 1-4 As shown in the accompanying drawings, compared with Comparative Example 2, the soft polyurethane foams prepared in Examples 1-3 have better opening performance and more regular pores. This is because a large amount of dichloromethane used in Comparative Example 2 causes local pores to be combined, resulting in slightly rough and disordered pores that are not regular and prone to sesame holes.

[0059] The softener for soft polyurethane foam of the present invention adopts alkyl glycoside compounds. The alkyl glycoside nonionic surfactant contains four primary alcohols and reacts with isocyanate first in the reaction process, thereby reducing the foam stiffness problem caused by the formation of urea groups. The polyethylene glycol monoether can increase the foam opening, thereby ensuring that the softener can obtain open-cell soft foam when used at an index of 95 to 115. The secondary alcohol polyoxyethylene ether can increase the compatibility of the alkyl glycoside nonionic surfactant and the polyethylene glycol monoether, thereby obtaining a stable clear and transparent solution. The softener participates in the reaction in the polyurethane soft foam system to form a part of the polyurethane foam structure, and the polyurethane soft foam material prepared under the condition of reducing or not using dichloromethane has excellent softness and excellent physical properties, thereby solving the safety and environmental protection problems caused by dichloromethane. The raw materials used all have good biodegradability and good biodegradability, thereby being a green and environmentally friendly softener.

[0060] The softener for soft polyurethane foam of the present invention solves the problems that the existing softener needs to be used under low index conditions to obtain soft foam with better open-cell performance and the softener itself contains a strong odor or affects the foam support and poor resistance to moisture and heat aging. The purpose is to provide a softener for soft polyurethane foam, which has low odor and good biodegradability, and can maintain good open-cell performance of soft foam under isocyanate index conditions of 95 to 115 when replacing part of or not using dichloromethane.

[0061] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A softener for soft polyurethane foam, characterized in that: It comprises an alkyl glycoside compound, polyethylene glycol monoether, a nitrogen-containing compound, a secondary alcohol polyoxyethylene ether and distilled water; in terms of mass percentage, the alkyl glycoside compound accounts for 1-85% of the softener, the secondary alcohol polyoxyethylene ether accounts for 1-25% of the softener, the polyethylene glycol monoether accounts for 1-25% of the softener, the nitrogen-containing compound accounts for 0.01-5% of the softener, and the distilled water accounts for 1-50% of the softener; The polyethylene glycol monoether has a structure shown in the following formula (1): RO(CH2CH2O) m H (1) In the formula, R is C 1~5 Alkyl, m = 2-23; The secondary alcohol polyoxyethylene ether has a structure shown in the following formula (2): （2） In the formula, n=8-90.

2. The softener according to claim 1, characterized in that The alkyl glycoside compound is selected from methyl glucoside, C 8-14 One or more of alkyl glucoside, polyol glucoside, N-dodecyl glucoside lauramide, N-hydroxyethyl lauryl glucoside, n-octyl-β-pyranoglucoside, nonyl-β-D-pyranoglucoside, glucosamine lauramide, fatty alcohol lactose monoglycoside, and fatty alcohol lactose diglycoside.

3. The softener according to claim 1, characterized in that The nitrogen-containing compound is triethylenediamine, dimethylaminopropylamine diisopropyl alcohol, pentamethyldiethylenetriamine, tetramethyldipropylenetriamine, N,N-dimethyl-1,3-diaminopropane, 3-dimethylaminopropyl urea, (dimethylaminoethyl) ether, N,N-di[3-(dimethylamino)propyl]-N',N'-dimethyl-1,3-propanediamine, hexadecylamine, 2-[[3-(dimethylamino)propyl]methylamino]ethanol, 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, N,N-dimethylethanolamine, N,N-dimethylbenzylamine, triethanolamine, diethanolamine, 1, 8-diazabicyclo[5,4,0]undec-7-ene, 6-dimethylamino-1-hexanol, N-methyldicyclohexylamine, hexadecylamine, tetramethylguanidine, 1-isobutyl-2-methylimidazole, 2-amino-α-[[2-(1,1-dimethylethoxy)-2-oxoethoxy]imino]-4-thiazoleacetic acid, N-ethylmorpholine, N-methylmorpholine, benzylamine, diethylaminoethanol, N,N'-diisopropylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1,2-dimethylimidazole, N-methylimidazole, 2,2-dimorpholinodiethyl ether, dimethylaminoethoxy 2-Dimethylaminopyridine, 2,4-diaminopyrimidine, 4,5-diaminopyrimidine, 2-methylaminopyridine, 4-dimethylaminopyridine, 2,4-bis(dimethylamino)pyrimidine-6-carboxylic acid, 1-(methylamino)-3-(4-methylpiperazin-1-yl)-2-propanol, aminopiperazine hydrochloride, 2,2,4-trimethyl-2-silamorpholine, 1-(2-dimethylaminoethyl)piperazine, 1-(3-dimethylaminopropyl)piperazine, (2-morpholinopyridin-4-yl)methylamine, 4-chloro-6-dimethylaminopyrimidine, N,N-dimethyl(morpholin-2-yl)formamide, 4-methylmorpholine- 2-methylamine, N,N-dimethyl (4-methyl-1-piperazinyl) ethylamine, hexahydro-1,3,5-trimethyl-S-triazine, 1,3,5-triethylhexahydro-S-triazine, N,N'-carbonyldiimidazole, dicyclohexylcarbodiimide, 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, N-hydroxy-7-azobenzotriazole, tripyrrolidinylphosphonium bromide hexafluorophosphate, O-benzotriazole-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(N-succinimide)-1,1,3,3-tetramethyluronium tetrafluoroborate.

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