CN106905225A - A kind of preparation method of multi-functional Polvamide stabilisers - Google Patents

Abstract

The present invention relates to the preparation method of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide, using dimethyl isophthalate or Diethyl isophthalate and 2,2,6,6-tetramethyl-4-aminopiperidine are used as raw materials, without solvent and catalyst, react at 190°C for 1-2 hours, and then heat up to 220- Reaction at 240°C for 3-6 hours, direct aminolysis to prepare the target product.

Description

A kind of preparation method of multifunctional polyamide stabilizer

technical field

The invention relates to a preparation method of polyamide stabilizer N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide (I).

(I).

Background technique

N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide (I) is an excellent polyamide light stabilizer and processing aid ;It is compatible with polyamide through "molecular recognition" and cross-link amidation, making its stability to nylon beyond the limit of traditional light stabilizers, and can be used in combination with UV-absorbers to significantly improve the light stabilization effect; it can also Improve the processing process of polyamide melt, stabilize the pressure of polyamide melt, smooth the processing process, reduce the breakage of polyamide fiber during spinning; the basic group and its secondary effect in its molecular structure can strengthen metal dyes and acid dyes The affinity of polyamides makes polyamides stable, economical, compatible and deeply dyeable.

The preparation of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide (I), the current main method is to use 1,3-benzene Diformyl chloride (IPC) reacts with 2,2,6,6-tetramethyl-4-aminopiperidine (II).技术不断改进，有以下专利报道：EP 1556350( 等同CN 1671664 A， CN 1279024 C， WO 2004016591A1，US 7632949 )，CN 105481759 A， CN 103554009 A ，CN 103554009B，CN 103508938 A， CN103508938B，CN 103030588 A。 These methods all use 1,3-phthaloyl chloride (IPC), because the acid chloride is easily hydrolyzed, and the hydrogen chloride produced needs to be neutralized with an acid-binding agent. Moreover, the generated N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide (I) is insoluble in inert solvents (such as aromatic hydrocarbons, chlorinated Alkanes, etc.), resulting in difficulty in reaction control, troublesome purification treatment, and a lot of sewage.

(I)

The application filed in CN 104974075 A involves a new design without 1,3-phthaloyl chloride (IPC): using isophthalic acid diester (III) and 2,2,6,6-tetramethyl-4-amino Piperidine (II) is subjected to alkylaluminum catalyzed atmospheric pressure aminolysis, which specifically mentions trimethylaluminum (Example 1-4, 7, 8, right 6), or diethylaluminum (Example 5, 6 , right 6), or tripropylaluminum, triisopropylaluminum, tributylaluminum (right 6) as catalyst, toluene (embodiment 1-5, right 7), methanol (embodiment 7, right 7) or Ethanol (Example 6, Claim 7) is the solvent, dimethyl isophthalate, or diethyl isophthalate, or diisopropyl isophthalate and 2,2,6,6-tetramethyl - 4-aminopiperidine, azeotropic distillation, then cooling, washing with water, filtering and drying to obtain the target product.

(I)

However, the catalyst trialkylaluminum is flammable and explosive. Trimethylaluminum is a colorless and transparent liquid at normal temperature and pressure. It ignites spontaneously in the air and can catch fire instantly. It reacts violently with alcohols and acids with active hydrogen; it reacts violently with water, and can produce hydrogen even in cold water. Explosive decomposition reaction with formation of methane, sometimes pyrophoric. CN 104974075 A mentions that the name of the diethyl aluminum substance is incorrect and incomplete, and CN 104974075 A mentions azeotropic distillation of methanol (with active hydrogen), so this application has scientific principles and serious safety problems and cannot be implemented.

Contents of the invention

In order to solve the problems in the above prior art, the present invention provides a safe and feasible N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1, 3-phthalamide preparation method.

Technical scheme of the present invention is as follows:

Using isophthalic acid diester (III) and 2,2,6,6-tetramethyl-4-aminopiperidine (II) as raw materials, without using solvent and catalyst, the aminolysis reaction is directly carried out to obtain N, N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide (I).

The isophthalic acid diester (III) is dimethyl isophthalate or diethyl isophthalate.

(I)

The mass ratio of isophthalic acid diester to 2,2,6,6-tetramethyl-4-aminopiperidine is 1.0:2.0-1.0:7.0, preferably 1.0:3.5.

First react at 190°C for 1-2 hours, then raise the temperature to 220-240°C for 3-6 hours.

Lower the temperature to below 180°C, and recover excess 2,2,6,6-tetramethyl-4-aminopiperidine by distillation under reduced pressure.

Then wash the generated N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide with water, filter and dry to obtain the crystal product .

To sum up, the present invention successfully solves the problems existing in the prior art, and is suitable for actual industrial production.

detailed description

The present invention will be described in further detail below in conjunction with the examples; the following examples are explanations of the present invention, and the protection scope of the present invention is not limited by the following examples.

Example 1

Add 6.0 kg of dimethyl isophthalate and 21.0 kg of 2,2,6,6-tetramethyl-4-aminopiperidine into a 50-liter reactor, and close all inlets and outlets of the reactor. First react at 190°C for 2 hours, then raise the temperature to 230°C for 5 hours. Lower the temperature to below 180°C, and recover excess 2,2,6,6-tetramethyl-4-aminopiperidine by distillation under reduced pressure with a circulating vacuum water pump. Then wash the N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide with water, filter and dry to obtain 12.8 kg Acicular white crystal product, yield 93.5%. The melting point is 278-280°C.

Example 2

Add 6.8 kg of diethyl isophthalate and 24.0 kg of 2,2,6,6-tetramethyl-4-aminopiperidine into a 50-liter reactor, and close all the inlets and outlets of the reactor. First react at 190°C for 2 hours, then raise the temperature to 230°C for 6 hours. Lower the temperature to below 180°C, and recover excess 2,2,6,6-tetramethyl-4-aminopiperidine by distillation under reduced pressure with a circulating vacuum water pump. Then wash the generated N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide with water, filter and dry to obtain 12.4 kg Acicular white crystal product, yield 91.6%. The melting point is 278-280°C.

Example 3

Add 6.0 kg of dimethyl isophthalate and 21.0 kg of recovered and purified 2,2,6,6-tetramethyl-4-aminopiperidine into a 50-liter reactor, and close all inlets and outlets of the reactor. First react at 190°C for 2 hours, then raise the temperature to 230°C for 5 hours. Lower the temperature to below 180°C, and recover excess 2,2,6,6-tetramethyl-4-aminopiperidine by distillation under reduced pressure with a circulating vacuum water pump. Then wash the N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide with water, filter and dry to obtain 12.6 kg Acicular white crystal product, yield 92.1%. The melting point is 278-280°C.

The N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide prepared by the method of the present invention has good quality and has been subjected to differential thermal analysis , Infrared spectroscopy and proton magnetic resonance tests.

Figure 1 DSC differential thermal analysis of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide.

Figure 2 N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide infrared spectrum.

Accompanying drawing 3 N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide H NMR spectrum.

Claims (6)

1. Method for preparing polyamide stabilizer N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide with structure (I) (I), It is characterized in that: using isophthalic acid diester (III) and 2,2,6,6-tetramethyl-4-aminopiperidine (II) as raw materials, without using solvent and catalyst, direct aminolysis to obtain N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-phthalamide (I). 2. according to claim 1, its technical characteristic is: described isophthalic acid diester is dimethyl isophthalate or diethyl isophthalate. 3. According to claim 1, its technical feature is that: the mass ratio of isophthalic acid diester to 2,2,6,6-tetramethyl-4-aminopiperidine is 1.0:2.0-1.0:7.0. 4. According to claim 1, its technical feature is: first react at 190°C for 1-2 hours, then raise the temperature to 220-240°C for 3-6 hours. 5. According to claim 1, its technical feature is: lower the temperature to below 180°C, and recover excess 2,2,6,6-tetramethyl-4-aminopiperidine by distillation under reduced pressure. 6. According to claim 1, its technical characteristics are: then use water to generate N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedimethanol The amide was washed, filtered, and dried to obtain a crystal product.