阅读说明：本技术 一种检测乙烯类单体是否变质的新方法 (Novel method for detecting whether ethylene monomer is deteriorated ) 是由 张梁 肖志军 范艳平 程康康 刘志超 刘福仁 于 2020-04-17 设计创作，主要内容包括：本发明涉及一种检测乙烯类单体是否变质的新方法。其技术方案是：包括以下过程,按质量百分比：首先,将乙烯类单体配置成浓度为10%-50%的溶液,然后加入浓度为0.1%-1%的引发剂,使其发生聚合反应,利用检测装置采集整个反应过程中的发热情况,通过对比标准样品和待测样品的反应釜内温度变化曲线来判定样品是否变质；有益效果是：乙烯类单体发生聚合反应时,在反应过程中会释放热量,这是聚合反应的特点,本发明是利用乙烯类单体自聚变质后,聚合反应放热会减少,通过对比标准样品和待测样品的反应放热情况来检测样品是否变质,该发明的检测设备结构简单,制造技术门槛低,设备便宜,易于推广,该发明的检测方法操作简单,检测精度高。(The invention relates to a novel method for detecting whether ethylene monomers are deteriorated. The technical scheme is as follows: comprises the following steps of: firstly, preparing a vinyl monomer into a solution with the concentration of 10-50%, then adding an initiator with the concentration of 0.1-1% to perform polymerization reaction, collecting the heating condition in the whole reaction process by using a detection device, and judging whether a sample is deteriorated or not by comparing the temperature change curves in a reaction kettle of a standard sample and the sample to be detected; the beneficial effects are that: the invention utilizes the characteristic that the ethylene monomer can release heat in the reaction process when undergoing polymerization deterioration, the exothermic heat of the polymerization reaction can be reduced, and whether the sample is deteriorated or not is detected by comparing the exothermic reaction conditions of the standard sample and the sample to be detected.)

1. A new method for detecting whether ethylene monomers are deteriorated is characterized in that: comprises the following steps of:

firstly, preparing a vinyl monomer into a solution with the concentration of 10-50%, then adding an initiator with the concentration of 0.1-1% to perform polymerization reaction, collecting the heating condition in the whole reaction process by using a detection device, and judging whether a sample is deteriorated or not by comparing the temperature change curves in a reaction kettle of a standard sample and the sample to be detected;

the detection device comprises a constant-temperature water bath kettle (1), a jacket kettle (2), a circulating pump (3), a flowmeter (4), a thermocouple (5), a stirrer (6) and a collection device (7), wherein the constant-temperature water bath kettle (1) is connected to the jacket kettle (2) through the circulating pump (3) and the flowmeter (4), the stirrer (6), the thermocouple (5) and the collection device (7) are arranged in the jacket kettle (2), constant-temperature hot water is prepared by using the constant-temperature water bath kettle (1), the circulating pump (3) is used for supplying the constant-temperature hot water for the jacket kettle (2), the thermocouple (5) is used for collecting the change of the temperature in the jacket kettle (2), and whether the monomer is deteriorated or not is judged by comparing a standard sample with a temperature change curve in the sample to be detected jacket kettle (2).

2. The novel method of claim 1, wherein the method comprises the steps of: the initiator is a redox system, the oxidant is sodium persulfate, and the reducing agent is sodium bisulfite or polyethylene polyamine.

3. The novel method of claim 1, wherein the method comprises the steps of: the ambient temperature was set to 23 ℃, the thermostatic water bath temperature was set to 45 ℃ to 50 ℃, the discharge capacity of the circulation pump was set to 1.8L/min, and the stirring rate of the stirrer of the jacketed kettle (2) was set to 150 rpm.

4. The novel method of claim 1, wherein the method comprises the steps of: the method comprises the following specific steps:

1) setting the environmental temperature of a laboratory to 23 ℃, the temperature of a thermostatic water bath to 45 ℃, the discharge capacity of a circulating pump to 1.8L/min, and the stirring speed of a stirrer of a jacketed kettle to 150 rpm;

2) preparing a solution with pH =6.5 and 20% of acrylic acid by mass by using sodium hydroxide, acrylic acid and distilled water, adding sodium bisulfite into the solution, stirring until the sodium bisulfite is dissolved for later use, and adding the acrylic acid and the sodium bisulfite after the solution is cooled when preparing the solution, wherein the mass of the sodium bisulfite is 0.2% of that of the acrylic acid;

3) preparing a sodium persulfate solution for standby, wherein the mass of the sodium persulfate is 0.22 percent of that of the acrylic acid, and the volume of the distilled water is 5 percent of that of the acrylic acid solution;

4) starting a pump for circulation, pouring acrylic acid solution into the jacket kettle when the temperature of a water bath kettle of the thermostatic chamber rises to 45 ℃, opening a temperature record when the temperature of reaction liquid in the jacket kettle rises to 43 ℃, and pouring sodium persulfate solution;

5) and respectively testing the temperature change curves in the reaction kettle of the standard sample and the sample to be tested, and judging whether the sample is deteriorated or not through a comparison curve.

Technical Field

The invention relates to a detection method of ethylene monomers, in particular to a novel method for detecting whether ethylene monomers are deteriorated.

Background

Ethylene monomer is an important raw material for synthesizing polymers, and is widely applied to industries such as petroleum, chemical industry, medical treatment and the like, however, the monomer has certain activity, and can deteriorate under natural storage conditions, and if the monomer deteriorates, the monomer can directly affect the performance of the polymer synthesized by the monomer, and even cause unqualified products.

Disclosure of Invention

The invention aims to provide a novel method for detecting whether ethylene monomers are deteriorated or not, which is low in cost and high in detection precision aiming at the defects in the prior art.

The invention provides a new method for detecting whether ethylene monomers deteriorate, which adopts the technical scheme that: comprises the following steps of:

firstly, preparing a vinyl monomer into a solution with the concentration of 10-50%, then adding an initiator with the concentration of 0.1-1% to perform polymerization reaction, collecting the heating condition in the whole reaction process by using a detection device, and judging whether a sample is deteriorated or not by comparing the temperature change curves in a reaction kettle of a standard sample and the sample to be detected;

the detection device comprises a constant-temperature water bath kettle (1), a jacket kettle (2), a circulating pump (3), a flowmeter (4), a thermocouple (5), a stirrer (6) and a collection device (7), wherein the constant-temperature water bath kettle (1) is connected to the jacket kettle (2) through the circulating pump (3) and the flowmeter (4), the stirrer (6), the thermocouple (5) and the collection device (7) are arranged in the jacket kettle (2), constant-temperature hot water is prepared by using the constant-temperature water bath kettle (1), the circulating pump (3) is used for supplying the constant-temperature hot water for the jacket kettle (2), the thermocouple (5) is used for collecting the change of the temperature in the jacket kettle (2), and whether the monomer is deteriorated or not is judged by comparing a standard sample with a temperature change curve in the sample to be detected jacket kettle (2).

Preferably, the initiator is a redox system, the oxidizing agent is sodium persulfate, and the reducing agent is sodium bisulfite or polyethylene polyamine.

Preferably, the ambient temperature is set to 23 ℃, the thermostatic water bath temperature is set to 45 ℃ to 50 ℃, the discharge capacity of a circulating pump is set to 1.8L/min, and the stirring speed of a stirrer of the jacketed kettle (2) is set to 150 rpm.

The invention provides a novel method for detecting whether ethylene monomers deteriorate, which comprises the following specific steps:

1) setting the environmental temperature of a laboratory to 23 ℃, the temperature of a thermostatic water bath to 45 ℃, the discharge capacity of a circulating pump to 1.8L/min, and the stirring speed of a stirrer of a jacketed kettle to 150 rpm;

2) preparing a solution with pH =6.5 and 20% of acrylic acid by mass by using sodium hydroxide, acrylic acid and distilled water, adding sodium bisulfite into the solution, stirring until the sodium bisulfite is dissolved for later use, and adding the acrylic acid and the sodium bisulfite after the solution is cooled when preparing the solution, wherein the mass of the sodium bisulfite is 0.2% of that of the acrylic acid;

3) preparing a sodium persulfate solution for standby, wherein the mass of the sodium persulfate is 0.22 percent of that of the acrylic acid, and the volume of the distilled water is 5 percent of that of the acrylic acid solution;

4) starting a pump for circulation, pouring acrylic acid solution into the jacket kettle when the temperature of a water bath kettle of the thermostatic chamber rises to 45 ℃, opening a temperature record when the temperature of reaction liquid in the jacket kettle rises to 43 ℃, and pouring sodium persulfate solution;

5) and respectively testing the temperature change curves in the reaction kettle of the standard sample and the sample to be tested, and judging whether the sample is deteriorated or not through a comparison curve.

The invention has the beneficial effects that: the invention utilizes the characteristic that the ethylene monomer can release heat in the reaction process when undergoing polymerization deterioration, the exothermic heat of the polymerization reaction can be reduced, and whether the sample is deteriorated or not is detected by comparing the exothermic reaction conditions of the standard sample and the sample to be detected.

Drawings

FIG. 1 is a schematic structural view of a detecting unit according to the present invention;

FIG. 2 is a graph comparing reaction temperature change curves of the standard sample and the sample to be measured in example 1;

FIG. 3 is a graph comparing reaction temperature change curves of the standard sample and the sample to be measured in example 2;

FIG. 4 is a graph comparing reaction temperature change curves of the standard sample and the sample to be tested in example 3;

FIG. 5 is a monomer structure diagram of a mono-substituted ethylene;

FIG. 6 is a diagram of a monomer structure of an ethylene binary ipsilateral substituent;

in the upper diagram: a constant temperature water bath 1, a jacket kettle 2, a circulating pump 3, a flowmeter 4, a thermocouple 5, a stirrer 6 and a collecting device 7.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The invention is mainly directed to ethylene mono-substituents (as shown in figure 5) and ethylene bi-homonyms (as shown in figure 6), wherein R is₁And R₂Can be but is not limited to COOH, CH2COOH, CONH₂、CONHC(CH₃)₂CH₂SO₃H, and the like.