阅读说明：本技术 一种嘧啶咪唑啉缓蚀剂及其制备方法 (Pyrimidine imidazoline corrosion inhibitor and preparation method thereof ) 是由 李艳艳 于 2021-01-18 设计创作，主要内容包括：本发明公开了一种嘧啶咪唑啉缓蚀剂及其制备方法,包括：1)对苯二甲酸与N1-(嘧啶-2-基)乙二胺进行酰化、环化反应,得到1,4-二((1-嘧啶-2-基)咪唑-2-基)苯；2)1,4-二((1-嘧啶-2-基)咪唑-2-基)苯经季铵化反应制备嘧啶咪唑啉缓蚀剂；该缓蚀剂有丰富的N原子以及季铵阳离子使得在金属表面附着力强,疏水端会定向进入腐蚀性介质中,从而形成疏水层,排斥腐蚀介质,可作为碳钢、铜的缓蚀剂。(The invention discloses a pyrimidine imidazoline corrosion inhibitor and a preparation method thereof, wherein the preparation method comprises the following steps: 1) carrying out acylation and cyclization reaction on terephthalic acid and N1- (pyrimidine-2-yl) ethylenediamine to obtain 1, 4-bis ((1-pyrimidine-2-yl) imidazole-2-yl) benzene; 2) preparing a pyrimidine imidazoline corrosion inhibitor from 1, 4-di ((1-pyrimidine-2-yl) imidazole-2-yl) benzene through quaternization; the corrosion inhibitor has abundant N atoms and quaternary ammonium cations, so that the corrosion inhibitor has strong adhesion on the metal surface, and the hydrophobic end can directionally enter into a corrosive medium, thereby forming a hydrophobic layer and repelling the corrosive medium, and can be used as a corrosion inhibitor for carbon steel and copper.)

1. A pyrimidine imidazoline corrosion inhibitor is characterized in that the pyrimidine imidazoline corrosion inhibitor has a molecular structure shown in a formula (I):

in the formula, R is a C1-C12 alkyl straight chain, and X is Br or I or OH.

2. The preparation method of the pyrimidine imidazoline corrosion inhibitor is characterized by comprising the following steps:

(1) carrying out acylation and cyclization reaction on terephthalic acid and N1- (pyrimidine-2-yl) ethylenediamine to prepare 1, 4-bis ((1-pyrimidine-2-yl) imidazole-2-yl) benzene (Md-IMZ-B);

(2) carrying out quaternization reaction on Md-IMZ-B.

3. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 2, wherein the reaction in step (1) is carried out in a solvent, and the solvent is xylene or a mixed solvent of xylene and N-methylpyrrolidone.

4. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 2, wherein the molar ratio of the terephthalic acid and the N1- (pyrimidin-2-yl) ethylenediamine fed in the step (1) is 1: 2-2.5.

5. The method for preparing the pyrimidine imidazoline corrosion inhibitor of claim 2, wherein the Md-IMZ-B in the step (2) is quaternized with a halogenated hydrocarbon.

6. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 5, wherein the halogenated hydrocarbon is alkyl iodide or alkyl bromide.

7. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 5, wherein the halogenated hydrocarbon is an alkyl straight chain with 1-12 carbon atoms.

8. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 5 or 7, wherein the halogenated hydrocarbon is alkyl bromide with 4-6 carbon atoms.

9. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 2, wherein the reaction in step (2) is carried out in a solvent, and the solvent is water or alcohol or a mixture of the two.

10. The preparation method of the pyrimidine imidazoline corrosion inhibitor as claimed in claim 2, wherein the reaction in step (2) is performed in a solvent, and the solvent is acetonitrile or toluene.

Technical Field

The invention relates to an organic corrosion inhibitor, in particular to a pyrimidine imidazoline corrosion inhibitor and a preparation method thereof.

Background

Imidazoline derivatives can form a compact adsorption layer on the surface of metal, and can be used as corrosion inhibitors for corrosion of hydrochloric acid, sulfuric acid, carbon dioxide and hydrogen sulfide, so that the imidazoline derivatives are widely applied to the production and chemical production processes of oil and gas fields. In recent years, imidazoline derivatives and natural plant green corrosion inhibitors with low toxicity, high efficiency and small dosage become research and development hotspots, and the synthesis of the imidazoline derivatives and the natural plant green corrosion inhibitors is also concerned.

Gemini imidazoline and its derivative are a new type of antirust agent which has been developed rapidly in recent years, and it has two (or more) hydrophilic groups, two (or more) hydrophobic groups and a spacer group, and this kind of special molecular structure makes it possible to adsorb on metal surface better. Meanwhile, the gemini imidazoline type antirust agent can inhibit corrosion more durably and more effectively at a lower concentration. Research shows that under the same concentration, the corrosion inhibition efficiency of the gemini imidazoline is more than 2 times of that of the conventional imidazoline, so that the gemini imidazoline has high application value in the fields of petrochemical industry, metal corrosion inhibition and the like. Therefore, the imidazoline corrosion inhibitor with better performance can be obtained by improving the unit cation density of the corrosion inhibitor.

Disclosure of Invention

The invention designs and synthesizes a pyrimidine imidazoline corrosion inhibitor, the molecule of the corrosion inhibitor is provided with pyrimidine base and imidazole, abundant N atoms and quaternary ammonium cations, so that the adhesion force on the metal surface is strong, a hydrophobic end can directionally enter into a corrosive medium, a hydrophobic layer is formed, the corrosive medium is repelled, and the pyrimidine imidazoline corrosion inhibitor can be used as a corrosion inhibitor for carbon steel and copper.

The pyrimidine imidazoline corrosion inhibitor has the following molecular formula:

in the formula, R is a C1-C12 alkyl straight chain, and X is Br or I or OH.

The preparation method of the pyrimidine imidazoline corrosion inhibitor comprises the following steps:

firstly, terephthalic acid and N1- (pyrimidine-2-yl) ethylenediamine are subjected to acylation and cyclization reactions to prepare 1, 4-bis ((1-pyrimidine-2-yl) imidazole-2-yl) benzene (Md-IMZ-B), and then the imidazole N2 is converted into quaternary ammonium through quaternization.

The specific reaction flow is as follows:

in the first step, in a solvent, acylation is carried out on terephthalic acid and N1- (pyrimidine-2-yl) ethylenediamine under the environment of heated nitrogen, the temperature is further raised to carry out dehydration cyclization, and the obtained reaction solution is recrystallized after concentration to obtain Md-IMZ-B.

And secondly, in a solvent, dropping halohydrocarbon into the Md-IMZ-B reaction liquid system, heating and refluxing to bond alkyl to the position of imidazole N2, extracting or dialyzing and purifying the obtained reaction liquid, and volatilizing the solvent to obtain the pyrimidine imidazoline corrosion inhibitor.

The solvent in the first step is xylene or a mixed solvent of xylene and N-methylpyrrolidone.

The feeding molar ratio of the terephthalic acid to the N1- (pyrimidine-2-yl) ethylenediamine in the first step is 1: 2-2.5.

In the second step, the halogenated hydrocarbon is alkyl iodide or alkyl bromide.

In the second step, the halogenated hydrocarbon is an alkyl straight chain with 1-12 carbon atoms.

Preferably, the halogenated hydrocarbon in the second step is alkyl bromide having 4 to 6 carbon atoms.

And in the second step, when the carbon number of the halogenated hydrocarbon is 1-4, the solvent is water or alcohol or a mixture of the water and the alcohol.

When the carbon number of the halogenated hydrocarbon in the second step is more than 4, the solvent is a mixture of water and alcohol or acetonitrile or toluene.

The invention has the following advantages and beneficial effects:

(1) the pyrimidine imidazoline corrosion inhibitor provided by the invention has the characteristics of low toxicity, no pungent smell and strong corrosion inhibition capability, and can be applied to carbon steel and copper corrosion inhibitors.

(2) The pyrimidine imidazoline corrosion inhibitor has abundant N atoms and quaternary ammonium cations, so that the adhesion force on the metal surface is strong, and the hydrophobic end can enter into a corrosive medium in an oriented manner, thereby forming a hydrophobic layer and repelling the corrosive medium.

(3) The preparation method of the pyrimidine imidazoline corrosion inhibitor has the advantages of cheap and easily-obtained raw materials, simple preparation process and easy industrialization.

Drawings

FIG. 1 is a representation of the pyrimidine imidazoline corrosion inhibitor Q1 prepared in example 1¹²C-NMR chart.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are not intended to limit the present invention in any manner. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

The test of the invention comprises the following steps:

elemental analysis: the content of each element in the dried 1, 4-bis ((1-pyrimidin-2-yl) imidazol-2-yl) benzene samples was analyzed by a Vario EL type III element analyzer (Elemeraor, Germany).

And (3) corrosion inhibition rate: a sample of 0.1 wt% was added to 1000mL of a 5% HCl aqueous solution, a Q235 steel sheet and a copper sheet were suspended in the solution, and the solution was left in a constant temperature bath at 60. + -. 2 ℃ for 6 hours with a magnetic stirring device at a stirring speed of 2000rpm at the bottom, and the change in mass of the steel sheet or copper sheet after immersion was measured.

The corrosion inhibition rate is calculated according to the following formula:

in the formula, W₀Is the weight loss of the substrate in the blank solution, W₁Is the weight loss of the substrate added to the corrosion inhibitor solution.

Nuclear magnetic carbon spectrum: measured by a Bruker AV-400 nuclear magnetic resonance spectrometer, and the solvent is CDCl₃(TMS internal standard).

Example 1

Adding terephthalic acid (5.06g, 0.03mol), N1- (pyrimidine-2-yl) ethylenediamine (9.26g, 0.07mmol) and 100mL dimethylbenzene into a three-neck flask provided with a water separator and a condenser, introducing nitrogen, carrying out reflux acylation reaction for 4h at 140 ℃, and continuously separating water from the water separator; and (3) continuously heating to 200 ℃ for cyclization reaction, ending the reaction after 12h, evaporating the volatile solvent to obtain a crude product, recrystallizing the crude product by using ethanol, and drying to obtain 1, 4-bis ((1-pyrimidin-2-yl) imidazol-2-yl) benzene (Md-IMZ-B) which is recorded as Z1, wherein the yield is 71.54%.

Elemental analysis results:

element(s)	N	H	C	O
					The actual value of the value is,％	29.76	4.95	63.74	1.37
theoretical value%	30.24	4.86	64.79	0

Weighing Z1(5.14g, 13.88mmol) and iodomethane (4.73g, 33.3mmol) and placing the materials into a flask provided with a condenser tube, adding 100mL of deionized water, heating to 120 ℃, carrying out thermal insulation reflux for 12h, carrying out rotary evaporation on reaction liquid to volatilize a solvent to obtain a crude product, recrystallizing the crude product with ethanol, and drying to obtain the pyrimidine imidazoline corrosion inhibitor, wherein the mark is Q1, and the yield is 86.42%.

Example 2

Weighing Z1(3.43g, 9.26mmol) and bromohexane (3.67g, 22.22mmol) and placing the materials into a flask provided with a condensing tube, adding 100mL of ethanol, heating to 80 ℃, carrying out heat preservation and reflux for 12h, standing and cooling for 24h, separating out white solid, filtering, washing filter residue with acetone for 5 times, drying to constant weight to obtain the pyrimidine imidazoline corrosion inhibitor, marked as Q2, with the yield of 88.47%.

Example 3

Adding terephthalic acid (7.26g, 0.04mol), N1- (pyrimidine-2-yl) ethylenediamine (15.10g, 0.11mmol), 100mL of dimethylbenzene and 50mL of methyl pyrrolidone into a three-neck flask provided with a water separator and a condenser, introducing nitrogen, carrying out reflux acylation reaction at 160 ℃ for 7 hours, and continuously separating water from the water separator; heating to 220 deg.C for cyclization reaction, ending reaction after 12 hr, rotary evaporating to volatilize solvent to obtain crude product, recrystallizing with ethanol, and drying to obtain 1, 4-bis ((1-pyrimidin-2-yl) imidazol-2-yl) benzene (Md-IMZ-B), recorded as Z2, with yield of 78.33%

Elemental analysis results:

element(s)	N	H	C	O
					Actual value%	30.01	4.9	64.41	0.57
Theoretical value%	30.24	4.86	64.79	0.00

Weighing Z2(4.12g, 11.12mmol) and bromobutane (3.35g, 24.47mmol) into a flask provided with a condenser tube, adding 60mL of ethanol and 40mL of deionized water, heating to 100 ℃, keeping the temperature and refluxing for 12h, evaporating to volatilize the solvent by rotation to obtain a crude product, recrystallizing by ethanol, and drying to obtain 1, 4-di ((1-pyrimidin-2-yl) imidazol-2-yl) benzene (Md-IMZ-B) which is recorded as Q3, wherein the yield is 76.37%.

Example 4

Weighing Z2(3.84g, 10.37mmol) and bromododecane (7.75g, 31.10mmol) into a flask provided with a condensing tube, adding 100mL of toluene, heating to 120 ℃, keeping the temperature and refluxing for 12h, cooling the reaction liquid to room temperature, adding deionized water for extraction, repeating for 3 times, collecting the water phase, and carrying out rotary evaporation to obtain 1, 4-bis ((1-pyrimidin-2-yl) imidazol-2-yl) benzene (Md-IMZ-B) which is recorded as Q4, wherein the yield is 63.54%.

Example 5

The corrosion inhibition (%) of the samples Q1-Q4 was tested:

the above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.