▎ 摘　　要

NOVELTY - Covalent modification of graphene oxide by a six-membered heterocyclic ring comprises adding graphite, sodium nitrate and concentrated sulfuric acid to a three-necked flask, reacting, adding potassium permanganate, reacting, adding distilled water, adding distilled water and hydrogen peroxide solution, ultrasonicating, washing, adding cerium chloride solution, drying, grinding, sieving to obtain graphene oxide, dissolving lithium aluminum hydride in tetrahydrofuran to obtain solution of lithium aluminum hydride in tetrahydrofuran, adding graphene oxide to tetrahydrofuran solution, ultrasonically stirring, magnetically stirring, adding hydrochloric acid, vacuum drying to obtain hydroxylated graphene oxide, adding hydroxylated graphene oxide to tetrahydrofuran, adding cyanuric chloride and triethylamine, stirring, vacuum drying to obtain cyanuric chloride modified graphene oxide, adding acetonitrile, adding trishydroxyaminomethane and triethylamine, stirring, and vacuum drying. USE - The method is useful in modifying graphene oxide by a six-membered heterocyclic ring. ADVANTAGE - The six-membered heterocyclic ring: has better mechanical property; has more than 38% tensile strength; and more than 46% bending strength. DETAILED DESCRIPTION - Covalent modification of graphene oxide by a six-membered heterocyclic ring comprises (1) (a) adding graphite, sodium nitrate and 96-98% concentrated sulfuric acid to a three-necked flask, placing the three-necked flask in an ice water bath at 0-5 degrees C, reacting for 30-40 minutes at 300-400 revolutions/minute to obtain reaction liquid (I), where the ratio of the graphite to concentrated sulfuric acid is 6-8 g:360-500 ml, the ratio of sodium nitrate to concentrated sulfuric acid is 2-4g:360-500 ml, (b) adding potassium permanganate to reaction liquid (I), placing the three-necked flask in an ice water bath at 0-5 degrees C, reacting at 300-400 revolutions/minute for 2-3 hours to obtain reaction liquid (II), where the ratio of potassium permanganate described in the step (b) to graphite described in the step (a) is 20-25:6-8, (c) heating the reaction liquid (II) to 35-40 degrees C, reacting at 35-40 degrees C for 17-19 hours, adding distilled water to obtain a reaction liquid (III), where the ratio of distilled water in the step (c) to the ratio of graphite in step (a) is 400-600 ml:6-8 g, (d) stirring the reaction solution (III) at 300-400 revolutions/minutes for 1-2 hours, adding distilled water and 30% hydrogen peroxide solution to obtain reaction liquid (IV), where the ratio of distilled water to graphite in the step (a) is 600-800 ml:6-8 g, the ratio of hydrogen peroxide in step (d) to graphite in step (a) is 40-60 ml:6-8 g, (e) stirring the reaction solution (IV) at 300-400 revolutions/minute for 20-40 minutes, ultrasonically processing for 30-50 minutes at 350-360 W, allowing to stand for 6-8 hours to obtain mixture I, (f) washing mixture I at a centrifugal speed of 6000-8000 revolutions/minute with 14-16% hydrochloric acid as a cleaning agent, adding 0.1-0.15 mol/l cerium chloride solution until there are precipitates, (g) washing with deionized water, adjusting the pH to 7 with hydrogen chloride solution, (h) drying in a freeze dryer to obtain a solid I, grinding, sieving through a 300 mesh to obtain graphene oxide, (2) (i) dissolving lithium aluminum hydride in tetrahydrofuran to obtain a solution of lithium aluminum hydride in tetrahydrofuran, where the ratio of lithium aluminum hydride to tetrahydrofuran is 4-5 g:100-120 ml, (j) adding graphene oxide to tetrahydrofuran solution of lithium aluminum hydride, ultrasonically stirring for 0.5-1 hour at 350-360 W, magnetically stirred at 300-400 revolutions/minutes for 2-3 hours to obtain mixture II, where the ratio of graphene oxide to tetrahydrofuran is 2-3 g:100-120 ml, (k) adding 37% hydrochloric acid to the mixture II until the supernatant of the mixture becomes clear, neutralizing with deionized water, vacuum drying in an oven at 80-90 degrees C for 6-12 hours to obtain hydroxylated graphene oxide, (3) (l) adding hydroxylated graphene oxide to tetrahydrofuran, ultrasonicating for 1-2 hours at 350-360W, adding cyanuric chloride and triethylamine, heating at 70-80 degrees C, stirring at 300-400 revolutions/minute for 24-36 hours to obtain reaction product I, where the ratio of hydroxylated graphene oxide to tetrahydrofuran described is 1-2 g: 100 ml, the ratio of cyanuric chloride to tetrahydrofuran is 3-4 g:100 ml, the ratio of triethylamine to tetrahydrofuran is 4-6 g: 100 ml, (m) washing the reaction product (I) 3-5 times with tetrahydrofuran and washing 3-8 times with absolute ethanol, drying in vacuum drying oven at 80-90 degrees C for 4-6 hours to obtain cyanuric chloride modified graphene oxide, (4) (n) adding cyanuric chloride modified graphene oxide to acetonitrile, ultrasonically dispersing for 1-2 hours at 350-360 W, adding trishydroxyaminomethane and triethylamine, heating and stirring at 70-80 under reflux for 12-18 hours to obtain the reaction product (II), the ratio of cyanuric chloride-modified graphene oxide to acetonitrile is 0.2-0.4 g:30-60 ml, the ratio of trishydroxyaminomethane to acetonitrile is 0.4-0.6g:30-60 ml, the ratio of triethylamine to acetonitrile is 4-6g:30-60 ml, (o) washing the reaction product (II) 3-8 times with anhydrous ethanol, drying in a vacuum oven at 80-90 degrees C for 4-6 hours to obtain a graphene oxide which is covalently modified by a six-membered heterocyclic ring.