Chapter 85: Repeated practice

　　 Xu Qiu summarized his experience gained from high-level deductions in the experimental logbook:
　　 First, the monomers stored for a long time can be recrystallized or dried in a vacuum oven to remove the adsorbed water molecules and improve the purity of the monomers.
"Secondly, under the condition that the monomer can be dissolved, reducing the amount of toluene solvent in the reaction can increase the concentration of the monomer and shorten the reaction time.
　　Third, when using a vacuum pump to pump air, use a hot blower to blow the outer wall of the glass instrument to heat up and improve the effect of oxygen removal.
　　 Fourth, apply vacuum silicone grease to the mouth of the glass instrument to improve its air-tightness, but be careful not to apply too much to prevent silicone grease from entering the reaction vessel and contaminating the reaction raw materials.
　　 Fifth, the monomer raw materials are best stored in a nitrogen glove box, but if there is no glove box, they can also be stored in a sealed jar with a desiccant and protected from light.
　　 Sixth, the entire reaction process should be completed as soon as possible without operating errors.
　　……
　　 Xu Qiu invested in the synthesis of PBT4T polymer in Zhang Jiang's laboratory. He decided to use this system to practice his hands in the simulation laboratory.
　　 Although there is no need to worry about personal safety in the simulation laboratory, he still wears his lab coat, gloves, and mask.
　　 This is mainly for cultivating experimental habits. If you get used to not doing protection, one day you forget to wear protective equipment in reality, it may be dangerous.
　　 Xu Qiu first set up the device for re-vaporizing toluene, let the toluene begin to heat to reflux, and turn it on for 2 times acceleration.
　　 During this period, he cleaned the required glass instruments with absolute ethanol, put them in the oven, and turned them on for 2 times acceleration.
　　 Then, make a nitrogen ball.
　　 Next, the monomer is weighed.
　　 The two monomers add up to a total of about 160 mg, and Xu Qiu poured them into a two-necked flask.
　　 As for recrystallizing the monomer, he has not considered it for the time being.
　　 The monomer state obtained is white or yellow crystal, which is a relatively normal monomer state.
　　Moreover, the merchant also issued NMR spectroscopy, infrared spectroscopy and other characterization results, which proved that the purity of the monomer was greater than 99%, and the quality of the merchant's monomer can be trusted for the time being.
　　……
　　 After the toluene indicator changed color, Xu Qiu collected about 50ml of toluene in the solvent distillation head.
　　 After the toluene in the distillation head has cooled, pour the toluene into a disposable PE cup.
　　Considering that using less toluene solvent helps to increase the reaction speed, he slowly added toluene to the two-necked flask containing the monomer with a disposable dropper, while turning on the stirring.
　　 After adding less than 3 ml of toluene, the monomer has completely dissolved.
　　 It seems that the solubility of the monomer in toluene is still relatively high, and it must be greater than 50 mg/ml.
　　 However, the amount of solvent in 3 ml is still a bit low. It is estimated that when the toluene is heated to 120 degrees Celsius, the following solvent will be evaporated to dryness.
　　 Xu Qiu thought for a moment, and increased the amount of toluene solvent in the bottle to 8 ml, which is about half of the reaction in Zhang Jiang's laboratory during the day.
After 　　, he followed the third and fourth points in the logbook.
　　 First apply vacuum silicone grease to approximately one-third of the mouth of the glass instrument, and then rotate the joint to make the silicone grease evenly coated.
　　 Then perform vacuuming and deoxygenation operation, first blow the outer wall of the glass instrument with a hot blower, and then control the three-way valve to complete the pumping operation, repeat three times.
　　 Then quickly weigh the catalyst, add it to the bottle, and vacuum again to remove oxygen.
　　 Finally, the temperature is raised rapidly, and the outside of the reaction vessel is covered with aluminum foil.
　　……
　　 Next, Xu Qiu repeated the same reaction three times, constantly getting familiar with the experimental operation and strengthening his muscle memory.
　　 Now he no longer cares about the proficiency data on the system panel like when he first got the system, he cares more about his actual operating experience.
　　 After all, using only one parameter of proficiency to judge the entire complex experimental operation can only make a general judgment.
　　 Relatively speaking, the feedback from the body may be more accurate.
　　 It was another two-hour experiment, and Xu Qiu felt a little tired.
　　 He sat on the round stool in the laboratory to rest, and at the same time began to think:
　　 This reaction takes too long. It is estimated that it will take at least 12 hours.
　　 If the simulation laboratory is always open, the waste of points is second, and it is mainly a waste of time. Now the acceleration rate is still low.
　　Perhaps after completing advanced tasks, the effect of the simulation laboratory will be further enhanced.
　　 For the time being, I will still be familiar with the experimental operation.
　　 Only, there are only four magnetic constant temperature heating stirrers in the laboratory, or oil baths.
　　 Therefore, only four reactions can be cast at the same time, and the number of glass instruments is not enough.
　　 Is there any way to solve this problem?
　　 Xu Qiu was clever and asked the system:
　　 "The system, can you copy the same thing, are there any restrictions?"
　　【You can copy the same thing, the cooling time is 24 hours. 】
　　 can be like this.
　　 Xu Qiu discovered that he had done a lot of waste operations before, such as washing a pile of substrates for use.
　　 In fact, it only needs to copy a clean substrate once in a while.
　　 However, UU reading www.uukanshu.com now knows that this feature is not too late.
　　 After that, you can copy more instruments, equipment, and medicines, so you don’t have to worry about not having enough.
　　 Xu Qiu glanced at the time, but it was already past 11 o'clock in the evening.
　　 He quit the simulation laboratory and returned to reality.
　　……
　　 There was a message on the phone, and Xu Qiu clicked on it. It was a message sent by the counselor Yu Qiang in the WeChat group:
　　"@All
　　 The class meeting will be held at 7 o'clock tomorrow evening in the conference room on the second floor of the Advanced Materials Building. "
　　 Xu Qiu thought of going to Zhangjiang tomorrow to do the post-processing of the reaction, and did not know how long it would take, so he found Chen Wanqing’s WeChat and edited a message:
　　 "Senior sister, I have a class meeting at 7 o'clock tomorrow evening, can I come back in time?"
　　 waited for a minute but did not receive a reply.
　　 Xu Qiu thought she was probably asleep, so he got up and got out of bed to take a shower.
　　 Ren Bin is sitting next to the computer, playing games with headphones on, while Tao Yan is missing.
　　 Hearing Xu Qiu's movement, Ren Bin took off his headphones and said:
　　 "Wake up from sleep."
"Oh, yes."
　　 "You have to pay attention to your body."
　　 Facing the concern from his roommate, Xu Qiu nodded in embarrassment.
　　 It seems that after entering the simulation laboratory, I still need to find a good place.
　　 However, what Ren Bin said is indeed reasonable. It is necessary to combine work and rest without long-term high-intensity experiments.
　　Before doing photovoltaic devices in Handan campus, operating in the glove box, spin coating, evaporation and other experiments, it is not very tired, and there is also free time between experiments.
　　 It is like a synthesis experiment. Once it starts, it is a continuous experiment for several hours. There is no way to stop it in the middle, and it consumes a lot of energy and energy.