Chapter 211: Brother, come quickly~

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In the process of product separation and purification, the rotary evaporation operation lags behind the column.
So when Xu Qiu and Han Jiaying exchanged the division of labor, Xu Qiu got some free time.
He went back to the office to drink saliva, and went to solve the physiological problem, just when Chen Wanqing was going to deal with the reaction, he followed.
On the way, the senior sister took the initiative to introduce: "My reaction is divided into two steps. The first step is to react with n-butyllithium to form a lithium metal reagent, and the second step is to react with an aldehyde group reagent such as DMF to add aldehyde groups."
"Yeah," Xu Qiu nodded, "The first step is to extract hydrogen from n-butyllithium to produce carbanion, and the second step is that carbanion attacks the aldehyde group of DMF, and the dimethylamino group leaves to form the target product." Rough reaction mechanism He can still infer, how can he say that he took two A rounds in the second semester of "Organic Chemistry".
"How do you know so clearly? It's not because you checked the information in advance." Chen Wanqing said in surprise.
"No, don't you know this after a little analysis." Xu Qiu replied casually while wearing the lab coat.
"Okay," Chen Wanqing smashed, "I have almost returned the knowledge I learned in college to the teacher. I prepared this reaction before, including checking the literature on the reaction mechanism, plus flipping on the little tree worm, and it was spent. I spent half a day in my youth."
Walking into the laboratory, Xu Qiu took a long look at the situation on the liquid chromatograph. The blank silica gel column was still white, and there was no product. The school girl should be able to handle it alone, so she followed her to the fume hood. .
The re-steaming device is still there, but the solvent inside is no longer the previous tetrahydrofuran, but replaced with N,N-dimethylformamide DMF.
Now that the re-steaming and cooling have been completed, a lot of solvents are stored in the solvent distillation head. When DMF is required to participate in the reaction, it also needs to be re-steamed in an anhydrous and oxygen-free environment.
Chen Wanqing used a syringe to the re-vaporized DMF, and then injected it into the reaction vessel, saying: "There is no need to add liquid nitrogen to keep the temperature low, just let it heat up naturally."
"Then how to deal with the remaining n-butyl lithium?" Xu Qiu asked.
"The information I checked, some said that it was quenched directly with water, some said that it was quenched with ethanol, and some said that saturated ammonium chloride and sodium chloride aqueous solutions were used. There are different opinions." Chen Wanqing smiled, "I plan to use saturated chlorine. For the aqueous solution of ammonium chloride, I only put 500 mg of material anyway. Although the n-butyllithium is added at 4.4 times the equivalent, there should not be much remaining."
Xu Qiu nodded. Although the whole low temperature reaction was performed by the senior sister, he was watching the whole process, and he had remembered the experimental process and various precautions.
If the senior sister is successful this time, if he wants to use it later, he can directly use this as a template instead of re-exploring it himself.
Next, after Chen Wanqing added DMF to the reaction flask, she collected some extra distilled DMF solvent into a small 10 ml reagent bottle, and then she began to prepare nitrogen balloons, new reaction flasks, etc., obviously intended Cast the second response.
It seems that there is nothing for him here. Xu Qiu was waiting to leave when he suddenly heard the call of the school girl: "Brother, come quickly~" He hurried over.
Han Jiaying said weakly: "Brother, I adjusted my polarity faster, and then the first point and the second point are not separated..."
Xu Qiu picked up the spot plate corresponding to the fifth test tube and took a look. There were two sample spots on it, one deep and one shallow, corresponding to the first product and raw material.
‘The two points are very close to each other. It is more difficult to separate the two products than the two products I dealt with before. No wonder the school girl will overturn. ’
‘If this sample is handed to me, it will be better. ’
‘But when assigning tasks, I didn’t think so much. I just followed the sample number. ’
‘This is the end of the matter, let’s find a remedy. ’
"Don't worry," Xu Qiu thought for a while: "Just keep the current polarity, wash down these two products together, then collect the pure second product, and finally re-process the first product and the raw material mixture. The pillars again."
"Oh, yes," Han Jiaying said in a low voice, "it can only be so."
"Don't take it too seriously, it's not a common occurrence for experiment failures." Seeing her look downcast, Xu Qiu reassured her: "Actually, I can't blame you. Today's products are close to each other, just use yesterday. Experience, this will happen."
"Yes," Han Jiaying nodded, "My polarity increased at the same speed as yesterday. At that time, when I saw two red groups coming down one after another, I felt it was wrong. I wanted to adjust my polarity, but it was too late."
"But we are lucky. The first product and raw materials are both relatively shallow."
"Yeah, it's a blessing in misfortune."
After that, Xu Qiu collected the second product and rotary steamed to obtain the product, and then personally performed the operation to separate the mixed sample of the first product and the raw material. It took less than an hour to obtain two pure products.
Chen Wanqing handled the first reaction and voted for the second reaction.
Time also came to six o'clock in the evening, dinner time.
Before Xu Qiu left the laboratory, he copied the six products obtained from the three reactions and the crude products obtained from the first reaction of the sister to the simulation laboratory and handed them over to the simulation experimenter for analysis.
At the same time, I also checked the results of the simulation experimenters today:
Now the efficiency based on simple PDI molecules has been optimized to 3.61%, which is very close to the internationally reported maximum value of 4.0%.
Xu Qiu's inner analysis:
In less than a day, hundreds of devices have been made, and the efficiency of simulation experimenters is quite high.
Of course, this is also related to the transformation of the simulation laboratory. Now the simulation laboratory has integrated more than a dozen evaporation machines, which can produce more than ten batches of devices at the same time.
Even the points are consumed quickly. The simulation laboratory II has been opened up to now, and it has almost spent 2000 points.
2400 points a day, 16800 points a week, my points are less than 50,000 points, if you keep on, it will be emptied in less than a month.
How can this work?
Hmm... The upper limit of the current simple PDI molecules is too low. You can stop exploring the performance of their devices and start with a better system in the future.
Thinking of this, Xu Qiu decisively changed the instructions of the simulation experimenter and removed the device optimization part.
Only basic characterization tests on the purity and composition of new materials are left, such as infrared spectroscopy, mass spectroscopy, elemental analysis, and nuclear magnetism.
These are the experiments he must do now, and they are related to his further experiments.
The raw material for the next reaction is the PDI molecule substituted by monobromo, but he still cannot judge the corresponding situation of the two products.
If you send samples to the school's public instrument platform for testing, and wait until you get the analysis results, and then proceed to the next step, it may take a week.
No way, it is so troublesome to do experiments related to the synthesis of organic small molecules.
A new material that can be used to post articles. If you can make a pure product in a month, the boss will have to praise you for your high efficiency.
...
After dinner, A501 office.
Han Jiaying stretched her waist and yawned, "I have been too tired these days."
Xu Qiu was also infected by her, she realized that she covered her mouth, and echoed: "Well, tomorrow we two will take a day off from the experiment. It happens that the senior sister can do liquid chromatography to separate and purify today's product. How about?" Look at Chen Wanqing.
"Of course I have no opinion." Chen Wanqing nodded and added, "But Xu Qiu, you have to come and help, and you can watch it next to you. I don't have much experience with pillars."
"Okay, no problem." Xu Qiu had no objection.
Han Jiaying lay on the sofa, changed her posture, and vomited: "I wrote a review in my free time for the experiment, but it has been almost a week since I came to Zhangjiang, and he didn't move a word."
"I haven't moved a word either," Xu Qiu sighed. "The intensity of the subsequent experiments can be appropriately reduced, otherwise the body will not be able to bear the long-term high-intensity experiments, that is, I have just returned from vacation.
By the way, how about your writing, senpai? "
"I..." Chen Wanqing looked hesitant.
"Senior Sister is not going to chase drama, right." Xu Qiu tentatively asked.
"Hey, after the experiment failed in the morning, I wanted to watch a half episode to adjust my mood, but when I didn't pay attention, I watched...three episodes."
"Okay." Zhang Jiang Lab, Tiangao boss far away ~EbookFREE.me~ is really easy to make people worry about watering.
The three of them rested in the office, chatted for a while, and continued on their new journey.
The school bus at nine o'clock now only has more than two hours left.
After entering the laboratory, Han Jiaying and Xu Qiu continued to use columns and rotary evaporation methods to separate and purify the products.
Chen Wanqing added DMF to the second reaction, using the DMF collected in the small bottle after the previous re-steaming, which saved the time for another re-steaming.
The subsequent experiments went smoothly without any accidents.
It was just a little bit late. After the three people closed the laboratory, carrying their schoolbags, they ran all the way to the school bus waiting point.
It turned out that it was 8:58 and the school bus hadn't arrived yet.
"Call ~ Call ~" Han Jiaying one hand propped waist, blushing gasped:. "As early ...... know, slowly, slowly I ran"
"School girl, you lack exercise," Xu Qiu suggested: "Would you like to get up tomorrow morning and work out together?"
"It's hard to take a day off tomorrow," Han Jiaying tilted her head and tentatively asked, "Why not next time?"
"It's up to you," Xu Qiu shrugged helplessly, turned his head and said, "Senior sister, how's your reaction? It's going well."
He actually got the results in the simulation laboratory ahead of time. The senior sister’s response was successful. The yield was about 50%-70%, and the separation was not difficult.
"Um... it's not clear yet," Chen Wanqing paused: "The result of tapping the board is one dark, one shallow, one very light, and the other light is the raw material. I hope the dark one is the product I want, not very light. The one."
"Don't think so, the darker one is your product." Xu Qiu said in a positive tone.
"I borrowed your good words." Chen Wanqing just responded with a smile as a comfort.