Chapter 295: It's exciting to think about it

After dinner, Wu Shengnan's experiment has been completed. She did not rush back to Handan, and stayed in Zhang Jiang to continue writing her two articles, an overview of planning to invest in AFM, and an experimental work planning to invest in ACSAMI.
Generally, the friends who come to Zhangjiang like to catch the last bus back at night. On the one hand, the earlier school bus will get stuck in the evening rush hour, which may take more than half an hour. On the other hand, it is also because in Zhangjiang. Jiang won’t be caught by Teacher Wei, and it’s OK to paddle occasionally.
Xu Qiu still has an experiment plan at night. Two synthesis reactions are required, ICIN-2F and ICIN-2Cl, the third step. He has no plans to return to Handan today. He plans to stay overnight in Zhangjiang again. He thought about it carefully. , Zhang Jiang’s bed seems to have slept with Xu Qiu himself and Chen Wanqing's senior sister. This can be regarded as "sharing the same bed" in the literal sense, but not at the same time.
Speaking of which, the entire building of Zhangjiang Micro-Analysis Building, except for Teacher Wei’s research group, that is, Wanyousheng's research group is more active. However, there is no bed in Wanyousheng’s laboratory, although some of their students have stayed on the Zhangjiang campus for a long time. , But they applied for a dormitory on the Zhangjiang campus and do not need to sleep in the laboratory building.
In other words, in most cases, there is only one living person in this building at night.
At night, in an unknown laboratory building, the corridor glowing with green light, the air was filled with an inexplicable smell, and there was only one living person around, and it was quite exciting to think about it.
While Xu Qiu was thinking about it, he suddenly received a WeChat voice call request from a school girl. Wu Shengnan heard the sound and looked in his direction.
Xu Qiu picked up the phone and pointed to the screen. Wu Shengnan nodded and said he didn't mind. He put on the headphones and answered the phone call of the school girl.
"Brother, is the experiment going well today?"
"Everything is normal at the moment. We have helped to deal with your two reactions H21 and H22. Now we are doing Soxhlet extraction of chloroform."
"Great~"
"By the way, didn't you want to try the PBDB-T system before, why didn't you do it later."
"When I was buying monomer raw materials, Shencheng said that it was temporarily out of stock, so I asked them to contact them later."
"Okay, then don't forget to follow up, the school girl is looking for me... is it the article?"
"Well, my review comments and reply files have been written, and Teacher Wei asked me to send it to you first."
"Send it over, no need to hang up, I will help you change it directly online."
"Okay~"
Xu Qiu’s computer was hung on the WeChat computer version, and soon received the file from the school girl. He downloaded the file, clicked to start viewing, and then modified one by one while explaining to her:
"First of all, the ways of thanking should be diversified, so that the reviewers can feel our sincerity..."
"Since we have answered the fourth question of the first reviewer in such detail, we can completely modify this reply and put it in the main text. After all, the reviewer’s opinion is the core function of perfection. In our article, the questions they raised, if they can be implemented in the article, try to reflect in the article..."
"The third question of the second reviewer is that their statement is wrong. You can argue with them. You don't need to follow the reviewer's meaning completely. Well, let's quote a document here. Let me find... …I found it, I marked the DOI number directly in the WORD file..."
Xu Qiu made several suggestions in a row, and Han Jiaying kept responding with "um" and "um".
In response to the review comments, Mr. Wei's requirements are usually strict and the urging is relatively tight, which he called "the last battle before dawn".
Xu Qiu estimated that Teacher Wei would want it tonight, so he didn't chat with Han Jiaying much, and after returning the revised WORD file to the school girl, he hung up the phone.
At around nine o'clock in the evening, Wu Shengnan carried his schoolbag on his back and boarded the school bus returning to Handan. Xu Qiu continued the experiment to deal with the second step reaction of ICIN-2F unit synthesis.
The post-treatment of this fluorination reaction is more complicated. The solvent needs to be distilled out, and the reaction product will be distilled out simultaneously with the solvent.
The reaction solvent is sulfolane, and the boiling point is as high as 285 degrees Celsius, so ordinary rotary steaming equipment cannot be used.
On the one hand, the temperature of the water bath of rotary steaming can only reach 100 degrees Celsius, and the temperature is too low, even under reduced pressure, it may not reach the boiling point of sulfolane; on the other hand, the water pump used in rotary steaming and decompression has a poor vacuum effect , Cannot provide high vacuum.
Therefore, it is necessary to manually set up a distillation device, use a mechanical pump to increase the high vacuum, and use an oil bath/electric heating mantle to provide a high temperature. At the same time, the temperature cannot be raised to a particularly high level. If it exceeds 220 degrees Celsius, sulfolane will quickly decompose. This produces black polymer and sulfur dioxide.
"The fluorination reaction is troublesome." Xu Qiu sighed and started to work.
The distillation device is not difficult. I learned the device for distilling water when I was in elementary and high school chemistry. Xu Qiu's current device is similar to that of the time, but with an additional decompression system.
Xu Qiu erected the installations in the order of "from bottom to top, from left to right".
At the bottom left is an oil bath, on which a distillation flask is fixed with an iron clamp;
The top of the distillation flask is connected with a glass tube with a branch nozzle, a thermometer is inserted in the middle of the glass tube, and it is inserted directly into the liquid surface of the distillation flask, but does not touch the wall of the flask;
The branch pipe mouth is connected to a condenser pipe to the right, and the condenser pipe is connected with the condensate in the way of "bottom in and top out" and at the same time is connected diagonally downward to a horn pipe with branch pipe mouth;
A small flask is connected to the bottom of the horn tube as a liquid contact bottle, and the branch port of the horn tube is connected to a mechanical pump to provide a vacuum atmosphere.
After setting up, start the vacuum distillation experiment.
Turn on the condensate, and the tap water flow slowly flows in the condensate pipeline.
Turn on the mechanical pump, the vacuum of the system will decrease, and the boiling point of sulfolane will decrease accordingly.
Set the temperature of the oil bath to the previous reaction temperature, which is 185 degrees Celsius. At this temperature, sulfolane will not decompose for a while.
The thermometer in the distillation flask detects the real-time temperature of the solution and is steadily rising.
After that, it is necessary to wait for the sulfolane vapor to entrain the reaction product to come out of the distillation flask, become liquid at the condenser tube, and then enter the wetted flask along the condenser tube and horn tube under the action of gravity.
Xu Qiu predicted that the entire distillation process would be slower.
On the one hand, the amount of reactants in this step is relatively large, involving nearly 10 grams of reaction, so a total of 50 ml of sulfolane solvent was added before, and the distillation process usually comes out drop by drop, and a drop of water is 0.04- With a volume of about 0.05 ml, for other types of liquids, the volume level of each drop is also near this value, and the second rate of distillation is about 1-2 drops per second;
On the other hand, the pre-heating process takes a lot of time. It is impossible to rise up at 185 degrees Celsius at once, and it takes time for the temperature to be transmitted to the inside of the entire distillation flask.
To convert it to the nearest whole number, it takes... a long time.
But Xu Qiu was not in a hurry. He had already planned to take advantage of this distillation gap to start another reaction, that is, the synthesis of ICIN-2Cl.
The first step of the previous ICIN-2F reaction is the reaction of reactant A and acetic anhydride to form reactant B; the second step is the reaction of reactant B and potassium fluoride to form reactant C; the third step is the reaction , Is the reaction of reactant B or reactant C under the conditions of acetic anhydride, triethylamine, and tert-butyl acetoacetate to generate IN-2Cl or IN-2F respectively; finally, the fourth step reaction, IN-2Cl or IN- 2F and malononitrile react under the conditions of ethanol and sodium acetate to produce ICIN-2Cl or ICIN-2F.
What is being distilled now is reactant C, and Xu Qiu’s reaction is to use the remaining half of reactant B for the third step to obtain IN-2Cl.
Xu Qiu feels that the synthesis reaction he is now exposed to is becoming more and more complicated, but he is not interested in the specific reaction mechanism for the time being. Since there are ready-made documents that report the synthesis of similar structures, there are wheels made by others, just use them directly, etc. When the literature is not working, then study it by yourself.
After all, in this era of information explosion, knowledge is vast. It is impossible to grasp all knowledge with the power of mortals. It is very rare to be able to achieve the ultimate in a small field.
Including the last fluorination reaction using potassium fluoride, Xu Qiu did not know what the added polyethylene glycol monomethyl ether (mPEG) was for, but this did not affect his use.
As for the triethylamine used in this reaction, he probably understands its function, which should provide an alkaline atmosphere.
After a little recollection of the experimental procedures, Xu Qiu started the experiment.
First, 30 ml of acetic anhydride and 15 ml of triethylamine are used to prepare a mixed solvent for the reaction, and a nitrogen ball is connected to provide a nitrogen atmosphere.
MSDS shows that triethylamine is a colorless oily liquid that is irritating and toxic. It will be poisonous if swallowed and will burn the skin. Its vapor will strongly irritate the eyelids and mucous membranes. It will cause fire and explosion hazards when exposed to open flames, high temperatures, and strong oxidants. Strong ammonia smell.
"It's sour and smelly, why did I think of snail powder..."
Xu Qiu spit out, and then decisively put on the gas mask. One acetic anhydride is already sour and cool, and now another one.
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He was not interested in personally experiencing what "strong ammonia smell" is. He still remembers that during the high school chemistry experiment, a classmate overturned the ammonia, and the smell filled the room, and the students were evacuated urgently...
In contrast, microwave oven-baked durian, pressure cooker stew, this level of biochemical weapons, is really too low.
Xu Qiu didn't know why ammonia and concentrated sulfuric acid were used in high school chemistry experiments. He felt that random color changes or reactions such as generating beautiful precipitates were not good for attracting students' interest. Well, why do you have to play with these dangerous things that are acidic and alkaline.
In addition, some chemistry teachers do experiments more vigorously, because in a special age, there is a gap in talents, and many old teachers in N-tier cities have rushed to work without good training.
He heard that a teacher conducted a teaching experiment in class, and then overturned the alcohol lamp. The eyebrows of the classmates at the front desk were all burned, but fortunately, there was no disfigurement.
In fact, the problems of chemistry teachers are generally not big, after all, there are still a few problems.
The more serious problem is English teachers. Many English teachers in elementary and junior high schools have substandard pronunciation. The students who are taught naturally have dialect accents, and some elementary schools do not even have English courses.
There is no way to get fast in subjects like language, and English is one of the subjects in the college entrance examination. Students from underdeveloped areas are born with shortcomings in this area.
After preparing the mixed solvent of acetic anhydride and triethylamine, Xu Qiu added the remaining few grams of reactant B, leaving only 100 mg for characterization.
Next, Xu Qiu kept the nitrogen atmosphere in the reaction flask ~EbookFREE.me~ and used a disposable syringe to inject tert-butyl acetoacetate into the two-neck flask reaction flask via a rubber stopper, and then stirred at room temperature overnight.
At this time, the vacuum distillation device on the other side was also doing almost the same, the distillation flask had bottomed out, and there was almost no distillate on the horn tube.
It took a bit shorter than imagined, it only took less than an hour.
Xu Qiu added a small amount of water to the flask, white crystals precipitated, and reactant C was obtained by filtration.
From the perspective of the product style, the fluorination reaction should be a success. After all, the previous reactant B was pale red, and now the reactant C has become a white crystal.
The yield of this step is about 60%, which is still acceptable, because he knows that many reactants must be left in the sulfolane solvent.
Xu Qiu quickly dried reactant C in a vacuum oven, and then put reactant C into the third step of the reaction in the same way as reactant B.
After some toss, it was already 12 o'clock in the morning when Xu Qiu cleared up the mess in the laboratory, shut down the laboratory and returned to the A501 office.