Chapter 296: System that is difficult to implement

In a chemical laboratory, time will pass very fast, because almost a moment can not be stopped, there is no time to consider the concept of "time", being busy is really like a "gyro".
Especially players like Xu Qiu who like to deal with multiple reactions at the same time, don’t have to worry about having nothing to do. During this reaction, you have to see if the other reaction is normal, return to continue processing, and then another reaction later I have to check it again, even if I have time occasionally, I have to deal with the experimental garbage and dirty glass equipment produced by the reaction.
Back to the A501 office, Xu Qiu carefully washed his hands in the sink. After all, potassium fluoride is used, so he should be a little more cautious. In case some dust gets on his hands, he will be slapped by licking it when he is idle. .
While washing his hands, Xu Qiu looked at himself in the mirror. As he wore a gas mask for a long time, the band formed a diamond-like mark on his face. He rubbed his face vigorously, and the mark gradually disappeared.
At this time, Xu Qiu heard the message prompt from the mobile phone. He shook his hand, wiped off the remaining water with toilet paper, turned on the mobile phone, and saw a lot of news from the school girl:
"Brother~"
"What about people?"
"[Suddenly appear.jpg]"
"So sleepy, I'll take a shower first."
"I'm back, brother still busy?"
"I can't support it, I have to go to sleep and mess with it."
"Send me a message after doing the experiment."
Xu Qiu smiled. While the experiment was busy, there was a person caring about himself, which was a good feeling.
He thought about it and replied:
"I just finished the experiment, everything is fine, school girl, go to bed first, good night."
"Then I'm going to sleep, good night, brother~"
"The other party is typing..."
After waiting for a long time, there was no news. Xu Qiu chuckled slightly, guessing that the school girl was planning to send a message, but she fell asleep.
After putting down the phone, Xu Qiu rinsed, locked the door, turned off the lights, and started to rest.
...
On Thursday morning, Chen Wanqing was still supplementing the experimental characterization data of her IDT-T(EH)-ICIN system, and there was no time to come over for synthesis.
Wu Shengnan and Han Jiaying took the school bus to Zhangjiang together.
Together with Xu Qiu, the three chatted for a while in room A501, prepared for the experiment and entered the laboratory.
The school girl is going to do the post-processing of H21 and H22 today. The experimental task is relatively easy. It only needs to be rotated to remove part of the chloroform solvent, and then the polymer product is precipitated with methanol anti-solvent, and finally dried.
However, Xu Qiu and Wu Shengnan’s experimental tasks are more arduous. They add up to a total of five reactions to deal with, and they are all relatively complex reactions. The synthesis of two D units requires the use of n-butyllithium low-temperature reactions. The synthesis of an A unit requires malononitrile to introduce cyano groups. In addition, the purification of small molecules will inevitably involve columns.
After yesterday’s investigation, Xu Qiu judged that Wu Shengnan’s experimental operation level was good, and both of her responses were relatively smooth. Therefore, Xu Qiu gave Wu Shengnan the reference directly today, and no longer taught her how to do experiments. Post post.
Start the experiment.
First, the third step of ICIN-2Cl/F overnight reaction has been completed, and post-reaction treatment is required, involving the use of ice-water mixture.
When Xu Qiu was doing "Organic Chemistry Experiment", the school’s aging building had a special ice-making room where ice buckets could be used directly to take ice cubes. Now Zhang Jiang’s laboratory does not have that condition and can only prepare ice by himself The water is ready, that is, buy the cheapest ice dew mineral water directly and freeze it in the refrigerator for later use.
Xu Qiu opened the freezer compartment of the double-door refrigerator in the laboratory. There were more than 20 bottles of frozen ice water stored in it, all of which were prepared a long time ago. Now they have become old ice. It feels cold to the touch...
Take out two bottles of frozen sturdy ice water, then cut them along the axis with scissors, put them in a plastic basin, and mash them with a metal chisel.
Although it sounds a bit wasteful, the price of a bottle of water is only one dollar. A gram of materials in the laboratory costs a few dollars, dozens of dollars, and some materials are even tens of thousands. The cost of mineral water is negligible. .
Xu Qiu prepared about 50 ml of ice-water mixture, then added 20 ml of concentrated hydrochloric acid, then slowly poured the reactant solution into it, and then raised the temperature to 70 degrees Celsius for one hour.
No money to read novels? Give you cash or points, and receive it within 1 day! Follow the public·public·number【Book Friends Base Camp】, get it for free!
Xu Qiu judged that the reaction was over. The ice water and concentrated hydrochloric acid were most likely to be used to treat acetic anhydride and triethylamine, respectively, and let the product precipitate out.
After filtering and drying, two solid products IN-2F and IN-2Cl were obtained, the yields were 69% and 74%, and the yield was about 6 grams.
Wu Shengnan also succeeded in synthesizing IN-DM, because she did not divide the reaction in half, so she got more products, reaching more than 10 grams.
During the process at 70 degrees Celsius, Xu Qiu and Wu Shengnan also processed the products of the first synthesis reaction of unit D at the same time.
The product was first extracted with dichloromethane, then washed with water, dried with anhydrous magnesium sulfate, and finally the solvent was removed by rotary evaporation to obtain the crude product, which stopped at the previous step of the column.
This synthesis reaction is a Stille reaction, which is not difficult in itself, but the post-treatment of the reaction requires a column, which is more troublesome.
Moreover, the TT unit substituted by monotrimethyltin was used in the reaction. The tin reagent is still relatively expensive. Although the structure of TT is relatively simple, it costs several hundred per gram. Therefore, Xu Qiu and their reaction do not have too much material. After throwing about 1 gram, the yield of crude product that has not passed the column is about 85%, which is not bad.
Generally, as long as you can get about 200 mg of product, it is enough to publish an article. If you save some, 100 mg is even enough.
This is mainly thanks to the "spraying method" developed by Xu Qiu. This method greatly reduces the amount of solution required for coating. 1 ml of solution consumes about 10 mg of material, and theoretically 50 tablets can be painted. Device.
The morning experiment ended smoothly without any accidents.
The three people put the processed products in a vacuum oven for drying, or put them in a special reagent tank, and store them in a nitrogen atmosphere, protected from light.
In the afternoon, Han Jiaying had successfully obtained H21 and H22 products, and Xu Qiu copied them to the simulation laboratory to arrange device performance exploration.
The school girl did not experiment, so she was arranged to run errands to beat liquid nitrogen.
It is worth mentioning that Chen Wanqing used to use liquid nitrogen frequently and found that the eight-pound bottle was inconvenient and unsafe, so she received a ten-liter liquid nitrogen container.
The liquid nitrogen container is like a small gas tank, hollow inside, with a thermal insulation layer, a lid on the top, and two spoon-like things to scoop out the liquid nitrogen in the container.
With a liquid nitrogen container, you can use a cart to pick up liquid nitrogen. Unless the vehicle is overturned, there is generally no risk of liquid nitrogen being poured out, and the internal liquid nitrogen can be stored for a longer period of time. It will definitely not be stored for a week or two. As for all missed.
Xu Qiu continued the final step of the synthesis reaction of ICIN-2Cl/F, that is, the reaction of IN-2Cl/F with malononitrile under the conditions of sodium acetate and ethanol.
The process of this reaction is not difficult, that is, malononitrile is more toxic.
Xu Qiu inquired that malononitrile is highly toxic and toxic like cyanide. The specific effect of cyanide is to inhibit cell respiration and cause tissue hypoxia. Rats were injected subcutaneously with a near-lethal dose of this product, causing dyspnea, cyanosis and convulsions, and increased urine excretion of thiocyanate.
"This is the key reaction to the introduction of cyano groups, and it cannot be bypassed. The elder sister has done similar reactions before, and she is still alive, so don't worry."
After some self-comfort, Xu Qiu arranged gas masks, polyethylene protective clothing, and three-layer gloves for herself and Wu Shengnan. He also put the cyanide acute detoxification spray next to the experimental bench for any eventuality, which was then locked. Take out the malononitrile reagent bottle from the reagent cabinet.
Theoretically, this high-risk experimental drug must be "double-locked", that is, two designated security officers should be arranged with two locks, and only two security officers can be used at the same time. However, the school's current investigation is lax. In other words, no one checks at all, so there is no such system in the laboratory...
Many rules and regulations have a good starting point, but they are very difficult to implement.
For example, Wu Feifei and Chen Wanqing are two security officers (Xu Qiu and Han Jiaying are undergraduates, strictly speaking, they cannot be regarded as teachers of Wei’s students, and cannot be security officers. Wu Shengnan has not come before, so they are not counted), every time Chen Wanqing does The dangerous experiment Wu Feifei must come here once, and the commute time on the road is more than two hours, and she tossing two or three times a week, Wu Feifei still does not do the experiment.
It is important to know that there is more than one high-risk drug for malononitrile. In theory, the fluoride and tin reagents in the laboratory are also highly toxic. One of these three is suffocating, one is painful, and the other can cause hair loss...
It is June. The temperature outside the magic city is not low, but the indoor temperature is maintained at about 20 degrees Celsius under the action of air conditioning. Therefore, malononitrile with a melting point of 32-34 degrees Celsius is still in the state of white crystals.
Xu Qiu carefully weighed 2 times the equivalent of malononitrile, dissolved it with IN-2Cl/F in absolute ethanol, and added anhydrous sodium acetate.
The expected reaction conditions are that the reaction is stirred at room temperature for 1 hour, and then reacted in an oil bath at 60 degrees Celsius for 3 hours.
Completing the experiment ~EbookFREE.me~ Xu Qiu felt the body functions, except for a rapid heartbeat, there was no other abnormalities, there should be no poisoning.
Fortunately, this kind of cyano experiment does not need to be done many times, and it can be used for a long time when it is synthesized once, otherwise it is really overwhelming.
PS: Starting from January, the monthly pass rules were revised. As long as the monthly pass is updated steadily, you can get more than 200 monthly passes, which is a lot more stressful... In addition, if the monthly pass reaches 1,000, the bonus can be shared in the following month. So set a small goal this month, 1,000 monthly tickets, I don’t know if it can be done, the probability is a little overhang...
PS2: It is now during the period of double monthly pass. One vote equals two votes. If you vote after the expiration date, it will only count as one vote. Ask for a guaranteed monthly pass.
PS3: During the New Year's Day, there is no way to make changes. After the holidays, the number of words owed will be paid off. At present, the number of words owed is about five or six thousand words.
PS4: Synthesizing the experimental plot may be boring, but it is not very good to take it in a single stroke. You can't "Xu Qiu waved the material and the material is synthesized", I try to write it as interesting as possible. In fact, I seldom mention repeated experiments. They have been taken in one stroke. Most of the experiments detailed now are new experiments.