I Have a Research Support System

Sister, how was the experiment? On the way to the cafeteria at noon, Xu Qiu timely mentioned the matter of reaction.

It failed. Chen Wanqing sighed.

Then is there any stock for the last reaction? Although Xu Qiu had already guessed the result, he still asked.

No... Chen Wanqing said in a low tone, The reactions in the first few steps were too smooth, so I just used up all the products from the previous step.

Then what should we do, make another batch? Han Jiaying interrupted.

I haven't figured it out yet, Chen Wanqing shook her head, But after some analysis, I probably know the reason for the failure of the reaction. It should be that I didn't remove several by-products in the previous reaction.

Then, she paused and said: The two reactions in the previous step only had two and three sample points respectively. I originally thought that this reaction would be purified after the end of this reaction, but now the results of this point board must be Inseparable, she sighed again, I still have too little experience in compositing.

Xu Qiu was silent. The senior sister failed to respond. On the one hand, she was a little impatient and used up all the products directly. On the other hand, it was also related to him and the junior sister occupying the liquid chromatography equipment. The reaction has passed through the column once, and it is best to obtain a pure product, which can avoid the by-products of the previous step to produce by-products again.

‘This is a bit embarrassing. After the bromine substitution reaction is over, they will have to occupy the liquid chromatography again for a while. '

'Furthermore, further PDI dimerization, or the synthesis of 3D-PDI molecules, will also frequently use liquid chromatography. '

'How can we do the peak shift experiment? '

‘Sister’s experimental idea of ​​synthesizing A-D-A small molecules is divided into three steps, first synthesizing A and D units separately, and then connecting A and D units together. '

'Currently she is doing the synthesis of unit A. If she switches to the synthesis of unit D, the number of reaction steps is less and the by-products are less. Even if liquid chromatography is used, it will not be so frequent. '

Xu Qiu had an idea, and suggested: How about, sister, try another route and synthesize unit D first?

I have also considered it, but this route is more dangerous. It needs to introduce aldehyde groups on the central D unit, which involves liquid nitrogen and butyllithium reagents. Chen Wanqing said.

This is indeed a problem, but if we are all in the laboratory, even if it is a dangerous reagent, there is a way to use it. Xu Qiu said that liquid nitrogen and butyllithium are two reagents that he is not unfamiliar with. Both are dangerous reagents. It was more troublesome than the liquid bromine he used today.

Liquid nitrogen can provide a low-temperature reaction environment of minus 78 degrees Celsius, and there is a risk of frostbite; butyllithium will undergo an exothermic reaction when it meets water and oxygen, and a high-concentration butyllithium solution will burn rapidly when it meets humid air, and there is a risk of spontaneous combustion or even explosion.

The senior sister seemed to have guessed Xu Qiu's thoughts, and gave him a blank look, Even if I vote for the synthesis reaction of Unit A, I can proceed until the reaction stopped at yesterday's step, and then wait for your liquid chromatograph to be idle, and then proceed to the synthesis reaction. It’s not too late to purify.”

Xu Qiu smiled awkwardly and said nothing.

After a while, Chen Wanqing spoke suddenly and made a decision: Listen to you, let's synthesize unit D first today.

Okay, Xu Qiu nodded, and then asked curiously: The synthesis of unit D will use liquid nitrogen. Is there a place to pump liquid nitrogen here in Zhang Jiang?

He had only used liquid nitrogen in the electron microscope experiments before, and had not personally conducted low-temperature experiments. Of course, he had come into contact with it in the simulation laboratory, but it was not reality after all.

There are some at the School of Pharmacy. I have already done my homework in advance. Chen Wanqing replied.

I have a question, Han Jiaying interjected, There seems to be no container for liquid nitrogen in Zhang Jiang's laboratory, but I have seen one in Handan.

You can use a thermos instead. When you go to the drug warehouse, you can get two 8-pound thermos bottles. Chen Wanqing added, I also need a pot-shaped Dewar to keep warm.

Pot-shaped Dewar? What does it look like? Han Jiaying asked, tilting her head.

Probably the kind of food bowl that puts cat food? It's like this... Chen Wanqing tried to gesture with his hands, but failed, Anyway, you'll see it later.

...

After the meal, the three of them went to the drug warehouse and took two 8-pound bottles. Xu Qiu picked up one in each hand, and the empty bottles were not heavy.

After confirming that the pot-shaped Dewar was in stock, I was not in a hurry to get it. This is a fragile product, and it would not be too late to get it when I came back from liquid nitrogen.

The school girl fulfilled her wish and saw the appearance of a pot-shaped Dewar bottle, a short cylindrical shape, with a hollowed-out hemispherical inner tank in the middle, which was plated with a layer of silver.

It is indeed a bit like a food bowl for cat food.

The Zhangjiang campus is divided into two areas, separated by a large road. The school of pharmacy is on the other side of the road, which is far away from Xu Qiu's laboratory in the microelectronics building.

They went to deliver the waste liquid once before, and walked back and forth for nearly an hour. Of course, this was related to the slow moving speed during the process of transporting the waste liquid.

This time, it took them less than a quarter of an hour to follow the navigation to find the location where the liquid nitrogen was pumped, and the door sign next to it said Cryogenic Physics Laboratory.

This is a bungalow connecting front and back, and there is a huge liquid nitrogen tank outside the room, which is constantly spraying white mist outside.

The three of them entered the bungalow, and the environment was a little cold. In the inner room, there were two uncles lying on the bed, watching TV, who should be in charge of taking care of the place.

The two uncles glanced at each other, one of them stood up, walked to Xu Qiu and the others, and pointed to the ground.

Xu Qiu understood, put the 8-pound bottle on the ground, removed the two corks, and held the corks in his hands.

Ticket. Uncle A stretched out his hand.

What kind of ticket... do I have to pay for it? How do I pay for it? Xu Qiu suddenly thought that there should be a fee for testing liquid nitrogen just like doing a test.

Look here, bring it here next time. Uncle A pointed to the notice posted on the door next to him.

Then he ignored Xu Qiu, put on thick protective gloves on his own, and then took a metal tubular object about 40 cm long from the side. The back of the metal tube was connected to the pipeline on the wall.

While looking at the notice, Xu Qiu distractedly observed Uncle A's actions.

The notice reads: From now on... Use the intra-campus transfer method to transfer to the 'Low-Temperature Physics Laboratory of Shanghai Comprehensive University'. You can purchase liquid nitrogen tickets at the low-temperature laboratory with the intra-campus transfer slip. There are two types of liquid nitrogen tickets. 8 Each sheet is 17 yuan for a pound bottle, and 40 yuan for a 10-liter liquid nitrogen container.

‘Sure enough, you have to pay, and it doesn’t look like it’s very expensive. '

Senior sister, how do I transfer money within the school? Xu Qiu turned her head.

I sent a message to Wu Feifei, Chen Wanqing explained, She is usually responsible for such small transfers within the school, including the various tests we do in the school and in the department, which are finally completed through the transfer of funds within the school. of.

At the same time, the uncle put the metal pipe in his hand into the 8-pound bottle, and with the other hand, he unscrewed a valve on the wall.

Soon, the sound of liquid nitrogen hitting the inner wall came from inside the bottle, and a trace of white mist drifted out from the mouth of the bottle.

Teacher, I'll bring the school transfer slip next time. Do I need to leave a student number or contact information? Xu Qiu said.

No need. Uncle A stared at the TV without turning his head.

After tens of seconds, Uncle A approached the 8-pound bottle, moved the metal tube tentatively, and looked at the mouth of the bottle to confirm that the liquid nitrogen was about to be filled, then closed the valve and took out the metal tube.

Cover it. He ordered.

Oh, okay. Xu Qiu quickly put the cork back on the bottle, and the white mist passed by his hand, feeling a little cool.

Uncle A started to add liquid nitrogen to the other bottle in the same way. After tens of seconds, he closed the valve, retracted the metal tube, put it back to the original place, and said:

alright.

Thank you teacher. Xu Qiu corked the bottle and picked up two 8-pound bottles.

The three walked out of the gate of the cryogenic laboratory. Xu Qiu was about to complain, but Han Jiaying took the lead: You are so cold and cold.

Well, Xu Qiu nodded, Master who looks like liquid nitrogen? It seems strange... But he is not bad, we didn't have a ticket and didn't send us back.

Yes, the school really trusts the students. Chen Wanqing also felt the same way, We go to the drug warehouse to get it. We just need to report a student number and sign and we can get it directly.

...

Even if the two 8-pound bottles are filled with liquid nitrogen, Xu Qiu doesn't feel very heavy when he lifts them.

It's just that when he walked, he was a little frightened, as if he was holding two pots of bombs in his hands.

The three of them walked back to the medicine warehouse slowly, and took a pot-shaped Dewar bottle.

Afterwards, they exchanged the division of labor, Xu Qiu held the Dewar bottle, the senior sister and the junior sister each carried a pot of liquid nitrogen, and returned to the microelectronics building.

Wu Feifei's work efficiency is very high. When they returned to A501, she had already completed the transfer. Small transfers within the school did not need to be reviewed by the Finance Office, and they could be transferred directly.

She transferred 170 yuan to the cryogenic physics laboratory, which was just enough to buy ten tickets for 8-pound bottles of liquid nitrogen.

However, another trip to pharmacy school is too much trouble.

The three discussed it and decided to talk about it next time.

Definitely next time.

Walking into the laboratory, Xu Qiu suddenly remembered that his reaction was still in progress, because there was a small episode of pumping liquid nitrogen in the middle, which delayed a lot of time.

It won't be timed out, will it?

He hurried to the fume hood to check the stopwatch.

Two hours, six minutes and twelve seconds.

Really timed out.

Fortunately, Xu Qiu had experienced many battles, so he quickly calmed down and began to think about countermeasures.

This bromine substitution reaction is different from the past, and the reaction cannot be stopped just by trying to stop the reaction.

Because the condition is normal temperature, as long as the liquid bromine is still in the reaction flask, the reaction will continue continuously.

In order to stop the reaction, excess liquid bromine must be removed.

But if the bromine is removed directly, in case the reaction is not complete, it needs to be reacted again.

Xu Qiu quickly made a decision, ordering the board first to see the product.