Chapter 231: Unexpected news

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Back at the office, Xu Qiu received an unexpected message.
"Senior sister will use pyridine in this afternoon's experiment?" Xu Qiu asked in surprise. He knew that pyridine was a big killer, and its toxicity was second, mainly because the taste was too unpleasant and lasted for a long time.
For example, there are almost a lot of similar questions on the "What is the experience of taking a sip of pyridine?" "If you are given 10 million, but the price is that you smell pyridine every day, how would you choose?"
"Hmm... I forgot to talk about it before. I just noticed it when I was preparing for the experiment," Chen Wanqing explained with an apologetic expression: "The last step of connecting D and A units requires pyridine as a catalyst and chloroform as a solvent. ."
"The last time the senior sister synthesized..." Xu Qiu recalled, and suddenly said: "Oh, I remember, the last time it happened to be Saturday, and we were not there."
"Yes," Chen Wanqing nodded and continued: "My suggestion is that you finish the experiment first, and then after I finish using pyridine, we will directly end our experiment today. You can write a summary or paddle the rest of the time. What."
"I'm fine, you can finish the experiment before night." Han Jiaying agreed, it seems that the two have already discussed it.
"In this case, I don't have a problem. I don't have much experiment content today. I'll just let me go through a pillar later." Xu Qiu nodded in response. Senior sister's proposal is very reliable. Once pyridine is used, it is estimated The laboratory can't work normally all day, unless the experiment is forced against DEBUFF.
"Well, the laboratory will be handed over to you two that afternoon, and I will respond in the evening." Chen Wanqing said.
Suddenly receiving this news, Xu Qiu didn't take any rest and went straight into the laboratory.
Although the three discussed the experimental plan, there may be uncertainties in the actual experiment process, and the plan may change at any time. If the experiment between him and the school girl is not completed by night, it will slow down the progress of the school girl.
Therefore, we still have to fight quickly.
Xu Qiu put on his lab coat and gloves, closed the vacuum oven, took out the dried third-generation 3D-PDI crude product from the vacuum oven, re-dissolved and mixed the sample with dichloromethane, and installed the sample column.
The disposable blank silica column has been completely used up, but he did not choose a reusable sample column.
The main reason is that it takes a lot of time to fill the columns by hand, and now needs to save time, and the other is that he is also prepared.
Xu Qiu took out the disposable columns that he had used before. On the plastic shells of these old silica gel columns, there were some marks he had made with a marker before, and the content was the composition of the previously separated and purified samples.
After choosing for a while, he picked up a relatively short, clean-looking silica column.
Because they are all PDI systems, even if there are some dead-adsorbed molecules in the column, when eluted with an eluent of similar polarity, there is a high probability that they will not be re-desorbed.
Even if a little molecule is desorbed, it will not have a big impact on the product. For the preparation of photovoltaic materials for organic photovoltaic devices, 99% purity can already meet the basic needs.
There is no perfect thing in the world, and it is definitely unrealistic to want to guarantee 100% purity of the sample.
Connect the sample column and the blank silica gel column to the liquid chromatograph, confirm that there is no problem with the test tube rack, solvent, and waste tank, and turn on the instrument.
...
This time there was only about 40 mg of crude product, and the polarity difference between several sample points was not big, so the separation and purification were not difficult. Xu Qiu completed it in just over an hour.
However, because the amount of product is too small, during the process of rotary evaporation to dry the solvent, the product appears to be evenly plated on the inner wall of the bottle, dark red, with only a thin layer.
‘It’s troublesome. Xu Qiu smashed his mouth and patiently used a stainless steel scraper to scrape the product from the eggplant-shaped bottle wall, just like a plow, where the scraper and the bottle wall formed a ravine.
The scraper and the curved glass bottle wall are almost in point contact. To get as much product as possible, it is necessary to traverse most of the points in the bottle, which is a test of patience.
Ten minutes later, Xu Qiu laid down most of the product, collected it in a glass bottle, and weighed it. A total of 33.1 mg of product was obtained.
The yield is not bad, about 80%.
The third-generation 5 series 3D-PDI synthesized this time was copied to the simulation laboratory II, and simulation experimenters were arranged to explore the device performance.
After successfully completing today's experimental task, Xu Qiu was in a good mood.
He watched the laboratory around, Han Jiaying processed the reaction in front of the fume hood and walked to her.
Seeing the school girl wearing a white lab coat and steadily operating her back, it is really difficult to connect with her who is usually lively and free.
When approaching Han Jiaying, Xu Qiu deliberately used his shoes to make a noise.
This time, he didn't want to make a surprise attack. The school girl was still holding the reaction bottle in her hand. If she accidentally frightened the other party and made her shake her hand without the product, it would be bad.
"Brother?" Han Jiaying obviously heard the movement behind her, stopped her work and tilted her head.
"Well, my experiment is over, come and see you." Xu Qiu explained.
Han Jiaying turned her head, continued the experiment, and then briefly said the result, "I just ordered the plate. The yield of the two reactions is estimated to be about 50%. There are many by-products, but the polarities of each other are quite different. Separation and purification It shouldn't be difficult."
"No way, the central nuclear unit is relatively large, which may indeed cause a decrease in production rate." Xu Qiu guessed at random a reason, which was considered comfort.
"Hmm... By the way, our disposable blank silica gel column is used up, and we will re-install the column this time. Did the brother just use the column to install it manually?" Han Jiaying asked, when she arrived in the laboratory, she promised Qiu has already started to pass the pillar, so he is not sure.
"It's not..." Xu Qiu briefly said what he did just now, and then said: "However, sooner or later, you will have to manually install the columns. I will teach you today. We will share the next two products."
"Great." Han Jiaying nodded happily, pointing to an oil bath next to him, "Brother, please."
"It's really not polite to me." Xu Qiu smiled, naturally did not refuse, and it would not take much time to deal with a reaction.
The two reactions of the school girl are the synthesis of the first generation 3D-PDI, using two nuclear units designed by herself, 3TB and 4TB, the PDI molecule used is PDI-6, so the names are PDI3-3TB-6, PDI4-4TB-6.
The reaction type is the Suzuki reaction. Xu Qiu has done it many times before. The post-treatment is naturally easy to do. The product is dropped into the methanol solution, vacuum filtered with Buchner funnel, and dried in a vacuum oven.
Then, he took out two bags of silica gel from the cabinet under the fume hood No. 5 and transferred them to the fume hood for inorganic synthesis.
The main component of silica gel is amorphous silica, which has stable chemical properties and generally has specifications such as 100-200 mesh, 200-300 mesh, and 300-400 mesh.
Xu Qiu took the box with the blank silica column, turned around and asked, "Sister, what is the quality of the product?"
"Probably..." Han Jiaying thought for a while and said: "It's about 100 mg, exploratory experiment, I didn't dare to add more materials, but only so much is left at this stage."
"Then you don't need to choose a silica gel column that is too large..." Xu Qiu muttered, while selecting silica gel columns from the box.
In the end, he picked two relatively short pillars, the same size, about 20 cm in length and 3 cm in inner diameter, and nodded in satisfaction, "Just them."
Han Jiaying took one of the silica gel columns and stood by the side.
Xu Qiu took a plastic funnel and a disposable PE cup, unscrewed the upper end of the silica gel column, inserted it into the funnel, and then used the PE cup as a spoon to add 300-400 mesh silica gel to the silica gel column. At the same time, he introduced:
"The larger the mesh number of silica gel, the smaller the silica gel particles, the better the adsorption effect. The smaller the mesh number, the larger the silica gel particles, the worse the adsorption effect. The 100-200 mesh silica gel was used for sample mixing, normal blank silica gel. The column usually chooses 300-400 mesh silica gel."
After it was installed to about 90% of the height of the silica gel column, Xu Qiu stopped adding silica gel, put a few layers of toilet paper on the laboratory bench, held the silica gel column with both hands, and shook it back and forth on the paper vertically, sending out "duang" "duang" "" the sound, explained:
"Although the silica gel is now filled, it is not compact and uneven. It is necessary to make the silica gel firm. Otherwise, after the solvent is passed in, the column may break or the sample may quickly pass through the side of the column. "
"It's like... side leakage?" Han Jiaying tilted her head.
"What are you thinking about, day by day." Xu Qiu was speechless for a while, then after careful consideration, he said, "However, the metaphor is quite appropriate."
Xu Qiu "duang" for about a minute, and saw that the height of the silica gel column had dropped a lot, so he stopped, added some silica gel to it, made up to about 90% of the height, and continued to oscillate up and down.
After that, Han Jiaying also started to fill the columns in a similar manner, and began to dance the silica gel columns up and down, like a low-power pile driver, "Brother, how long will this take?"
"Until the height of the silica gel column no longer changes with the shock," Xu Qiu paused: "Be conservative, let's 15 minutes."
Later, he explained: "There is no quantitative standard. Only when the column is officially started can the effect be known. The main reason is that the consequences are serious. If the column breaks, the product must be washed off with a highly polar solvent. ~EbookFREE.me~ Reinstall the column and do it again, so try to get it right.
In fact, it is easier for us to experiment with the column before. The disposable blank silica column without manual filling has played a great role and significantly reduced the failure rate of the experiment. "
"I understand." Han Jiaying nodded.
After more than ten minutes, Xu Qiu took a long breath, stopped the movements in his hands, and said, "Almost done."
"I'm getting better too, just... my hands are a bit sore." Han Jiaying's condition at this time is like a pile driver with insufficient power.
"Well, but the sample is still drying. I can't take it out for a while, and there is no way to load it." Xu Qiu turned to the vacuum oven and just saw a batch of waste liquid barrels next to him, and proposed:
"It's better to take advantage of this gap to dispose of the waste liquid."
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