Chapter 232: Pyridine really deserves its name

After clamping the blank silica gel column filled with silica gel on the iron stand, Xu Qiu called out Chen Wanqing to deal with the waste liquid and the experimental garbage accumulated these days.
"By the way, have we returned the liquid nitrogen voucher we owed to the cryogenic physics laboratory?" Xu Qiu asked. He remembered that the waste liquid disposal site was very close to the cryogenic laboratory.
"I paid it back. Later I did a low temperature reaction again, and went to get another pot of liquid nitrogen. Three tickets were used. I put the remaining liquid nitrogen coupons in the drawer of the A501 office," Chen Wanqing regretted. : "It's a pity that the two pots of liquid nitrogen I hit last time were not used up at that time, and then they all evaporated and ran away."
"Yes." Han Jiaying interjected: "It might as well be used by us, such as liquid nitrogen ice cream, or using liquid nitrogen to make frozen pears seems good."
"Just know to eat." Xu Qiu Shi smiled.
There are no twists and turns in the treatment of waste liquid and experimental garbage.
Because the main components of the waste liquid in the laboratory are marked, and there is no special waste liquid like hydrofluoric acid, so the school of pharmacy accepted all of it after registration.
Xu Qiu went out through the air, and returned to the laboratory again. The vacuum-dried product was completely dried.
Dissolve the product again with dichloromethane, mix the sample, and rotatory steam.
Pack the mixed product in the 10% space reserved above the blank silica gel column, compact it vertically with a gasket, install a baffle, and finally tighten the upper cover of the silica gel column.
Among them, the main function of the gasket and the baffle is to make the mobile phase passing through the silica gel column uniform in the horizontal direction.
Compared with disposable silica gel columns, manual column packing is a lot of trouble.
The quantity of the two products was not large, and the school girl was able to cope with it, so Xu Qiu did not stay much.
After returning to the office, after washing his hands, Xu Qiu looked back at the senior sister who was chasing the drama, and couldn't help but think of pyridine.
There is a well-known saying in the organic laboratory, "Men don't use pyridine, and women don't use furan."
It means that if these two solvents are used for a long time, exposure to these two types of solvent vapors will affect male/female fertility.
One spermicide, one contraceptive.
Of course, these two solvents are just typical of people's attention. Most organic solvents have potential carcinogenic, teratogenic, organ toxicity, and reproductive toxicity.
In the course of "Organic Chemistry", Xu Qiu generally understood that there is a set of classification standards for organic solvents in the world, which can be specifically divided into one, two, and three solvents.
At this moment, he happened to be free, so he checked on the Internet by the way, and he was able to vaccinate himself. There is never too much knowledge about safety.
"The so-called first-class solvents are solvents that are known to cause cancer and are harmful to humans and the environment. Avoid using them as much as possible. If it is unavoidable, the residual amount must be controlled within the specified limit:
Benzene (2ppm), carbon tetrachloride (4ppm), 1,2-dichloroethane (5ppm), 1,1-dichloroethylene (8ppm), 1,1,1-trichloroethane (1500ppm). "
Xu Qiu thought to himself that the requirements for their residues should be in the brackets. The first four are all within 10ppm, which is within a few hundred thousandths.
There are few solvents in the first category, only five. It is not easy to stand out from a bunch of organic solvents. The two benzene and carbon tetrachloride are more famous, and he is fairly familiar.
Benzene was a product of early petrochemical industry. It was once a popular organic reaction solvent. Later, because of its great harm, it has been banned by many parties. Now it has basically withdrawn from the stage of history and is replaced by its derivatives such as toluene and chlorobenzene.
Carbon tetrachloride is a kind of fire extinguishing agent with strong fire retardant ability. There used to be fire extinguishers with carbon tetrachloride as the main component, but because it is easy to form highly toxic phosgene, and its destructive power to the ozone layer is very strong, it will The ozone has a hollow, which was banned from the production many years ago, and was gradually replaced by carbon dioxide and dry powder fire extinguishers.
"The second category of solvents refers to solvents that are not genotoxic but have animal carcinogenicity, including ... 26 kinds."
‘This is more used in the laboratory. Xu Qiu secretly calculated the solvents he had come into contact with, and while checking the list, he counted with his fingers.
There are 10 kinds in total, just don’t need to borrow toes:
Chloroform, chlorobenzene, dichloromethane, N,N-dimethylformamide, ethylene glycol, n-hexane, methanol, ethylene glycol methyl ether, N-methylpyrrolidone, toluene.
'10/26...' Xu ​​Qiu thought about it.'I have been exposed to 38% of the second type of solvent. This ratio is not too low. As the experiment progresses, the ratio will definitely increase. Higher. ’
Chloroform and chlorobenzene are solvents for organic photovoltaic cell devices;
Dichloromethane, toluene and N-methylpyrrolidone are solvents for organic synthesis;
N,N-Dimethylformamide is one of the common solvents for perovskite, which was used in the perovskite transport layer before;
Ethylene glycol is the coolant of the low-temperature circulation device;
Hexane and methanol are solvents used for Soxhlet extraction and purification of polymer donors;
Glycol methyl ether is a solvent used to prepare zinc oxide precursor solutions.
Of course, some solvents have more than one function, such as:
Chloroform is also used as the solvent for the synthesis reaction and the solvent for Soxhlet extraction of the polymer. Methanol is also used as the polymer donor material and the antisolvent for the PDI acceptor material.
Xu Qiu noticed that pyridine is also in the second category of solvents, but he has not been exposed to it yet.
‘I heard that pyridine has a unique taste. Before leaving at night, do you want to go to the laboratory and smell it? ’
‘Emmm...Don’t be dead. ’
"The third category of solvents, low-toxic solvents, including ethanol, ethyl acetate, tetrahydrofuran, acetone, isopropanol, etc."
Xu Qiu was slightly surprised. Ethanol is easy to understand, and tetrahydrofuran is actually in the third category.
Furan and pyridine are equally famous, and he thought it was also a second-class solvent, but the tetrahydrofuran written on the MSDS is indeed very low toxicity.
But in any case, it's better not to touch directly or not.
"Other solvents that are not in these three categories do not mean that there is no risk at all. It may be because the minority has not received widespread attention or does not have toxicological data. For example, ether, although not in the above three categories, but high concentrations of ether will cause People were shocked and even died."
After reading, Xu Qiu crossed the webpage, and the useless knowledge seemed to have increased again. He deeply felt that the laboratory was too dangerous, and he should pay more attention to protecting it in the future.
After that, Xu Qiu stayed in the office and concentrated on writing a summary, pushing the progress of the third part of his responsibility to almost 60%.
At more than five o'clock, Han Jiaying completed the separation and purification of the two products, and received 55.1 mg and 53.6 mg of products respectively. Then, she took Xu Qiu from the office to the laboratory and shook the sample like a treasure. Of two transparent glass bottles.
"Not bad." Xu Qiu exclaimed that the 3D-PDI material that the school girl got was also a dark red powdery solid, and the color changes were similar to the several 3D-PDI materials he synthesized, but the brightness was different.
He easily copied the two materials into the simulation laboratory II and arranged them for the simulation experiment personnel.
"Brother, I will ask you tomorrow." Han Jiaying chuckled lightly.
"No problem." Xu Qiu agreed directly. According to the previous division of labor, he was responsible for preparing the devices, and the school sisters and senior sisters were responsible for the synthesis. Then, he pointed to his fume hood and said: "These three reactions need to be handled by me tomorrow. under."
"Okay, it's a photocyclization reaction catalyzed by iodine, I remember the post-processing steps are..." Han Jiaying recalled, and said slowly.
"Yes, the three reactions are the synthesis of the second-generation 3D-PDI molecules. I have recorded the results of the 5/6 series and can be directly compared at that time. The 8 series and the 5/6 series will not be very different. "Xu Qiu nodded in satisfaction.
His progress is relatively fast, so he has made up lessons for the school girl in advance for the operation steps and post-processing of the subsequent experiments, and now it seems that she has a good grasp of it.
...
After dinner, the laboratory became Chen Wanqing's stage.
Xu Qiu and Han Jiaying stood at the door of the laboratory, watching the senior sister seriously putting on the gas masks, looking like death at home.
"Come on." "It's okay." The two encouraged the elder sister, her face looked better, and she stepped into the room.
After not taking a few steps, Chen Wanqing heard a "click". It was obvious that the door of the laboratory had been brought up. She paused, shook her head, and moved on.
Their approach is correct. If the laboratory must use unpleasant volatile reagents, the impact needs to be controlled in the laboratory and not spread out.
There are no people in the Zhangjiang Microelectronics Building, so it doesn’t matter. If it’s the Handan campus, the entire building is full of laboratories and teachers’ offices. If there is a leak, the consequences will be much more serious.
Previously, there was a laboratory on the fourth floor in Caiyi. The mercaptan reagent leaked and spread to the entire building along the corridor. A faint smell of rotten garlic could be smelled at the gate on the first floor. Of course, the fourth floor was the worst affected. All the teachers and students on the whole floor went out for emergency evacuation for a long time.
Including the glove box in Mr. Wei’s laboratory, the atmosphere in the glove box is regenerated regularly, which essentially exhausts the solvent molecules in the glove box into the atmosphere. Each time the room is regenerated, the door is closed and the windows open for ventilation. , Otherwise it will leak into the corridor.
Solvents such as chlorobenzene, chloroform, and DMF are not that good, and they smell astringent, which is hard to describe.
Returning to the office, Xu Qiu received the cover picture of the completed version from Tian Qing. The round PC[70]BM molecule painted before has been changed to an ellipsoid shape.
After coloring and post-processing the whole picture, although it is in cartoon style, it is a little bit sci-fi and the effect is very good.
Xu Qiu immediately said that there was no problem, and his main task was just to check, and the rest of the liaison with the editor was the responsibility of Teacher Wei.
One hour later, Chen Wanqing reappeared at the door of A501.
"Senior sister is back, why..." Xu Qiu paused suddenly, sniffed the surrounding area vigorously, and there was a seemingly odor, "Pyridine, really well-deserved."
"Sorry, it should be pyridine attached to the clothes," Chen Wanqing sniffed her body and frowned, "I can't smell it myself."
"I can't smell either..." Han Jiaying shook her head in confusion.
"I only used one milliliter of pyridine, it shouldn't be so exaggerated, but there is a smell in the laboratory. When I took off the gas mask, I was disgusted." Chen Wan finished washing her hands, opened the window, and began to ventilate.
"Maybe different people have different sense of smell." Xu Qiu explained.
Opening the windows is still very effective. With the continuous exchange of air between the room and the outdoors, the smell of pyridine is basically inaudible.
...
Before leaving Zhangjiang in the evening, Xu Qiu brought three 3D-PDI products synthesized today. These products were packed in garbage bags and placed in the corridor before Chen Wanqing started the experiment.
Then the three totaled the progress of their respective reviews. Chen Wanqing was the fastest, 90% completed, Xu Qiu and Han Jiaying were evenly divided, about 80% completed.
In this way, the third part of the review can be completed in one day.
On the returning school bus, Xu Qiu entered the simulation laboratory II and got some experimental results.
The efficiency of the third-generation 5 series reached 5.98%, which was an increase of 0.57% compared to the 5.41% of the second-generation 5 series.
In addition, the best aptamer was changed from the second generation PCE10 to P3TEA, which is consistent with the first generation.
"What do you mean, stepping on two boats and jumping repeatedly?"
Xu Qiu spat out casually, and then thought about the performance of the device, and couldn't help shaking his head.
The PDI series is really boring, and the efficiency improvement is little by little.
However, it is a good thing to be able to improve, at least it shows that the previously designed route is correct.
Moreover, because now only 3000 system points can be obtained every week~EbookFREE.me~ just use it and make ends meet, Xu Qiu can not use the simulation laboratory II as he pleases, so what he gets in the simulation laboratory is preliminary exploration As a result, the purpose is only to verify that the route is correct.
After all, the exploration time allocated to the same system is only six to ten hours, and several donor materials have to be tested.
Since the time flow rate is synchronized, this time is kept in reality, which is just one or two batches of devices.
In other words, when Xu Qiu conducts experiments in reality, there should be a lot of room for improvement and improvement in device performance.
As for the current path he designed, the third-generation 3D-PDI molecule is basically the final state.
If you count the side chain modification of the nitrogen position, that is, the 5/6/8 series, it is actually four generations developed.
In the optimization of molecular structure, it has been considered relatively complete.
The main reason is that the active reaction sites are now all occupied. If you want to further optimize, it is not impossible, but the molecule must be redesigned and synthesized from scratch.
Many optimization strategies are mutually exclusive. For example, the introduction of heteroatom selenium does not allow modification of the bay side chain, and vice versa.
After analyzing his own system, Xu Qiu looked at the two materials of Xuemei again, and the device performance exploration has not yet been completed.
He was surprised to find that the current highest results of the two systems were 3.92% and 4.77% respectively.
This result is already very good, comparable to the system he designed himself, and may even exceed his system after getting the final result.
Xu Qiu muttered to himself, is 3D-PDI more complex and NB?
After exiting the system space, Xu Qiu looked at Han Jiaying who was curled up in his arms. She was sleeping and her eyelashes were still moving.
Let's tell her the good news tomorrow after finishing the parts.