I Am the President of the University

"I think zinc oxide (ZnO) should be used as the catalyst. After all, zinc oxide is cheap. Most domestic companies use tin oxide as a catalyst for the synthesis of lactide."

"Director Chen, I also know that zinc oxide is cheap, but we must objectively consider the catalytic effect. I still firmly believe that the catalyst must be stannous octoate (C16H30O4Sn)!"

"Professor Fang, I don't agree with your idea. I also think zinc oxide should be chosen!"

Listening to the discussion inside, Chen Hao probably understood. \b

"Ahem."

A sudden cough made Chen Chong and Fang Haosen look over. When they saw the appearance of the visitor, they stopped arguing and greeted each other.

"headmaster."

"headmaster."

"I heard the discussion between you two while I was still outside. I almost thought you were going to fight." Chen Hao smiled and said teasingly.

"Principal, you have misunderstood. Professor Fang and I were discussing." Chen Chong explained awkwardly.

Fang Haosen also replied: "Director Chen is right, we are just discussing it reasonably, there is no big problem."

"Well, what are you discussing?" Chen Hao had a warm smile on his face.

"It's like this. We, Professor Fang, have different opinions on the catalysts for lactic acid oligomers. No one can convince anyone else." Chen Chong said with some embarrassment.

"Oh, that's it." Chen Hao raised his eyebrows, looking very interested, "Then tell me what you two think."

Although Fang Haosen had just joined Guanghua University not long ago, he also knew that the president Chen Hao was a great figure in the material world. After all, it was Chen Hao who launched the photon screen.

Not to mention Chen Chong, as the second person in the photon screen technology laboratory, he admired the principal so much that he was a little fanboy.

The two explained the cause and effect to Chen Hao in detail.

Chen Hao nodded while listening, but he had already figured it out while eavesdropping.

After listening, Chen Hao looked like he was thinking and said to the two of them: "I roughly understand it. I think both of your ideas are good, whether it is to follow Director Chen's zinc oxide route or Professor Fang's stannous octoate. I think the route is fine.”

Isn't this nonsense?

Chen Chong and Fang Haosen listened to a black line, and there was no difference between what was said and what was not said.

Looking at the expressions of the two, Chen Hao laughed, "Then we will divide into two groups. One group uses Professor Chen's zinc oxide as a catalyst to synthesize lactide, and the other group uses Professor Fang's stannous octoate as a catalyst to synthesize lactide. ester catalyst."

"I think it's good to divide it into two groups to form a controlled trial."

Chen Hao's words were reasonable, but Chen Chong said with some worry: "Principal, we don't have many people to begin with. If we divide them into groups... I'm afraid it will affect efficiency."

Fang Haosen also nodded. Although he and Chen Chong had differences, both of them aimed to break through lactide technology as soon as possible. After all, the news about Beautiful Country also reached their ears yesterday, and they learned that NatureWorks held a press conference to ridicule Regarding school matters, the principal is probably under a lot of pressure right now.

Fang Haosen did not hesitate at all, looked at Chen Chong and said: "In that case, I support Director Chen's idea of ​​using zinc oxide as a catalyst!"

There are two main methods for preparation, namely the lactide ring-opening polymerization method and the direct condensation polymerization method. The ring-opening polymerization method is mainly used in industry.

The lactide ring-opening polymerization method, also known as the two-step method, is a process in which lactic acid is first dehydrated to form oligomers, then depolymerized to form lactide, and then ring-opening polymerized.

The core technology lies in the synthesis and purification of lactide.

The synthesis of lactide is the dehydration of two molecules of lactic acid to produce lactic acid oligomers, and then the lactic acid oligomers undergo a catalytic transesterification reaction called "back-biting" under the action of a catalyst.

There are many factors that affect the synthesis of lactide, but the main ones are the type and amount of catalyst, dehydration temperature and depolymerization temperature.

As for catalysts, there are still many types to choose from. For example, oxides, metal oxides, such as Sb2O3, P2O5, ZnO, SbF3, and tin compounds such as stannous sulfate, stannous octoate, tin octoate, tin lactate, etc.

This is also where Fang Haosen and Chen Chong have their differences. The two can be said to be the twin stars of the Lactide Laboratory. No matter who they are, they can stand alone. Each has its own ideas and it is difficult to convince the other.

Hearing what Fang Haosen said, Chen Chong was also a little moved. He opened his lips slightly and asked Chen Hao: "Principal, after all, I came to school earlier than Professor Fang. I am an old man and I should take a step back. Let's do this, laboratory There’s no need to divide it into two groups, just use stannous octoate as the catalyst!”

Watching the two of them give in to each other, Chen Hao laughed dumbly, waved his hand and said, "How about you guys imitate Kong Rong's give-and-take? I already told you to group them into groups, so this is more reasonable!"

It doesn't really matter who leads this laboratory. The main thing is that Chen Hao thinks it is a good idea to divide into two groups and choose different directions.

Different catalysts and different dosages will have different effects on lactide.

For example, if the amount of catalyst is too much or too little, the yield of lactide will decrease.

If the dosage is small, lactic acid will not be able to form lactic acid oligomers with sufficiently large molecular weight. There will still be a lot of unreacted lactic acid in the steamed product, so the yield of the product will not be high.

When too much is used, the dehydration rate becomes faster, and the molecular weight of the lactic acid oligomer formed is too large. Because the molecular weight is too high, it is difficult to depolymerize during the depolymerization process in the later stages of the reaction, and remains in the reactor, which also causes the recovery of the product. rate dropped.

Therefore, the entire choice of catalyst and dosage is a very rigorous one!

"But there are not enough manpower!" Chen Chong and Fang Haosen looked at each other, and then asked Chen Hao.

"Wouldn't it be nice to transfer a few from the Photon Screen Laboratory?" Chen Hao said with a chuckle.

After hearing what Chen Hao said, Chen Chong's eyes lit up. This was really a solution.

Polylactic acid is a polymer material. Although it is slightly different from photon screens, in terms of experimental operations, some experimental personnel are recruited anyway. The two people who take the lead are Chen Chong and Fang Haosen in formulating the general direction and steps.

"Principal, I almost forgot! This is indeed a solution!" Chen Chong said excitedly, and now the problem was solved.

"Then the two of you will be divided into two groups based on the catalyst, and then see which group synthesizes the best lactide, and the subsequent experiments will be decided by whom." Chen Hao said, looking at the two of them, and asked with a smile, "Do you think this is okay?"

"OK!"

"I'm OK!"

Fang Haosen and Chen Chong nodded, and were quite interested in the competition proposed by Chen Hao, and immediately gained more motivation.

"Okay, then we are waiting for your good news!" Chen Hao smiled and patted Chen Chong and Fang Haosen on the shoulders.

After talking to the two of them, Chen Hao walked out of the research institute and stood at the door, looking up at the dazzling sunshine.

The reason why I came to the laboratory was to check the attributes of the two people, and then decide who to add enlightenment and attribute points to.

Chen Hao shook his head and sighed:

"Old Chen, it seems that I will be sorry for you this time."

ps: Please give me recommendation votes and monthly votes!

The information on lactide is so hard to find. I finally downloaded a few papers from CNKI, which made me dizzy. If there are any mistakes, please don’t take it seriously, materials majors. I tried my best... Remember the website address. ,Www. biquxu． Com for easy reading next time, or enter " " in Baidu to enter this site