Chapter 206 Old Su shows his power at the beginning (6.2K)
After deciding to overcome the barrier of transition metal catalysis first, Xu Yun and others quickly put on a standard experimental suit.
Students who have passed high school chemistry should know this.
According to the periodic law of elements, people often look for catalysts in the region of transition metals.
For example, the catalyst for ammonia synthesis is an iron catalyst.
Vanadium pentoxide is a catalyst for the synthesis of sulfuric acid and nitric acid.
Raney nickel and so on are often used for the addition of olefins and hydrogen.
Why do these transition elements and compounds often play the role of "moon elders"?
Let me first explain a concept to you in human terms:
Feedback π key.
When a coordination bond is formed between the transition metal atom, that is, the central atom and the ligand.
Coordinating atoms will donate lone pairs of electrons to fill the empty orbitals provided by the central atom.
This forms a σ bond in the form of a coordination bond.
sometimes.
Some electrons from the central atom may also fill in the empty orbitals of the ligand molecules.
This is the feedback π bond.
And in this process.
The antibonding orbitals π2py* and π2pz* of the ligand molecule are empty.
when it acts as a ligand.
It can not only provide lone pairs of electrons to coordinate out, but also provide π anti-bonding empty orbitals to coordinate electrons in.
As long as the central atom and ligands have lone pairs of electrons and empty orbits, they have the prerequisites for travel.
Coupled with the suitable symmetry of the two, a feedback π bond is formed.
See here.
Smart students should understand.
That’s right!
If a ligand molecule forms a feedback π bond with a certain transition metal atom, its originally empty π antibonding orbital will be filled with electrons.
The bond level is negatively related to the number of electrons in the antibonding orbital.
The more electrons filled in the antibonding orbitals, the smaller the bond order and the weaker the bond.
N≡N, which was originally very strong, has been weakened by the feedback bond, indicating that its chemical activity has been greatly enhanced.
In other words.
It will be easier to make the ligand molecules react again.
This is the principle of transition element catalysis.
Very simple and easy to understand.
The transition metal used by Xu Yun and others in the laboratory is ruthenium, a metal with very stable properties and strong corrosion resistance.
There is another very special situation about this thing:
Found in only one part per billion in the Earth's crust, it is one of the rarest metals.
But it is very cheap and is the cheapest metal among the platinum group metals.
But cheap is cheap.
Because its crystal structure is a hexagonal unit cell.
It can only be used in the laboratory during the production process of imidacloprid and cannot be successfully used in industrial production.
"So among the candidate solutions given, we appended three metals: lanthanum, scandium, and gallium, and handed them over to Nutrien for adaptation."
In the laboratory.
Xu Yun is introducing the relevant situation to Yu Yuanyong:
"The final reply given by Nutrien was lanthanum metal, which is also the transition metal catalyst with the highest comprehensive energy efficiency. The actual operation results after receipt were fully in line with expectations."
"Of course, because of this, their equipment quotation is much higher than expected."
Opposite him, Yu Yuanyong nodded clearly.
Among the three metals: lanthanum, scandium, and gallium, scandium is the most expensive.
According to the current price.
One kilogram of 99.9% grade scandium costs about 32,000 yuan.
Next is gallium.
The price per kilogram is 2805.
Lanthanum is the cheapest.
One ton only costs more than 27,000 yuan, which is cheaper than the above two. It’s worth it to my grandma’s house.
at the same time.
Gallium is also the best choice for catalysis.
But the price and effect are completely opposite.
The difficulty of mass production of the three metals in industrial production lines increases in sequence.
The same goes for equipment requirements.
Think of this.
Yu Yuanyong picked up a report from the table next to him and turned to a certain page.
Then he introduced to everyone:
"Dr. Xu, to tell you the truth, we are currently stuck on the molecular sieve of the catalyst."
"Our team tried many methods, but in the end they all unfortunately failed."
"Don't talk about lanthanum, we haven't even made a breakthrough on scandium."
"Because no matter what kind of metal it is, the coordinated framework heteroatoms must be highly isolated in the molecular sieve."
"For example, the neighbors in Ti-O-Si are mainly Si-O-Si. On the other hand, Ti mainly exists in four-coordinated form. We must complete the atomic defect site reaction inside the container, but this is thermodynamically unfavorable. ”
Hear these words.
Lin Zhenhua on the side suddenly interrupted him and asked:
"Xiao Yu, how did Nutrien accomplish this step? Can you learn from their ideas?"
Yu Yuanyong shook his head, pointed at the computer at the other end and said:
"Nutrien uses a chemical grafting patent. The entire link is connected by seams, and no point can be changed."
“If you want to make a complete copy, not to mention the difficulty of the process, the patent protection aspect will be difficult to overcome.”
"They can include FOERDA-T632 in the Wassenaar Agreement, but Dr. Xu and others cannot plagiarize the patent, otherwise it will be like handing a knife to others."
Lin Zhenhua opened his mouth when he heard this, as if he wanted to say something.
But in the end, he remained silent and turned into a sigh.
Just as Yu Yuanyong said.
Huadun Biotechnology is not a small private workshop. Xu Yun and the others will be stared at with magnifying glasses every step they take, looking for your sore feet all the time.
Once the production capacity of ‘One Mantis Destruction’ is increased.
At that time, someone will inevitably instigate Nutrien to file a patent review and ask to verify whether patent infringement is involved.
A scoundrel?
Of course a bummer.
The equipment on the other end is prohibited, and the other end is not allowed to imitate it. This is a double standard to the extreme.
Is it legal?
The answer is also yes.
Even if Huadun Biotech has the support of the University of Science and Technology or even the Academy of Sciences, it will not help.
Once this happens, what awaits them will be extremely severe punishment and crazy attacks from public opinion.
So Nutrien and the people behind it are not afraid of Huadun Biotechnology at all to copy this chemical grafting process. Perhaps they are even eager for you to do this.
Then Xu Yun thought for a while and came up with a new idea:
"Director Yu, what do you think about using ion beam implantation?"
Yu Yuanyong blinked:
"Ion beam implantation method?"
Classmates who were Ions in their previous lives should all know this.
The so-called ion beam implantation method.
It refers to a method in which metal ions generated by ionization are accelerated in an electric field to form a high-speed ion beam and hit a designated substrate.
Due to the high speed of the ion beam, it can be injected into the surface layer and crystal lattice of the substrate to achieve regular effects.
However, it is different from the chemical grafting method.
Ion beam implantation is mostly used in the fields of physics and materials science, especially in semiconductor surface modification and doping treatments.
Rarely used in catalyst preparation.
Seeing that Yu Yuanyong was a little confused, Xu Yun patiently explained:
"Think about it, the metal ions in the ion beam are all positively charged and will repel each other and separate."
"So the metal ions driven into the matrix will basically remain in a highly isolated state."
"Let's add a chemical intermediate to it, such as catechol or something. Then, wouldn't a Y-shaped molecular sieve come out?"
Yu Yuanyong's eyes widened the more he listened, and his mouth opened involuntarily with a stunned expression.
A few seconds passed.
He suddenly made a fist with his right hand and struck it hard on the palm of his left hand:
"Yes, we can definitely use the method of introducing isotopic metal ions to force out the cations in the antibonding orbitals. Wow, look at my head, why can't I think of this layer?"
When Xu Yun heard this, he smiled and said nothing.
Ion beam implantation method.
This was the last paper he published before leaving the field of scientific research in his previous life, which involved the defect site reaction transition effect of vanadium metal and molecular sieves.
doi is. Ahem, I can’t say it. If I say it, I will lose my screen name.
all in all.
The last paper before quitting is like your first love, and you may never forget it in this life.
Therefore, after learning that Yu Yuanyong and the others were stuck on the molecular sieve, Xu Yun immediately thought of this idea.
With Xu Yun's suggestion, the next thing is very simple.
In addition to the final product, the detection method of transition metal catalysis can also be determined using ultraviolet Raman spectroscopy technology.
Especially in terms of molecular sieves.
The accuracy of the Raman peaks is even better.
So it's quick.
Yu Yuanyong then prepared for the detection of Raman spectroscopy.
Half an hour later.
Yu Yuanyong's team has completed preparations and officially started testing.
Ten minutes after the test started.
Transition metal heteroatoms begin to enter the molecular sieve framework.
at the same time.
In the UV-visible absorption spectrum, the charge transfer transition absorption between pπ of the skeleton oxygen atoms and dπ of the skeleton transition metal atoms immediately appeared.
More than twenty minutes passed.
A report appeared on the equipment table in front of Yu Yuanyong.
"The absorption peak is in the ultraviolet region between 200 and 350nm, and the center of the charge transfer transition absorption band is at 220nm"
Yu Yuanyong excerpted several pieces of information and started calculations with Xu Yun at the same time.
Five minutes later.
Xu Yun and Yu Yuanyong raised their heads one after another.
Lin Zhenhua noticed from the side.
At this moment, the expressions of both of them were a little solemn, not as happy as expected.
Then the two looked at each other and heard Xu Yundao:
"Director Yu, by how many orders of magnitude did the Raman signal you calculated increase?"
Yu Yuanyong frowned and reported a number:
"Five magnitudes, what about you?"
Xu Yun raised the calculation paper in his hand towards him:
"It's also five, five characters won't work."
Yu Yuanyong's brows suddenly knitted deeper. He looked at the report again and said with a puzzled expression:
"It's strange. The center of the charge transfer transition absorption band is around 220nm. The nearest ultraviolet laser close to this absorption band is 244nm. The data must be correct."
"According to the resonance Raman principle, when the energy of the excitation light source is close to the electron absorption band, resonance will inevitably occur between the electronic state and the vibrational state."
"The intensity of the Raman signal of the vibration mode related to this resonance conforms to the transition formula, so the magnitude of the four-coordination should be 6 to 7."
Xu Yun also picked up the report, shook it like a doctor looking at a CT scan, and looked at it carefully.
A few minutes passed.
Xu Yun's expression suddenly condensed, he pointed at a certain column and said to Yu Yuanyong:
"Director Yu, look here, why is there such a strong Raman peak at position 530?"
After a while.
Yu Yuanyong and Xu Yun thought of something at the same time, and said in unison:
"Selective excitation?"
Selective excitation.
It refers to a situation where the feedback of a statement is lower than expected within a certain range.
It may be man-made, or it may occur spontaneously due to lack of energy during the reaction.
Just like the gas stove in our lives.
Sometimes you turn on low heat because the dish must be simmered over low heat.
You can always turn up the heat if necessary.
But sometimes you turn on a low fire because the pipe is really running out of air.
What Xu Yun and the others encountered was the latter situation, or an enhanced version of the latter:
The gas pipeline in your home is out of gas, and the gas company also sent the gas that should have been delivered to your home to your neighbor's home, causing an overflow.
Looking at the two people who were frowning like street writers who saw subscriptions in the background, Lin Zhenhua on the side couldn't help but said:
"Xiao Yu, Xiao Xu, my major is in industry. I don't know much about the concept of selective excitation. Anyway, is there any way we can solve it?"
After hearing this, Xu Yun pondered for a moment and said:
"I'm afraid it's difficult. We used scandium, which is the least difficult, and the ion beam chose iron, which has non-selective oxidation properties."
"Therefore, selective excitation occurs, mostly because certain pulse characteristics appear during the interaction phase."
"For example, iron ions and chemical intermediates produce some band feedback, delaying the reaction that should have occurred in the third minute to the fifth minute."
"Of course, this is just a metaphor. In short, it is difficult to solve this kind of problem in a short time."
"Our only choice at the moment is to bite the bullet and use this method to produce. After all, although the wave band is different from the straight line, we can still produce some products."
"Just like this, our production costs and efficiency will be affected."
Lin Zhenhua frowned:
"That's it."
Xu Yun then pondered for a moment and was about to say some kind words to comfort Lin Zhenhua.
As a result, no words came out.
Lao Su on the side suddenly pulled his sleeve gently.
Xu Yun then stopped his mouth and turned his head.
He found that Lao Su gave him a look that said, "Come to the side and talk."
Xu Yun thought for a moment, pretended to be casual and patted Lao Su on the shoulder, pointed to the water dispenser not far away and said:
"Xiao Su, come with me to pour a few glasses of water for everyone. After doing this experiment for so long, everyone who doesn't drink water will die."
Lao Su immediately understood:
"Okay, senior."
After walking to the water dispenser.
Xu Yun glanced around, lowered his voice and asked Lao Su:
"What's wrong?"
Lao Su first put a disposable water cup into the water outlet, pressed the switch, and said to Xu Yun:
"Xiao Xu, I don't know much about the specific concepts you are talking about, but that so-called chemical intermediate reminds me of something. I wonder if it will inspire you."
"So let me just talk about it, and you can listen to it as you please."
"It would be best if I can help. If I am wrong, just ignore it."
Xu Yun put a plastic cup filled with water aside and replied:
"Su Gong just said it doesn't matter."
Lao Su nodded, pondered for a moment, and said:
"When you were assembling the telescope that day, you mentioned something that I have never forgotten."
"What you roughly meant at that time was that the telescope needed a paraboloid as an intermediary carrier to reflect the object image, but the industrial level of the Song Dynasty was limited and could not process a spherical mirror that met your requirements."
"So then you took a different approach and used rotating mercury to achieve the parabolic effect."
"In my opinion, since the so-called chemical intermediate is also intended to have a relay effect, its principle may not have any intersection with the mercury paraboloid, but the two may have some similarities in nature."
"In this case, I would like to ask a question."
"Can we bypass the current situation and try to use liquid as this intermediate to avoid selective excitation through the special properties of liquid?"
Hear these words.
Xu Yun was stunned at first.
Immediately the pupils shrank suddenly!
What Lao Su said is a classic operation he compared in the Northern Song Dynasty copy:
At that time, the copy lacked a knife-edge instrument and an interferometer, so Xu Yun was unable to grind an accurate spherical lens.
Therefore, he cleverly used rotating mercury to realize a paraboloid, and achieved the same effect through an RC-like structure.
Although this operation has no intersection with catechol.
But as Lao Su said.
The two are actually somewhat similar in nature.
One reflects light, the other feeds back the band.
They all serve as a relay.
Therefore, if we can expand this idea, we can replace catechol with some other special liquids.
At the same time, through the centrifugal force of the liquid, the band in which solid matter exists is fed back to the balance.
It seems
Is it really possible? (End of chapter)