The instruments and equipment for catalyst preparation have been installed, and the preparation of a group is basically ready, and only need to be debugged to officially start the work.

Most of the catalyst preparation relies on manual operation, but its process indicators are controlled by instruments and equipment. Due to the limited conditions at that time, for example, the crushing and sieving of activated carbon could only be carried out in a batch operation equipment, and the impregnation of palladium salts required very careful manual operation, which was a test of the operator's proficiency and sense of responsibility.

During the commissioning of the instrument and equipment, Fang Hanmin went to a group to check the progress of the work, and saw that Jiao Tiehui was practicing the crushing and sieving of activated carbon in the special equipment under the guidance of Jiang Guoxin, and the other two workers were practicing the impregnation of palladium salt solution under the guidance of Wancheng.

Nominally, Jiang Guoxin and Wan Cheng are two technicians to guide the workers to operate, in fact, their operation level is not much stronger than the workers, seeing Fang Hanmin observing on the side, Wan Cheng, who is also from the seventh or ninth level, may have had some tacit understanding with Guo Peng of the second group in private, Guo Peng tested Fang Hanmin's theoretical level, Wan Cheng wanted to test Fang Hanmin's hands-on ability, he took the initiative to turn around and greet Fang Hanmin, "Section Chief Fang, do you think we are a little clumsy?" ”

"Everything is difficult at the beginning, everyone is the same, after a long time of operation, it will naturally become proficient."

"I heard that Section Chief Fang used to do experiments in large-scale equipment, so I guess the operation of the laboratory should be better. It's the first time for us, I wonder if Section Chief Fang can give us a demonstration? ”

In his previous life, Fang Hanmin's doctoral dissertation in pharmaceutical science was completed in a famous laboratory at the University of Oxford, and after joining the work, he worked as a project director in the new drug development center of RGP Company.

Fang Hanmin didn't think much about it, he felt that it was also appropriate to do a demonstration, "No problem, but when you speak, it's best to save a mouthful of Section Chief Fang, and have something to say." ”

"I'm not wrong, you're the section chief, what's wrong with that?"

"There's nothing wrong with it, it's just that I don't think it sounds good to the ear, so it's better to call it by its name."

Fang Hanmin walked to the test bench, took over the utensils and tools from the hands of the operators, whether it was dissolving, stirring, solution transfer, or filtration and washing, they were very proficient, and did not waste a drop of solution, which needs to be paid attention to, because palladium is a metal that is more precious than gold, even if it is wasted, the loss caused is obvious.

From beginning to end, the whole set of operations took nearly two hours, during this period, Fang Hanmin was engrossed in the work at hand, every step was meticulous, everyone present was fascinated, near the end, an operator couldn't help but admire, "Section Chief Fang, I didn't expect you to have this hand!" ”

An operator next to him, who was also from the acylation chemical section of the second workshop, immediately corrected, "Section Chief Fang has more than this hand, he has a lot of hands, in the past few years, are we still rare?" ”

Wan Cheng and Xu Hui also nodded frequently, "This operation method is too professional!" It's a pro of the majors! ”

Putting down the equipment in hand, Fang Hanmin showed a weird smile, then turned around and asked, "Is my operation technique professional?" ”

"Section Chief Fang, I didn't expect your basic laboratory skills to be so good, not only the actions are particularly standardized, but also very rigorous, to put it inappropriately, those of us who have been professionally trained are too far away from you!"

"Professional training? Hahaha! "What Fang Hanmin means, only he knows.

After washing his hands, Fang Hanmin was about to leave, but Wan Cheng stopped him again, "Fang, Section Chief Fang, I have one more question for you." ”

"Tell me! As I said just now, we only have to discuss here, not ask for advice. ”

"Activated carbon is a porous substance in its own right, so it stands to reason that it can be used directly, so why should it be ground into an ultrafine powder?"

"Yesterday, when I was discussing the problem with Guo Peng, I mentioned a technical term called specific surface area. Ordinary activated carbon is indeed a porous substance, but its specific surface area is not large enough, and if it is ground to a certain fineness, the specific surface area can be greatly increased. Specific surface area is one of the most important performance indicators of a catalyst, and the purpose of grinding is to maximize this indicator. Fang Hanmin explained.

"According to the definition, the smaller the particle size, the larger the specific surface area, should we aim for a smaller fineness of grinding?"

"Theoretically, this is the case, but the test results show that after the particle size is small to a certain extent, the increase in specific surface area is not very obvious, even if with the further reduction of particle size, the specific surface area increases, but the processing difficulty is significantly increased, because the processing difficulty is not proportional to the increase in the specific surface area, and people do not pursue the minimization of activated carbon particle size in practical work." ......

According to the test conditions given by Fang Hanmin, within half a month, the first team prepared the first batch of palladium-carbon catalysts, which can be used for hydroreduction tests of p-nitrophenol, also known as the evaluation of palladium-carbon catalysts.

In the process of aging test, Xu Hui and Wan Cheng had doubts about the process conditions given by Fang Hanmin, "Why must the aging temperature be 300 °C and the time must be 24 hours?" It's all a test anyway, so why can't you try it at 250°C, 280°C, or 320°C? Why can't the aging time be 15 hours, 20 hours, or 30 hours? ”

After hearing about the doubts of the two technicians, Fang Hanmin not only did not have other ideas, but thought that the technicians dared to ask questions, which was worth encouraging. Because the catalyst is relatively expensive and cannot tolerate more waste, Fang Hanmin only gave the other two sets of aging test conditions, which are 280 °C, 30 hours and 320 °C, 20 hours.

In order to distinguish the catalysts under the three sets of test conditions, Fang Hanmin labeled the first batch of catalysts given by him at 300°C and 24 hours, and the catalysts under the other two groups of aging conditions as the second and third batches, respectively.

After the first batch of catalysts was prepared, the catalytic hydrogenation test device of the second group was ready, and according to Fang Hanmin's suggestion, they first evaluated the first batch of palladium-carbon catalysts.

According to the test conditions given by Fang Hanmin, the second group used the first batch of catalysts to carry out the hydrogenation reduction reaction, six hours later, the evaluation test ended, through the laboratory analysis test, the selectivity of the catalyst to the target product reached 99.5%, and the conversion rate was 62%.

The evaluation test continued, the reaction time was extended, the selectivity of the catalyst remained basically unchanged, and the improvement of the conversion rate was very limited. The shortened reaction time had little effect on the selectivity of the catalyst, but the conversion rate quickly dropped to 55%.

A week later, one group completed the preparation and aging of the second batch of palladium-carbon catalysts, and the two groups did evaluation tests under the same conditions, and the results showed that the selectivity of this batch of catalysts reached 98.5%, while the conversion rate was only about 50%.

The evaluation of the third batch of palladium-carbon catalysts was completed a month later, and the data showed that the best selectivity was only 97% and the conversion rate was 55%.

The data will not lie, three batches of palladium-carbon catalysts were prepared according to different conditions, only the first set of process conditions given by Fang Hanmin, the prepared catalysts were the best in terms of selectivity and conversion rate, and the other two sets of process conditions were obviously not the first choice for the preparation of palladium-carbon catalysts.

The scientific research team led by Fang Hanmin spent less than half a year to complete the small-scale research on the preparation of acetaminophen by hydroreduction from catalyst preparation to efficiency evaluation.

After receiving the arrangement of the work summary, Jiang Guoxin and other four technicians felt incredible, in their impression, the technical development of this kind of project, even if it is a small test in the laboratory, it is impossible to complete the project without two or three years, Fang Hanmin wants to finish the problem in such a short time, is it too hasty?

The four technicians compared Fang's decision with what they had seen during their university years, and they doubted whether Fang Hanmin understood the general process of scientific research.

"Section Chief Fang, is this the end of the small test?"

"Yes, the work of the laboratory is basically over, and then we have to prepare for the pilot scale-up test."

"However, it has only been three or four months, and we have only done three sets of comparative experiments on process conditions, so is it a bit too rigorous to end the small test?" The four technicians, represented by Guo Peng, spoke very bluntly.

Fang Hanmin doesn't like to beat around the bush, he is very comfortable with this straightforward way of speaking, "Oh, do you think the small test is not rigorous? Okay, everybody go to my office, let's talk about it in detail, and I want to know what is not being done rigorously. ”

Borrowing a few chairs from other offices, Fang Hanmin sat around with the four technicians, and he wanted to create an atmosphere of knee-to-knee conversation, "Which of you four will talk about the previous stage of laboratory work, what aspects of the laboratory work we didn't do carefully enough?" ”

Guo Peng took the lead, "During the university, we also did some research and development projects with our teachers, although we were only assistants, but we also knew the general technology development process. In the test some time ago, whether it is the preparation of palladium carbon catalyst or the performance evaluation, we only tested three sets of different process conditions, which I think is too little, a bit arbitrary, and too unrigorous. ”

"I agree with Guo Peng's statement, it is too hasty to end the small test project in such a short time! It should also take two or three years to test all possible process conditions, even if other process conditions are not feasible, it is convincing to verify through experiments. Wan Cheng then echoed that he did have a tacit understanding with Guo Peng.

Fang Hanmin did not comment for the time being, he looked at Xu Hui at level seven and Jiang Guoxin at level seven or eight, "The two eldest brothers also talk about your opinions." ”

"Like them, we have similar opinions."

Fang Hanmin nodded, "The opinion is very good, but it feels a bit general, I wonder if you can make things more specific?" ”

"For example, I think that in the preparation process of the catalyst, we should further test the catalyst obtained by impregnating with different concentrations of palladium salt solution of activated carbon, and what are the differences in the catalytic performance under different activation conditions." ”

"The catalysts prepared according to different process conditions also need to be verified by multiple batches of tests under different hydrogenation process conditions for different effects on hydrogenation reactions. It is impossible to complete this work without two years. Guo Peng sang and harmonized with Wan Cheng.

From the speeches of the two peers, Fang Hanmin only saw their sense of responsibility, and he was pleased with this, which is much better than the kind of work attitude that can be passed!

However, for the purpose of setting up a scientific research team for the in-depth technical transformation project of the second workshop, Fang Hanmin did not plan to do experiments in the laboratory in a slow and orderly manner.