"I have a question. In the literature, methanol, acetone, and n-hexane are generally extracted separately. Why do we use mixed solvents?" Xu Qiu asked.

   "It is indeed better to extract with three solvents separately," Chen Wanqing said:

  "But it needs to be changed every few hours, which is more difficult for people like us who do experiments across campuses.

  Considering that the boiling points of the three solvents are not much different at about 60-70 degrees Celsius, they can form azeotropes, so I simply mixed them and extracted them for 24 hours. "

   "There is another question. I think they will use chloroform to extract the polymer at the end of the synthesis process, and then drop it into methanol for precipitation. Should we also try it?" Xu Qiu asked.

   "Using chloroform for Soxhlet extraction, it is estimated to use more than 250 ml. The toxicity of chloroform is not small, and I am not sure of the specific effect, so I didn't dare to use it before." Chen Wanqing

   Xu Qiu nodded to express understanding, and he also thought in his mind:

  If it is extracted with chloroform, there is a risk of chronic poisoning, but there is a chance to improve the performance of the material, will he use it?

  ……

   Let's think about it later.

   Leaving this question behind, Xu Qiu started to build the Soxhlet extraction device.

   In a 1-liter Erlenmeyer flask, add 200 ml each of methanol, acetone, and n-hexane, and put in a magnetic stir bar.

   Then, wrap the filtered product with filter paper, put it into the extractor, connect the spherical condenser, and connect the condensed water.

   Finally, set the temperature of the oil bath to 75 degrees Celsius and turn on the stirring.

  ……

   The toluene indicator in the toluene re-distillation device turned blue after the device was started.

   Xu Qiu collected about 50 milliliters of toluene, shut down the re-evaporator, and let the toluene in the solvent distillation head slowly cool down.

   Then, he went to verify the airtightness of the vacuum tank and found that it had been left for a whole morning and still had a high vacuum degree, which showed that the vacuum silicone grease sealing effect was very good.

   told the senior sister of the news, he evacuated the vacuum tank again, filled it with nitrogen, and stored it in a dark cabinet.

   It's already twelve o'clock noon.

   The two finished the morning experiment and returned to A501. After washing their hands, Xu Qiu reminded:

   "Senior sister, I want to talk to Teacher Wei about the oil bath."

   "Yes, I almost forgot." Chen Wanqing dialed Teacher Wei's phone.

   Xu Qiu looked at her mobile phone screen curiously. The memo she gave to Teacher Wei was "wei".

   The phone is connected and she turns on the speakerphone.

   "Hey, what's the matter?"

   "The number of oil baths in Zhang Jiang's laboratory is not enough. I want to buy more."

"How much is it?"

   "I haven't checked..."

   "Taobao is about four or five hundred and one," Xu Qiu hurriedly interjected:

   "If we continuously react, we need one for re-distilled toluene, one for Soxhlet extraction, and one or two for the reaction. Two people are definitely not enough."

   "Okay, then buy it.

   The unit price of the equipment is less than 1,000, and there is no need to make fixed assets. Chen Wanqing, you pay first, and then tell me after you have paid, I will transfer the money to you.

  Remember to ask them to issue a VAT invoice, and leave a screenshot of the payment voucher, don’t forget. "

   Teacher Wei paused and said:

   "By the way, how is your experiment doing."

   Chen Wanqing was a little guilty and looked at Xu Qiu.

   Xu Qiu is spreading out.

   "We are dealing with yesterday's reaction. We don't know the result yet. We plan to vote for another reaction today." Chen Wanqing evasively said.

   "Okay, you two pay attention to safety."

   After speaking, Teacher Wei hung up the phone.

   Chen Wanqing took a long breath and said:

   "I didn't expect him to ask about the experiment. He didn't prepare at all."

   "Just tell the truth, how can experiments be successful?"

   During the call, Xu Qiu found a well-reviewed oil bath on Taobao.

   He handed the phone to Chen Wanqing and said:

   "Senior sister, what do you think of this house? I read good reviews."

   Chen Wanqing read the introduction and comments for a while, and said:

   "This one looks good, how many are we going to buy?"

   "Four stations, considering the extreme situation of each of us casting two reactions, and Duan Yun may also use it." Xu Qiu said.

   "Then four stations, you send me the link, I will chat with the customer service, and see if I can bargain." Chen Wanqing said.

   After Xu Qiu sent the link, the two sent to the cafeteria.

  ……

   Zhangjiang Canteen has two floors, but the number of windows is less than the first floor of Handan Canteen.

   But similarly, there are fewer students eating here.

  The contractor is also different. There are more dishes here, but the price is a bit more expensive.

   Xu Qiu made a dish of vegetable rice and bone soup with braised short ribs, while Chen Wanqing took a small bowl of steamed vegetables with two vegetables and one meat.

   After finding a seat and sitting down, Chen Wanqing took out her mobile phone and contacted Taobao customer service.

   "The customer service said that buying four sets can be discounted. The original price is 1,800 yuan, and the discount is 200 yuan. However, if you issue a ticket, you will have to pay 6% more, so the final price is 1,696 yuan."

   Xu Qiu nodded. It is also an unspoken rule to pay more for invoices.

   Seeing the senior sister put away the phone, he asked:

   "Don't you report to Teacher Wei?"

   "Let’s talk later."

   "Should we pay for this small instrument?"

  "Yes, this kind of small amount is usually paid by ourselves, and then we ask Teacher Wei for the money. If the amount is large, we can contact him in person and let him pay.

   Anyone pays the same, and can be reimbursed afterwards. "

   "Is it reimbursed with the money in the fund project?"

   "That's right~www.ltnovel.com~ Most of them are for materials.

   It is like the oil bath we are going to buy. Although it is an instrument, it also costs material because the amount is too small.

   Teacher Wei delegates the power to Wu Feifei to be in charge of finances, but she can't leave all the reimbursements to her.

   Therefore, we agree who buys the things and who is responsible for the reimbursement.

   For reimbursement, the steps are still more cumbersome.

   First, wait for the invoice to arrive, then fill out the appointment reimbursement form online, and wait for the department and the financial department to review.

   After the review is passed, we will print out the appointment reimbursement form, together with the invoice and other supporting materials, such as payment vouchers, and submit it to the financial office.

   The Finance Department will re-check whether the materials are complete, and only after the review, will the account be paid.

   The entire process runs down, usually more than a week.

   When I was studying for a master's degree in the early years, it was not so strict. Now the requirements for reimbursement are getting stricter. "

   After hearing the reimbursement situation mentioned by the senior sister, Xu Qiu thinks that the threshold for entering colleges is getting higher and higher.

   If you want to enter a better teaching position, you basically need more than two years of overseas study experience.

  The current scientific research field has slowly transitioned from the blue ocean to the red ocean unknowingly.

   Guo Jia's tightening of financial reimbursement is also one of the manifestations.

   In the early years, scientific research talents were particularly scarce, so some people made small moves in financial reimbursement, and they turned a blind eye.

   At present, although high-end scientific research talents are still in short supply, with the continuous introduction of talents from overseas and domestic talent cultivation, basic scientific research workers are no longer so scarce, and there is an increasing trend.

   Naturally, I won’t tolerate people who do little tricks anymore, and it may not be necessarily after the fall.

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