I Have a Research Support System

Is it because the main valve and pressure reducing valve are not open? Xu Qiu asked.

It makes sense, maybe Duan Yun turned it off, Chen Wanqing said:

If the nitrogen cylinder is not used for a long time in the laboratory, the main valve needs to be closed, otherwise the gas may slowly leak.

Chen Wanqing unscrewed the main valve and pressure reducing valve, and opened the nitrogen valve again, but the balloon still showed no signs of getting bigger.

Why are you still not angry?

Xu Qiu pointed to the barometer of the pressure reducing valve beside him, and said:

The reading is 0, the cylinder should be empty.

Then, he unscrewed the main valve of a steel cylinder next to him, saw that the air pressure gauge of the pressure reducing valve had an indication, then opened the pressure reducing valve, and said:

Senior sister, try this time.

It's full this time. Chen Wanqing slowly unscrewed the nitrogen valve, the sound of air flow came, and the balloon was also slowly getting bigger.

The three-way valve connected by the balloon has three ports of ABC and one valve, and the three-way valve can be in four states by turning the valve: AB connection, BC connection, AC connection or three-way connection.

Among them, the A port corresponds to the balloon, the B port can be inserted into a 19-port glassware, and the C port can be connected to a rubber hose, connected to a nitrogen flow or a vacuum pump.

...

When the balloon was inflated to the size of a fist, Chen Wanqing closed the nitrogen valve, turned the three-way valve to connect the balloon with the outside world, and then flattened the balloon to discharge the residual gas inside.

The senior sister filled the nitrogen again and exhausted it.

After three consecutive times, she filled the balloon with a large amount of nitrogen gas to inflate it to the size of a human head, and then turned the three-way valve to the three-way state.

Next, she took the nitrogen balloon with the three-way valve and inserted it over the top of the spherical condenser.

Subsequently, connect the vacuum pump to the C interface of the three-way valve, and connect the vacuum pump and the distillation device.

Start the vacuum pump to pump air until the toluene boils. At this time, the air in the distillation device is basically pumped out. Turn the three-way valve to connect AB, and use a nitrogen balloon to supplement nitrogen in the distillation device.

Continuous pumping and deflation, repeated three to five times, can ensure that the atmosphere in the system is basically nitrogen.

After completing this operation, Chen Wanqing sighed:

Actually, our synthesis equipment is the beggar's version. Like the research group specializing in synthesis experiments, they will use double-row pipes to realize the nitrogen protection operation, so it is not so troublesome.

Moreover, there is also a microwave reactor dedicated to polymerization reaction, which can greatly save the time required for reaction.

The equipment is probably very expensive, Teacher Wei is not willing to buy it. Xu Qiu guessed.

That's right, it costs tens of thousands or hundreds of thousands to buy any instrument. After Mr. Wei returned to China, he had 3 million start-up funds for scientific research, and he has already spent more than half of it.

However, he has also applied for the National Natural Science Foundation of China, and some other small funds, which add up to more than one million yuan, which is not considered short of money for the time being.

While replying, Chen Wanqing opened the condensate pipe, set the temperature of the magnetic constant temperature heating stirrer to 130 degrees Celsius, and adjusted the speed to 400r.p.m.

The temperature rises slowly.

Shortly after the temperature stabilized at 130°C, the toluene in the round bottom flask began to boil.

The toluene vapor passes through the solvent distillation head, reaches the spherical condenser, condenses into a liquid state, and flows back to the solvent distillation head again.

There is also a three-way valve on the solvent distillation head, which is respectively connected to the round bottom flask at the lower end and the outside world.

Chen Wanqing adjusted the three-way valve to the state connecting the round bottom flask, and said:

This way, the condensed toluene solvent can be refluxed back into the round bottom flask again.

The solution is still white now, and we have to wait for the indicator to turn blue before we can collect the distilled toluene.

Because it is a newly opened toluene reagent, the bluening speed should be quite fast.

During the waiting period, we can do some preparatory work, such as cleaning and drying glassware.

Because this is a new glass instrument, you only need to rinse the inner wall of the glass instrument with absolute ethanol, and the stirring bar can be rinsed in a disposable PE cup.

After cleaning, pour ethanol into the waste liquid bucket, and then dry the glassware in an oven set at 70 degrees Celsius.

This time we cast a reaction to test the water. Each person needs to prepare a 25ml two-necked flask, a 19-necked spherical condenser, a three-way valve, and a magnetic stirrer.

Xu Qiu followed the senior sister's instructions, cleaned the glass instruments and put them in the oven.

Then it is to calculate the ratio of material input, the molar ratio of the monomer with trimethyltin, the monomer with bromine group, and the catalyst is generally 1:1:0.05.

The relative molecular mass of each material should be calculated before weighing, and then converted to the corresponding mass.

To calculate the relative molecular mass, you can use Chemdraw software to draw the molecular structure, and then use the functions that come with the software to calculate the relative molecular mass.

In our first experiment, we used less raw materials and kept the total mass of materials at about 200 mg.

You can fix the mass of one of the monomers to be 100 mg, and then calculate the mass of the other monomer and catalyst, which is also easier to weigh.

Mine has already been calculated, you can go to the office and use the computer to calculate it, then write it down on a sticky note and bring it with you. Chen Wanqing said.

Xu Qiu nodded, took off the protective suit, and returned to the A501 office.

As for the goal of being the first to test the water, he has already thought about it.

One kind of monomer is a T-BT-T unit connected with a bromine group, wherein each of the two T units has a 12-carbon alkyl side chain to ensure the solubility of the final polymer product.

The other unit is a 2T unit with trimethyltin attached. He bought one gram each of these two raw materials, so he is not afraid of wasting them.

The main chain of the expected polymer is roughly like this:

…BT-T-T-T-T-BT-T-T-T-T-BT-…

Xu Qiu even thought of the name of the polymer, which is called PBT4T, where P stands for polymer, 4T stands for four consecutive thiophenes, and BT stands for BT unit.

This is a product of his own synthesis, so he is naturally qualified to name it.

For example, some researchers or research groups, in order to save trouble, also simplify the naming. For example, a researcher surnamed Xu can name a series of materials he synthesized as X1, X2, X3, ....

Of course, whether other researchers admit it is another matter, because everyone can give these structures a different name.

However, in order to facilitate communication, there is generally a set of common naming methods. For example, Xu Qiu adopts a common naming method, starting with P, followed by the name of each monomer unit.

Xu Qiu drew the molecular structure with Chemdraw software, and after obtaining their relative molecular masses, set the BT unit connected with bromine group as 100 mg.

Then calculate the feeding mass of another monomer and catalyst, and write them on the label paper.

He returned to the laboratory again and put on his protective suit again.

Is it ready so soon? Chen Wanqing said:

Didn't you miss the branched chain when calculating the relative molecular mass?

No.

Trimethyltin and bromine groups are also included.

No.

That's good, Chen Wanqing said:

The first time I submitted a response, Teacher Wei was watching from the side, and I was too nervous to miss these two.

In the end, a pile of scum was synthesized, which was scolded by Mr. Wei.

The past is unbearable.

Thanks to Fei Bing, Lanshan Zhe, and Swimming in the Desert for their 100-point rewards, and Liu Qigongzi V for their 500-point rewards.