From a chemical point of view, nitro compounds themselves are unstable and generate oxygen after thermal decomposition. The carbon in organic molecules provides fuel. Therefore, the combustion of nitro compounds can proceed spontaneously without the need for oxygen from the outside. During the entire combustion process, A large amount of heat will be released, further causing positive feedback and accelerating the self-decomposition of the nitro compound, causing the overall reaction speed to expand instantly.
Most nitro compounds, including nitrocellulose, nitroglycerin, nitrated diethylene glycol, nitrated triethylene glycol, etc., are flammable and explosive substances.
In a large-dose beaker, delicate cotton undergoes an esterification reaction under the influence of a saturated solution of concentrated nitric and sulfur mixed acids. Sulfuric acid acts as a catalyst to continuously increase the entire reaction rate and process. The reaction formula is [c6h7o2 (oh) 3] + nyhno3? [c6h7o2 (oh) )3-y(ono2)y】n+nyh2o, a reversible reaction produces h2so4.
Fifteen minutes have passed and the scheduled time has arrived.
Yu Hua turned his eyes to the beaker. At this time, the refined cotton in the nitrate-sulfur mixed acid solution had undergone subtle changes and became more transparent. According to the experimental steps, he carefully took out a ball of refined cotton that had undergone the esterification reaction and washed it with water first. Then wash with ethanol, and then put it into a beaker filled with alcohol ether acetone solvent.
Next, is the most critical testing link.
As the refined cotton that has undergone the esterification reaction comes into contact with alcohol, ether, and acetone solvents, the seemingly flexible refined cotton breaks immediately and dissolves at a speed visible to the naked eye.
Yu Hua holds the experimental notebook in his left hand and a pen in his right hand. While observing the inspection situation in the beaker, he records the entire process in detail.
Two minutes later, the entire ball of refined cotton was completely dissolved, which was initially indicated as complete nitrification. Yu Hua immediately conducted other tests on it. Regarding the esterification degree of nitrocellulose, it is mainly represented by three key parameters. First, the most important percentage of nitrogen content. , two, the degree of esterification, three, the degree of nitration.
Three key parameters determine the quality of nitrocellulose and distinguish its final use. Later gunpowder science divided nitrocellulose with different nitrogen contents into four levels: ABCD.
The nitrogen content of Grade A nitrocellulose is in the range of 12.5%-12.7%, and the solubility of alcohol, ether and acetone solvents reaches more than 99%. This is the most ideal top-quality nitrocellulose for single-base propellants.
The nitrogen content of Grade B nitrocellulose is more than 13.2%, and the solubility of alcohol ether solvent is about 40%. It is also used to prepare single-base propellants.
C-grade nitrocellulose has a nitrogen content of 11.9%-12.4% and a solubility of 95%, and is used to prepare double base drugs.
D-grade nitrocellulose has a nitrogen content of about 11.8%-12.1% and a solubility of more than 98%. It is used to prepare double-base chemicals and rocket propellants.
And Yu Hua’s current goal is to produce Grade A nitrocellulose.
With nearly a thousand times of similar thinking simulation training + brain, Yu Hua accurately controlled his hands and continuously conducted a series of tests as required. His movements were particularly skillful, and the process was quick and steady.
It has to be said that Yu Hua at this moment has extremely rich experience in making nitrocellulose by hand. He is no worse than the master craftsman in the gunpowder workshop of Hanyang Arsenal, or even more.
stable!
Whether it is preparing nitrocellulose or testing nitrocellulose, the most important requirement is stability.
Yu Hua relied on his brain's ability to precisely control his hands, and the entire detection process was without any tremors. The stability was beyond imagination and comparable to machinery.
Standing aside, Xu Rui methodically handed over various expensive chemical reagents and equipment in accordance with Yu Hua's requirements.
Twenty minutes later, Yu Hua, who had completed more than a dozen chemical tests, got the final result - the nitrogen content was 12.6%, the solubility of alcohol ether solvent reached 99%, the quality was top-notch, and it met the standards of Grade A nitrocellulose.
The first experiment to prepare nitrocellulose was successful.
Now, after a completely tested esterification reaction, the refined cotton will be officially renamed nitrocellulose and become another substance.
This is the power of chemistry that can turn cotton used for heating into a deadly murder weapon with just one simple operation.
After Yu Hua finished recording, he quickly took out the nitrocellulose from the nitrate-sulfur mixed acid and processed it according to a series of subsequent steps: deacidification with soda ash, washing with water, and then dehydration and drying.
After a while of busy work, the finished grade A nitrocellulose, which was purely hand-made, was quietly sitting in the container on the operating table, a total of 9 balls.
"The next step is to use b-grade nitrocellulose with an alcohol ether solubility of about 40%." After completing this operation, Yu Hua immediately followed the formula of single-base propellant to prepare b-grade nitrocellulose.
Among the components of the entire single-base propellant, nitrocellulose accounts for about 95%. It is mainly composed of a mixture of two types of nitrocellulose with different nitrogen contents, which can also be called mixed nitrocellulose.
It can be said that the quality of the two nitrocellulose determines the final performance of the single-base propellant.
With the first successful production experience, about an hour later, Yu Hua, who was busy in the laboratory, successfully produced B-grade nitrocellulose with incomplete nitrification.
There is a ball of nitrocellulose in a gel-like state inside the beaker, which is an ideal carrier for various energetic solvents and grade A nitrocellulose. It is exactly the same as the nitrocellulose produced in the video of the boss of station B that I have seen.
With the raw materials ready, the research and development progress of single-base propellant technology has reached the final step - configuring the propellant.
This is the most important and critical part of the entire research and development process. One wrong step will affect the performance of the propellant and prevent it from achieving the expected goals.
Fortunately, Yu Hua remembered the complete recipe and detailed experimental steps of the original video, and he could get it done just by following the instructions.
If he were allowed to truly develop a new type of single-base propellant from scratch, the development process would never be so easy.
It's useless to just know the raw materials and formulas. There must be detailed steps. Just like the formula of Coca-Cola, everyone knows that it contains water and saccharin, but who can make it taste exactly the same?
cannot.
"Ruizi, go get diphenylamine, camphor and graphite." Yu Hua, whose hands were sore, stood aside to rest for a moment, looking at the two kinds of nitrocellulose on the operating table, his eyes revealed a ray of light, and said to Xu Rui.
"Yes!" Xu Rui seemed to have understood something, nodded, and turned around to get the corresponding chemical materials.
Yu Hua left the operating table and came to the experimental product storage area on the left side of the laboratory. Holding his breath, he picked up the nitroglycerin that was first prepared in his hands, carefully transferred it to the operating table, and put it down gently.
If nitrocellulose will spontaneously ignite if you are not careful, then these two kilograms of nitroglycerin are extremely unstable and will explode if you are not careful.
At this time, Xu Rui had already brought the three required chemical materials and placed them on the operating table.
Yu Hua put down the nitroglycerin and stood in the main position. He closed his eyes and recalled the detailed steps in the video for the last review. After ten seconds, he opened his eyes and picked up the beaker containing colloidal nitrocellulose with his right hand.
Next, add diphenylamine.
Diphenylamine is used as a chemical stabilizer in the entire formula, mainly used to improve the chemical stability of the single base drug storage composition and extend the storage life.
