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Ingredients needed for 1,5kg of Picric Acid secondary/booster
1. 10 liters of 90%+ sulfuric acid (requires 2 days of labour, cost: aprox 200 euro)
2. 1,6 kg of Acetylsalicylic acid (requires 4 days + 2 days of labour, cost: aprox 1500 euro)
3. 3 kg of Sodium Nitrate (pre-ordered at apothecary, 1 week delivery time, cost: aprox 500 euro). This can also be synthesized relatively easily if you are having trouble buying it.
4. 80 liters of distilled water/distilled ice cubes (cost: aprox 440 euro)
1. 10 liters of 90%+ sulfuric acid
Estimated time required: 1-3 days to purchase the product (28-37%) and it requires 2-3 days of labour to concentrate it to 90%+.
Boiling down 35 liters of un-concentrated sulfuric acid (28-37%) to 10 liters of 90%+ concentration
In order to concentrate sulfuric Acid bought from stores (containing 28-37%) you will have to boil down the liquid. In order to get 10 liters of 90%+ sulfuric acid you need approximately 30 liters containing 28-37%.
I bought a container of 25 liters (28%) from one supplier (supplies car shops etc) and I bought 5 bottles from 3 other retailers each containing 1 liter. I also bought 4 car batteries in case I needed more.
I was uncertain how I should approach the "boiling down process" at first. The guides I had reviewed suggested you use specialty hot-temperature porcelain plates, use of specialty lab beakers, use of cooking stones to prevent sprouting and to use all necessary protection gear. As such; I assumed you needed specialty cooking plates that could reach very high temperatures and that I would need boiling stones and specialty laboratory glassware that could sustain extreme temperatures. Needless to say; the guide was wrong on all accounts! You don't need any of this to concentrate sulfuric acid! Not hot-temperature porcelain plates (any plates will do), not specialty lab beakers (any regular Duran lab beakers will do) and not boiling stones (I tried with boiling stones and it made it harder).
I initially bought 3 induction plates (flat porcelain) but they didn't function as my 2L beakers didn't cover the minimum diameter required for the induction plates to function. I used standard inexpensive lab beakers made from Duran glass btw. I also broke two other beakers made from Duran glass (crushed them to small pieces with a hammer under a towel) in order to use it as boiling stones (to prevent the liquid from sprouting).
As the induction plates didn't work for me I purchased 2 regular single cooking plates; the more expensive ones with iron plates retailing for 140 euro a piece. I had a very cheap single plate from before. Using the boiling stones was a failure for me so I reduced the amount of stones until I decided to remove them all and try without. I was also unsure how to store the concentrated sulfuric acid once I was done boiling. Some sources said glass was required while other said you needed specialty plastic. This was incorrect, as I stored my 90-95% acid in regular plastic bottles, in both 1 liter bottles (the bottles which were intended for 28% sulfuric acid) and 4 liter bottles (bottles produced for distilled water). I encountered absolutely no problems doing this whatsoever (I had them in these bottles for up to 6 weeks).
I did the boiling outside using a 10 meter electrical extension cord and I placed the cooking plate on a wooden TV rack I had carried outside. I wore a lab coat with apron with standard nitril washing-up gloves and a 3M half mask with 3M acid filter (nr. 60923 - multifilter). Skipping the stones made wonders and it quickly started boiling (set it on the highest temperature from the start). After 1,5 hours of boiling (concentration at about 70-80%) the more or less unnoticeable water damp developed into thick smoke (NOx gas). After around 2 hours of boiling the smoke was so thick I got really worried that my neighbours would notice it so I quickly cut the power. Even after turning it of it generated insane amounts of white smoke (NOx gas) for 20 more minutes. I then decided I had to do the rest during nighttime, not to attract any attention.
That night, I started the next boiling session with 3 boiling plates at around 21.30 since it got dark at 23.00 when the heavy smoke would begin to generate. I started with 1,8L of un-concentrated sulfuric acid in each of my 2 x 2L beakers and 600ml in my 1 x 1L beaker which was used on my "weaker" plate. I worked from 21.30 to 07.00 in the morning for three consecutive days before I finally was done. End note: I tried to extend the working day past 07.00 on day two which almost ended in disaster. At around 09.00 AM, I was about to put on my hazmat suit and 3M gas mask to start another boiling session when I noticed the neighbour just outside the house entrance. Had I not noticed this in time I would have to explain to him why I was wearing the protective gear, and that wouldn't end well... So if possible, even when on an isolated farm; do the boiling between 23.00-07.00 if possible. No use taking unnecessary risks. I spent 5-6 days on this process considering the fact that I had to combat false information, misconceptions and work out efficient procedures. If I had access to this guide before I started I would have been able to shorten down this process to 2 days.
Additional boiling tips:
a. Consider buying 5 or even 6 single cooking plates to reduce the boiling time drastically. Cutting the boiling time in two will drastically reduce your vulnerability to detection considering the fact that you are forced to work outdoors.
b. You will quickly learn your "progress" (purity level of sulfuric acid) by evaluating the thickness of the smoke and how many ML has been boiled away. If you start at 1,8L of 28% purity just boil it until it reaches 550ml or so to be sure you have 90%+.
c. Unless you are using identical cooking plates you will want to adjust the amount of ML per cooking plate so that you have maximum uptime and so that the concentration reaches 90% on all plates at the exact same time. You will learn this after the first session.
d. Let the acid stand for 30-40 minutes after you cut power to the plates by unplugging the electrical cord extender.
e. You can store 90-95% sulfuric acid in plastic bottles.
f. Concentrated sulfuric acid does not fume or evaporate.
g. You don't need to go overboard with protection. It will take 10-20 seconds for 90%+ sulfuric acid to burn through regular nitril gloves (medium thickness washing-up-gloves) and several seconds for it to burn through clothing. Just be rested and careful and you'll be fine. I got several drops on my gloves on several occasions and I just wiped it off with a napkin (napkin quickly turns black) before it could burn through. Avoid the "one-time-use" super thin gloves, even if its nitril. The most important things to wear are regular nitril gloves, an apron and some kind of full face visor. 3M masks are excellent since they prevent fogging on the visor.
Kg of Acetylsalicylic acid
Purifying the aspirin to pure acetylsalicylic acid. All the guides I reviewed, around 8, had flawed or even dysfunctional methods. I had to locate an entirely different method from YouTube which proved to work excellently.
Estimated time required: 4 days to purchase the product in a secure manner (assuming each apothecary has a 2 box cap). You would need to set up an "apothecary route" visiting 20-30 apothecaries in one day, then wait 1-2 weeks for safety and repeat 3 more times the next 4-8 weeks. As soon as you have all the aspirin it will require 10 minutes to pulverize it with a regular stationary or handheld blender and approximately 2 days to synthesize.
Other reagents needed: distilled water, mineral and distilled ice cubes: around 40-50 liters
You will need purified aspirin equivalent to 2,5kg of aspirin tabs/270 boxes of 20 tabs (mostly containing 440mg (producer: Nycomed, brand name: Globoid) but about 1/6th was a different brand containing 500mg tabs (producer: Bayer, brand name: Aspirin). You will be synthesizing 1,6 kg or more of pure acetylsalicylic acid from 2,5 kg of impure aspirin tablets. The reason you need to purify the aspirin is to remove the 17% of so called "fillers", stark etc. The maximum yield of pure acetylsalicylic acid you can extract from aspirin is 83%, if I remember correctly. I managed to extract aprox 67% (1,68kg out of 2,5kg) which is a good yield. It's worth noting that all the guides I could locate online were either incorrect or significantly flawed. All the guides I read failed to inform me that if you heat the aspirin to more than 70C it will destroy the acetyl and convert it to salicylic acid which is worthless for our purpose.
Of course, I had to learn it the hard way and managed to create a lot of worthless goo... Fortunately, I eventually managed to locate a method that worked optimally and I only ruined the first batch.
a. Grinding the aspirin; some retarded guides suggested I use a mortar and pestle... Needless to say, after a few hours, my wrists hurt like hell, and I realized this was an extremely poor method for the quantities I was working with. There must be a better way? I ended up experimenting and I found a very nice method. I put out a large plastic sheet on the floor and poured aprox 1000 tabs on it, spreading it evenly. I then used a 20kg dumbbell (single hand weight used for weight training) and crushed the tabs with even strokes by using gravity. It took me less than 4 hours to crush all the tabs. In retrospect I realize that using a blender would be even better. Providing you use a blender (I prefer stationary, but I guess handheld works as well) which assures a good and even spread/circulation as you grind them (same principle as when grinding AN prills) it should only take you 10 minutes to grind up 2,5kg of aspirin tabs. It's worth buying several brands of blenders to find out which offers the best circulation. Basically; only 1 out of 5 blenders offers appropriate circulation. Handheld blenders are probably the exception here since your motion determine the circulation, providing you grind it in an appropriately shaped container. With circulation I mean that as the lower part of the tabs gets grinded to fine dust, the heavy pieces of the tabs rise to the top until they are "sucked" down the "downward whirling current" - providing optimal grinding. I bought a total of 8 different blenders and only 2 of them worked efficiently for this purpose (at least for AN prill grinding). When completed; you now have 2,5kg of fine aspirin powder.
B. Manufacturing method
· 2,5kg of aspirin powder
· 5L of 95% ethanol (you can use the concentrated blue ethanol used for cleaning the windshield of cars f example, other types of alcohol works as well like isopropanol or butanol)
· Distilled water, distilled ice cubes: 40-50L
You will need 1ml of 95% ethanol for every tablet. This means that for 50g of aspirin (114 tabs x 440mg) you will need 114ml ethanol. Since you have larger quantities of materials you should use higher ratios as an effective way to save time:
I used the following ratios when manufacturing (these ratios are optimal!):
· 1040ml ethanol (I used primarily Isopropanol, 80-95% concentrated blue sprinkler fluid)
· 400g aspirin powder
· 6L distilled ice water
Alcohol note: I believe I used 95% concentrated sprinkler fluid: ethanol-Isopropanol (the liquid used for cleaning car windshields) but it might have been lower grade (80%?). I can't know for sure since it wasn't specified on the bottle. I performed a fire test and it burned, that's all I know...:P I also made a batch with butanol (concentrated red spirits used as a fuel for some apparatuses). Since this batch was successful as well, I assume a large range of alcohols will do the job. However, I have read that methanol is not suitable.
1. In a 2L beaker, heat up 1040ml of 95% ethanol on a hot plate stirrer. Drop a spin bar in the beaker and start mixing in 400g of acetylsalicylic acid powder, under stirring, f example as the temperature reaches 50C. Very important; keep the heat between 60-70C. Do NOT let the heat surpass 70C as it will start to break down the acetyl and convert the compound into salicylic acid, which is useless for our purpose! The acetylsalicylic acid should be dissolved within 5-10 minutes if it is powdered, 10 more minutes if it is clumped, and up to 45 minutes if you are using whole tablets.
2. Filter hot, for regular gravity filtration you should use 4-6 funnels with 1-2 coffee filters in each (I used 1 but you should probably use 2) over f example 4-6 x 600ml beakers. Wash the 2L beaker with a small amount of ethanol and pour it through the filter to collect any residues. Then you may wash the filter 1-2 times with a small amount of ethanol to collect any residues. The compound left in the filter will be the aspirin fillers. Discard the filters and its content.
3. As you now have approximately 1,4L ofethanol-acetylsalicylic acid in your 2L beaker; pour 350ml into 4 x 2L beakers.
4. Place the first 2L beaker with hot 350ml of ethanol-acetylsalicylic acid mix into an ice bath. As an ice bath container; you may f. example use a regular 10 liter plastic bucket (a 2L beaker fits this type of bucket perfectly with enough space for ice) filled with 0,5 liter of cold spring water and 3-4 plastic-pocket-sheets of distilled ice-cubes. You must use a weight of some sort to keep the 2L beaker submerged in the ice-water mix or it will float to the surface and fail to properly chill. You must now measure out approximately 5 times the volume of your ethanol-acid mix in ice cold distilled water that you cooled earlier. So for 350ml you will need 1750ml of distilled ice-water (very important; ensure that the distilled water is as cold as possible or you will not achieve maximum yield!). Add the ice cold water to the ice cold ethanol mix. This should more or less completely fill up your 2L beaker. The addition of the distilled ice-water will cause the acetylsalicylic acid to precipitate as it is insoluble in ice cold water.
5. Now filter the white slurry by gravity filtration using 6-10 funnels/filters/ 500ml beakers. You will obtain a white slurry-like compound in the filters. Remove the filters and its content, by wrapping them (so that the contents doesn't fall out) and temporarily store them in a large plastic box. Empty the beakers (just pour the liquid in the sink) and get ready to repeat this process as soon as possible with your 3 other 2L beakers filled with 350ml of hot ethanol-acid mix. Try to complete the batch while the ethanol-acid mix is still hot as it might impact the yield if the hot ethanol-acid mix is allowed to chill to room temperature. I used more than an hour from start until I completed the last beaker and I didn't notice any difference regarding the end result though.
· If you follow the above "aggressive" manufacturing method you should be able to complete all the batches (1,68kg total) within one single day of labouring.
· I managed to achieve a 67% yield (1,68 kg out of 2,5kg aspirin) because I was a bit sloppy when chilling the ethanol-acid mix (did not use weight to keep container submerged, and I could probably have chilled the ice water even more). If it hadn't been for that I would have managed to increase my yield.
· The guide further suggest that you purify the acetylsalicylic acid a second time. I did not purify the acetylsalicylic acid. I do not know how this would impact PA production. Will the picric acid yield achieved be lower or even significantly lower if the acetylsalicylic acid isn't purified a second time?
· Alternatively; you may use vacuum filtration for speed if you have the equipment.
This method - further discussed:
Q1: Can you use cheap 70% isopropanol or methanol?
A: The extra water in 70% IPA would reduce the solubility of ASA and increase the amount of water required to precipitate most of the ASA.
As for methanol, you have a lower BP and higher vapor pressure to deal with. You have to prevent loss of solvent (round bottom flask + condenser) and deal with the fire hazard (methanol is significantly more flammable, vapors even more so; and the flames in a well lit lab aren't visible).
A: I used the 70% IPA and it worked fine. Just used a little more distilled water...
A: You don't want to use too much alcohol otherwise you will dissolve other impurities such as triacetin. The ratio mentioned is the best ratio that has worked for me.
Q2: Is there any way to check if what I got is ASA?
A: An absolute way to test would be using FTIR spectroscopy or NMR spec. which may tell you what else is in the precipitate. If you want to test *only* for the ASA/SA in the precipitate, you could add sodium carbonate (CO2 = positive for ASA or SA), test melting point, etc.
The easiest way though would be to add some metal cation that would selectively precipitate the ASA such as Cu+2, Ni+2
C. Gathering and drying
I chose to store wrap up the coffee filters containing the wet acetylsalicylic acid in a large plastic container until I was ready to process it.
I placed the filled filter papers on a super absorbent rag 5 times to get out most of the water. Afterwards I gently squeezed another rag on top of the papers absorbing even more liquid.
I then used a plastic board, opened the seaming on the coffee filters and flattened them out like a pancake scraping off the content using a rubber scraper (the item used to evenly distribute cream on cakes is optimal).
After I had scraped out all the acid from the filter papers I spread the substance out evenly on the plastic board and placed the board in a room with an oven set to max. The temperature rose to around 30 degrees in the room. The day after much of the water had evaporated. I then semi grinded the acid clumps and again spread it out evenly. After three to four days the acid was completely dry. Note: I'm not sure whether this is optimal way of drying as it takes several days for the acid to dry this way.
It would probably be a better idea to dry the acid in a large glass Pyrex dish in the oven at around 50-70C. 1,6kg would be too much for one dish so you would in this case have to divide it into 400g batches. However; I do not know for sure how this will impact acid, which is why I chose the hard way. It is definitely worth testing though as you will save several days drying it in the oven versus my other method.
You now have 1,6kg of acetylsalicylic acid and you have just completed the second most tedious task of PA manufacturing.
Sodium nitrate can be purchased from specialty chem stores, online or at an apothecary. It is commonly used to prevent bacteria growth in meat so many hunters buy it to prepare meat before freezing. Half a teaspoon is mixed with salt and other herbs and rubbed into 25kg of moose meat f example.
Alternatively; you may synthesize sodium nitrate relatively easily. However, I will not add the guide for this manufacturing method here.
Always use distilled water when preparing and manufacturing acetylsalicylic acid and picric acid. You may buy it in car-stores as it is used as battery water. I ended up buying a total of 170L for creating 1,5kg of picric acid.
Practical tips - preparing large quantities of ice cubes: acquire a big freezer where you can store a lot of distilled ice (you fill the plastic "pocket sheets" with distilled water and squeeze the frozen cubes out of the plastic as your need arises). I converted 40-50L of distilled water into ice cubes this way (took me about 10 hours) and I filled up a large freezer for this purpose. You can only prepare smaller batches of ice cubes at a time though as you can only stack 2 layers of plastic ice-cube sheets at a time. Then you will need to wait 30-60 mins for it to freeze or the weight of the water will cause leakage in the lower levels of ice cube sheets. I also prepared ice cubes made from spring water. Just mark the plastic sheets of mineralized water with a large black X, from a permanent marker, on each side, prior to filling, so you know which sheet contains distilled and which contains mineralized water.
Producing Picric Acid
Now that you have prepared 1,6kg of acetylsalicylic acid and 9-10L of 90%+ sulfuric acid you are halfway into manufacturing picric acid.
I used the following measurement for creating PA. I had a negatively disproportionate amount of sulfuric acid so I used a little more acetylsalicylic acid and sodium nitrate.
In a 1L conical flask I heated 600ml (700 is optimal) of 90%+ sulfuric acid in a 1L conical flask up to 60C. I then, over the next 2-4 minutes mixed in 112g of acetylsalicylic acid under stirring (using a hotplate magnetic stirrer). I then turned off the heat as the nitration would ensure enough heating.
I then started the nitration process (adding 190g of sodium nitrate slowly the next 140 minutes. I added 0,3g each 15 seconds for a total of 1,2g per second making sure to keep the temperature between 60-70C. I kept the temperature at around 66C to be precisely. Keeping the temperature stable at around this heat is essential. After about an hour I had to turn up the stirring power to max as the liquid thickened.
After 140 minutes the solution was fully saturated (even though I had 24g of sodium nitrate left) and it "bloomed". Blooming is like a reversed melting process in which the solution solidifies and no amount of stirring can stop it. I do not know for sure if this is correct as I have never seen a guide describing it. Regardless, I kept on stirring every 5 minutes for the next 30 minutes, and then every 10 minutes for the next 30 minutes to prevent the increasingly "growing" substance from overflowing. This was one of my "successful" batches which contained approximately 40-50% pure PA crystals. 80% of my batches "bloomed" in this manner. It took around 4-5 hours for the container with the unpurified PA to reach room temperature. The 1L conical flask was 800ml full. At this point, I could continue the process by slowly scraping out 400 ml of semi-clumps of PA into a 2L beaker with 500ml of distilled water and the rest distilled ice cubes (filled up to 1400 ml). After proper precipitation I poured it into 6 x 500ml beakers with the same amount of funnels/filter papers, saving the filtrate and pouring out the liquid into a 100L plastic bucket (which was later to be dumped near a death-sentenced-bush, outside:)
Corrections to previous guide based on my own experiences and research while producing 10 batches of unpurified PA. When I first started this production process I assumed I would end up with a relatively pure end product, perhaps 70-80% pure after washing a couple of times. Needless to say; it was significantly more time consuming than I thought and I had to learn the hard way due to significantly lacking and even misleading guides. The positive surprise though, was that handling PA was significantly safer than I thought. I started out as overly careful as regards to PA and metal. Although you have to be careful, know that PA is perhaps the most safe booster you can work with. Unpurified PA isn't, in most cases, even flammable. So you don't need an exceptional fume hood and fan. An improvised version will work just as well for this purpose. After I had bought a fume hood I invested in two fans, one cheap version (it was actually just a dust collector suction fan) retailing for 140 euro. I also invested in a much more expensive fan (especially manufactured to prevent explosion) retailing for 950 euro. It would seem I was way too paranoid as the only dangerous gas you ever need to worry about when manufacturing PA or DDNP is the NOx gas during nitration and also H2S and SO2 during DDNP manufacture when acidifying the sodium picramate solution but these gasses aren't explosive at all. I was somehow worried that the anti-metallic nature of PA would prevent me from using a metallic fan-tube. However, using one is not a problem at all as all the PA remains in the beakers. So don't worry at all about explosive gasses cause there aren't any. And you don't need a hazmat suit either. Just use regular nitril washing-up-gloves and a good 3M face mask with visor and acid filter/vapor gas filter (nr. 60923 - multifilter) and you're more than fine.
A few guides states: after you mix in the acetylsalicylic acid with the 90%+ pure sulfuric acid, slowly mix in the sodium nitrite. A few guides did not even specify in more detail than this.
1. What many guides failed to mention and which I had to learn the hard way after ruining several batches; it is ESSENTIAL that you do the nitration (mix in the sodium nitrite) between 60-70C. I found out that if you mix in the sodium nitrite below 60C some of it turns into a layer at the bottom of the conical flask which grows ever thicker. This layer can potentially sabotage and ruin your whole batch. If the temperature suddenly rises this layer may suddenly "melt/loosen" and cause a nitration "overdose" as it mixes with the rest of the content which may increase the temperature with up to 20C within minutes and severely deteriorate the yield of the batch. This layer may also affect the magnetic stir bar and cause it to not stir properly. So make sure you prevent this from happening by keeping the temperature around 65C and never let it drop below 60C.
2. What ALL the guides failed to mention was the fact that the addition of the sodium nitrate increases the temperature of the content. So basically; as you start the nitration just after you add the acetylsalicylic acid at around 50-60C, you don't need any heat at all during the process as you can keep the heat between 60-70C by adding sodium nitrite (or potassium nitrate). Rapid heat fluctuations is the most severe threat to your batch and temperatures above 70C (not exactly sure about 70C perhaps 75C) will deteriorate your batch and cause a significantly lower yield. By deteriorating I mean lowering your yield of pure PA crystals from an optimal 50% down to 10% in a worst case scenario.
3. What all except one guide failed to mention was the importance of the glassware you are using. I used 2 x 1L beakers and 1 x 1L conical flask. All of my beaker batches ended up with a very low yield for the following reason; the magnetic stir bar works significantly better in a conical flask. I had problems in the beaker as the stirring was significantly reduces (even at max power) due to the shape of the container and the fact that I had a glass temperature rod which very presence significantly reduced the stirring output created by the stir bar. In any case; use a conical flask instead of a beaker if possible.
4. On my most successful batch I used a 1L conical flask with 600ml of sulfuric acid (90-95%). On average; I added 1,2g of sodium nitrate per minute (for my two most successful batches). Instead of dropping 1,2g in one go each 60 sec, I added aprox 0,3g every 15 sec (in other words 4 times x 0,3g per minute). I sat there for 2 hours and 15 minutes doing that on my most successful batch (with 2 x 5 minute breaks). You can imagine the agony of sitting there with a 3M gas mask on a rotten chair with your back hurting adding 0,3g every 15 sec. Its repetitive, extremely boring and frustrating. You will start to curse the fact that you didn't set up a TV nearby, or the fact that you only bought one hot plate stirrer instead of three. The prospect of doing this 10 times can be psychologically challenging. So take all measures to make your time more efficient. I managed to barely survive with my sanity intact thanks to my iPod<3
5. Acquire 3 x hot plate stirrers if possible. The nitration process is an extremely tedious and frustrating process. With three hot plate stirrers you can add 0,3g in three separate conical flasks speeding up this bitch of a task 300%. A hot plate stirrer retails for 300-500 euro so its affordable. Also, its less suspicious to buy 1 than 3:) as three mostly indicates that you are going to resell them<3
6. Creating PA proved to be a very unforgiving manufacturing method. Several things can go wrong, and most of these things relate to impatience -> too much sodium added per minute -> temperature rising to fast f example; I took a break a couple of mins too long and came back to see the thermostat at 59C. I tried to compensate with a little extra sodium nitrite, which didn't seem to have any effect on the temp. I added more and suddenly the temperature exploded and ended at 81C. A couple of other times I got too impatient and added too much per minute (although at the time I believed that a temperature above 70C wouldn't make a difference - I eventually learned that it makes all the difference). You need to be rested and focused before you begin this process (I was exhausted on several occasions which made me lose focus a few times and thus ruin the batch). As long as you focus and add the sodium nitrite 2-4 times per minute x 0,2-0,4g you should be fine.
Prepare mentally for the nitration process. Don't start if you are physically tired or if you need to eat any time soon. Just prepare and if possible have a radio, TV or iPod at your disposal.
7. Don't assume that the precipitate you end up with will be above 60% purity. Consider the precipitate you end up with grapes, whereas the actual pure PA crystals are the seeds in the grapes. If you do the process flawlessly the seeds will be large, but if you make mistakes, they will be significantly smaller. This will save you the disappointment I encountered:-). Out of 1,2kg of unpurified PA substance I ended up with only 200-300g of pure PA crystals. Had I done everything optimally I would have ended up with 1,5kg of unpurified PA substance and perhaps 0,8-1kg of pure PA crystals.
8. You can mix in the acetylsalicylic acid quickly. I never spent more than 5 minutes mixing it in, in the beginning of the process. As soon as you have mixed it in and it has fully dissolved you can start the nitration process. I usually mixed it in at around 60C and started the nitration process at around 60-65C.
It says in most guides that you need to wash with ice cold water 2-10 times. Basically, if you want to do this; just pour water over the filter to clean away sulfates. However, as you need to purify your yellow PA substance anyway, it is pointless to wash it! As I didn't know this at that time I washed the PA-substance 2 times, and the batch intended to create DDNP; 4 times.
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