Acid/Base Step-by-Step for the Novice

by Jamiroquai

So Your Rp/I Reaction is over? What does one do with this nasty stuff now? How is it turned into White Powder?

A simple, basic, no-frills, post-reaction work-up, for early dreaming.

Preface

This method or some variation of is used (theoretically) by most Dreamers. It is basic, well-known, well documented and often ignored, until the last minute, by those who need it. It has been written here, in fair detail, to benefit those who, have never been exposed to such things before. There are better procedures available, which provide a cleaner and more intense end result. This Procedure however, should become well familiar to the Novice, initially. This account should be an adequate and descriptive step-by-step guide, hopefully answering many questions.

Step 1. Boil the Post Reaction Solution

At this point, the dreamer should see before him/her a container, that has some red/yellowish/brownish/dark, material inside, the result of an RP/I reaction, in all likelihood.

First, the dreamer must decide whether or not this container, in which the reacted materials are held, is able to withstand direct heat from a stove or similar burner, without breaking. If it is a pyrex or similar piece of kitchenware, it is not stove top safe. If it is Lab ware or Visio nware it is stove top safe. If it is anything else other than something specifically designed for stove top use, it will likely break. All could be lost.

Heat up some distilled water (dH2O), until it is nice and hot, like a very hot cup of coffee. Pour some onto the reaction solution; just enough to raise the volume of material, approximately 5 times that of the reaction material alone. A minimum of 75ml is a good guideline for first timers. As one is more acquainted with the procedure, less or more may be used, as preferred.

Swirl it around inside the reaction vessel, to loosen any material clinging to the inside. If the vessel is stove top safe, place it on heat and boil it for 5-10 minutes. If the reaction vessel is not, transfer the solution to one that is.

The post reaction solution should appear as a clear fluid, it may appear a little "milky or clouded", with the Red Phosphorus (Rp) swirling around inside. It will have a characteristic odor of "boiled onion" or "cat pee".

If it is any darker, it should be boiled for the full ten minutes, sometimes the Rp gives the illusion the solution is dark. Let it settle and double check the color. If it is yellow, boil it for up to 10 minutes or so, it will likely clear. This color is usually excess Iodine.

If the solution remains dark with Iodine,and strong Iodine Odor or Vapor are noticed, in all likelihood the reaction was incomplete. Although when refluxing in particular, it could be clear and still not complete, so keep this mind.

If it is very dark, it should be placed on very low heat, allowed to evaporate to it's original volume. At that time new Iodine, at least 75% of the original amount, H2O, to discretion, and Rp, about 15-25% of the original weight, should be added, and the reaction restarted.

If the reaction solution is no darker than "honey" after boiling, proceed. Though a clear or possibly a clouded whitish solution is to be strived for on subsequent reactions.

Step 2 Make a NaOH Solution

In a separate container, which should be oven safe glass, a beaker, or a thick glass/ceramic mug. Pour in 100ml dH2O, slowly add lye (NaOH), with stirring until no more will dissolve, at which time the solution is saturated. A saturated solution contains as much of a given material(s) that it can possible dissolve. The amount of material they can dissolve, increases as they are heated, and decreases as they are cooled. It may take a few minutes so keep stirring. Do not inhale the fumes, they may sting the eyes, the solution will become quite hot. As the liquid stands it will cool off and become clear, allow it to cool to room temperature, it may be chilled if desired. Do not touch, drink, or store this liquid where it could unknowingly be a hazard. It is highly caustic and will burn living human tissues, with only brief exposure.

It will be used later. Set it aside to cool.

Step 3 Filter Out the Rp

The post reaction solution, will now carefully be filtered to remove all the Rp. A coffee or similar filter is adequate, vacuum filtration is optimal. Remember that the Rp may be saved, dried and re-used. It is best to filter the solution directly into the separatory funnel (or sep funnel), to keep the amount of containers to a minimum, and reduce loss. Make certain the filter has been pre-saturated with dH2O, so it will not soak up product. Make sure to rinse the Reaction Vessel, with dH20 and filter that as well. This will help get any product or Rp sticking to the sides, so it will not be lost.

Now go thoroughly clean the Reaction Vessel, and thoroughly rinse it with dH2O, if it is of sufficient size it will be used in the next step, if not use another suitable container.

A separatory funnel, is a laboratory tool, consisting of a container with a opening at the top, which can be sealed, and an outlet at the bottom, which can be opened and closed with a small valve . It resembles an enclosed funnel, and in fact, is. It is, indeed, the best tool to be used in this process. 500ml, is the optimum size, for Dreaming hobbyists. If one intends to be a Dreamer, it is an indispensable tool, and no substitute, is as good. A sep funnel and a reaction flask, are the most important lab ware, a Dreamer could acquire. Suitable substitutes, can be fashioned for this purpose easily, and plans are everywhere. Even a Jar, could substitute, with a Turkey Baister, to remove fluids, but it makes the process less efficient and more difficult.

Step 4 Post Reaction NP Wash

Pour Xylene, Toluene, Hexane, Naphtha, Petroleum Ether, Diethyl Ether or any suitable Non Polar Solvent (NP), into the separatory funnel, in the amount of 1/3 the volume of the Filtered Reaction Solution. Swirl and shake the sep funnel gently for a few minutes (not seconds), and allow it to settle for a few minutes. Two layers will be formed, one layer or phase, at the top contains the NP, its called the organic layer. The bottom layer is the dH2O, or the aqueous layer. It should be noted that some less common NP solvents, such as DCM (dichloromethane), settle to the bottom, however, these aren't commonly available, to New Dreamers or necessarily to be used in this application.

After the solution settles for a minimum of 5 minutes, and interface between the layers is distinct, drain the aqueous layer carefully into the reaction flask. Drain the organic layer into a suitable container and set it aside. Pour the aqueous layer carefully back into the sep funnel.

The sep funnel must be swirled or shaken very gently, otherwise an emulsion could form. An emulsion will cause the layers to separate slowly. Should this happen, careful swirling may help to break the emulsion. Simply allowing the emulsion to break over time is otherwise employed. The key is being careful to not proceed until the layers are well separated, leaving a very distinct interface between them.

Repeat Step 4 again. More than once if desired.

Step 5 Basifying

The aqueous layer, should now be in the sep funnel alone.

This will begin a process, known to chemists as an "Acid Base Extraction" ( A/B), reference material should be read on the matter, so the Dreamer will understand how it works. A true understanding, will make any unforeseen problems, easier to overcome.

For this step and others, New Dreamers, must obtain a ph measuring device. Ph, means Power of Hydrogen , it is a scale from 0 to 14, with 0 representing a totally acidic solution, and 14 being a totally basic solution, dH20 should be a ph7, or neutral, on the ph scale. Strips, tape, and electronic checkers are easily obtained, they should measure 0-14, and are extremely inexpensive. Other ph checking methods may be employed, the Red Cabbage Scale, is excellent as well, look around for the plans.

Add some fresh NP Solvent to the sep funnel, about 1/2 the volume of the aqueous layer is best in the beginning, at this stage. If the NP is Naphtha make sure it is warmed before adding, otherwise it will not easily absorb the product. Xylene or Toluene are, far and away the best choices for New Dreamers here. Xylene smells better, and is more widely accessible, it is the Authors solvent choice, in these dreams.

Retrieve the now cooled NaOH solution, made in Step 2, slowly and carefully add a small amount to the sep funnel, 1-5ml. The aqueous layer may get cloudy. Gently swirl the funnel, moving it around, gently mixing and agitating the fluids for 30 seconds. Continue adding NaOH, a little at a time, and swirling, until the ph, reaches 14 (12.5 or higher, is adequate, but 14 is best used initially). Small particles or bubbles may be observed, rising toward the top of the aqueous layer. Only the aqueous layer will have a ph reading to be checked, the organic laye r is not checked.

When the ph 14 has been reached, the product in the aqueous layer has became it's free base (FB) form, and will begin to move into the organic layer. This process takes some time, it is not instantaneous.

Now begin adding some plain table salt (NaCL), to the sep funnel, slowly, with swirling, 2 or 3 grams at a time, until no more will dissolve. This will take awhile, gentle swirling is best, do not hurry. This will help the H2O, to release its grasp on the product, so it may migrate to the organic layer. Once this process is complete, allow the sep funnel sit undisturbed, until the layers are well separated, or a minimum of 30 minutes.

Step 6 Water wash the NP layer

After the sep funnel has sat at least 30 minutes, carefully drain the aqueous layer, into a suitable container. Do not, throw it away at this time. It may contain product, and can be re-extracted later. Occasionally some material will precipitate in the aqueous layer, and hover just below the organic layer. It should not be drained away when the aqueous layer is removed at this time.

The organic layer should be in the funnel, alone, at this point.

Now, more hot dH20, amounting to 1/2 the volume of the organic layer, is added. The sep funnel should now be gently stirred and swirled, for 3 or 4 minutes, to mix the layers. This step will remove water soluble compounds, that may contaminate the product, which is not water soluble at this time. NaOH, will often be trapped in the organic layer, this will remove it. Allow the sep to sit until the layers are well separated, a minimum of 5 minutes, undisturbed. Then drain away the aqueous layer, saving it with the NaOH solution previously removed. Drain away any precipitant left over when the aqueous layer was drained as well. Most likely it fell to the bottom of the fresh dH2O. Repeat this Process 2 more times.

The organic layer will likely appear rather opaque or cloudy at this time, as o pposed to crystal clear. It is not a cause for alarm.

Step 7 Titriation or Titriating

Now the organic layer, should be in the sep funnel alone.

Now add dH20, amounting to 1/4 to 1/2 the volume of the organic layer.

Carefully drip 2 or 3 drops of Hydrochloric or Muratic Acid (HCL), to the sep funnel. Shake the sep funnel vigorously. Allow it to settle until the layers are thoroughly separated (2 or 3 minutes minimum). Check the ph, if the ph is 6 or lower, shake again, and allow the funnel to sit for 10 minutes. Check the ph again if it is still ph6 or lower, proceed to the next step. If the ph is higher than 6, add 2 or 3 more drops, repeating this process until ph6 is achieved. If the ph is 7 or 8 when checked, add only 1 drop at a time. This may require time, and many ph checks, do not rush, do not add large amounts of acid rapidly. The amount of acid required relates directly to the amount of product in the solution.

If the starting material for the reaction, was 3 grams or less, add only 1 drop of acid at a time, with any addition of acid.

Before continuing, in any case, when ph6 or less is obtained, shake the solution, allow it to settle for 10 minutes, then double check the ph.

This process, allows the FB product, to attach itself to the HCL, and it becomes a consumable water soluble salt. It will move in to the aqueous layer again. This process should be performed carefully and slowly. If the ph should, inadvertently become below 6, do not panic, although it is undesirable.

Step 7 Evaporating

Now that the aqueous layer, is a stable ph6, it will be ready to evaporate.

Carefully drain the aqueous layer into a suitable evaporation dish (evap dish). Should any waxy or "skin-like" substance be visible in the aqueous layer, it should be filtered as it is added. Make certain the filter has been pre-saturated with dH2O, so it will not soak up product. Filtering will remove these solid contaminants. A small funnel and filter should be used. A tea strainer fitted with, a cut to size coffee filter can be utilized if necessary. Add the organic layer to the waste container, containing the aqueous layer and water rinses from Step 6, to be saved and re-extracted, at a later date. The sep funnel should now be thoroughly cleaned, dried and put away for safe keeping.

The evap dish itself, should be an oven safe dish at bare minimum. A stove top safe dish or appropriate lab ware are best. If the evap dish isn't stove top safe. It must not be allowed to touch any heat source directly, or be over heated. It could easily break. It should be thoroughly cleaned and rinsed well with dH2O before use.

Using very low heat, and a small fan gently blowing over the surface of the dH2O/product solution. The H2O will be slowly evaporated and crystals should be left behind. Do not allow them to burn or be over heated. The crystalline substance should be transparent, to those well versed, the particular pattern of crystallization can be recognized.

Once they have been thoroughly dried, they may be scraped up carefully, with a razor blade or similar device. They should be gathered in a small, clean glass stove top safe jar or beaker and crushed to powder. The powder should be a brilliant, sparkling white, composed of tiny transparent crystals. It may have a yellow tint if contaminated or the ph was below 6, in the previous step.

Once they have been gathered and dried. A small amount of very cold, 0C, dried acetone (tone), should be poured over them so they are covered. A dried solvent contains little or no H2O, they are dried with a drying agent like Magnesium Sulfate Heptahydrate (Epsom Salt), which has been dehydrated in the oven and added to the solvent. A drying agent soaks up residual H2O, and will not dissolve in the solvent. The solvent is then either filtered, or simply decanted off the drying agent, and used as needed. Sol vent drying techniques are easily performed, and many techniques are written in detail. Swirl the acetone, allow the crystals to settle a moment, and carefully decant the acetone, leaving the crystals in the jar. The acetone should be decanted, into another container, in the event some crystals are poured inadvertently. Repeat this step 2 more times. If the powder was discolored, more repeats may be required The crystals should then be allowed to dry.

Once they have dried, the product is in the form of a crude HCL salt, that is ready to undergo Recrystalization. Recrystalizing them is key to obtain maximum potential of the product. Documents describing it are abundant, several methods are available. A simple dual-solvent recrystalization should be adequate, for New Dreamers.

Afterward

This simple procedure, is possibly the least understood, by those just starting. It very often is the main barrier between first time success and failure. No step can be skipped, this is the crudest version, which should ever be pondered. Many refinements and options, can, and have been made, to better achieve it's end. Such as, Titriation could replaced with bubbling the dried organic layer with anhydrous HCL gas, to directly precipitate crystals, or once the Reaction solution was basified, it could be distilled. Distillation is a far superior process, which should be studied once this one is well familiar. May Joy and Success follow the Gentle Reader, into eternity.