Phosphorus trichloride

The phosphorus/chlorine cell is heated until the red phosphorus rearranges to white, at which point oxidation via the gaseous chlorine should commence and continue until the chlorine is exhausted.

Now, this is merely an outline. I haven't done any calculations or started putting anything together. If there are any flaws in this setup (or if there is a more efficient setup) I'd appreciate knowing it.

As for specifics, I would like to know how best to put together such a setup that would not explode or burst. Quantities would also be helpful.

And lastly, I need to know more about the final step. Is sustained heating required? What temperature is necessary to minimize pentachloride formation?

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simba - 6-5-2012 at 15:39

Some time ago I made a thread about making POCl3 (phosphorus oxychloride) at home, where someone posted an interesting paper about making POCl3 by heating phosphorus pentoxide with table salt at 250 ºC or so, where it also said that along with POCl3, a small fraction o PCl3 is also generated from the reduction of POCl3 by the iron from the metal container used to carry out the reaction (the reaction can't be done in glass container).

I think reduction of POCl3 could be a more suitable way to make PCl3 at home. Phosphorus pentoxide isn't controlled so can be easily bought also.

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AndersHoveland - 6-5-2012 at 17:41

Phosphorous trichloride is a volatile liquid that gives off extremely poisonous fumes. The mechanism of toxicity is similar to carbon monoxide, and the fumes from PCl3 are very much more poisonous than the chlorine gas used to make it. For this reason working with PCl3 can be very hazardous. I recommend you NOT try to make this, especially if you are an amateur hobbyist.

To make PCl3, phosphorous is reacted with chlorine. But excess chlorine will oxidize the PCl3 to PCl5. For best yields, it is important that the chlorine be free from moisture, this is usually done by passing the gas through porous CaCl2 powder that has been baked dry.

Red phosphorous spontaneously ignites in chlorine gas (it also ignites in bromine vapor).

[Edited on 7-5-2012 by AndersHoveland]

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Lambda-Eyde - 8-5-2012 at 17:54

Quote: Originally posted by simba

Some time ago I made a thread about making POCl3 (phosphorus oxychloride) at home, where someone posted an interesting paper about making POCl3 by heating phosphorus pentoxide with table salt at 250 ºC or so, where it also said that along with POCl3, a small fraction o PCl3 is also generated from the reduction of POCl3 by the iron from the metal container used to carry out the reaction (the reaction can't be done in glass container).

Looking for this?

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simba - 10-5-2012 at 19:11

Quote: Originally posted by Lambda-Eyde

Quote: Originally posted by simba   Some time ago I made a thread about making POCl3 (phosphorus oxychloride) at home, where someone posted an interesting paper about making POCl3 by heating phosphorus pentoxide with table salt at 250 ºC or so, where it also said that along with POCl3, a small fraction o PCl3 is also generated from the reduction of POCl3 by the iron from the metal container used to carry out the reaction (the reaction can't be done in glass container). Looking for this?

yes, thats it.

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AndersHoveland - 10-5-2012 at 22:37

Sulfur dichloride can often be used in place of PCl3 as a regent in organic chemistry. Another common regent for this purpose is benzene chlorosulfonate.

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killswitch - 15-5-2012 at 10:41

I'm trying to make triethyl phosphite, so I need the phosphorus chloride rather than the sulfur chloride

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killswitch - 15-8-2012 at 13:51

Can phosphorus pentoxide be heated in the presence of chlorine to produce phosphorus chlorides?

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woelen - 15-8-2012 at 23:15

If you have access to red P, then you could make PBr3. The latter is more easily made than PCl3. With PBr3 you can also make the organic phosphite you want to make. I have written a web page about making PBr3. Have a look at this thread for more info:

http://www.sciencemadness.org/talk/viewthread.php?tid=17228

That thread also contains the link to my web page.

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thanos thanatos - 2-9-2012 at 14:48

Quote: Originally posted by simba

Some time ago I made a thread about making POCl3 (phosphorus oxychloride) at home, where someone posted an interesting paper about making POCl3 by heating phosphorus pentoxide with table salt at 250 ºC or so, where it also said that along with POCl3, a small fraction o PCl3 is also generated from the reduction of POCl3 by the iron from the metal container used to carry out the reaction (the reaction can't be done in glass container). I think reduction of POCl3 could be a more suitable way to make PCl3 at home. Phosphorus pentoxide isn't controlled so can be easily bought also.

Why can't it be done in a glass container, such as a quartz tube? The paper this idea comes from discussed generating POF3 and PF3, which would certainly be problematic in a glass vessel (as it generates fluorine gas as an intermediate). But if you're limiting yourself to chlorides, why would glass or quartz be a problem?

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Lambda-Eyde - 2-9-2012 at 14:53

Because phosphorus pentoxide itself will etch glass at these temperatures.

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Rogeryermaw - 8-9-2012 at 20:10

i have looked and looked and looked but i can't find it anymore. i copied the synthesis a long time back for my notes but i will not publish it without the writer's consent. there is a simple and elegant home chemist level synthesis for PCl3 written by garage chemist complete with pictures and a detailed write up. u2u him for instructions. i believe it is in german (possibly dutch, can't remember now. translated it long ago). basically it consisted of a flask charged with white phosphorus and fitted with a reflux condenser. two additional gas generators were used. the first using a carbonate and HCl to produce CO2 which was led through the second gas generator whose purpose was to produce chlorine by reacting TCCA with HCl. the gases from these generators was dried in a washing bottle containing concentrated H2SO4. after flushing the reaction flask with CO2 (at which point CO2 production is minimal or stopped altogether) chlorine production begins (extremely slowly). there was described a violent exothermic reaction with bumping and sloshing, but crude PCl3 is produced. one must stop production of chlorine gas before the consumption of all the P4 to reduce the chance of PCl5. afterwards, distill the crude product.

the extreme toxicity of PCl3 has been mentioned here. do not discount that warning. efficient fume hood only.

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plastics - 9-9-2012 at 12:13

Quote: Originally posted by Rogeryermaw

i have looked and looked and looked but i can't find it anymore. i copied the synthesis a long time back for my notes but i will not publish it without the writer's consent. there is a simple and elegant home chemist level synthesis for PCl3 written by garage chemist complete with pictures and a detailed write up. u2u him for instructions. i believe it is in german (possibly dutch, can't remember now. translated it long ago). basically it consisted of a flask charged with white phosphorus and fitted with a reflux condenser. two additional gas generators were used. the first using a carbonate and HCl to produce CO2 which was led through the second gas generator whose purpose was to produce chlorine by reacting TCCA with HCl. the gases from these generators was dried in a washing bottle containing concentrated H2SO4. after flushing the reaction flask with CO2 (at which point CO2 production is minimal or stopped altogether) chlorine production begins (extremely slowly). there was described a violent exothermic reaction with bumping and sloshing, but crude PCl3 is produced. one must stop production of chlorine gas before the consumption of all the P4 to reduce the chance of PCl5. afterwards, distill the crude product. the extreme toxicity of PCl3 has been mentioned here. do not discount that warning. efficient fume hood only.

http://www.versuchschemie.de/topic,5775,-Phosphortrichlorid....

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Rogeryermaw - 9-9-2012 at 15:41

that's the one. makes me wonder if it was written by garage chemist. i did get the link from one of his posts though, and i know he frequents versuchschemie.de

the method, while requiring some expensive glass (especially the washing bottle), is well within the reach of the home chemist.

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Lambda-Eyde - 9-9-2012 at 16:17

Stefan would be garage chemist, yes. He also posted a synth of PCl₅ on this forum IIRC. I'll look it up.


Edit: At least I found the topic at Versuchschemie: http://www.versuchschemie.de/topic,8040,-Herstellung+von+Pho...

But I could have sworn I've seen it here on SM, too.

[Edited on 10-9-2012 by Lambda-Eyde]

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Rogeryermaw - 9-9-2012 at 20:01

man, stefan/garage chemist has done some amazing work. did you read at the bottom where he proposes the synthesis of phosphoryl chloride from the PCl5 using either H2SO4 or Na2CO3? awesome!

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Lambda-Eyde - 10-9-2012 at 08:28

The route with Na₂CO₃ isn't all that awesome - phosgene as a byproduct? No thanks!

[Edited on 10-9-2012 by Lambda-Eyde]

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S.C. Wack - 10-9-2012 at 11:47

Phosgene can be used to make POCl3 from phosphate, at an easy temperature in a tube furnace, so a stream of it is not entirely inconvenient.

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Rogeryermaw - 10-9-2012 at 12:18

Quote: Originally posted by Lambda-Eyde

The route with Na<sub>2</sub>CO<sub>3</sub> isn't all that awesome - phosgene as a byproduct? No thanks! [Edited on 10-9-2012 by Lambda-Eyde]

true, but it would seem like the easiest method since the reaction products are a gas, a liquid and a solid. should make for easier separation than to distill POCl3 from chlorosulfonic acid. good fume hood should keep you safe.

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Yamato71 - 5-12-2012 at 14:17

The Vogel synthesis of phosphorus tribromide (5th ed. pp 458-459) involves the dropwise addition of bromine to a vigorously stirred suspension of red P in carbon tetrachloride followed by fractional distillation. I've seen phosphorus trichloride generated in a similar manner by bubbling dry chlorine through or dripping liquified chlorine into the same suspension. IIRC, dichloromethane or chloroform can be substituted for CCl4 since both will react with excess Cl2 to form CCl4 and HCl. A dry ice/acetone condenser is set up for reflux to condense any escaping chlorine or CCl4 vapor and return it to the reaction flask. The reaction is complete when the suspended RP is consumed. Fractional distillation is employed to isolate the product from the solvent. Any formed phosphorus pentachloride will be precipitated as a white to yellow solid in the reaction flask. Filter this out and rinse with fresh CCl4 as this is a very useful chlorinating agent, especially for generating acyl chlorides from carboxylic acids. For example, when 2 equivalents of dry PCl5 are shaken with 1 equivalent of dry oxalic acid, the mixture liquifies into crude oxallyl chloride.

[Edited on 5-12-2012 by Yamato71]

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Boffis - 7-12-2012 at 06:06

Reading this thread raises some interesting question:

Can you produces PCl3 by reducing PCl5 with red phosphorus say in CCl4 solution?

How do you seperate PCl3 from CCl4 since the the former boils 76.1 and the later 76.7 C?

In the presence of excess red phosphorus could you chlorinate it to PCl3 in the dark (temperature will be limited by the reflux temperature of CH2Cl2) to limit chlorination of the solvent?

Can you use the solution of PCl3 in CCl4 directly in you intended reaction?

My interest in this compound is its reaction with Aryl diazonium tetrafluoroborates in ethyl acetate to give phosphonic acids. Trialkyl phosphites may also be used in a related reaction but are equally hard to get and their preparation requires PCl3.

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Yamato71 - 7-12-2012 at 08:35

Freezing might work to separate CCl4 and PCl3. Their melting points are -23c and -94c respectively. Cooling to -78c with a dry ice/acetone bath should cause the CCl4 to crash out so that it can be filtered from the PCl3. I don't see why the PCl3 can't be used as a solution in CCl4 however as this would allow the reaction to be moderated.

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neptunium - 8-12-2012 at 19:05

check out this site..
http://www.hottdealss.com/Red%20phosphorus.html

is that a set up or what?

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woelen - 9-12-2012 at 03:29

This is a ridiculous price, $30 for 20 grams.
And then have a look at the top 2 chemicals, red P at number 1, iodine at number 2, also for a ridiculous price. This looks either like someone who wants to grab a lot of money from cooks or it is a setup.

A normal price for red P is around EUR 10 per 100 gram or maybe $15 per 100 gram.

There are more signs of a not-so-professional thing. The red P is listed as P4, while having a molar mass of 31 grams. P4 is the formula of white P. This is someone who does not have any real chemical knowledge.

Conclusion: I would not buy a gram of any chemical from this place.

[Edited on 9-12-12 by woelen]

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neptunium - 9-12-2012 at 04:08

thought so....there is a lenghty thread on making phosphorus with very interesting process...and results

[Edited on 9-12-2012 by neptunium]

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neptunium - 9-12-2012 at 18:12

check out this fool!

http://www.ebay.com/itm/Black-Phosphorus-crystal-clusters-0-...

300 bucks for .5 gram ha ha ha ha ha ha!!!!!

what a dicK!

[Edited on 10-12-2012 by neptunium]

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kristofvagyok - 9-12-2012 at 18:25

Quote: Originally posted by neptunium

check out this fool! 300 bucks for .5 gram ha ha ha ha ha ha!!!!! what a dicK!

Since there is NO commercial supplier for black phosphorous what is not a DIY form of this awesome element so I would say that price could be okay.

Just check the Sigma or the Merck catalog and you will find several more common thing with much higher price that that.

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neptunium - 9-12-2012 at 18:51

no thanks!
getting phosphorus out of phosphates is a fascinating experiment and has been since 1669! i am making my own thank you very much!
the thread on elemental phosphrus on SM is very interesting by the way!
damn greedy bastards!

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Boffis - 10-12-2012 at 08:19

Back to the subject of this thread:

I checked out various chemistry books on the Forum library to check out the chemistry of PCl3 and PCl5. Interesting...

PCl5 sublimes at 160 C and melts under confinement at 166 C. However, the section goes on to discuss the vapour density of this compound and cites references that indicate that the vapour is 47% dissociated at 180 C (Textbook of Inorganic Chemistry Vol VI part II). The dissociation being:

PCl5 --> PCl3 + Cl2

It is therefore possible that even at the temperature of say refluxing carbon tetrachloride there will be sufficient dissociation to allow the reaction with a red phosphorus suspension in this solvent (other solvents such as nitrobenzene and o dichlorobenzene might be possibilities too. Though they may be more difficult to accomadate in subsequent reactions). If this were to work it would allow a fairly easy means of accessing PCl3; admittedly as an inseparable solution in CCl4. However, for the preparation of alkyl phosphites I don't think this would be a problem, the mixture of say triethyl phosphite and carbon tetrachloride should be fairly easy to fractionate (Bp's 156 and 76 C respectively). I'll look into this over the coming months as it is an intreging possibility.

[Edited on 10-12-2012 by Boffis]

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Lambda-Eyde - 10-12-2012 at 10:06

Quote: Originally posted by neptunium

check out this fool! http://www.ebay.com/itm/Black-Phosphorus-crystal-clusters-0-... 300 bucks for .5 gram ha ha ha ha ha ha!!!!! what a dicK!

Well, if you take into account Kristof's point and the preparation of this unusual allotrope, the price isn't that ridiculous:

Quote:

Amixture of50 g. of distilled, white P and 50g. of Hg is placed in an ampoule filled with pieces of copper-plated welding rods. At the same time, 0.5 g. of black P, which has been well pulverized beforehand in an atmosphere of N2, is added as seed crystals. The ampoule is fused shut and gently heated until the white P melts. It is then shaken to achieve a good mix. As a result, a layer of seed crystal powder adheres to the newly amalgamated surface of the welding rod. The ampoule is heated in a protective iron tube to 220°C and then, over a period of two days, to 370°C. After a total of eight days, black P forms quantitatively. Its surface sometimes shows traces of white and red phosphorus. To produce the seed crystals, a small ampoule filled with freshly distilled white P and 30-40 at .% Hg is placed in a furnace preheated to about 370°C. It is left there for three days at this temperature. It is then heated for one day at 380°C, one day at 390C and three to four days at 410°C. The well-formed spherule s of black P can be easily separated from the other material. To extract the crude product from the admixed Hg, the pulverized sample is placed next to a piece of Pb and heated in an evacuated ampoule for several days at 300-450°C. After repeating the process with the repulverized sample and fresh Pb, the remaining Hg amounts to about 1 at.%. If gold is used instead of Pb in the second amalgamation the amount of Hg after heating to between 370°C and 440°C is reduced to about 0.5 at.%. The Hg content cannot be further reduced by this or any other method.

(From Brauer)

[Edited on 10-12-2012 by Lambda-Eyde]

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Hawkguy - 14-4-2015 at 20:17

There's another method of preparing Phosphorous Trichloride from Calcium Phosphate. Its here (somewhere) http://catbull.com/alamut/Bibliothek/Kings_Chemistry_Surviva... Good luck and please post results! I haven't yet tried, and so I am curious as to effectivity.

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Magpie - 3-9-2015 at 18:31

A lab report

Introduction
Based on my successful preparation of PCl5 from white P (see Prepublication) I decided to try the same technique in making PCl3.

Solvent Selection
As PCl3 is a liquid I planned to separate the PCl3 from the solvent by distillation. The boiling point of PCl3 is 76°C so I wanted a solvent that had a significantly higher or lower boiling point. My original selection was pentachloroethane (bp 162°C) as it is a chlorocarbon and therefore I assumed it would be as good a solvent as CHCl3 (1g/40 ml) or CCl4. But I could not find a source although it could be made from trichloroethylene, which is available on eBay. I probably could also use heptachloropropane but I also would have to make this (from perchloroethylene).

My next thought was to use dichloromethane (bp 40°C). But I suspected that the chlorination would produce significant CHCl3 (bp 61°C) and CCl4 (bp 77°) as by-products. These would be difficult or next to impossible to separate from PCl3 by distillation.

Then I remembered that I had 500 ml of chlorobenzene (bp 131°C) on hand from a trade with a forum member. Benzene is a good solvent for white P (1g/35 ml) being, in fact, the best I have seen in the literature excepting CS2. I therefore assumed that chlorobenzene would also be a good solvent. Availability and fire hazard preclude me from using CS2 although it is by far the best solvent for P.

Chlorination
A 3-neck 500ml RBF with reflux condenser was loaded with 250ml of dried, redistilled chlorobenzene and 5.2g of white P. The pot was heated with a mantle and magnetically stirred. The P slowly and steadily dissolved until complete dissolution was achieved. Dried Cl2 was then slowly injected into the hot chlorobenzene. The mantle was then turned off as the heat of reaction kept the pot very hot although not boiling.

Because I had not pre-purged the gas train, condenser, and RBF headspace with an inert gas, considerable P2O5 smoke initially formed. This deposited on the dome of the RBF. It was white with an orange cast, due to slight tar formation I assume. This was dangerous as it tended to plug the CaCl2 guard tube and I changed out the tube’s cotton plug twice during the initial part of the chlorination when the smoke was being generated.

Fractional Distillation
The RBF was set up for fractional distillation using a 20cm Vigreux column. With the ΔT in bps of 55°C I assumed this would easily give a good separation. It did not, and the still head temperature went up over 110°C. So I changed to a 20cm Hempel column packed with a ss scrub pad. This also did not provide a separation no matter how carefully I adjusted the mantle heat. After collecting about 15ml of condensate I quit for the night.


Fractionation with Vigreux column


Fractionation with Hempel column

Today I set up the 25mL RBF pot containing the distillate for a second fractional distillation, again using the Hemple column. I placed an aluminum foil tent on the pot and heated the column up very slowly. When the temperature reached 75°C distillate started coming over. It continued to come over at 74°-75° steadily (0.5d/s) until there was insufficient heat to bring any more distillate over. So I did manage to capture 6.4g of PCl3. About 12 ml of liquid remained in the pot, ie, chlorobenzene.


2nd fractionation


PCl3 distillate

Yield
The yield was 6.4g for a 27.8% yield.

Discussion
The difficulty encountered during the fractionation really has me puzzled. With a 55° degree separation in boiling points this fractionation should have been easy. I can’t believe it was just poor technique.

Clearly I made a mistake in not first purging the system with an inert gas (I have argon). But this cannot account for the low yield entirely. I’m wondering if the bulk of the phosphorus is still in the 500ml RBF pot.

Comments, questions, and suggestions are welcomed.

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Magpie - 5-9-2015 at 17:19

Yesterday and today I have done some labwork to try to find the missing P from my PCl3 synthesis posted above.

Missing P: (1-0.278)5.2g = 3.75g

Firstly, I weighed the 500 mL RBF before and after cleaning. Assuming the weight differential was P2O5 this accounts for 0.39g of P. This is nearly twice my estimate of 0.2g. Perhaps more O2 was sucked in through the CaCl2 guard tube as the existing O2 was consumed. Incidentally, the RBF cleaned up easily using only soap and water.

Secondly, I redistilled the residual 200 ml of chlorobenzene left in the 500 ml pot. I only recovered about 6mL of distillate. To this I added about 10ml of fresh chlorobenzene then redistilled this in a 25ml RBF. I only retrieved a few ml of doubtful quality PCl3 and chose not to add it to my yield. I did add water to it in a small beaker. At first I saw nothing then noticed about 3 large drops of PCl3 on the bottom of the beaker. I also noticed that the beaker was getting very hot. Eventually the drops disappeared. The assumed reaction is:

PCl3 + 3H20 ---> H3PO3 + 3HCl

Based on this small scale experiment I have to conclude that this is not a good way to make PCl3. DJF90 has informed me that the German chemistry forum Lambda-Syn has a high yielding method using PCl5 and red phosphorus.

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Edit:
Other hiding places are possible for the missing P:
(1) unreacted P dissolved in the chlorobenzene, and
(2) dissolved PCl5.

I may do some more investigations.

[Edited on 6-9-2015 by Magpie]

[Edited on 6-9-2015 by Magpie]

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macckone - 6-9-2015 at 06:08

Chlorobenzene seems a poor choice as it will get chlorinated just like the dichloromethane. There could be polymeric side products with insufficient chlorine.

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Magpie - 6-9-2015 at 07:44

Quote: Originally posted by macckone

Chlorobenzene seems a poor choice as it will get chlorinated just like the dichloromethane. There could be polymeric side products with insufficient chlorine.

Isn't a Lewis acid required for chlorination of the benzene ring? However, chlorination of CHCl3 isn't supposed to happen either without radical formation by UV light but it does to a certain extent. I suppose heat can substitute for the UV.

I wouldn't be surprised to find some dichlorobiphenyl. A small amount of biphenyl is formed when making benzene from benzoic acid.

[Edited on 6-9-2015 by Magpie]

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Magpie - 7-9-2015 at 13:39

I am now convinced that most all of the missing P is still dissolved in the chlorobenzene. In my effort to not form PCl5 I simply did not chlorinate long enough.

The below picture shows an abandoned distillation to recover the chlorobenzene. You can see the P2O5 smoke in the pot as the hot P reacts with the oxygen in the air.



The composition of the yellow colored residue is still unknown. It is not soluble in the chlorobenzene and settles out as a gummy yellow residue. At first I though it was P4S10, but where would the sulfur come from (thiophene?). I carefully cleaned and redistilled the chlorobenzene before use. Also, I have never smelled a sulfur smell. When I heated some strongly with a match it did not catch fire but melted slightly and turned partially black. It is soluble in water and turns the water pH acid.

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Magpie - 9-9-2015 at 14:24

I gave some thought to continuing the chlorination but decided to just cut my losses. There are reactions taking place that I don't understand. Also, I'm getting tired of running the hood fan, cleaning glassware, and generating used nitrile gloves. Working with dissolved phosphorus and a halogenated solvent requires extra caution and maintenance of good hygiene.

The product continues to form the yellow residue. Today I filtered most of it out then set up for distillation to recover the chlorobenzene and try to burn off the P to P2O5 using a controlled burn, ie, get it hot and expose it to the air. This did occur during the distillation. As the P vapor came in contact with air at the entrance to the condenser it would form smoke. This in turn would cause a partial vacuum and suck in more air, repeating on and on. I would have taken a picture but my camera quit as the battery needs recharging.

The distillation is done. The distillate is tainted a fluorescein yellow and there is an orange deposit in the pot.



[Edited on 9-9-2015 by Magpie]

[Edited on 9-9-2015 by Magpie]

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macckone - 10-9-2015 at 09:47

Chlorination of chlorobenzene happens more readily than benzene.
In an ideal world you would need a catalyst or UV light or heat.
But we don't live in an ideal world. And even a regular light bulb
emits some UV and glass is not totally opaque to UV. Plus you have
some activated chlorine floating around from your primary reaction.

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Magpie - 10-9-2015 at 10:26

Also, I no doubt created some FeCl3 due to the SS316 welding rod immersed in Cl2. But there is much more going on in this product mix.

The pot residue from yesterday's distillation contained most of the remaining P, ~ a gram, mixed with a lot of orange gunk. I burnt most of it off. I will treat the rest of the waste with 1M CuSO4 using a 1 week soak.

I still think this method could be successful if the right solvent could be found. Chlorobenzene is not the right solvent, however.

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PHILOU Zrealone - 10-9-2015 at 11:58

@Magpie,
Based on the "tiny amount" of reactants, your Hemple column with glass beads must hold quite some PCl3 (by capilarity you may have several grams in there)...this may account for the apparent low yield.

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Magpie - 10-9-2015 at 12:22

I didn't use glass beads but ss scrub pad. But, yes, there was some of the yellow residue on the pad coils.

The 1M CuSO4 reacts fast with the small particles of waste, turning them black immediately. I will let it set a few days then treat this with 5% NaOCl to destroy the phosphides.

The only waste left will then be ~ 150ml of chlorobenzene*. I see my choices here as 1) incineration, 2) evaporation, or 3) absorb in kitty litter.

I have tried some incineration on a small scale: very nasty with sooty smoke likely containing nasties like HCl and dioxin. I think this choice is out.

*It is interesting to note that there was a fair amount of solid waste (orange gunk) in the chlorobenzene distillate. The chlorobenzene is therefore also getting treated with 1M CuSO4.

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