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Need help preserving flowers

Yippee's picture
Yippee

Need help preserving flowers

Hi, 

I'd like to find out where I can get the following materials:

1. ethyl alcohol - is this something I can get in a drug store

2. polypropylene glycol 

 

 

I learn about using the above materials from here

3. Are these materials toxic?

4. Is the method described in the article similar to this process?

 

Thank you, 🙏🙏🙏

Yippee

 

 

idaveindy's picture
idaveindy

Ethyl alcohol is ethanol, which is what our yeast friends make. see: https://en.wikipedia.org/wiki/Ethanol

It can come in 95% form in the Everclear brand of "grain alcohol" at liquor stores (if it's not banned in your state.)  The other 5% is water. Also known as "190 proof" alcohol. It can be consumed in small quantities, usually diluted with other beverages.  It's the alcohol portion of what we  call "booze."

It also comes in the form of "denatured alcohol" a.k.a. "methylated spirits" which contains varying percentages of ethanol, methanol, and other poisonous and bitter additives to deter human consumption. This is usually intended as fuel for heating/cooking.  see: https://en.wikipedia.org/wiki/Denatured_alcohol

The big question is what form of ethanol was used/intended by the authors of that article.  Was it 100% or 95% or other?  Was it denatured?

--

It it helps, the article specifies that polypropylene glycol with a molecular weight of 400 was used, a.k.a. PPG 400.  That is important to know as PPG comes in varying molecular weights, up to 4000.  

I noticed that duckduckgo, amazon and ebay keep returning "propylene glycol" when searching on "polypropylene glycol".

breadforfun's picture
breadforfun

Hi Yippee,

You may have some difficulty sourcing the ethyl alcohol. Because it is drinking alcohol, it is highly regulated to prevent abuse. It is widely used industrially so it is available. There may be some lab supply distributors that have it and you may need some kind of (for lack of a better word) license before they sell it to you. As Dave said Everclear is as close as you can come without jumping through regulatory hoops, but it won’t be 100% pure. If you are lucky enough to know someone with an illegal backyard still you can purify it to pretty close. According to your first reference you may not want to use alcohol denatured with methanol because it wI’ll tend to discolor the flower (Fig. 2D). But if you don’t mind a slight color shift, denatured alcohol doesn’t have much methanol so it may work. It is easy to source in hardware or paint stores, and it is inexpensive but toxic. 

[Edited] Polypropylene glycol is available from specialty chemical suppliers like this. There are probably many others. It appears to come in a number of different molecular weights (which is how the chain lengths are measured, but let's not get too technical). The one mentioned in the article is MW 400 which can be found here. It's quite pricey, and it appears to be relatively safe.

 -Brad

[Removed reference to Propylene glycol, which is not the same chemical]

Yippee's picture
Yippee

Hi, Brad:

Would this be the right product, assuming I can purchase it?

And is this NOT the right product? 

Thanks,

Yippee

breadforfun's picture
breadforfun

They both say 200 proof, which is 100% ethanol. The one from xtractor has a link to an MSDS (material safety data sheet) that lists ethanol as the only ingredient, so that is straightforward. But they say Not for beverage use but do not say what makes it so. I’m pretty sure it is fine for flowers. 

The one from alliance also says 200 proof, so the only question is what they are using to denature it. There is no MSDS listed, but since it is required by law they would have to send one if requested. I’m betting it would be fine, too. 

If you want to dig more deeply you could ask for a lot analysis which would show what the contaminants are and what percentage. They may or may not have it for these Technical grade materials. 

-Brad

alcophile's picture
alcophile

If you believe the picture of the label, the Alliance Chemical ethanol is denatured with methanol. I would handle only with nitrile or latex gloves in a very well-ventilated area.

The Food Grade 200 proof ethanol would be safer from a dermal and inhalation exposure risk, but be safe nonetheless.

Yippee's picture
Yippee

As my gardening skills improve, there are more and more beautiful flowers in my garden.  I want to preserve some, make them into a bouquet, and put it in a vase as gift. 

I have concerns about the toxicity of polypropylene glycol. Would it be harmful if people touch or smell the preserved flower? 

I can buy Everclear for ~$20 here, but polypropylene glycol is quite expensive - $100/gallon💲💲💲.  Can I use antifreeze instead? 😁😁😁

Thanks again!

Yippee

 

idaveindy's picture
idaveindy

I don't know for certain, but if "Mn avg 425" would work as well as "P 400", the former is only $51.10 for 5 gal. ;-)

Maybe you could contact the authors and get their opinions/guesses to see if Everclear 95% ethanol, and PPG Mn avg 425 would get you "close enough."

UPDATE:   Oops!! comparing to Fisher Scientific, that might be 5 grams, not 5 gallons.  In my defense, it said 5G not 5g.

I  better shut-up and let Brad guide you.

Yippee's picture
Yippee

I'm going to email him now.

Yippee

idaveindy's picture
idaveindy

Yippee, I didn't detail-read the whole article, but you should.   I didn't pick up how much liquid it take per flower, how much of the stem you can include, whether the liquids are re-usable, how much of the PPG is used up per flower. Do you just dip the flower in PPG or immerse and keep it immersed overnight?

The devil is in the details. Please remember that is an academic paper, not a how-to for consumers. Maybe that $60 of PPG can only do three flowers at a time, and can only be used 3 times. Just guessing.  Or maybe the net cost per flower is going to be $5 to 10 each.  And are 100% of the results gift-able?  What if you have to process 3 flowers to get one good one?

What about other preservation techniques?  Like in those clear acrylic blocks?

Yippee's picture
Yippee

The system requires a company name when ordering. I asked them about it in an email. I'll find out when they reply.    The protocol of flower processing is quite simple. The only thing I don't know is whether I can re-use the solvents, but you bet I will. Regardless of what the outcome would be, I will try to get my money's worth. I probably need to double my order, i.e. 250ml x2,  because they use 300ml in the process. 

Yippee

 

Yippee's picture
Yippee

😩😩😩

"products are sold to end-users for the purpose of laboratory research only"

alcophile's picture
alcophile

Yippee,

Is there a botanic garden, arboretum, or horticulture department at a university in your area? You may want to contact them to see if they can assist you in finding the polypropylene glycol you need for flower preservation.

Yippee's picture
Yippee

Thanks, Alco.

Yippee

breadforfun's picture
breadforfun

I just added a link above to the safety data sheet. Polypropylene glycol appears to be relatively safe.

I also edited my comments about antifreeze - it is very much *not* the same thing as the chemical you are looking for, sorry. 

Thanks idaveindy for pointing out my error.

-Brad

Yippee's picture
Yippee

🙏🙏🙏

Yippee's picture
Yippee

The one Sigma sells ships in October, but I need it much sooner. So I found two other places that sell it. Just want to make sure it is the right product because it's more expensive than I thought - I was looking at the wrong product before:

https://hamptonresearch.com/product-Polypropylene-glycol-P-400-165.html

https://www.fishersci.com/shop/products/polypropylene-glycol-400-2/AA4081130

Thx!

breadforfun's picture
breadforfun

The best way to compare is to use the CAS number, in this case 25322-69-4, and they both have the same as the Sigma P400 variety.

Note that these are relatively small quantities, 200-250 mL which is just about a cup of liquid. OK if you have only small flowers...

-Brad

 

alcophile's picture
alcophile

CAS numbers are usually reliable, unique identifiers for a chemical compound. Sometimes, though, the number may be used for similar compounds, depending on how the compound was identified. That seems to be the case with the polypropylene glycol; several different molecular weight polymers have been assigned the same CAS number. This is probably because it is a generic CAS# for all PPGs. I would have to search SciFinder to know for sure.

 

idaveindy's picture
idaveindy

(Sorry, but this subject intrigues me.)

Here's an article about how near 100% ethanol makes cells go dormant. This might be what's happening with the flowers.

https://www.compliancenaturally.com/blog-page/2018/4/15/why-70-ethanol-is-the-most-effective-disinfectant-for-any-food-or-pharma-facility

It is not explicit, but it hints that 95% (Everclear) may be as effective as 100% to make cells go dormant.

In regards to 100% ethanol, it says: "It should also be noted that 100% ethanol would be highly flammable and not suitable for use in manufacturing industries. It can even be an explosion hazard if it gets too hot. Besides being hard to store due to its flammability, particularly in the summer, it’s hard to store for any length of time as it evaporates quickly."

 --

Also be advised that Everclear now comes in 60%, 75.5%, 94.5% and 95% alcohol by volume, as per https://en.wikipedia.org/wiki/Everclear

alcophile's picture
alcophile

I think the goal of the procedure is to replace the internal moisture of the flower with a stable solvent that allows the color to be retained. The 190 proof Everclear may have too much water to allow enough dehydration of the flower to allow replacement by the polypropylene glycol.

We used 200 proof and denatured ethanol all the time in a chemical manufacturing industry. But it is flammable (flash point 57 °F) and needs to be handled in a well-ventilated area.