[Peter57]

Hi there I have a dust mite allergy and have bought a spray containing a low molecular weight Tannic acid. TANACETANE™ possibly (LMGG) galloylglucose (C14H1009)?

The acid denatures the enzymes in dust mite faeces that cause the allergy.

The product is expensive and I have been told I can make my own by buying tannic acid and mixing a 3% solution with water.

I have bought some Tannic Acid but it produces a solution of a very dark colour that would probably stain my carpet.

Is the colour difference between my home made solution and the bought product due to a pigment or impurity in my tannic acid? in which case could i remove the colour through distillation?

Or, is it the natural colour of tannic acid and i need to use 'low molecular weight tannic acid' which is found in the product i bought?

If the latter is true how do I turn tannic acid into low molecular weight tannic acid?

[Illuminatus]

Hello Peter57,

TANACETANE™, tannic acid in aqueous solution, is naturally yellow by colour; either your product has diluted it a lot further or you may just not be noticing the yellowish color. Keep in mind that if your product contains a percentage of TANACETANE™ then you need to factor in the dilution of tannic inside that. Could you please provide the product specifications?

There are some companies, such as Allersearch, which specifically manufacture dust mite spray without tannic acid or other staining ingredients. You may want to research their formulae as well.

Anticipating.

[Peter57]

Hi Illuminatus, thanks for your reply.

The product I am specifically referring to is http://www.allergystore.com/ads_antiallergen_spray.htm

http://www.allergyhelp.com/ADSJune12011MSDS.pdf It does give a chemical formula that is exactly the same as the tannic acid I bought,

I tested the ph of my homemade (3% tannic acid) stuff and compared it to the ADS spray and the results were the same, about 3.5. So I am fairly sure the tannic acid content is the same in both.

On the ADS spray label, it says it contains '3% TANACETANE™ low molecular weight tannic acid'

The difference between the ADS spray and my homemade solution is that mine is very dark brown (balsalmic vinegar brown) and the ADS spray is a very slight tinge of yellow.

Either there is a pigment in raw tannic acid that can be removed through distillation? or that I need to alter the raw tannic acid I purchased to be 'low molecular weight' tannic acid?

I have found reference to 'low molecular weight tannic acid' elsewhere and it has a different chemical formula http://www.emsdiasum.com/microscopy/technical/datasheet/21700.aspx

[Illuminatus]

Hello again Peter57,

Examining the polymeric low molecular weight Tannic acid from your last link and standard Tannic acid, it would be my educated guess that a reverse synthesis of the former from the latter would be impractical.

However, if the acid contained in your spray is indeed identical, it is very probable that the Tannic Acid product you have purchased separately was prepared in the presence of metal ions and has gained its color from them (I see this quite often in pharmaceutical compounds, however I would hesitate to compare their preparation processes with that of complex acids). These ions can give your solution a very distinct color ranging anywhere from a light yellow to a very dark purple.

Unfortunately I haven't had a need to remove these metal impurities myself; you should try researching the process yourself, distillation sounds like a very reasonable path at this point. If your distillation product retains the color, then you may indeed have a different form of the acid.

Enjoy

EDIT: Arkcon is right in his other post, I didn't realize this was a powdered organic in natural state. He slightly incorrect about it only being brown however, as it ranges from yellow to dark brown. It is unlikely that you have ion impurities in your solution, but if you would like to try this anyways, the way to go at this point would be deionization, not distillation.

Tannic acid is available as a reasonably pure substance.  Its brown.  You can't purify away any impurities and change its color.  Mixing a solution won't purify it or change its color.  Distilling a powdered organic compound isn't possible.  And mixing, then distilling is also a process that doesn't purify anything.