Making a BHT solution

[Lankan]

I'm planning to use BHT as the antioxident in my liquid & bar soaps. Since the recommended % are very small 0.1%- 0.5%, I find it difficult to measure in small quantities. Hence trying to create a solution containing higher concentration of BHT so that I can use in required amounts.

This is somewhat similar to the approach suggested by @DeeAnna for EDTA, however with BHT the solvent will be an oil.

Although I tried many sources, I still couldn't find out the composition in which the oil and BHT to be mixed, so that I will not have any undissolved BHT particles left.

Appreciate your inputs on this.

 

[DeeAnna]

Sometimes information like this isn't available in the literature because it's not something chemists do much. So you may have to experiment. If you haven't already, try slowly dissolving BHT in a fat -- add a small amount, let it dissolve if it's going to. If it does, add a little more, let dissolve, etc. Keep track of each small addition of BHT so you can get a rough idea of the solubility.

What is freely available in the literature is that BHT is "readily soluble" in ethanol (ethyl alcohol). The implication from one paper* suggests you might be able to make something like a 25% solution concentration (25 grams BHT in enough ethanol to make a total of 100 g). I know people say to not use alcohol in soap, but in this case you might have to -- and the amount of ethanol you'd be adding is going to be really small.

I'm not sure what purity of ethanol is being used for the BHT solutions. Given the info is coming from chemist types and chemical databases, however, I'd guess the % ethanol should be as high as you can find. BHT is nearly insoluble in water.

Disclaimer -- I haven't tried any of this, so YMMV.

Another solution would be to get a jeweler's scale that can read to 0.01 grams for measuring the solid BHT.

* https://pubs.acs.org/doi/pdf/10.1021/je00042a006

 

[Baqn]

Hallo. BHT has solubility in oils at about 25-40%. If you can not dissolve it quickly you can heat the solution at about 65 degrees Celsius. At that temperature BHT will be melted and will mix with the oil quickly. If you take 1 ml from 10% (10 g/100 ml) solution there would be 0.1 g BHT. Enough to preserve 100 ml of oil FOR TOPICAL USE ONLY. Level of BHT in foods is much more different.

Here comes the bad news. I was thinking about using BHT as antioxidant in soap and here what came to my mind.

1. Saponifying oils turns them in salts. They are not lipids anymore and become water soluble. BHT preserves LIPIDS because it is soluble in lipids. The thing that encourages me is that usually there is SF which is not saponified. This fraction of the soap is getting rancid first. You can not save sodium salts of FA with BHT effectively. In liquid soap you don't have SF usually.

2. Conditions in solid soaps and liquid soaps are much more different than in cosmetic products like creams, lotions and other leave-on products. Soaps are highly alkaline products. When you make solid soap you have to start with pH - 14. Even if you add BHT as SF in liquid soap it has to face pH about 9. I am not sure and I couldn't find any certain information about how effective and stable is BHT in pH above 9. BHT is phenolic compound and phenolic compounds become oxidized several times quicker in alkaline media than in acidic (pH < 7). I don't think BHT is good antioxidant for soaps. If you find BHT in commercial liquid soap I doubt the have pH higher than 6.

3. I found that BHT preserves better animal fats, middle chain triglycerides (MCT oil), Coconut oil and Palm Kernel oil. The last three have short to middle length of their FA.

4. Very interesting that I have forgotten - as BHT is phenolic compound it forms colored complexes with Ferrum, Copper and other metallic ions in water solutions with pH above 9. If you ask me how? isn't it lipid soluble - yes it is but it is soluble in water with pH above 9-10. So your soap may accidentally becomes colored.

5. There is doubtless information that BHT causes CANCER in rats.

I suggest to you to use natural antioxidants as Sesame oil, Rosemary EXTRACT (NOT Essential oil), Clove EO. In liquid soaps you can add citric acid for pH balance, so it may help to stabilize the soap against oxidation.

If I helped you somehow I will be happy.

 

[Zany_in_CO]

I suggest to you to use natural antioxidants as Sesame oil, Rosemary EXTRACT (NOT Essential oil), Clove EO. In liquid soaps you can add citric acid for pH balance, so it may help to stabilize the soap against oxidation.

I add antioxidant ROE (Rosemary Oleoresin Extract) at a rate of 1/4 - 1/2 teaspoon PPO (per pound oil) to both hard bars and liquid soap. It's really all you need. I also add it to less stable oils as soon as the container is opened to extend shelf life.

The extract is thick, so to make it easier to incorporate, I make up a solution of 2 oz ROE in 4 oz jojoba oil which has a long shelf life. It is sometimes sold already mixed in a solvent. In that case you would follow the manufacturer's directions for use rate.

 

[Lankan]

Hallo. BHT has solubility in oils at about 25-40%. If you can not dissolve it quickly you can heat the solution at about 65 degrees Celsius. At that temperature BHT will be melted and will mix with the oil quickly. If you take 1 ml from 10% (10 g/100 ml) solution there would be 0.1 g BHT. Enough to preserve 100 ml of oil FOR TOPICAL USE ONLY. Level of BHT in foods is much more different.

Here comes the bad news. I was thinking about using BHT as antioxidant in soap and here what came to my mind.

1. Saponifying oils turns them in salts. They are not lipids anymore and become water soluble. BHT preserves LIPIDS because it is soluble in lipids. The thing that encourages me is that usually there is SF which is not saponified. This fraction of the soap is getting rancid first. You can not save sodium salts of FA with BHT effectively. In liquid soap you don't have SF usually.

2. Conditions in solid soaps and liquid soaps are much more different than in cosmetic products like creams, lotions and other leave-on products. Soaps are highly alkaline products. When you make solid soap you have to start with pH - 14. Even if you add BHT as SF in liquid soap it has to face pH about 9. I am not sure and I couldn't find any certain information about how effective and stable is BHT in pH above 9. BHT is phenolic compound and phenolic compounds become oxidized several times quicker in alkaline media than in acidic (pH < 7). I don't think BHT is good antioxidant for soaps. If you find BHT in commercial liquid soap I doubt the have pH higher than 6.

3. I found that BHT preserves better animal fats, middle chain triglycerides (MCT oil), Coconut oil and Palm Kernel oil. The last three have short to middle length of their FA.

4. Very interesting that I have forgotten - as BHT is phenolic compound it forms colored complexes with Ferrum, Copper and other metallic ions in water solutions with pH above 9. If you ask me how? isn't it lipid soluble - yes it is but it is soluble in water with pH above 9-10. So your soap may accidentally becomes colored.

5. There is doubtless information that BHT causes CANCER in rats.

I suggest to you to use natural antioxidants as Sesame oil, Rosemary EXTRACT (NOT Essential oil), Clove EO. In liquid soaps you can add citric acid for pH balance, so it may help to stabilize the soap against oxidation.

If I helped you somehow I will be happy.

thanks for the detailed explanation

I read http://cavemanchemistry.com/DreadedOrangeSpot-Dunn.pdf where it was concluded that BHT + EDTA giving the best result followed by ROE + EDTA. However I find it inconsistent with your first & second points.

In point 4, do you meant to say the that BHT is water soluble if the pH value is higher than 9-10, if so can I add BHT at a later stage, either to the lye water or diluted liquid soap, without going thru the hassle to preparing a BHT on Oil solution. Wouldn't EDTA, which is said to be a good chelater help to bind the metallic ions, thus preventing the color changes, when used in combination with BHT.

I read BHT is a GRAS ingredient and instead BHA is what regarded as carcinogenic.

Quoted from the BHT page from Wiki

The US Food and Drug Administration classifies BHT as generally recognized as safe (GRAS) as a food preservative when used according to approved uses.[19][20] There is, however, some debate surrounding a possible link between BHT and cancer risk, asthma, and behavioral issues in children;[21] some studies show a potential to increase risk and some to decrease risk.[22][23][24] Because of this uncertainty, the consumer group Center for Science in the Public Interest recommend to avoid BHT and puts BHT in its "caution" column.[25] The National Cancer Institute determined in 1979 that it was noncarcinogenic in a mouse model.[12] BHT has low acute toxicity,[5] as do other closely related phenol antioxidants. For example, the LD50 of 2,6-di-tert-butylphenol is greater than 9 g/kg.[9]

In early stage research, BHT has shown anti-viral activity.[26][27][28][29][30][31][32]

Whilst Quoted from BHA page from Wiki

The U.S. National Institutes of Health report that BHA is reasonably anticipated to be a human carcinogen based on evidence of carcinogenicity in experimental animals. In particular, when administered in high doses as part of their diet, BHA causes papillomas and squamous cell carcinomas of the forestomach in rats and Syrian golden hamsters.[5] In mice, there is no carcinogenic effect;[5] in fact, there is evidence of a protective effect against the carcinogenicity of other chemicals.[4]

When examining human population statistics, the usual low intake levels of BHA show no significant association with an increased risk of cancer.[6] The state of California has, however, listed BHA as a carcinogen.[7]

Also its a general advise given in this forum that not to attempt to reduce the pH value of the soaps, due to the fact that it will cause the saponified salts to break, making the soap unusable. I also noted what is available as pH balanced liquid soaps commercially are actually SLS/SLES/ALS based detergents. Is there an effective way to reduce the pH of the Liquid soaps without rendering it unusable..

 

[Baqn]

Dear Lankan,

I suggest that you give up with BHT and BHA as well in soaps.

1. Yes, concomitant use of BHT and EDTA Sodium gives better results. BHT and BHA are so called "chain killers". They stop the chain reaction of forming free radicals. Usually free radicals are formed from organic compounds in cosmetic products. They come from lipids and other components. BHA and BHT react with that radicals to give harmless products. The reaction of forming free radicals from lipids and others is catalysed by ions of metals like Ferrum, Copper and others. EDTA scavenges that ions. The scavenging property of EDTA strongly depends on pH. At high values of pH EDTA has different ability to works than in acidic. The pH in creams is below pH 7. At pH 9 EDTA still can scavenge Ferrum but there is no certain information. Adding second chelator as citric acid is good idea. But in soap you can't have citric acid since it will be transformed in sodium citrate. EDTA Sodium is also half acid in it's usable form. If you fully neutralise EDTA it won't be chelator. It's not that simple to use that compounds everywhere.

2. If you dissolve BHT in water at pH 9 BHT is no more lipid soluble and it can not work effectively to protect the oil. Maybe BHT has lipid solubility above pH 9 but I doubt it is enough to do it's work. Also the water soluble form may work as free radical also. So instead protection it may be oxidizer. You need the antioxidant to be soluble in the media that is protecting. That is why you can't use vitamin C to protect lipids and BHT to protect aqueous solutions. Modern chemistry makes different antioxidants for different fields of use.

3. You can't neutralise liquid soap below pH 8 or 9 for two reasons. First it will precipitate. Second it won't be soap anymore. Soaps are ionic detergents and their abilities are strongly dependent on pH. Yes commercial soaps are SLS, SLES and other non-ionic detergents like coco glycoside. They are more tolerant to pH lower than 8-9.

4. Both BHA and BHT can cause cancer. As I told you they can act as oxidizers in specific conditions. None of the modern chemicals legally used in cosmetic products can cause cancer ALONE. In combination with other compounds, conditions and so on, they can become beasts we want to keep away.

 

[Lankan]

Dear Lankan,

I suggest that you give up with BHT and BHA as well in soaps.

1. Yes, concomitant use of BHT and EDTA Sodium gives better results. BHT and BHA are so called "chain killers". They stop the chain reaction of forming free radicals. Usually free radicals are formed from organic compounds in cosmetic products. They come from lipids and other components. BHA and BHT react with that radicals to give harmless products. The reaction of forming free radicals from lipids and others is catalysed by ions of metals like Ferrum, Copper and others. EDTA scavenges that ions. The scavenging property of EDTA strongly depends on pH. At high values of pH EDTA has different ability to works than in acidic. The pH in creams is below pH 7. At pH 9 EDTA still can scavenge Ferrum but there is no certain information. Adding second chelator as citric acid is good idea. But in soap you can't have citric acid since it will be transformed in sodium citrate. EDTA Sodium is also half acid in it's usable form. If you fully neutralise EDTA it won't be chelator. It's not that simple to use that compounds everywhere.

2. If you dissolve BHT in water at pH 9 BHT is no more lipid soluble and it can not work effectively to protect the oil. Maybe BHT has lipid solubility above pH 9 but I doubt it is enough to do it's work. Also the water soluble form may work as free radical also. So instead protection it may be oxidizer. You need the antioxidant to be soluble in the media that is protecting. That is why you can't use vitamin C to protect lipids and BHT to protect aqueous solutions. Modern chemistry makes different antioxidants for different fields of use.

3. You can't neutralise liquid soap below pH 8 or 9 for two reasons. First it will precipitate. Second it won't be soap anymore. Soaps are ionic detergents and their abilities are strongly dependent on pH. Yes commercial soaps are SLS, SLES and other non-ionic detergents like coco glycoside. They are more tolerant to pH lower than 8-9.

4. Both BHA and BHT can cause cancer. As I told you they can act as oxidizers in specific conditions. None of the modern chemicals legally used in cosmetic products can cause cancer ALONE. In combination with other compounds, conditions and so on, they can become beasts we want to keep away.

Dear Baqn

1. I see lot of red flags raised with regard to BHT above. the fun part is , when I was searching for videos on how to disolve BHT on YouTube, I even found a video prescribing BHT tablets daily as a health supplement. I'm not claiming any credibility based on that video, but my understanding is that BHT apart from being banned as a food additive in EU & Australia, it is not red flagged anywhere else. also even in this forum, I haven't come across any postings which details BHT as such an harmful ingredients, in fact the Dunn's article I've quoted in my previous post, also does't describe BHT as a must avoid or anything a soap-maker should avoid. Anyway thank you for yours input and I'll try to do little further research on this subject. On the other hand, finding certain ingredients, such as ROE is nearly impossible where I live, unless I order online.

2. Isn't soap is a mix of both salts of oil & water, I mean an emulsified mix(hope I've used the correct words here), If so what's with water should reach oils/saponified salts also isn't it. Isn't that the reason why water soluble colours disperse in the diluted soap, without being stay separated only in the water. Correct me if my understanding is wrong.

3. Well understood

4. I'm also totally against using carcinogenic ingredients in soaps, in fact finding such an ingredient in a baby shampoo is what go me into soapmaking. So far I have not found a paper or a authorized entity categorizing BHT as carcinogenic, in fact, as I learnt its added in food as antioxidant/preservative in US & categorized as GRAS ingredient. as far as chemical reactions, I seriously lack knowledge on what it can turn out to be when mixed with rest of the soap, in fact I do not have any short of idea what could be the results between the ingredients. ie, table salt turns the soap into honey thick syrup, but I have no idea what it ready does (I think @DeeAnna wrote about this), the Castor Oil plant produces one of the potent toxin, few grain of such is said to be enough to kill a man, But we use castor oil as a preferred ingredient in soaps - again I have no idea whether traces of such toxin is present in the castor oil. Let me keep reading on this subject, I'm supposed to give some samples to a laboratory to recommend a thickener and preservative to my soaps, they have requested me to make 5 liters of my finished product so that they can try few ingredients to reach my expectations. I'm planning to add BHT to that batch for the moment, and keep my search out for a better ingredient.

Many thanks.

 

[Baqn]

Dear Lankan,

I see you have great desire to use BHT. I doubt that something harmful may cause BHT to you. Hope it works for you. When an agency has putted red flag on an ingredient that means red flag for you too. You are not able to investigate if this is true or not. That is a rule for me unless someone insist on using that compound knowing the bad consequences. My soaps are OK for about an year. Keep unsaturated fats like linoleic below 15% and linoleinic acid below 3-5% and everything will be fine. Try to find which EO and FO are alkaline stable and they will last longer. Keep you soap in dry and cool place, protected from direct sunlight. Ah and also use distilled water instead of tap water. Also don't SF your soap more than 8 to 10% unless you intend to use the soap quickly after cure. The only exception may be the 100% CO soap. If someone has better experience, let us now about it.

I didn't clearly understand your vision for soap. Soap is not an emulsion. Maybe a little if you have superfatted it. Pure Soap is a bar of salts, water and glycerin. No lipids in it when it is finished.

I live in Bulgaria and here we don't have mich ingredients for soaping. I purchase most of my ingredients except lye and some oils. They are even cheaper that local ones. Crazy situation

 

[Lankan]

Dear Lankan,

I see you have great desire to use BHT. I doubt that something harmful may cause BHT to you. Hope it works for you. When an agency has putted red flag on an ingredient that means red flag for you too. You are not able to investigate if this is true or not. That is a rule for me unless someone insist on using that compound knowing the bad consequences. My soaps are OK for about an year. Keep unsaturated fats like linoleic below 15% and linoleinic acid below 3-5% and everything will be fine. Try to find which EO and FO are alkaline stable and they will last longer. Keep you soap in dry and cool place, protected from direct sunlight. Ah and also use distilled water instead of tap water. Also don't SF your soap more than 8 to 10% unless you intend to use the soap quickly after cure. The only exception may be the 100% CO soap. If someone has better experience, let us now about it.

I didn't clearly understand your vision for soap. Soap is not an emulsion. Maybe a little if you have superfatted it. Pure Soap is a bar of salts, water and glycerin. No lipids in it when it is finished.

I live in Bulgaria and here we don't have mich ingredients for soaping. I purchase most of my ingredients except lye and some oils. They are even cheaper that local ones. Crazy situation

By the way I'm not keen to use any chemicals, in fact if I can make soaps without adding any chemicals, other than Lye, I would be more than happy. However the challenge is that Liquid soaps that I made and gave away to my brother went rancid and became unusable. I'm fine with it as it is within family. However, I do feel the need to meet those challenges, I use the table salt as thickener, food colouring (which someone in the forum later said it is banned in US & Canada, for the reasons I'm not sure of), tried using citric acid + baking soda (thus sodium citrate) solution as cheleting agent. Although I'm sticking to salt & food colouring, I've shifted to EDTA from Citrate as chelator.

Similarly when I met the laboratory which I mentioned earlier, I made it clear to them that I do not want a petroleum based additives & any chemicals known to be a carcinogenic or harmful to human health. This is all stems from the fact that my journey into soaping begins with finding some ingredients not so desirable in a baby shampoo. So my vision is clear to me, I would strive to make use of a better ingredient than going behind a cheaper alternative which can have flags attached.

Zeroing on BHT is only based on the fact that, I couldn't find any credible article to suggest BHT is not good for human health and Mr.Dunn's article suggested it as the best when combined with EDTA.

I'm still in search of finding the best ingredients for my soaps. may be I might change my mind on BHT and join you in the future