"6PPD


From Wikipedia, the free encyclopedia
6PPD is an organic chemical widely used as stabilising additive (or antidegradant) in rubbers, such as NR, SBR and BR; all of which are common in vehicle tires.[1] Although it is an effective antioxidant it is primarily used because of its excellent antiozonant performance. It is one of several antiozonants based around p-phenylenediamine.[2]

Manufacturing
6PPD is prepared by reductive amination of methyl isobutyl ketone (which has six carbon atoms, hence the '6' in the name) with phenyl phenylenediamine (PPD).[3] This produces a racemic mixture.

Application
6PPD is a common rubber antiozonant, with major application in vehicle tires. It is mobile within the rubber and slowly migrates to the surface via blooming. Here it forms a "scavenger-protective film", reacting with the ozone more quickly than the ozone can react with the rubber.[4] This process forms aminoxyl radicals[5][6] and was first thought to degrade only to the quinone diimine, but has since been understood to continue to oxidize to quinones, amongst other products.[7] Despite 6PPD being used in tires since the mid 1960s, its transformation to quinones was first recognized in 2020.[8][9] The oxidized products are not effective antiozonants, meaning that 6PPD is a sacrificial agent.


The tendency of 6PPD to bloom towards the surface is protective because the surface film of antiozonant is replenished from reserves held within the rubber. However, this same property facilitates the transfer of 6PPD and its oxidation products into the environment as tire-wear debris. The 6PPD-quinone (6PPD-Q, CAS RN: 2754428-18-5) is of particular and increasing concern, due to its toxicity to fish.

Environmental impact
6PPD and 6PPD-quinone enter the environment through tire-wear and are sufficiently water-soluble to enter river systems via urban runoff. From here they become widely distributed (at decreasing levels) from urban rivers through to estuaries, coasts and finally deep-sea areas.[10]

6PPD-quinone is of environmental concern because it is toxic to coho salmon, killing them before they spawn in freshwater streams.[11][12][13]

A 2022 study also identified the toxic impact on species like brook trout and rainbow trout.[14] The published lethal concentrations are:[14][15]

coho salmon: LC50 = 0.095 μg/L
brook trout: LC50 = 0.59 μg/L
rainbow trout: LC50 = 1.0 μg/L
It is not known why the ozone-oxidised 6PPD is toxic to coho salmon. The Nisqually and nonprofit Long Live the Kings installed a mobile stormwater filter at a bridge in the Ohop Valley in 2022. The Washington Department of Ecology, Washington State University and the US Tire Manufacturer's Association are working on regulation and education.[16]

6PPD itself is deadly to rotifers, especially in combination with sodium chloride, though not at the level generally found in the runoff from road salt.[17] A small-scale biomonitoring study in South China has shown shown both 6PPD and 6PPDQ to be present in human urine; concentrations were low but the health implications are unknown.[18] A synthetic route to the 6PPD-quinone has been posted on ChemRxi"

The green highlight above also IMO helps explain why a sitting stationary tire dry rots much faster than a regularly exercised tire.

I admit I have not previously read about 6PPD.

I have read about Dioxin for 40 or more years and it is very low on my “worry list.”

“Tire Dust” has certainly started “popping up in the news” over the last 3 to 4 years.

I am growing more and more worried about a common chemical.
Everyone reading this consumes this worrying chemical, most at every meal.
The chemical is fruit sugar.
Fructose.

Most people really like how it tastes.

There is an old, old saying:
Poison is in the Dose.
or alternately -
The Dose makes the Poison.

The new P.E.T. scanners have shown that Fructose
ramps up activity in some parts of the brain,
and enormously damps down activity in other parts of the brain.

A high enough consumption of Fructose also makes the human small intestine grow longer.

The brain activity and intestine growth was not known until roughly 5 years ago.

I have been around lots of dangerous stuff starting from a young age.
I “respect” what some risks entail.

Fructose deserves attention,
maybe even the respectful underlying fear
one should have when working with explosives or high voltage.

Well awareness is always the first step, hence my posting, and I'm in the same boat on the discovery of 6PPD.

The connection to Dioxin I believe pertinent here is, many decades ago it was not on the radar, it's danger was early thought to be insignificant, and that later was found to be very wrong, and its use has been severely limited, and many today know little of its harmful effects.
That is good I suppose.

6PPD might follow the same path. What we are fairly certain of currently, it kills Salmon quickly.

Sugar is todays Tobacco. It is highly subsidized. It's cost to society and general health is huge, and it's just another non-essential addiction that is very profitable to legally exploit.

I am not personally exempt from that addiction nor its downsides if anybody is thinking high horse here,

I am a diabetic and am very aware of the amount of sugar in EVERYTHING. Campbell's tomato soup has 12g of sugar or 16% of your daily recommended amount. Skim milk has 13g of sugar. Even white bread has 2g of sugar. It's everywhere. 4g in catsup. I am convinced that the increase in the number of diabetics in this country is due to the assault in our food with sugar.

I remember well when Hoss on TV's Bonanza was cast as a big large character, today he would be just almost normal size, that is not a good direction for us to be headed.

.

everywhere you look, people are getting HUGE !
i'm not up on a high horse here, as i weigh 198, but my body mass index is 2.46, which i guess is good.
however it seems the whole population is getting FAT, and has been for many, many, years.
that's sad...........

When you see pics of spectators at the races from the 50's and even 60's, you very seldom see anybody "Hoss" size, today it's the norm, and not sure even many even realize it.

That is so true. The obesity rate in youths is especially concerning! They've become so sedentary compared to generations past.

I also agree, Sugar is evil and I believe it's damaging health effects are missed by the general population. I know how much sugar is in everything I eat, and I eat very little Sugar. When I get some Sugar it's because I'm eating an entire fruit and not just the juice. My diet is nutrient dense, low Sugar and bad fats, filled with leafy greens. I don't eat any red meat. Wild Salmon only. I'm not diabetic nor am I obese. I don't mean to sound judgmental or as a know it all. Along with Mopars, diet and nutrition are a passion.

Sugars,
for more than 40 years I knew there actually several but thought when you ate them they were pretty much the same.

Fructose now seems to be “way different”.
Fructose is unique in what it does to the brain.

Lactose is another sugar,
why is there so much in mother’s milk and what is it doing to help the baby?
Why do some humans lose the ability to digest lactose when they are adults?
Some tribes in Africa that herd cattle use the milk for children and “bleed” their cattle for adults to drink.

The “blood” of some fast flying insects is packed with the unusual sugar
Trehalose
instead of glucose,
kinda like super aviation gasoline for fighter airplanes.

https://en.wikipedia.org/wiki/Trehalose

Some suspect tiny amounts of Trehalose in human food is driving the big increase in C. diff disease.
Trehalose can do the moisturizing job for packaged food what glycerin traditionally did, but Trehalose tastes better than glycerin, especially in candy.

More questions than answers.

[i][/i]

And to circle back on the opening topic of why 6PPD should now be on everybody's radar, the Salmon may be the canary in the coal mine on 6PPD's long-term effects.

Shortage of white sugar

https://www.arcamax.com/currentnews/newsheadlines/s-3026419?fs

sample quote

Prolonged droughts in major cane-producers Mexico and Louisiana have helped push U.S. sugar futures to the highest ever for this time of year and forced users to turn to high-cost imports instead. Sweets-makers paying up to snag supplies are choosing to protect their margins by raising prices for consumers — and hoping shoppers don’t balk at the mark-up.

“We just found that it was better to just pay more for sugar and pass it along to the consumer than to be completely out of sugar,” said Kirk Vashaw, chief executive officer of Dum Dums lollipop maker Spangler Candy Co. “And there’s a lot of other companies that I think thought the same thing.”

Candy is big business in the U.S.: Confectionery retail sales are forecast to be $48.8 billion this year, according to consumer research group Euromonitor International. With about 1,600 manufacturing sites across all 50 states, the U.S. sector employs more than 200,000 people, the National Confectioners Association estimates — with more than double the number of indirect roles, like suppliers.

end quote