If you have any background at all in the petroleum, fuel distribution, or industrial dye industries, chances are you’re intimately acquainted with Red 164-or at least its omnipresence, whether you realize it or not. Remember that certain shade of off-road diesel? Yep, that’s Solvent Red 164 (CAS No. 92257-31-3).We hardly think of them as such, and, before we know it, they are there in our lives everywhere. From taxes on fuel used in vehicles to industrial colorants or even gas additives. In our post today, we will give you a complete summary of Red 164: what it is, how it is used, and what makes it different from other industrial dyes.
What Exactly Is Red 164?
Red 164 Chemical and Physical Data Chemical Description Solvent Red 164 (C.I. Solvent Red 164) is a manufactured chemical belonging to the azo family of diazo dyes. Molecular weight CHNO (cid: 523.63 g/mol) Molecular Formula: In actual use, Red 164 is a deep red to bluish red oil-soluble dye that dissolves quickly in hydrocarbon and petroleum solvents. It was created as a more solvable dye relative to Solvent Red 26-the first reference standard used in the U.S. for fuel marking.
So, what is the major difference in structure? Red 164 has extra alkyl (hydrocarbon) chains. They don’t alter the color-the absorption spectrum in the visible region remains practically the same-but they significantly boost solubility in fuels such as diesel and burner fuels. That was the reason the industry adopted Red 164 for practical fuel dyeing.
Primary Applications of Red 164
1. Tax-Exempt Fuel Marking (The Biggest Use Case)
This is where Red 164 truly excels-the reason why it made such a big difference in our industry. In the US, the law – specifically, 26 CFR 48.4082-1(b)-says that any fuel that is tax exempt has to be dyed red Solvent Red 164 (CAS 92257-31-3) and that dye concentration has to be exactly spectrally equivalent to 3.9 lbs Solvent Red 26 per 1,000 BBL of fuel (11.1 mg/L).
Since Red 164 is more soluble than Solvent Red 26 and less expensive, it has become the standard colorant for refineries and terminals throughout North America. The ASTM D6258-17 test method was created to determine the concentration of Red 164 in commercial diesel fuels via visible spectroscopy.
The idea is pretty simple: tax-free diesel (i.e., for off-road applications such as farming, construction, and heating) is dyed so that enforcement officials can easily see whether a vehicle is using taxed or untaxed fuel. Using the dyed fuel in on-road vehicles is a serious crime with stiff penalties.
2. Petroleum Product Colour-Coding
Red 164 is not only used for tax purposes. Red 164 is also routinely used by refineries to color-code various grades of fuel and petroleum products. It’s a standard practice to avoid confusion when handling high-sulphur diesel versus low-sulphur diesel, for example. This is a “safety for all” situation-a visual cue makes costly cross-contamination mistakes unlikely.
3. Industrial and Speciality Applications
Similar to scarlet 7H, this dye may be used for colouring oils and lubricants (for example, hydraulic oil, transmission fluid, etc.), waxes, greases, candles, printing inks, and in some plastics and polymers. Because of its solubility in oil, it can be used in any application where a bright red colourant is required in an oil base.
Red 164 vs. Solvent Red 26: What Is the Difference?
At one of the most asked questions we are asked. Solvent Red 26 is the regulated pure standard reference; it is the standard as compared to Red 164 level concentrations. Red 164 is the commercial, field-grade that has been alkylated, i.e., has been modified with more hydrocarbon chains so it can work better in the field.
Put simply, Red 164 is the workhorse hauling at every refinery and fuel terminal, while Solvent Red 26 is the benchmark waiting patiently in the lab.
Case Study: How a Mid-Size Fuel Distributor Solved Compliance Challenges with Red 164
Background: A regional fuel distributor spanning three states in the American Midwest was identified by the IRS during a normal audit process due to varying dye concentrations on their tax-free diesel. The plant’s dyeing process involved injecting a less-soluble red dye into the fuel at each of the plant’s terminals. Analysis determined that the levels were changing by as much as 40% from batch to batch, and some were below the required 11.1 mg/L spectral equivalency.
The Problem: Inconsistent dye dispersion was causing uneven colour across storage tanks, raising compliance risks. The distributor faced potential penalties and needed a reliable, uniform dyeing solution that could work across their existing injection infrastructure.
The Solution: Having tested and compared multiple solutions, the distributor made the transition to a liquid material containing the high-flash solvent Red 164 (CAS 92257-31-3) red dye from a manufacturer known for its work in petroleum dyes. It dissolved fully in diesel, did not need to be pre-mixed and injected at elevated temperature, and preserved a consistent concentration in large-volume storage tanks.
Key Takeaway: By switching to a quality-assured Red 164, not only was the distributor fully compliant with regulations, but they saved money on dye. This case shows how buying Red 164 from an ISO-certified, experienced dye manufacturer that guarantees zero insoluble residue and consistency between batches can have a real impact on your business.
What to Look for When Sourcing Red 164
All Red 164 CAS 92257-31-3 isn’t the same as Red 164 CAS 92257-31-3, which is actually the catch-all for a series of alkylated materials. So it will vary from one company to the next and even from one production lot to the next. These are the aspects you should search for in an al171107 table.
- Purity and consistency: A good dye is one that does not have any insoluble impurities that might clog injector systems or leave sediments in fuel tanks. Thus, it is a good idea to choose suppliers who follow a rigorous quality-testing regimen on each batch.
- Full miscibility: Red 164 must be miscible in diesel fuel, kerosene, and other petroleum products to give a complete solution in the latter that has no cloudiness or phase separation.
- Regulatory compliance: Check whether the product complies with ASTM D6258-17 as well as local fuel-marking regulations in your area.
- ISO certification: Both ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018 certifications indicate that the manufacturer follows a responsible approach.
- Custom formulations: Custom formulations are used in the case when a specific base such as high-flash, xylene, or toluene is required.
One more is Anar Chemicals LLP-a manufacturer of Anar Chemicals LLP dyes and special chemicals, an ISO 9001:2015, ISO 14001:2015 & ISO 45001:2018 manufacturer with over 40 years of expertise in dyes and specialty chemicals, manufacturing Red 164 (CAS 92257-31-3), in high-flash or xylene solvent base, and many more petroleum dyes. See their complete Liquid Petroleum or Fuel Dyes product range on their site.
Frequently Asked Questions About Red 164
What can Red 164 be used for?
Known as Solvent Red 164 (CAS 92257-31-3), Red 164 is mostly used to dye tax-exempt diesel red for enforcement. It can also be used to colour lubricants, hydraulic fluids, printing inks, waxes, candles, as well as some plastics.
Is Red 164 Solvent Red 26?
No. Red 164 is an alkylated form of Solvent Red 26, with additional hydrocarbon chains that help it dissolve in diesel fuel. While the visible absorption spectrum of both Red 164 and Solvent Red 26 is virtually identical, Red 164 is the commercial-grade dye sold in the field and Solvent Red 26 is the certified laboratory reference standard.
What is the Red 164 CAS number?
It is most often sold under CAS # 92257-31-3, as this is the most common CAS registered for this ingredient, but depending on the alkylated form and base solvent, sometimes it can be sold under CAS # 92257-31-3.
What colour is the dyed diesel?
Since the 1990s, all dyed diesel has been required to be dyed red, and motor fuels exempt from excise tax can also be colored red.
What concentration of Red 164 is used in diesel fuel?
Federal regulations for the United States specify that tax-exempt diesel fuel must contain Red 164 as a spectral equivalent of 3.9 pounds of Solvent Red 26 in 1,000 barrels (1 barrel = 42 gallons = 159 liters), which is equivalent to about 11.1 mg/L (ASTM D6258-17).
Does Red 164 impact fuel performance?
No. Solvent Red 164 (CAS 92257-31-3) is inert to hydrocarbon systems and has no impact on fuel performance, cetane number or knocking.
Where can I purchase quality Red 164?
Red 164 can be purchased from specialised chemical manufacturers such as Anar Chemicals LLP (anarchem.com) – which supply Red 164 Petroleum grade Solvent Red 164 in high-flash and xylene solvent bases. Ensure the manufacturer is ISO certified and can provide products free from impurities, with batch-to-batch consistency.
Is Solvent Red 164 safe to use?
Solvent Red 164 is an industrial dye and as such should be handled with standard precautions – gloves and eye protection should be worn, and ensure you work in well-ventilated conditions. Read the MSDS or SDS for this product to inform your handling procedures.