CAS 169682-12-6: A high-performance naphthopyran based photochromic material
When molecules encounter ultraviolet radiation
Imagine a scene where a pair of glasses automatically darken in sunlight, and then return to transparency when entering the room; A banknote displays a hidden anti-counterfeiting pattern under ultraviolet light irradiation; A smart window adjusts its light transmittance based on the intensity of sunlight. These seemingly sci-fi scenes cannot be separated from a special type of molecule – photochromic compounds.
CAS number 169682-12-6 (chemical name: 2) H-Naphtho[1,2-b]pyran-5-carboxylic acid, 6-methoxy-2,2-bis(4-methoxyphenyl)-, methyl ester， The molecular formula C ∝₀ H ₂₆ O ₆, with a molecular weight of 482.52, is precisely such a naphthopyran compound with photochromic properties. This article will systematically introduce its structural characteristics, core uses, and market prospects.
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Chemical Structure and Photochromic Principle
Naphthopyran skeleton: the “heart” of photochromism
169682-12-6 belongs to the naphthopyran class photochromic compounds. Naphthopyran is an important branch of photochromic materials, whose core structure consists of a system formed by the fusion of a naphthalene ring and a pyran ring.
The photochromic mechanism of such molecules can be summarized as follows: under ultraviolet light irradiation, the C-O bond in the molecule breaks, isomerizing from a colorless closed-loop structure to a colored open-loop structure with a longer conjugated system (partial cyanine structure); After removing ultraviolet light, under the action of heat or visible light, the molecule returns to a closed loop structure and the color fades away.
The structural characteristics of this compound
169682-12-6 has the following structural features based on the naphthopyran skeleton:
1）6-position connected methoxy (- OCH ∝)
2）Connecting two para methoxyphenyl substituents at the 2-position
3）Position 5 is methyl ester group (- COOCH ∝)
The design of these substituents is not arbitrary, but precisely regulated – the introduction of electron donating groups such as methoxy can adjust the electron density of the molecule, thereby affecting the response speed, color depth, and fading rate of its photochromic behavior.
Core application areas
1. Photochromic lenses (largest market)
The market for photochromic optical resin monomers has reached $157 million in 2024 and is expected to grow to $394 million by 2031, with a compound annual growth rate of 8.0%. Another market report shows that the market size has reached 498 million US dollars by 2025.
This compound can be used as a photochromic monomer and applied to lens manufacturing through two technical routes
1) Matrix technology
2) Thin film technology
2. Optical anti-counterfeiting and information encryption
Photochromic materials have demonstrated unique advantages in the fields of dynamic anti-counterfeiting and information encryption. For example, a newly disclosed patent for a triarylethylene based photochromic material incorporates a naphthopyran structure. After excitation, the color can gradually change from red to orange or yellow over time, eventually returning to colorless, achieving a dynamic anti-counterfeiting effect of “multi-color switching”.
Similarly, fluorescent polymer nanoparticles based on naphthopyran light switches can be used for information encryption and dynamic anti-counterfeiting.
3. Intelligent glass and advanced optical devices
Photochromic materials also have potential in applications such as building smart windows, car rearview mirrors, camera filters, etc. Automotive rearview mirrors are subdivided into exterior mirrors and interior mirrors, while building windows are divided into commercial windows and residential windows – each application imposes specific requirements on the optical properties, mechanical strength, and durability of photochromic materials.
Market prospects and industry trends
Regional pattern
North America: The largest market for photochromic glasses and the earliest research and development base. After years of market education, the demand is extremely strong
Asia Pacific region: rapidly growing emerging markets, Chinese companies increasingly active in the field of photochromic materials
Europe: Mature market with high requirements for product quality and environmental protection
Technological development trends
The current focus of attention in the industry includes:
1）Faster response speed: Shorten discoloration and fading time
2）Improved fatigue resistance: prolongs reversible cycle life
3）Color neutrality: achieving more natural color changes
Multi attribute optimization: balancing color change speed, cycle life, and environmental stability
Research has shown that the fading rate of naphthopyran compounds can be significantly improved through molecular structure design, such as introducing specific substituents or fusing with other functional units. For example, the fading half-life of naphthopyran-tetrastyrene fused compounds can be shortened to 0.75 minutes, exhibiting advantages such as rapid light response and good fatigue resistance.
Summary
CAS 169682-12-6, as a naphthopyran based photochromic compound, has clear application value in high-tech fields such as photochromic lenses, optical anti-counterfeiting, and smart glass due to its precisely designed molecular structure. With the continuous growth of the global photochromic material market (expected to exceed $600 million by 2032), these high-performance photochromic monomers will usher in a broader development space.
Product Manager Email:ada@coreychem.com
