- Greener Dye Synthesis: Continuous, Solvent-Free Synthesis of Commodity Perylene Diimides by Twin-Screw Extrusion
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A continuous, scalable, and solvent-free method for the synthesis of various naphthalic imides and perylene diimides (PDIs) using twin-screw extrusion (TSE) is reported. Using TSE, naphthalic imides were obtained quantitatively without the need for excess amine reactant or product purification. With good functional-group tolerance, alkyl and benzyl amine derived PDIs (incl. commercial dyes) were obtained in 50–99 % yield. Use of K2CO3, enabled synthesis of more difficult aniline-derived PDIs. Furthermore, an automated continuous TSE process for Pigments Black 31 and 32 is demonstrated, with a throughput rate of about 1500 g day?1, corresponding to a space time yield of about 30×103 kg m?3 day?1, which is 1–2 orders of magnitude greater than for solvent-based batch methods. These methods provide substantial waste reductions and improved efficiency compared to conventional solvent-based methods.
- Cao, Qun,Crawford, Deborah E.,James, Stuart L.,Shi, Chengcheng
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supporting information
p. 4478 - 4483
(2020/02/05)
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- A perylene pigment preparation method
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The present invention provides a perylene pigment preparation method, is to adopt the N - substituted - 1, 8 - naphthalene imide as the starting material, in order to N - methyl imidazole with DBU or DBN N - methyl imidazole with the mixed solvent as reaction medium, sodium alcoholate or polysiloxane as catalyst, through 130 - 170 °C reaction 3 - 10 hours, after the reaction, the reaction system cooling, concentrated under reduced pressure, recycling the reaction solvent, collects the product make the perylene pigment. Preparation of perylene pigment coloring high, bright color, good dispersibility, and this process is simple, time consuming and short, the reaction temperature is low, to reduce the use of strong alkali and concentrated sulfuric acid, the production cost is reduced, the reduction of the waste water and the solid waste discharge.
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Paragraph 0035; 0036
(2019/04/11)
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- A "green" route to perylene dyes: Direct coupling reactions of 1,8-naphthalimide and related compounds under mild conditions using a "new" base complex reagent, t-BuOK/DBN
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The direct coupling reactions of 1,8-naphthalimide compounds efficiently occurred at 130 or 170 °C without the intervention of the leuco form dyes in the presence of base complex reagent, t-BuOK/1,5-diazabicyclo[4.3.0]non-5-ene (DBN), to give the corresponding perylene dyes in good yields with >95% purities. A possible mechanistic speculation for these oxidative coupling reactions is briefly discussed.
- Sakamoto,Pac
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