Pyrazole Disazo Dye Solubility in Hydrocarbon Solvents

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Solution Overview

Problem

Existing pyrazole disazo dyes have limited solubility in nonpolar solvents, particularly hydrocarbon solvents, which hinders their effectiveness in display materials and thermal transfer recording applications.

Innovation Solution

A pyrazole disazo dye with a C2-C10 alkyl group and a C3-C10 alkyl group, specifically designed to have high solubility in nonpolar organic solvents like n-decane, achieving a solubility of 1% by weight or higher at 25°C and ordinary pressure, and a high molar extinction coefficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing pyrazole disazo dyes are used, then high color density and light resistance are achieved, but solubility in nonpolar solvents particularly hydrocarbon solvents is insufficient

Engineering Contradiction:

Improvelight resistanceVSAvoidsolubility in hydrocarbon solvents

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent modifies the molecular structure parameters of pyrazole disazo dyes by introducing specific alkyl groups (C2-C10 at position 1 and C3-C10 at position 3) to change the solubility parameter, enabling the dye to dissolve in nonpolar hydrocarbon solvents while maintaining its optical properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure combining pyrazole disazo chromophore with alkyl substituent groups, where the alkyl groups provide solubility in nonpolar solvents while the pyrazole disazo core maintains high color density and light resistance

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If dyes with high molar extinction coefficient are used, then coloring efficiency is heightened, but solubility in nonpolar solvents deteriorates

Engineering Contradiction:

Improvemolar extinction coefficientVSAvoidsolubility in nonpolar solvents

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality modification by introducing alkyl groups at specific positions (1 and 3) of the pyrazole ring, where these local modifications enhance solubility in nonpolar solvents while the central chromophore structure maintains high molar extinction coefficient

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8143382B2Pyrazole disazo dye and ink containing the dye

Publication Date: 2012.03.27 MITSUBISHI CHEM CORP

AI summary

The invention provides a specific pyrazole disazo dye which is a yellow dye having excellent solubility in nonpolar solvents, in particular, hydrocarbon solvents, and having a high extinction coefficient. The dye preferably is preferably a pyrazole disazo dye represented by the following general formula (I):(wherein R1 represents a C2-C10 alkyl group; R2 represents a C3-C10 alkyl group; the six-membered ring A represents a phenyl group which may have a substituent; and the six-membered ring B represents a phenylene group which may have a substituent).