Compound emulsifier with switching property

A composite emulsifier and switching technology, which is applied in chemical instruments and methods, chemical/physical processes, dissolution, etc., can solve problems such as unstable emulsions and poor surface activity of amphiphilic compounds, and achieve good switching properties and high efficiency Effect

Inactive Publication Date: 2013-09-18
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process is called in situ surface activation, and the required concentration of ionic amphiphile is much less than its critical micelle concen

Method used

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  • Compound emulsifier with switching property
  • Compound emulsifier with switching property
  • Compound emulsifier with switching property

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: Switching of N'-long-chain alkyl-N,N-dimethylethylamidine.

[0016] Add N'-dodecyl-N,N-dimethylethylamidine to water at a concentration of 3×10 -4 mol L -1 , transfer the solution to as figure 1 In the bubbling (transition) device shown, CO was introduced at ice bath temperature 2 (160mL / min), the conductivity reaches the maximum after 50min, showing that N'-dodecyl-N, N-dimethylethylamidine is completely converted into bicarbonate, a cationic amphiphile. Then N2 (160mL / min) was introduced at 65°C, and the conductivity of the solution was measured over time. As a result, the conductivity continued to decrease until it reached the lowest value after 80 minutes, indicating that the bicarbonate was completely transformed into ethylamidine. Reintroduce CO 2 The conductivity rises again, so it can be cycled repeatedly, that is, N'-dodecyl-N, N-dimethylethylamidine has switchability, and can be reversibly converted between active and inactive forms. figure 2 ...

Embodiment 2

[0017] Example 2, complex emulsifier stabilizes Pickering emulsion.

[0018] 0.035g of unmodified nano silica particles (HL220, BET specific surface area 220m 2 / g, Wuxi Jinding Longhua Chemical Co., Ltd.) ultrasonically dispersed in 7mL different concentrations (1×10 -4~6×10 -3 moL -1 ) of N'-dodecyl-N,N-dimethylethylamidine bicarbonate aqueous solution, add 7mL n-octane, and use IKA high-shear emulsifier (rotor diameter 1cm) at 11,000rpm After emulsifying for 2 minutes, an ultra-stable Pickering emulsion was obtained. image 3 This is the photo of the appearance of the emulsion. The emulsion is O / W type with excellent stability and no change in appearance after one week. Figure 4 It is a photomicrograph of the emulsion, and the diameter of the liquid droplets can be seen to be 100-200 μm.

Embodiment 3

[0019] Example 3: On-off properties of complex emulsifiers and their stable Pickering emulsions.

[0020] Dissolve N’-dodecyl-N, N-dimethylethylamidine in water to a concentration of 3×10 -4 moL -1 , CO was introduced at ice-bath temperature 2 , the flow rate is 160mL / min for 50min. Take 10mL of the solution and put it into a vial, add 0.05g of nano-silica, ultrasonically disperse, add 10mL of n-octane, and emulsify with an IKA high-shear emulsifier at 7,000rpm (use a lower speed to prevent liquid from overflowing) 2min, a stable O / W emulsion was obtained. Appearance and micrographs are as Figure 5 (a) and Figure 6 (a) shown.

[0021] The emulsion was transferred to a bubbler bottle, and N was passed through at 65°C. 2 (160mL / min), last for 80min, the emulsifier activity is closed, the emulsion breaks and separates into oil / water two phases, such as Figure 5 (b) and 5(c). Use IKA high shear emulsifier to emulsify at 7,000rpm for 2 minutes, but a stable emulsion can...

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Abstract

The invention discloses a compound emulsifier with a switching property, belonging to the field of colloid and interface chemistry. The emulsifier consists of nano silicon dioxide particles without any modification and a switching-type amphiphilic compound, wherein the original particle size of the nano silicon dioxide particles is 20-200nm, and the use concentration is 0.1-2.0% (based on an aqueous phase); and the switching-type amphiphilic compound is an N'-long chain alkyl-N,N-dimethylacetamidine substance, wherein the total carbon atom number of the long chain alkyl is 8-18, the long chain can be a straight chain or branch chain, the alkyl is a saturated or unsaturated alkyl containing a benzene ring or not, and the use concentration is less than the critical micelle concentration (based on an aqueous phase). A proper oil phase comprises mineral oil (hydrocarbons), animal/vegetable oil (triglycerides) and water-insoluble polar organic matters such as long-chain fatty acid, fatty alcohol and the like. The emulsion prepared by the compound emulsifier belongs to Pickering emulsion, is generally an O/W type and has hyperstability. By introducing nitrogen (N2) or air, the emulsifier can be deactivated to cause demulsification of the emulsion; by introducing carbon dioxide (CO2), the surface activity of the emulsifier can be recovered; and the system becomes stable Pickering emulsion after homogenizing emulsification, namely that the compound emulsifier has a switching property.

Description

technical field [0001] A composite emulsifier with switchability belongs to the technical field of colloid and interface chemistry. Background technique [0002] In recent years, switch-type amphiphiles have attracted extensive attention. This kind of amphiphile can be reversibly interchanged between the "active" and "inactive" forms, so not only can its surface activity be artificially controlled, but also it is easy to separate, recover and reuse from the system after use. A green and environmentally friendly chemical. The "triggers" that trigger the switch include electrochemical, photochemical, and CO 2 / N 2 and other programs. Among them, the electrochemical scheme relies on the addition of chemical substances such as acids, alkalis, oxidants, reducing agents, etc., which are easy to cause damage to the application system; while the photochemical scheme is easily affected by the opacity of the system such as emulsion; relatively speaking, CO 2 / N 2 The scheme is m...

Claims

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Application Information

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IPC IPC(8): B01F17/54B01F17/00C09K23/54C09K23/00
Inventor 崔正刚朱玥蒋建中
Owner JIANGNAN UNIV
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