Detergent hydrophile part

A second family is based on isobutene polymers (PIB) having molecular weights from 600 to 2000 that are equally important raw materials for detergent additives. So as to render them reactive with the hydrophilic part, they can be chlorinated or condensed with the maleic anhydride. A third way is based on the utilization of polypropylphenols of molecular weights between 600 and 3000. 

The hydrophilic parts can contain oxygenated groups (glycol ether types) or amines. The first detergents used amine and phosphoric acid salts or... 

Phospholipids are detergents they have a hydrophobic part (the fatty acid tail) and a hydrophilic part (the head) (Fig. 3-1). The phospholipids... 

The hydrophilic part of the most effective soluble surfactants (e.g. soaps, synthetic detergents and dyestuffs) is often an ionic group. Ions have a strong affinity for water owing to their electrostatic attraction to the water dipoles and are capable of pulling fairly long hydrocarbon chains into solution with them for example, palmitic acid, which is virtually un-ionised, is insoluble in water, whereas sodium palmitate, which is almost completely ionised, is soluble (especially above its Krafft temperature - see page 93). 

Surface-active agents, or surfactants, all share interesting physicochemical characteristics at surfaces and interfaces. Surfactants (detergents and dispersants) are long chain hydrocarbons with polar headgroups which are called dipoles. Surfactants are molecules which consist of two well defined parts one which is oil-soluble hydrophobic and another which is water-soluble hydrophilic. The hydrophobic part is non-polar and usually consists of aliphatic or aromatic hydrocarbons. The hydrophilic part is polar and interacts strongly with water. 

Like a detergent, bile salts contain hydrophobic and hydrophilic components. The hydrophobic portions of the molecule associate with the fat, and the hydrophilic parts associate with water, serving to solubilize (emulsify) the otherwise insoluble fat. See Figure 18.4. 

The main component of detergents is surfactant. The eldest known surfaetant is soap. Chemically soap is an alkaline salt of fatty acid. Characteristic of soap (and surfactant) is the molecular structure consisting of apolar - hydrophobic - part (fatty acid) and a polar - hydrophilic - part (-COONa), causing surface activity in aqueous solution. 

The development of detergents based on the combination of fats and oils as the hydrophobic part and carbohydrates as the hydrophilic part gained importance with the discussion to reduce the petrochemical (fossil) resources in detergent production [10]. Important criteria for the use of these derivatives are price, quality, and availability of the raw material, and the processing costs [11]. 

The CMC of a detergent depends on the nature, size, and shape of the hydrophile as well as the hydrophobe. This can be understood from Figure 26.3. Here, the variations in the hydrophobic part as well as hydrophilic part can be made to design the detergents with the desired adsorption... 

In the same way aqueous dye solutions, like methylene blue or patent fast blue, are employed instead of water. Lipophilic substances, like anion active detergents, appear pale on a transparent blue background. This phenomenum is contrary on RP phases. The lipophilic part of the detergent is aligned with the RP chains, whereas the hydrophilic part is colored by the dye, and therefore deeply colored blue zones appear on a pale backgound. Using lipophilic dye solutions for the detection of lipophilic substances on a hydrophilic phase yields dark zones on a pale background. 

The most common example of surfactant behavior that you will be familiar with is that of a detergent-like molecule. Detergents localize at the interface between water and oil. They are able to do this because of the unique properties of many surfactant molecules, one part being hydrophilic (water loving) and another part hydrophobic (water fearing). The water-adverse part of the molecule orients into the oil phase, whereas the water-loving hydrophilic part preferentially orients into the water. Surfactants are also known as amphiphilic, which means loving both. ... 

The properties (e.g. cleaning and stabilizing capabilities) of surfactants depend on both solution properties (temperature, time, presence of salts and cosurfactants) and their own characteristics, especially CMC, the Krafft point and their chemistry. The surfactant chemistry and especially the balance between hydrophobic and hydrophilic parts is quantified using tools like the CPP or HLB (critical packing parameter, hydrophilic-lipophilic balance, respectively). For example, it is often observed that detergency increases with concentration especially up to CMC and is often best at CPP values around 1. We will meet the important concept of CPP again in Chapter 7 where we will see that surfactant adsorption on solid surfaces is connected to CPP. 

Lyotropic liquid crystals are obtained when an appropriate concentration of a material is dissolved in a solvent (Collings and Hird 1997 Neto et al. 2005). The most common systems are those formed by water and amphiphilic molecules (molecules that possess a hydrophilic part that interacts strongly with water and a hydrophobic part that is water insoluble), such as soaps, detergents and lipids. There are a number of phases observed in such water-amphiphiUc systems, as the composition and temperature are varied some appear as spherical micelles, and others possess ordered stmctures with one-, two-, or three-dimensional positional order. Examples of these kinds of molecules are soaps and various phospholipids, like those present in cell membranes (Lukask and Harden 1985). 

Dimer acid has surface active properties because it contains hydrophobic and hydrophilic parts in its molecule. This is the reason for its use in - corrosion inhibitors, - detergents, - lubricants and pigment dispersers in - coatings. 

Dispersants and detergents are surfactants in organic media and contain an oleophilic hydrocarbon part and a hydrophilic polar part. 

In the case of lubricant detergents, the hydrophilic or polar part is a metallic salt (calcium, magnesium) and at the center of the micelle it is possible to store a reserve of a metal base (lime or magnesia) the detergent will be able therefore to neutralize the acids produced by oxidation of the oil as soon as they are created. 

Compare and contrast the electrostatic potential map of a typical detergent with that of a typical soap (stearate). Which part of each molecule will be most water soluble (hydrophilic) Draw a Lewis structure that describes each molecule s water-soluble group (make sure you indicate all necessary formal charges and lone pairs). Which part(s) of each molecule will be most grease soluble (lipophilic) What kinds of atoms and bonds are found in these groups ... 

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