Household Chemicals. J. W. Hill and D. K. Kolb, Chemistry for Changing Times, Chapter 17.

Transcription

1 Household Chemicals J. W. Hill and D. K. Kolb, Chemistry for Changing Times, Chapter 17.

2 Soap and Detergent

3 Soap and Detergent Old way of making soap: Animal fats or vegetable oil + lye

4 How Soap Works Hydrophobic Hydrophilic

5 How Soap Works

6 Advantages and Disadvantages of Soap Relatively non-toxic From renewable resources Biodegradable 1. Animal fats or vegetable oil + lye (NaOH): excess NaOH 2. 3.

7 Water Softeners 1. Washing soda: Na 2 CO 3 10 H 2 O CO 3 2- (aq) + Ca 2+ (aq) CaCO 3 (s) Another benefit: Keep water basic: CO 3 2- (aq) + H 2 O (l) HCO 3- (aq) + OH - (aq) 2. Na 3 PO 4 2 PO 3-4 (aq) + 3 Ca 2+ (aq) Ca 3 3( (PO 4 4) 2 (s) Another benefit: Keep water basic: PO 3- (aq) + H O (l) HPO () 4 (aq) + OH - (aq)

8 Water Softening by Ion Exchange

9 Synthetic Detergents (Alkylbenzensulfonate) (Linear alkylsulfonate)

10 Typical Detergent Components Detergent Surfactants Builders Brighteners Others Anionic Surfactants Nonionic Surfactants Cationic Surfactants

11 Surfactants Anionic surfactants: so far the best (~ 65%) ( ) Nonionic surfactants: best for cold water (more soluble) (~25%) Cationic surfactants: may kill germs

12 Builders Builders: any substance added to a surfactant to increase its detergency (~ softeners) Na 5 P 3 O 10 : banned in some states Na 2 CO 3 : common Zeolites: complex aluminosilicates most promising Na 2 Al 2 Si 2 O 8 (s) + Ca 2+ (aq) CaAl 2 Si 2 O 8 (s) + 2 Na + (aq) Certain cationic complexes: (fabric softener)

13 Water Softeners 1. Washing soda: Na 2 CO 3 10 H 2 O CO 3 2- (aq) + Ca 2+ (aq) CaCO 3 (s) Another benefit: Keep water basic: CO 3 2- (aq) + H 2 O (l) HCO 3- (aq) + OH - (aq) 2. Na 3 PO 4 2 PO 3-4 (aq) + 3 Ca 2+ (aq) Ca 3 3( (PO 4 4) 2 (s) Another benefit: Keep water basic: PO 3- (aq) + H O (l) HPO () 4 (aq) + OH - (aq)

14 Brighteners

15 Others in Detergents Others Bleach Enzymes Perfumes Colorants Classic bleach Slow-chlorine releasing bleach Oxygen-releasing bleach

16 Bleaches: Oxidants 1. Classic bleach: sodium hypochlorite, NaOCl, in solution calcium hypochlorite, Ca(OCl) 2, in powder effective, cheap, but rapidly release chlorine that may damages fabric 2. Slow chlorine releasing bleach: symclosene 3. Oxygen releasing bleach: powder: sodium perborate: NaBO 2 H 2 O 2 sodium percarbonate: NaCO 2 H 2 O 2 liquid: hydrogen peroxide: H 2 O 2 Requires higher temperature, higher alkalinity and higher concentration.

17 Powdered Oxygen Releasing Bleach Sodium percarbonate: NaCO 2 H 2 O 2 has the highest solubility in water, used mostly in deck, carpet, household and laundry cleaning products Sodium perborate: NaBO 2 H 2 O 2 more storage stable in detergent formulations, used mostly in automatic dishwashing and laundry products as a hot water bleaching agent Advantages: Disadvantages: Little damage to fabric Costs more Longer shelf-life e than liquid qud H 2 O 2 Tk Takes time to dissolve in water Acts as a disinfectants Takes longer to work can be mixed or used with other Not suited for some finer household cleaners grades of silk or wool Non-toxic to animals, plants and humans. Environmentally friendly

18 Powdered Oxygen Releasing Bleach Ultra-Concentrated Oxygen Bleaches: % of oxygen Concentrated Oxygen Bleaches: 40-70% of oxygen Oxygen bleaches with additives and other cleaning agents: 20-40%of oxygen Cleaning products that contain oxygen bleach as an ingredient: < 25%of oxygen

19 Detergent Enzymes 1. Proteases: used most often specialty detergent enzymes that hydrolyse proteins and break down them into soluble polypeptides or free amino acids. Such enzymes effectively removes protein stains like blood, sweat etc. 2. Lipases: lipolytic enzymes capable of removing fatty stains like lipstick, frying fats, butter sauces and tough stains from collars and cuffs 3. Amylase : starch hydrolysing enzymes used to remove residues of starchy foods like spagetti, mashed potato, gravies and chocolate. Liquid bioamylases can be used in dishwashing formulations for effective results.. 4. Cellulase: complex cellulase enzymes which effectively handle particulate and dirt stains. Imparts brightness, sheen and softness to the fabric and

20 Cosmetics Cosmetics: articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced d into, or otherwise applied to the human body or any part thereof, for cleansing, beautifying, promoting attractiveness or alternating the appearance. n y y Soap Toothpaste lipsticks Vaseline (petroleum jelly) Antidandruff Shampoo y Vaseline (petroleum jelly) n Drugs: must be proven to be safe and effective Cosmetics: not necessary

21 Skins (Keratin) (melanocyte) Keratin: fibrous protein: moisture content: 10% Melanocyte: produces melanin (tan) or melanoma (skin cancer)

22 Skin Care Moisturizers: lanolin UV-protection: sun screen Ultraviolet rays result in melanin formation (a SLOW process) UVA (320 to 400 nm): causes tanning and some damage UVB (280 to 320 nm): causes damage in the form of sunburn UVC (< 280 nm): filtered out by the atmosphere SPF: skin protection factor: SPF of 30 = one can stay in the sun without burning 30 times as long as one could with unprotected skin (rated only for UVB protection)

23 Sunblocks - (Sunblock) (Aspirin) Cinnamate UVB protections: PABA (para-aminobenzoic Acid) & Derivatives: Used extensively in in the 1950's and 1960's, no longer a common ingredient in sunscreens Salicylates: Used mostly in waterproof sunblocks Cinnamates: not waterproof UVA protections: Benzophenones, Dibenzoylmethanes Physical Blockers: ZnO and TiO 2

24 Sunblocks Suggested SPF Type Characteristics Routine day Outdoor Activity I Always burns easily, never tans II Burns easily, tans slightly III Sometimes burns, tans gradually and moderately IV Burns minimally, always tans well V Burns rarely, tans deeply VI Almost never burns, deeply pigmented

25 Toothpaste CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 OSO 3- Na +

26 Toothpaste t Fluoride: SnF 2 (+ calcium pyrophosphate): early use, but few used now NaF (+ hydrated silica abrasive): leading Na(FPO 4 ) 2 (sodium monofluorophosphate (MFP): fair amount of use Sugars to dextrans (Plaque) and to acids (lactic acid) (Ca 5 (PO 4 ) 3 OH + F - Ca 5 (PO 4 ) 3 F Hydroxyapatite fluorapatite Fluoride concentrates in the growing bones and developing teeth of children, helping to harden the enamel on baby and adult teeth before they emerge; Fluoride helps to harden the enamel on adult teeth that have already emerged Mike McCoy, C&E News, 79 (16) 42 (April 16, 2001)