Organizing Organic Chemistry Applications E-Book

Jeongbin Park

• Herausgeber: 이즈그리민(izgrimean)
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 91

Veröffentlichungsjahr: 2024

Beschreibung

The "Applications" edition describes how organic chemistry is applied to biology and experimentation. Although primarily focused on organic chemistry, this book also incorporates essential biological knowledge, providing holistic scientific approaches. By bridging the gap between chemistry and biology, it offers readers a deeper understanding of the molecular foundations of life. Regarding experimentation, this book not only itemizes spectroscopy concepts to facilitate their application in problem-solving but also concisely summarizes experimental content for quick and easy understanding.

In addition to the advanced concepts, it reviews the fundamentals of organic chemistry and its key reactions to enhance the understanding of more advanced sciences. The author guarantees that the book is organized into well-structured categories that allow for quickly grasping concepts upon reading.

Leseprobe

Creative Commons

Organizing Organic Chemistry Applications

Author | Jeongbin Park

Editor | Jeongbin Park

Cover Design | EUNJOLEE

Published by | 이즈그리민(izgrimean)

Publisher | EUNJOLEE

Date of Publication | August 21, 2024

Publisher Registration | May 24, 2023, No. 2023-000052

Email ｜ [email protected]

Price |

ISBN ｜ 979-11-987080-9-0(95430)

© 2024, 이즈그리민(izgrimean). All rights reserved. Reproduction or distribution of this work, in whole or in part, without explicit permission from 이즈그리민(izgrimean) is prohibited by law.

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Getting Started

Comments from Jeongbin Park

I opened a blog called “Jeongbin’s Study Room” to collect knowledge from many people. The enthusiasm for organic chemistry is still strong today, but a few years ago, it was significant, as organic chemistry was essential for various exams. Since studying organic chemistry in elementary, middle, and high school was rare, I anticipated a significant academic demand for organic chemistry. Therefore, since 2018, I have been sharing articles on organic chemistry on “Jeongbin’s Study Room” and communicating, correcting, and discussing with people. I have had many discussions online with medical professionals, pharmacists, lawyers, current teachers, and professors, among others. Now, as we welcome the new year 2024, I declare that the compilation of organic chemistry knowledge through collective intelligence is complete and I am publishing this book. I hope that this book can lower the barrier of organic chemistry as a field of study.

If you send the purchase receipt of the book to [email protected], we will provide you with additional lecture materials and problem sets.

Ch. 1: Synthetic Polymers

Ch. 1: Synthetic Polymers

1. Characteristics of Polymers

2. Polymer Synthesis

3. Non-degradable Polymers

4. Degradable Polymers

1. Characteristics of Polymers

⑴ Degree of Polymerization (DP)

① Definition: The number of monomer units in a polymer chain.

⑵ Average Molecular Weight

① Number-average molecular weight (Mn): Related to freezing point decrease, boiling point increase, vapor pressure decrease, osmotic pressure, etc.

② Weight-average molecular weight (Mw): Related to viscosity, tensile strength, light scattering, etc.

③ Z-average molecular weight (Mz): Related to melt elasticity, centrifugation, etc.

④ Viscosity-average molecular weight (Mv): Related to viscosity, etc.

○ Mark-Howink equation

⑤ Mz > Mw > Mv > Mn

⑥ Polydispersity Index (PDI): Polydispersity index in the general sense

○ Generally, polymers have various molecular weights due to different numbers of monomers, leading to PDI > 1.

○ Molecular weight distribution graph types: narrow distribution, broad distribution, bimodal distribution which implies two environments.

○ PDI in the general sencse can be determined using techniques like gel filtration chromatography (GFC), HPLC, GC, etc.

⑦ Meaning of PDI in DLS, Zetasizer

○ σ: The Standard Deviation of the Particle Size Distribution

○ d: The Average Hydrodynamic Particle Size

○ If 0 < PDI < 0.2, the dispersion of the nanoparticles is very good.

○ If highly polydisperse, PDI can exceed 1.

○ Zetasizer sets PDI between 0 and 1.

⑶ Crystallinity

① Factors: Molecular structure, functional groups, processing temperature, cooling rate

② Measurement methods: X-ray diffraction, infrared spectroscopy, differential scanning calorimetry (DSC) which measures melting heat change

③ Partial Crystallinity

○ Polymers have a mixture of ordered crystalline and disordered amorphous structures.

○ Factor 1: Incomplete crystallinity due to numerous repeating units.

○ Factor 2: High branched structures hinder crystallinity due to steric hindrance.

⑷ Stereoregularity

① Random copolymers (e.g., PLGA): Arrangement like ABBAABBBABABAAAABBB.

② Alternating copolymers: Arrangement like ABABABABABABABABABA.

③ Block copolymers: Arrangement like AAAAAAAAABBBBBBBBBB.

④ Graft copolymers: Arrangement like AAAAAAAAAAAAAAAAAAA.

⑸ Glass Transition Temperature (Tg)

① Definition: Temperature at which a polymer solid becomes rubbery.

② Cause: Transition temperature for irregular motion of main chain. Only present in amorphous polymers.

③ T < Tg: Rigid, glass-like state

④ T > Tg: Rubber-like state

2. Polymer Synthesis

⑴ Type 1. Radical Addition Condensation

① Reaction goes under radical initiators (e.g., benzoyl peroxide) or acids/bases catalysts.

② Example 1: Polyethylene: Polymerization of ethylene

Figure 1. Polyethylene synthesis

③ Example 2: Polyisoprene (e.g., natural rubber)

Figure 2. Polyisoprene synthesis

④ Example 3: Polystyrene (PS) synthesis

○ Polystyrene has preferred direction in polymerization for maximizing the number of resonance contributors.

Figure 3. Polystyrene synthesis

⑤ Example 4: Polymerization of acetone

Figure 4. Polymerization of acetone

⑥ Example 5: Polyethylene oxide synthesis using epoxide ring-opening reaction

Figure 5. Polyethylene oxide synthesis

⑦ Example 6: Polyvinylchloride (PVC): (CH2CHCl)n

⑧ Example 7: Polyacetic acid vinyl: (CH2CHCOOCH3)n

⑨ Example 8: Nylon synthesis: Mankind's first synthetic fiber

Figure 6. Nylon 6 synthesis

○ Step A: Ketone Amination Reaction. Faster under weak acid conditions compared to weak alkaline conditions.

○ Step B: Beckmann Rearrangement. Ring expansion reaction through rearrangement.

○ Step C: Ring-opening polymerization. Catalysts can include either radical initiators, acids, or bases.

⑵ Type 2. Dehydration Condensation Polymerization: Utilizes nucleophilic addition reactions to carbonyl carbons.

① Capable of hydrolysis reactions.

② Example 1: Polymerization of acetaldehyde

Figure 7. Polymerization of acetaldehyde

③ Example 2: Polymerization via acetal formation reaction

Figure 8. Polymerization via acetal formation reaction

④ Example 3: Polyester

Figure 9. Polyester synthesis

○ glycolic acid → poly(glycolic acid)

○ lactic acid → poly(lactic acid)

○ 3-hydroxybutyric acid → poly(hydroxybutyrate)

⑤ Example 4: Polylactide (PLA, poly lactic acid)

Figure 10. Polylactide synthesis

⑥ Example 5: Polymerization of amides

Figure 11. Polymerization of amides

⑦ Example 6: Polymerization of ethylene glycol and cyanate

Figure 12. Polymerization of ethylene glycol and cyanate

3. Non-degradable Polymers

⑴ Polyethylene (PE)

① Low-density polyethylene: Weak properties. Vulnerable to high temperatures.

② High-density polyethylene: Used for tubes and catheters.

⑵ Polypropylene (PP)

① Has a linear structure.

② Good repeated bending properties.

③ Resistant to external shocks.

④ Applications: Finger joint replacements, disposable syringe body.

⑶ Polyamide (Nylon)

① Strong inter-chain hydrogen bonding and high crystallinity → Excellent fiber forming ability.

② High absorbency → Water acts as a plasticizer → Degradation of properties due to water and protein enzymes.

③ Applications: Surgical sutures

⑷ Polymethyl Methacrylate (PMMA)

① High light transmittance (92%).

② High refractive index (1.49).

③ Large in size.

④ High strength and hardness.

⑤ Applications: Hard contact lenses, artificial intraocular lenses, dentures, facial prosthetic materials, bone cement

⑸ Polytetrafluoroethylene (Teflon, PTFE)

① A polymer material with carbon-fluorine bonding: C-F bond is strong. Doesn't decompose even when heated.

② High molecular weight, high crystallinity (> 94%), hydrophobic, high density, low coefficient of friction, high heat resistance, stability, porosity.

③ Applications: Coating material for frying pans, small diameter artificial blood vessels, catheters

⑹ Polyvinyl Chloride (PVC)

① Hard but flexible with plasticizers.

② Long-term plasticizer leaching leading to toxicity.

③ Applications: Tubes used for blood transfusion and dialysis, blood bags

⑺ Polyurethane (PU)

① Stable in the body, blood-compatible, strong, elastic, tough.

② Applications: Artificial blood vessels, artificial heart valves, catheters, burn dressings

⑻ Polycarbonate

① Very hard and lightweight

② Excellent mechanical and thermal properties

③ Applications: Heart assist devices, lung assist devices, body of blood dialysis machines, heart valve opener/closer

⑼ Polyacetal

① Very hard and lightweight

② Formed by the polymerization of formaldehyde.

③ Applications: Joint connection part of artificial hip joints, heart valve opener/closer

⑽ Polysulfone

① Very hard and lightweight

② Applications: Porous coating material for metallic orthopedic implants, oxygen enrichment membrane

⑾ Hydrogel

① A polymer that swells (30% or more) in water.

② Formed by cross-linking of hydrophilic polymers.

③ Hydrogel formed by physical cross-linking: Freely undergoes sol-gel transition.

④ Hydrogel formed by chemical cross-linking: Once it becomes a gel, cannot transition back to sol.

⑤ Representative example: Polyhydroxyethylmethacrylate (PHEMA)

○ Water absorption is similar to living human tissue.

○ Biologically inert, heat resistant, stable, excellent refractive index, high oxygen permeability.

○ Applications: Contact lenses

4. Degradable Polymers

⑴ PLA(poly lactic acid): Aliphatic polyester

Figure 13. Structure of PLA

① Crystallinity: L-PLA is 1.25-1.29 g/cm².

② Melting point: L-PLA is 159 ~ 178 ℃.

③ Glass transition temperature

○ L-PLA is 54 ~ 59 ℃, D-PLA is 50 ~ 53 ℃.

○ As molecular weight increases, glass transition temperature increases, because of solidification due to increased intermolecular force.

④ Lifespan: 18 ~ 24 months.

⑵ PGA(poly(glycolic acid)): Aliphatic polyester

Figure 14. Structure of PGA

① Molecular weight: 20 ~ 145 kg/mol.

② Crystallinity: 1.5 ~ 1.64 g/cm².

③ Melting point: 210 ~ 226 ℃.

④ Glass transition temperature: 36 ℃. Semi-crystalline.

⑤ Has OH group at α position.

⑶ PLGA(poly(lactic-co-glycolic acid))

Figure 15. Structure of PLGA

① Definition: Copolymer of PLA and PGA.

② Comparison between PLGA and PLA

Type

PLGA Copolymer

Single Polymer (PLA)

Degradation Lifespan

Short

Long

Structure

Amorphous

Semi-crystalline

Molecular Weight

Low

High

Table 1. Comparison between PLGA and PLA

③ Physical properties depending on PLGA's crystallinity

Biodegradable Polymers

Glass Transition Temperature (T

g

)

Melting Temperature (T

m

)

Tensile Strength (MPa)

Elastic Modulus (MPa)

Flexural Modulus (MPa)

Yield (%)

Fracture (%)

Poly(glycolic acid) (

MW

: 50,000)

35

210

n/a

n/a

n/a

n/a

n/a

L-PLA (

MW

: 50,000)

54

170

28

1200

1400

3.7

6

L-PLA (

MW

: 300,000)

59

178

48

3000

3250

1.8

2.2

D,L-PLA (

MW

: 20,000)

50

-

n/a

n/a

n/a

n/a

n/a

D,L-PLA (

MW

: 550,000)

53

-

35

2400

2350

3.5

5

PLGA 85:15

50 ~ 55

-

-

-

-

-

-

PLGA 75:25

50 ~ 55

-

-

-

-

-

-

PLGA 65:35

45 ~ 50

-

-

-

-

-

-

PLGA 50:50

45 ~ 50

-

-

-

-

-

-

Table 2. Physical and mechanical properties of various biodegradable polymers

Figure 16. Relationship between PGA content and crystallinity

Figure 17. Relationship between PGA content and melting point

Amorphous PLGA has no melting point.

Figure 18. Change in half-life depending on PLGA's crystallinity

○ Lifespan comparison: PLA ＞ PGA ＞ PLGA

④ Decomposition time of PLGA

○ Decomposes into lactic acid and glycolic acid by non-specific hydrolysis.

○ The closer the weight ratio of PLA and PGA is to 1:1, the shorter the lifespan.

Polymer

Abbreviation

Decomposition Time (months)

poly(lactic acid)

PLA

18 ~ 24

poly(D,L-lactic acid)

PDLA

12 ~ 16

poly(glycolic acid)

PGA

2 ~ 4

poly(D,L-lactic-co-glycolic acid, 50:50)

PLGA

2

poly(D,L-lactic-co-glycolic acid, 70:30)

PLGA

6

poly(D,L-lactic-co-glycolic acid, 85:15)

PLGA

10

Table 3. Decomposition period of PLGA depending on composition

○ Ability to control lifespan is an advantage of PLGA.

○ Most protein enzymes do not participate in decomposition.

○ Exception: Decomposition of PLGA is accelerated in vitro experiments by microbial-derived proteinase K or lipase.

⑤ Decomposition process of PLGA

Figure 19. Change in device weight and PLGA molecular weight over time

○ 1st. Hydrolysis of ester: Water molecules attack the ester bond in PLGA.

○ 2nd. As the polymer breaks, the carboxyl terminus is exposed and molecular weight continues to decrease.

○ 3rd. Decomposition rate increases over time: Carboxyl end groups act as a catalyst for ester hydrolysis (autocatalysis).

○ 4th. Even if the polymer chain breaks, it remains insoluble at high molecular weight and does not diffuse into the solution.

○ 5th. After approaching the critical molecular weight (1,000 ~ 1,100), it dissolves → The device weight starts to decrease.

○ 6th. As the carboxyl terminus dissolves, pH decreases.

⑷ Other biodegradable polymers

① Polycaprolactone(PCL)

② Polyanhydride

③ Polyortho ester

④ Polyamino acid

⑤ Polyhydroxybutyrate(PHB)

⑥ Polyhydroxyvalerate(PHV)

⑦ Polyphosphazene: An inorganic polymer where the main chain is made of nitrogen and phosphorus.