Dichloroethane

9.1.1.2 Choice of Solvent

Dichloroethane (C₂H₄Cl₂) is found to be a good solvent for the extraction of LS with a distribution coefficient of 21.5 followed by carbon tetrachloride (8.5) and chloroform (1.25). Other organic solvents show negligible extraction of LS. It has also been observed that the solubility of LS is very low in absence of carrier agent even for dichloroethane. Hence, it is evident that mere solution diffusion is not enough for LS transport; some facilitation is required for it. On the other hand, it was observed that coconut oil could be used as an important alternative for solvent in lieu of toxic organic solvent (Chakrabarty et al., 2010b). It was also observed that LS is highly soluble in coconut oil even without any carrier agent. This fact augments the philosophy of green technology in LM-based operation. Nevertheless, addition of carrier agent (TOA) reduces the time for reaching equilibrium extraction.

11.11.6 Ethylene Dichloride

A relevant code for ethylene dichloride, or 1,2-dichloroethane, is the Code of Practice for Chemicals with Major Hazards: Ethylene Dichloride (CIA, 1975 PA13). Accounts are also given by V.L. Stevens (1979) and Rossberg et al. (1986).

Ethylene dichloride is made by the liquid phase chlorination of ethylene. It is used principally for the manufacture of vinyl chloride by cracking the ethylene dichloride to vinyl chloride and hydrogen chloride. Usually, the latter is then reacted in an oxychlorination process to produce more vinyl chloride.

Ethylene dichloride is a liquid with a normal boiling point of 84.4°C. It has a low solubility in water. Ethylene dichloride is flammable, the flammable range being 6–16%. The flash point is 13°C (closed cup) or 18°C (open cup).

Ethylene dichloride is toxic. It has a long-term maximum exposure limit of 5 ppm and carries the ‘Skin’ notation. Concentrations of about 3% can produce nausea, drowsiness, and stupor. It is detectable by odor at a concentration of 50–100 ppm. The decomposition products of ethylene dichloride in a fire include hydrogen chloride, which is toxic.

Plant handling ethylene dichloride is usually constructed in mild steel. Mild steel is suitable for dry ethylene dichloride and also for wet saturated ethylene dichloride below 50°C, provided the aqueous phase is alkaline. But at temperatures above 80°C wet ethylene dichloride undergoes hydrolysis, forms acid, and rapidly corrodes mild steel. Transfer of ethylene dichloride may be affected by pumping or inert gas padding.

Ethane derivatives

6.5.2.2 Preparation of conductive polylactic acid material

The ranges of mass percentage of each preparation composition are as follows: 75%–90% of polylactic acid, 0.5%–5% of carbon nanotubes, 0.01%–0.05% of coupling agent, 1%–5% of compatibilizer, 0.3%–0.6% of antioxidant, 0.1%–5% of toughening agent, 0.5%–2% of nucleating agent, and 0.5%–2% of plasticizer, the sum of the mass percentages of the above components is 100%.

Use Type

Fumigant, Insecticide

CAS Number

107-06-2

Formula

C₂H₄Cl₂; ClCH₂CH₂Cl

Synonyms

1,2-Bichloroethane; Dichloremulsion; Di-chlor-mulsion; α,β-Dichloroethane; sym-Dichloroethane; 1,2-Dichloroethane; Dichloroethylene; 1,2-Dicloroetano (Spanish); EDC; ENT 1,656; Ethane, 1,2-dichloro-; Ethane dichloride; Ethylene chloride; 1,2-Ethylene dichloride; Freon 150; Glycol dichloride; NCI-C00511

Trade Names

BORER SOL®; BROCIDE®; DESTRUXOL BORER-SOL®; DOWFUME®[C]; DUTCH LIQUID®; DUTCH OIL®

Chemical class

Chlorinated hydrocarbon

EPA/OPP PC Code

042003

California DPR Chemical Code

274

HSDB Number

65

UN/NA & ERG Number

UN1184/131

RTECS® Number

KI0525000

EC Number

203-458-1 [Annex I Index No.: 602-012-00-7]

Uses

Not approved for use in EU countries^[115]. Not registered for use in the U.S. When mixed with carbon tetrachloride, ethylene dichloride is used as a grain fumigant for bulk storage in bags, sealed containers, bins or on floors. In recent years, 1,2-dichloroethane has found wide use in the manufacture of ethylene glycol, diaminoethylene, polyvinyl chloride, nylon, viscose rayon, styrenebutadiene rubber, and various plastics. It is a solvent for resins, asphalt, bitumen, rubber, cellulose acetate, cellulose ester, and paint; a degreaser in the engineering, textile and petroleum industries; and an extracting agent for soybean oil and caffeine. It is also used as an antiknock agent in gasoline, a pickling agent and a dry-cleaning agent. It has found use in photography, xerography, water softening, and also in the production of adhesives, cosmetics, pharmaceuticals, and varnishes.

U.S. Maximum Allowable Residue Levels for Fumigants, including ethylene dichloride [40 CFR 193.225, 180.521, 180.522]

grain, cereal, milled fractions 125 ppm; corn, field, grits 125 ppm; rice, cracked 125 ppm.

Regulatory Authority and Advisory Information

Carcinogenicity^[83]: IARC: Animal Sufficient Evidence; Human Inadequate Evidence, possibly carcinogenic to humans, Group 2b, 1999; EPA: Sufficient evidence from animal studies; inadequate evidence or no useful data from epidemiologic studies; NTP: 12th Report on Carcinogens, 2011: Reasonably anticipated to be a human carcinogen; NIOSH: Potential occupational carcinogen

California Proposition 65 Chemical: Cancer (1/1/1987)

Health Advisory: Mutagen, Developmental/Reproductive Toxin, Skin irritant/sensitizer

Clean Air Act: Hazardous Air Pollutants (Title I, Part A, Section 112)

Clean Water Act: Section 311 Hazardous Substances/RQ 40CFR117.3 (same as CERCLA, see below); 40CFR423, appendix A, Priority Pollutants; Section 313 Water Priority Chemicals (57FR41331, 9/9/92); Toxic Pollutant (Section 401.15)

U.S. EPA Hazardous Waste Number (RCRA No.): U077, D028

RCRA Toxicity Characteristic (Section 261.24), Maximum Concentration of Contaminants, regulatory level, 0.5 mg/L

RCRA 40CFR268.48; 61FR15654, Universal Treatment Standards: Wastewater (mg/L), 0.21; Non-wastewater (mg/kg), 6.0

RCRA 40CFR264, appendix 9; TSD Facilities Ground Water Monitoring List. Suggested test method(s) (PQL μg/L): 8010 (0.5); 8240 (5)

Safe Drinking Water Act: MCL, 0.005 mg/L; MCLG, zero; Regulated chemical (47 FR 9352)

CERCLA Reportable Quantity (RQ): 100 lb (45.4 kg)

US DOT Regulated Marine Pollutant (49CFR172.101, appendix B)

US DOT 49CFR172.101, Inhalation Hazardous Chemical

Rotterdam Convention Annex III [Chemicals Subject to the Prior Informed Consent Procedure (PIC)]

European/International Regulations: Hazard Symbol: F, T; risk phrases: R45; F11; R22-36/37/38; safety phrases: S2; S53; S45 (see Appendix 1)

WGK (German Aquatic Hazard Class): 3-Severe hazard to waters

Description

1,2-Dichloroethane is a clear, colorless, flammable liquid. A pleasant, chloroform-like odor, and a sweet taste. Decomposes slowly: turns dark and acidic on contact with air, moisture, and light. The Odor Threshold is 100 ppm. Molecular weight = 98.96; Specific gravity (H₂O:1) = 1.245; Boiling point = 83.5°C; Freezing/Melting point = –35.7°C; Vapor pressure = 75 mmHg @ 23.70°C; Flash point = 13.33°C (cc)^[17]; Autoignition temperature = 413°C. Explosive limits: LEL = 6.2%; UEL = 16.0%. Hazard Identification (based on NFPA-704 M Rating System): Health 2, Flammability 3, Reactivity 0. Soluble in water; solubility = 0.869 g/100 mL @ 20°C.

Incompatibilities

Forms explosive mixture with air. Reacts violently with strong oxidizers and caustics; chemically active metals such as magnesium or aluminum powder, sodium and potassium, alkali metals, alkali amides; liquid ammonia. Decomposes to vinyl chloride and HCl above 600°C. Attacks plastics, rubber, coatings. Attacks many metals in presence of water.

Permissible Exposure Limits in Air

Conversion factor: 1 ppm = 4.05 mg/m³ @ 25°C & 1 atm

NIOSH IDLH: 50 ppm; a potential human carcinogen.

OSHA PEL: 50 ppm TWA; 100 ppm Ceiling Concentration; 200 ppm [5 minute maximum peak in any 3 hours]. For Construction and Shipyards: 50 ppm/200 mg/m³ TWA

NIOSH REL: 1 ppm/4 mg/m³ TWA; 2 ppm/8 mg/m³ STEL, a potential occupational carcinogen. Limit exposure to lowest feasible concentration. See NIOSH Pocket Guide, Appendix A

ACGIH TLV®^[1]: 10 ppm, not classifiable as a human carcinogen as chloroethanes

PAC values marked with a subscript “E" correspond to ERPGs (Emergency Response Planning Guideline) values and are in bold face.

DFG MAK: [skin] Carcinogen Category 2

Determination in Air

Charcoal adsorption, workup with CS₂, analysis by gas chromatography/flame ionization. See NIOSH IV, Method #1003 for halogenated hydrocarbons^[18]

Permissible Concentration in Water

Federal Drinking Water Guidelines: 4 ppb^[93]

Determination in Water

Inert gas purge followed by chromatography with halide-specific detection (EPA Method 601) or gas chromatography plus mass spectrometry (EPA Method 624). Log K_ow = < 1.5. Unlikely to bioaccumulate in marine organisms.

Routes of Entry

Inhalation of vapor, skin absorption of liquid, ingestion, skin and/or eye contact

17.3.4.3 Other graft functionalizations

Hydroxylated PHAs could also be modified to acrylated forms via coupling with acryloyl chloride in this presence of 1,2-dichloroethane (DCE) as a solvent. PHA-grafted-branched poly(ethyleneimine) PEI copolymers (PHA-g-bPEI) were synthesized by Michael addition between acrylated monomethoxy-PHA (mPHA-acrylated) and branched PEI. Owing to the hydrophilic nature and positive charge of PEI, the resultant P3/4HB-g-bPEI copolymer was soluble in the buffer solutions and also had a net positive surface charge. The copolymer was tested as nanocarriers delivering nucleic acids for gene therapy [97].

Babinot et al. employed click chemistry for the synthesis of amphiphilic scl and mcl PHAs-b- poly(ethylene glycol) (PHAs-b-PEG) diblock copolymers. For this, first, using thermal treatment length controlled oligomers of hydrophobic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), and poly(3-hydroxyoctanoate-co-hydroxyhexanoate) (PHOHHx) containing a carboxylic acid end group were obtained. Second, quantitative propargylamine functionalization of the carboxylic end-groups was achieved by click ligation resulting in a clickable-alkyne group [55]. Azide-functionalized PEG was prepared using methanesulfonyl chloride (MsCl) and sodium azide. Finally, to achieve copolymers preparation, the copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) was used, which has been proven to be a very efficient reaction in the ligation of azide and alkyne terminated preformed blocks or oligomers. Well-defined diblock copolymers were obtained up to 93% yield [56].

Thus, by and large the surface modification strategies assist in the generation of amphiphilic PHAs from swollen to soluble in aqueous environment, for various biomedical applications. Forthcoming section discusses the applications of PHAs as biomaterials in various medical fields.

3.2 Halogenation

At slightly higher temperatures, olefin derivatives and chlorine react by substitution of a hydrogen atom by a chlorine atom. Thus, in the chlorination of propylene, a rise of 50°C (90°F) changes the product from propylene dichloride [CH₃CH(Cl)CH₂Cl] to allyl chloride (CH₂CHCH₂Cl).

2.4 Porogen agents

Porogenic solvents act as reaction media (in the polymerisation process) and pore-forming agents. The most important porogens are acetonitrile, chloroform, dichloroethane, N,N-dimethylformamide, methanol, 2-methoxyethanol, tetrahydrofuran and toluene. For the non-covalent imprinting method non-polar and less polar solvents are used. The type of used solvent affects the imprinting efficiency, interaction between the template and functional monomers, absorption properties and morphology of polymers. The increasing amount of solvent used result in increasing of pores size, so proper amount of solvent will improve formation of specific cavities designed for binding template molecules. It should be also pointed out, the nature of used solvent plays also important role. Less polar solvents improve formation of functional monomer-template complexes (stabilization of hydrogen bonds), while the more polar solvent disturbing interactions in the formed complexes, so presence of water is impossible in many protocols [3,25].

4.6.2 SECM imaging with nano-ITIES-based tips

IT processes at nanopipette-supported ITIES tips have been used for nanoscale topography and reactivity imaging of various samples. A 103 nm radius pipette filled with DCE solution was scanned at a constant height over an IBM silicon wafer fabricated with the 90 nm process technology [124]. In negative feedback mode, the tip current produced by tetraethylammonium (TEA⁺) transfer from the external aqueous solution was blocked by the solid substrate. Approximately 10 nm high topographic features on the substrate surface were clearly resolved in the resultant image. The sharp nanopipette tip had a small RG (~ 1.5) and could be scanned over the nonflat surface features without crashing.

The same group carried out detailed characterization of nanopipette tips by TEM and found a significant tip roughness (∼ 5 nm roughness for a ∼ 30 nm diameter pipette) [166]. The IT current measured at the ITIES supported by a rough nanopipette was higher than expected for a 30 nm diameter disk tip, indicating that the ITIES is sphere-cap-shaped. However, finite-element simulations suggested that the spatial resolution of SECM imaging of nanopores should not be significantly affected by the sphere-cap shape of the tip and is mainly determined by the tip radius. The authors pointed out that sphere-cap tips have an advantage over flush disk tips whose insulating sheath could contact the substrate and limits the attainable closest tip − substrate separation distance. This advantage should be less significant for pipette-based tips with a small RG value. SECM images of a periodic array of 100 nm nanopores obtained using nanopipette tips were compared with TEM images of the same array. The circular pores appear to be elongated along the direction of the tip scan, in agreement with the finite-element simulation of SECM images.

12.4.2.5 Mixed volatile organic compound removal

A microbial membrane bioreactor investigated by van Ras et al. (2005) was able to reduce VOCs such as chlorobenzene, 1,2-dichloroethane, alcohols, methane, acetone, and BTEX (benzene, toluene, ethylbenzene, xylene), at an elimination capacity of 2–26 g/m³/h for inlet contaminant concentrations of 20–200 mg/m³ and retention times of 8–23 s. The bioreactor showed an operational stability up to a year and its performance was not affected by long starvation or microgravity. A plant membrane bioreactor prototype was also able to significantly reduce the level of methylethylketone and toluene from an air stream, which was considered sufficient by van Ras et al. (2005) to demonstrate the proof of concept.

The role of microorganisms in plant bioreactors treating VOCs was investigated by Russell et al. (2014) at Drexel University, where a five-story vertical biowall was installed. The biowall is a PBTF equipped with plants rooted into an inorganic, porous textile material. The plant roots are continuously irrigated with recirculated nutrient solution. The indoor air is drawn through the wall using a fan, allowing the VOCs to transfer from air to the liquid, where they are subject to biodegradation by microorganisms. The treated air is then delivered to other zones in the building via the mechanical system. VOCs removal efficiency of about 25–90% can be obtained in such a biosystem. The following plants have been monitored: Croton “Mammy”, Ficus elastica (rubber tree), Schefflera arboricola “Gold Capella”, S. arboricola, unknown Ficus sp. and Algerian ivy. The biowall-grown roots exhibited enriched levels of bacteria from the genus Hyphomicrobioum, which are VOCs degraders that are able to break down aromatic and halogenated compounds as often found in indoor environments. According to these authors, these bacteria play an essential role in VOC removal in plant bioreactors treating indoor air. The proof of the PBTF concept has been previously reported by Darlington et al. (2000, 2001) and Darlington (2004) and summarized by Soreanu et al. (2013). Similarly, a vertical planted cylinder equipped with hydroponic plants and trickled with nutrient-rich water was recently investigated within a European project (CETIEB report). This biosystem was able to reduce the VOC level by 50% in a registrar's office at the University of Stuttgart.

A BTF with a diameter of 9 cm, height of 100 cm, and equipped with pottery pieces was tested by Lu et al. (2010) for VOC removal from the indoor air of a newly renovated room. The BTF was inoculated with sludge from a municipal sewage treatment plant and operated at a gas flow rate of 600 L/h, surface liquid velocity of 3.14 m/h, pH of 6–7 and temperature of 30°C. When the air stream contained 0–6.5 mg/m³ formaldehyde, 2.2–46.7 mg/m³ benzene, 0.5–28.2 mg/m³ toluene, and 4.1–59.0 mg/m³ xylene, the VOC removal efficiency was about 100%, 65–70%, 93%, and 85–90%, respectively. The treated air can be recirculated to the room. The following bacterial species isolated from BTF have been associated with this performance: Pseudomonas sp., Kocuria sp., Arthrobacter sp. and Bacillus sp. Increasing the temperature up to 40°C resulted in a decrease of BTF performance by about 1.3 for all VOCs except formaldehyde, for which degradation was attributed to the thermotolerant bacteria. The better performance in formaldehyde removal was explained by its higher solubility in water in comparison with the other tested hydrophobic compounds.