Monoethylene glycol

Monoethylene glycol derivatives ate termed "ceUosolves" diethylene glycol derivatives, "carbitols" and triethylene glycol derivatives, triglycols. CELLOSOLVE and CARBITOL ate registered trademarks of EFnion Carbide Corp. 

ChemicalDesignations- no/ /ns 1,2-Dihydroxyethane 1,2-Ethanediol Ethylene dihydrate Glycol Monoethylene glycol Chemical Formula HOCHjCHjOH. 

The series-parallel type of reaction outlined in Section 1.10.1 is quite common among industrial processes. For example, ethylene oxide reacts with water to give monoethylene glycol, which may then react with more ethylene oxide to give diethylene glycol. 

Many workers including Hammerschmidt (1939), Deaton and Frost (1946), Bond and Russell (1949), Kobayashi et al. (1951), and Woolfolk (1952) investigated the effects of inhibitors on hydrates. In particular, many chloride salts such as those of calcium, sodium, and potassium, were considered along with methanol and monoethylene glycol. Methanol gradually became one of the... 

Other inhibitors such as monoethylene glycol (EG or MEG) and salts shift the hydrate lines similarly, but to a different degree. However, methanol is the most economical inhibitor on a weight basis. Quantitative predictions of inhibitor effects are provided in Sections 4.4 and 5.3. 

Figures 5.10 and 5.11 show that one may expect modem programs to predict the methanol- and NaCl-inhibited incipient temperature and pressure to within about 2 K and 20% in pressure, respectively. While comparisons for monoethylene glycol are not given, they might be comparable for low concentrations, such as below 30 wt% in free water. Second, the two figures show that the inaccuracies of mixtures of the two inhibitors (methanol and NaCl) are similar to that of the pure inhibitors.

The methods have yet to be extended to common thermodynamic inhibitors such as methanol or monoethylene glycol. In principal the extension is not a function of the ab initio methods since the thermodynamic inhibitors affect the water activity yet this extension has not been quantified. 

Hydrate Carbon dioxide with methanol and monoethylene glycol Reference Fan et al. (2000)... 

Note that regular methanol (or monoethylene glycol) injection is used only with gas-dominated systems. In oil-dominated systems the higher liquid heat capacity allows the system to retain reservoir heat, so that insulation maintains sufficient temperatures to prevent hydrate formation. Thermodynamic inhibitor is normally only injected for planned shutdowns in oil-dominated systems. 

By comparison, the catalyzed transesterification reaction between ethylene carbonate and methanol (Equation 7.3) offers an alternative for greening DMC production. In this Asahi Kasei process [27], the preferred catalyst is based on an anion-exchange resin operating under catalytic distillation conditions between 333-353 K. This reactor design shifts the thermodynamic equilibrium towards complete conversion of ethylene carbonate, such that both the yield and selectivity for DMC and monoethylene glycol are 99.5%. The process is capable of supplying monoethylene glycol to the market, and DMC for captive use to produce DPC. 

Similar dynamics play in other non-refinery petrochemicals that moved to fly-up conditions in 2004, such as monoethylene glycol (MEG) and styrene. Petrochemical producers had held back investments during the previous several years due to poor returns. The underlying upward trend in demand tightened the sup-ply-demand balance, and restored pricing power to producers hands, enabling them to harvest exceptional margins at this point in the cycle. 

NMP) process, Lurgi (12-20% by weight) or monoethylene glycol (40—50% by weight) must be added to the NMP to increase the selectivity and to decrease the boiling point of the solvent the NMP/water processes use a pentane countersolvent NMP/water, 35°C mixer—settler, 24—30 stages, up to 8 m in diameter required depends on the aromatics content of die feed... 

Part 7 Determination of monoethylene glycol and diethylene glycol in food simulants SML (T) 30 mg/kg... 

Castle, L., Cloke, H.R., Startin, J.R., Gilbert, J 1988, Gas chromatographic determination of monoethylene glycol and diethylene glycol in chocolate packaged in regenerated cellulose film. Journal of the Association of Official Analytical Chemists 71 (3) 499-502. 

Only for monoethylene glycol (MEG) and diethylene glycol (DEG), which under certain circumstances can be transferred in unacceptably high quantities, have migration limits in food been provided for in Directive 86/388/EEC. The positive list has been amended on two occasions (Directives 86/388/EEC and 92/15/EEC) and the Commission took the opportunity of a third amendment (Directive 93/10/EEC) to codify all the directives adopted. Now the positive list contains 72 compounds and 42 groups of substances, i.e. 114 chemical products. 

Ethylene Glycols. Monoethylene glycol or ethylene glycol is the major derivative of ethylene oxide. Ethylene glycol was initially made commercially by hydrolysis of ethylene chlorohydrin. Today, hydrolysis of ethylene oxide is the preferred route. 

Description In the Meteor Process, an EO/water mixture is preheated and fed directly to an adiabatic reactor (1), which can operate with or without a catalyst. An excess of water is provided to achieve high selec-tivities to monoethylene glycol (MEG). Diethylene (DEG) and triethylene (TEG) glycols are produced as coproducts. In a catalyzed mode, higher selectivities to MEG can be obtained, thereby reducing DEG production to one-half that produced in the uncatalyzed mode. The reactor is specially designed to fully react all of the EO and to minimize back-mixing, which promotes enhanced selectivity to MEG. 

Description Purified EO or a water/EO mixture is combined with recycle water and heated to reaction conditions. In the tubular reactor (1), essentially all EO is thermally converted into monoethylene glycol (MEG) with diethylene glycol (DEG) and triethylene glycol (TEG) as co-products in minor amounts. Excess water, required to achieve a high MEG selectivity is evaporated in a multi-stage evaporator (2,3). The last evaporator (4) produces low-pressure steam, which is used as a heat medium for other units in the plant. Crude glycol is purified in a series of vacuum columns (5,6,7,8). Selectivity toward MEG can be controlled with the feed composition. 

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