Abstract: A method of manufacturing a polarizing glass sheet includes subjecting, while heating, a glass preform sheet containing metal halide particles to down-drawing, to thereby provide a glass member having stretched metal halide particles dispersed in an aligned manner in a glass matrix, and subjecting the glass member to reduction treatment to reduce the stretched metal halide particles, to thereby provide a polarizing glass sheet. A shape of the glass preform sheet during the down-drawing satisfies a relationship of the following expression: L1/W1?1.0 where L1 represents a length between a portion in which a width of the glass preform sheet has changed to 0.8 times an original width and a portion in which the width of the glass preform sheet has changed to 0.2 times the original width W0, and W1 represents a length equivalent to 0.5 times the original width W0 of the glass preform sheet.

Abstract: An apparatus and method for producing foamed glass having a silo (1) for receiving a glass mixture containing a temperature-activated foaming agent, a sluice chamber (12) arranged to receive a volume of glass mixture from the silo, a feed chamber (22) arranged to receive a volume of glass mixture from the sluice chamber, an extruder chamber (26) arranged to receive a volume of glass mixture from the feed chamber where the glass is melted and the foaming agent is activated, one or more nozzles (32) arranged at an end of the extruder chamber, through which a viscous foamed glass material may exit under influence of a positive operating pressure and an expansion chamber (38) arranged to receive foamed glass mixture from the nozzles. The invention also includes a novel foamed glass product having a glassy, sealed outer surface and a unique internal cell structure.

Abstract: A method includes scoring a glass sheet to form a scored region of the glass sheet. The scored region extends in a longitudinal direction and comprises a plurality of deep score portions and a shoulder portion disposed longitudinally between adjacent deep score portions. The glass sheet is severed along a severing line extending in a transverse direction substantially perpendicular to the longitudinal direction and through the shoulder portion of the scored region.

Abstract: An electrical discharge, suitable for heating optical fibers for processing, is made in a controlled partial vacuum, such that saturation of available ionizable gas molecules is reached. The workpiece temperature is thereby made to be a stably controlled function of the absolute air pressure and is insensitive to other conditions. A system and method accomplishing the foregoing are provided.

Abstract: The invention relates to a glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass: 65?SiO2?78% 5?Na2O?20% 0?K2O<5% 1?Al2O3<4% 0?CaO<4.5% 4<MgO?12%; as well as a total iron (expressed in the form of Fe2O3) in a content ranging from 0.002 to 0.06% by weight and a (CaO/MgO) ratio which is less than 1. The invention corresponds to an easy chemically-temperable soda-silica type glass composition, which is more suited for mass production than aluminosilicate glass, and therefore is available at low cost, and with a base glass/matrix composition that is close to or very similar to compositions already used in existing mass production.

Abstract: The present invention relates to an ultraviolet-absorbing glass article containing, as represented by mass % based on oxides, as a glass matrix composition: SiO2: 66 to 75%, Na2O: 10 to 20%, CaO: 5 to 15%, MgO: 0 to 6%, Al2O3: 0 to 5%, K2O: 0 to 5%, FeO: 0.2 to 1.2%, total iron as represented by Fe2O3: 2.4 to 4%, and TiO2: more than 0% and 1% or less, containing from 50 to 400 mass ppm of CoO, containing from 0 to 70 mass ppm of Se, containing from 0 to 800 mass ppm of Cr2O3, having a total content of CoO, Se and Cr2O3 of less than 0.1 mass %, and having an ultraviolet transmittance (TUV) (ISO9050:2003) of 2% or less at a thickness of 3.5 mm.

Abstract: The present invention relates to an ultraviolet-absorbing glass article containing, as represented by mass % based on oxides, as a glass matrix composition: SiO2: 66 to 75%, Na2O: 10 to 20%, CaO: 5 to 15%, MgO: 0 to 6%, Al2O3: 0 to 5%, K2O: 0 to 5%, FeO: 0.1 to 0.9%, total iron as represented by Fe2O3: 0.6% or more and less than 2.4%, and V2O5: more than 0% and 1% or less, containing from 100 to 500 mass ppm of CoO, containing from 0 to 70 mass ppm of Se, containing from 0 to 800 mass ppm of Cr2O3, having a total content of CoO, Se and Cr2O3 of less than 0.1 mass %, and having an ultraviolet transmittance (TUV) (ISO9050:2003) of 2% or less at a thickness of 3.5 mm.

Abstract: The embodiments described herein relate to chemically and mechanically durable glass compositions and glass articles formed from the same. In another embodiment, a glass composition may include from about 70 mol. % to about 80 mol. % SiO2; from about 3 mol. % to about 13 mol. % alkaline earth oxide; X mol. % A12O3; and Y mol. % alkali oxide. The alkali oxide may include Na2O in an amount greater than about 8 mol. %. A ratio of Y:X may be greater than 1 and the glass composition may be free of boron and compounds of boron. In some embodiments, the glass composition may also be free of phosphorous and compounds of phosphorous. Glass articles formed from the glass composition may have at least a class S3 acid resistance according to DIN 12116, at least a class A2 base resistance according to ISO 695, and a type HGA1 hydrolytic resistance according to ISO 720.

Abstract: The embodiments described herein relate to chemically and mechanically durable glass compositions and glass articles formed from the same. In another embodiment, a glass composition may include from about 70 mol. % to about 80 mol. % SiO2; from about 3 mol. % to about 13 mol. % alkaline earth oxide; X mol. % Al2O3; and Y mol. % alkali oxide. The alkali oxide may include Na2O in an amount greater than about 8 mol. %. A ratio of Y:X may be greater than 1 and the glass composition may be free of boron and compounds of boron. In some embodiments, the glass composition may also be free of phosphorous and compounds of phosphorous. Glass articles formed from the glass composition may have at least a class S3 acid resistance according to DIN 12116, at least a class A2 base resistance according to ISO 695, and a type HGA1 hydrolytic resistance according to ISO 720.

Abstract: The glass composition of the present invention contains, in mol %: 58% or more and less than 70% SiO2; 0 to 14% B2O3; 10 to 16% Al2O3; 0 to 12.5% MgO; 0 to 11% CaO; 0 to 3% SrO; 0 to 3% ZnO; 4.5 to 11% Li2O; 0 to 2% Na2O; 2 to 7% K2O; 0 to 0.8% TiO2; 0 to 0.5% ZrO2; and 0 to 0.2% SnO2. In this glass composition, the total content of Li2O, Na2O, and K2O is in a range of 6.5 to 13%. The glass composition of the present invention is suitable for production by a float process and is suitable for chemical strengthening. The glass composition of the present invention has a low thermal expansion coefficient. The glass composition of the present invention has properties suitable for use in glass substrates for displays.

Abstract: Glasses that undergo rapid ion exchange. The glasses comprise SiO2, Al2O3, P2O5, Na2O, K2O, and, in some embodiments, at least one of MgO and ZnO. The glass may, for example, be ion exchanged in a molten KNO3 salt bath in less than 1 hour at temperatures in a range from about 370° C. to about 390° C. to achieve a depth of surface compressive layer of greater than about 45 microns, or in a range from about 0.05t to about 0.22t, where t is the thickness of the glass. The glasses are fusion formable and, in some embodiments, compatible with zircon.

Abstract: A photochromic glass that includes a base glass and a photochromic agent is described. The base glass is a modified boroaluminosilicate glass and the photochromic agent is a nanocrystalline cuprous halide phase. The photochromic glass exhibits a sharp cutoff in the UV or short wavelength visible portion of the spectrum along with an absorption band at longer wavelengths in the visible. The nanocrystalline cuprous halide phase includes Cu2+, which provides states within the bandgap of the cuprous halide that permit the glass to absorb visible light. Absorption of visible light drives a photochromic transition without compromising the sharp cutoff. The nanocrystalline cuprous halide phase may optionally include Ag.

Abstract: According to one embodiment, a glass may include from about 50 mol. % to about 70 mol. % SiO2; from about 12 mol. % to about 35 mol. % B2O3; from about 4 mol. % to about 12 mol. % Al2O3; greater than 0 mol. % and less than or equal to 1 mol. % alkali metal oxide, wherein Li2O is greater than or equal to about 20% of the alkali metal oxide; from about 0.3 mol. % to about 0.7 mol. % of Na2O or Li2O; and greater than 0 mol. % and less than 12 mol. % of total divalent oxide, wherein the total divalent oxide includes at least one of CaO, MgO and SrO, and wherein a ratio of Li2O (mol. %) to (Li2O (mol. %) +(Na2O (mol. %)) is greater than or equal 0.4 and less than or equal to 0.6. The glass may have a relatively low high temperature resistivity and a relatively high low temperature resistivity.

Abstract: To provide opaque quartz glass having no water absorbing properties and being excellent in infrared light shielding properties, and a method for its production. In the production of opaque quartz glass of the present invention, a fine amorphous silica powder and a pore forming agent are mixed, then molded and heated at a predetermined temperature, to obtain opaque quartz glass wherein contained pores are closed pores, the average pore size of pores is from 5 to 20 ?m, and the content density of pores is high, whereby the heat shielding properties are high.

Abstract: A hollow spherical glass particle, comprising aluminum oxide Al2O3, silicon dioxide SiO2 and at least one metal oxide, wherein the metal oxide is selected from the group consisting of alkali metal oxides and alkaline earth metal oxides, wherein the ratio of aluminum atoms to alkali metal atoms is about 1:1 and the ratio of aluminum atoms to earth alkali atoms is about 2:1, with the proviso that the hollow spherical glass particle is free of boron.

Abstract: A process for producing a glass substrate includes a step of forming an antiglare region on at least one of main surfaces of a glass plate, a cutting step of cutting the glass plate and a removal step of removing a part of the antiglare region.

Abstract: A process of producing a glass includes preparing a glass material including silicates; coating a refractory material on the glass material to form a refractory glass material capable of being resistant to 500-1,200° C.; subjecting the refractory glass material to heat to be deformed; shaping the deformed refractory glass material to form a half-finished product having a curved shape by molding; and cooling the half-finished product to produce a finished product. In one embodiment, the refractory material is insulating. In another embodiment, the refractory material is conductive.

Abstract: A glass article includes a glass core layer and a glass cladding layer adjacent to the core layer. A coefficient of thermal expansion (CTE) of the core layer is greater than a CTE of the cladding layer. The core layer has a tensile stress, and the cladding layer has a compressive stress. A retained strength of the glass article is a strength determined after abrasion of an outer surface of the glass article with 1 mL of 90 grit SiC particles for 5 seconds at an abrasion pressure, and a ratio of the retained strength at an abrasion pressure of 25 psi to the retained strength at an abrasion pressure of 5 psi is at least about 0.3.

Abstract: A glass sheet for pigment printing contains, as represented by mass percentage on the basis of oxides, from 60% to 75% of SiO2, from 2% to 12% of Al2O3, from 2% to 11% of MgO, from 0% to 10% of CaO, from 0% to 3% of SrO, from 0% to 3% of BaO, from 10% to 18% of Na2O, from 0% to 8% of K2O, and from 0% to 4% of ZrO2, or contains, from 60% to 75% of SiO2, from 1.5% to 12% of Al2O3, from 6% to 12% of MgO, from 0% to 4.5% of CaO, from 0% to 3% of SrO, from 0% to 3% of BaO, from 10% to 18% of Na2O, from 0% to 8% of K2O, and from 0% to 4% of ZrO2.

Abstract: Chemically strengthened glass and a method for making utilizing differential chemistry are provided. The method includes providing a substrate having a glass chemical structure. Host alkali ions are situated in the chemical structure. The substrate has a treatment-rich volume and a treatment-poor volume located as opposed to each other in the substrate. The method also includes providing an exchange medium characterized by including a composition associated with an ion exchange rate of invading alkali ions having an average ionic radius that is larger than an average ionic radius of the host alkali ions. The method also includes providing a modified exchange medium including a modified composition associated with a modified ion exchange rate of the invading alkali ions. The method also includes applying the exchange mediums and conducting ion exchange to produce the strengthened substrate.

Abstract: The present invention provides substantially nonionic brush polymers having pendant polyether groups, preferably poly(alkylene glycol) groups, which polymers are useful as synthetic polymer substitutes for cellulose ethers in mortars and hydraulic binders. The brush polymers are preferably crosslinked, such as with ethylene glycol di(meth)acrylates.

Abstract: A method for soil remediation by molecular binding for producing beneficial use determined polymer concrete product that removes hazardous pollutants from a quantity of contaminated soil. Hazardous pollutants are identified though chemical analysis in order to select at least corresponding polymer and at least one corresponding binder for each hazardous pollutant present in the contaminated soil. The at least one polymer chemically bonds with the hazardous pollutant in order to neutralize the hazardous pollutant within the contaminated soil to form a polymer concrete product. The polymer concrete product is then used as a concrete substitute for construction applications.

Abstract: A lightweight foamed polymer concrete admixture for use in fabricating building components, the polymer concrete comprising a mixture of a polyol, an isocyanate, an aggregate, and water, wherein once mixed, the mixture releases carbon dioxide gas creating a foamed mixture that may be shaped to form a building component such as, but not limited to, lap siding, shake siding, trim boards, stone and stucco sheeting.

Abstract: A method for making geopolymer cementitious binder compositions for cementitious products such as concrete, precast construction elements and panels, mortar, patching materials for road repairs and other repair materials, and the like is disclosed. The geopolymer cementitious compositions of some embodiments are made by mixing a synergistic mixture of thermally activated aluminosilicate mineral, calcium sulfoaluminate cement, a calcium sulfate and a chemical activator with water.

Abstract: A method for making geopolymer cementitious binder compositions for cementitious products such as concrete, precast construction elements and panels, mortar and repair materials, and the like is disclosed.

Abstract: The present invention relates to a cement compound. The invention also relates to a method for producing such a cement compound. More in particular, the present invention relates to a cement compound comprising at least a reactive glass compound, an alkaline activator and a filler, and optionally additives, said reactive glass compound comprising at least 35 wt % CaO, at least 25 wt % SiO2 and at least 10 wt % Al2O3, and optionally other oxides.

Abstract: A gasket material for high pressure high temperature presses, comprising: a proportion of a clay mineral a proportion of a hard material for increasing the viscosity of the clay mineral a proportion of a binder selected from the group of borate binders, phosphate binders, and mixtures thereof.

Abstract: An alumina sintered body according to the present invention has a degree of c-plane orientation of 90% or more as determined by Lotgering's method from an X-ray diffraction profile obtained by irradiating a plate surface with X-rays in a range of 2?=20° to 70°. The alumina sintered body has no pores when a cross-sectional surface formed in a direction perpendicular to the plate surface is polished using an Ar+ ion beam and a mask and is examined under a scanning electron microscope at a magnification of 5,000 times. The alumina sintered body has a total mass fraction of impurity elements other than Mg and C of 100 ppm or less. This alumina sintered body has a high degree of orientation, high density, and high purity and thus has a higher optical translucency than those known in the art.

Abstract: Ceramic granules having high reflectivity and a preparation method for the same comprise sand core particulates and at least one coating thereon, wherein said sand core particulates contain calcined tobelite that is obtained by calcining the tobelite ore at 700-1200° C.; and said sand core particulates are coated with an inorganic coating, and then calcined at 800-1200° C. to obtain ceramic granules. Said ceramic granules have a particle size of 0.1-3.5 mm, and have a solar reflectivity SR of not lower than 80% and a staining index DL* of lower than 6%. Said ceramic granules produce a solar reflectivity of not lower than 70% when being applied to the asphalt roll/sheet and a solar reflectivity of not lower than 72% when being applied to the polyurethane foam sheet.

Abstract: The present invention relates to a flexible composite organic aerogel (1) comprising: a textile reinforcement (5), an organic aerogel (3) placed within said textile reinforcement (3), said organic aerogel (3) being based on a resin resulting at least in part from polyhydroxybenzene(s) R and formaldehyde(s) F, said organic aerogel (3) being a polymeric organic gel comprising at least one water-soluble cationic polyelectrolyte, or said organic aerogel (3) being a pyrolysate of said gel in the form of a porous carbon monolith comprising the product of the pyrolysis of said at least one water-soluble cationic polyelectrolyte P, said organic aerogel (3) exhibiting a specific thermal conductivity of between 10 and 40 mW·m?1·K?1 at atmospheric pressure.

Abstract: The present invention provides for nutrient extraction and recovery devices that use the Donnan Membrane Principle (DMP) to cause spontaneous separation of dissolved ions along electrochemical potential gradients, wherein anions and cations such as H2PO4?, HPO42?, PO43?, Mg2+, Ca2+, NH4+, and K+ are moved from manure containing waste streams through cation and anion exchange membranes into a recovery stream thereby precipitating target compounds including but not limited to struvite, potassium struvite and hydroxyapatite.

Abstract: The invention relates to a microbial delivery system where biochar acts as a carrier for microbes.

Abstract: A method of determining the volume of organic material in a composting device includes rotating a mixing paddle in a composting bin that stores the organic material; monitoring the torque from a motor that rotates the mixing paddle as the mixing paddle rotates; and determining the height of the organic material in the composting bin based on the motor torque and the angular displacement of the mixing paddle. The resulting height can be used to determine the volume of the organic material.

Abstract: A propellant for a micro-gas generator, the propellant having 5-aminotetrazole, aluminum, a binder and an oxidizer and is substantially free from azodicarbonamide. This propellant substantially maintains its ballistic performance regardless of being aged at higher temperatures such as 120° C. Further, a method of manufacturing a propellant for a micro-gas generator, the method including providing a propellant mixture of 5-aminotetrazole, aluminum powder, potassium perchlorate, ethyl cellulose and fluoropolymers; adding acetone as a solvent to solvate ethyl cellulose and fluoropolymers; evaporating the acetone using a low level of vacuum until the mixture is a damp cake; and granulating and drying the damp cake forming dried propellant granules.

Abstract: An energetic material composite comprising fuel particles and a hydrated compound is disclosed. The energetic material composite is formed by dispersing fuel particles, which have a negative standard reduction potential relative to a standard hydrogen electrode, in a solvent containing dissolved hydrate, followed by a removal of solvent. When initiated, the fuel particles react with the water bound in the hydrated compound to release energy and hydrogen gas.

Abstract: In one aspect, there is provided a method of coupling a first aromatic compound having a fluorosulfonate substituent to a second aromatic compound having a boron-containing substituent. In another aspect, there is provided a method of coupling a first aromatic compound having a hydroxyl substituent to a second aromatic compound having a boron-containing substituent in a one-pot reaction.

Abstract: Catalytic systems and methods for treating process streams are disclosed. Catalytic wet oxidation and hydrolysis techniques may be used to treat one or more undesirable constituents such as HPAM and KHI. Methane may be produced in connection with at least some embodiments.

Abstract: Oligomerization processes include the steps of introducing a monomer containing a C3 to C30 olefin and a chemically-treated solid oxide into a reaction zone, and oligomerizing the monomer to form an oligomer product in the reaction zone. Fluorided silica-coated alumina and fluorided-chlorided silica-coated alumina are illustrative chemically-treated solid oxides that can be used in the oligomerization processes.

Abstract: The present invention relates to a process for the selective hydrogenation of a feed of hydrocarbons containing polyunsaturated molecules comprising at least 3 carbon atoms, using a single principal fixed bed reactor R1 containing at least two catalytic beds A1 and A2 and a fixed bed guard reactor which is reduced in size, said hydrogenation reactors being disposed in series for use in a cyclic manner in accordance with a sequence of steps which can be used to short-circuit the catalytic bed or beds of the principal reactor which have been at least partially deactivated with the aid of the guard reactor, while ensuring the continuous operation of the process.

Abstract: A process for the preparation of a chemical composition comprising an aromatic compound a in a concentration B by weight, based on the total weight of the chemical composition, including: providing the following reaction components: a chemical composition comprising the following: the aromatic compound a in a concentration A by weight based on the total weight of the chemical composition, and an olefin in an amount of about 50 to about 99.99 wt. %, based on the total weight of the chemical composition, and an acidic solid; reacting the components to obtain the chemical composition comprising the aromatic compound a in a concentration B by weight based on the total weight of the chemical composition; wherein the concentration B is less than the concentration A.

Abstract: The present invention relates to a fluorination process, comprising: an activation stage comprising contacting a fluorination catalyst with an oxidizing agent-containing gas flow for at least one hour; and at least one reaction stage comprising reacting a chlorinated compound with hydrogen fluoride in gas phase in the presence of the fluorination catalyst, so as to produce a fluorinated compound.

Abstract: The present invention is a method for producing a fluorohydrocarbon represented by a structural formula (3) comprising bringing a secondary or tertiary ether compound represented by a structural formula (1) into contact with an acid fluoride represented by a structural formula (2) in a hydrocarbon-based solvent in the presence of a boron trifluoride complex. (In structural formulae (1) to (3), each of R1 and R2 represents an alkyl group having 1 to 3 carbon atoms, R3 represents a hydrogen atom, a methyl group, or an ethyl group, and each of R4 and R5 represents a methyl group or an ethyl group, provided that R1 and R2 are optionally bonded to each other to form a ring structure.

Abstract: The present invention provides a process of catalytic fluorination in gas phase of product 1,1,1,2,3-pentachloropropane or/and 1,1,2,2,3-pentachloropropane into product 2,3,3,3-tetrafluoropropene in presence of a catalyst.

Abstract: Processes for isolating 1,1,1,2,3-pentachloropropane from a crude product stream containing the 1,1,1,2,3-pentachloropropane and ferric chloride. The processes may include deep distillation of the crude, treatment of the crude with a reagent that deactivates the ferric chloride followed by distillation on the deactivated crude stream, aqueous washing of the crude product stream to remove ferric chloride followed by distillation on the deactivated crude stream. Other embodiments simultaneously prepare 1,1,2,3-tetrachloroprene and 1,1,1,2,3-pentachloroprane.

Abstract: The present invention discloses a manufacturing process to produce high purity 1234yf from 245eb, which preferably includes the removal of impurities present in 245eb raw material, the dehydrofluorination of 245eb, and the removal of impurities present in final crude product. The disclosed manufacturing process allows the production of a 1234yf product with lower the levels of 1225ye and/or trifluoropropene, preferably in amounts of less than about 500, and 50 ppm, respectively.

Abstract: A mobile system and method that reform flare gas, methane, or natural gas, using air without steam, to directly produce methanol, a clean burning gasoline blend, component, and/or substitute are disclosed. The system first reforms the air-methane mixture at ambient atmospheric pressure, then compresses the resulting CO-hydrogen-nitrogen gas mixture to about 600 psi, and feeds it through a methanol reactor which reacts the gas mixture directly into methanol. The nitrogen is returned by the system back to the atmosphere. Methanol is a clean burning gasoline substitute, and can be used to displace significantly costlier and dirtier petroleum-based fuel, while solving a critical problem with flaring. For example, the over 120 billion cubic feet per year that was flared in North Dakota in 2014 could be converted into over 6 million tons of methanol.

Abstract: Provided is a process of preparing dichloropropanol, DCP. The process includes the step of: subjecting a three-carbon material to a first chlorination reaction with an aqueous hydrochloric acid solution in the presence of a carboxylic acid catalyst; adding the three-carbon material into the first mixture solution to undergo a second chlorination reaction and obtain a second mixture solution containing less than 13 wt % of hydrochloric acid; distilling the second mixture solution; and purifying the overhead product by oil-water separation to obtain DCP from the oil phase. By lowering the concentration of the hydrochloric acid contained in the mixture to be distilled, the DCP product can be straightly obtained via distillation and oil-water separation, thereby effectively simplifying the process of preparing DCP.

Abstract: A process is presented for the removal of acetaldehyde from mixture of oxygenates. Acetaldehyde is selectively removed in the presence of other oxygenates like ketones, alcohols and nitriles using an amorphous sodium doped alumina derived from thermally decomposed Dawsonite. The process successfully removes acetaldehyde which can adversely impact catalyst operation.

Abstract: A process for manufacturing purified glycerol including the steps of providing a starting glycerol fraction comprising glycerol, water, and fatty acid methyl esters, subjecting the glycerol fraction to a partial evaporation to form an evaporated fraction including glycerol, water, and fatty acid methyl esters, and a remainder fraction including glycerol, condensing the evaporated fraction to form a liquid, subjecting the liquid evaporated fraction including glycerol, water, and fatty acid methyl esters to a liquid-liquid separation step, resulting in the formation of a fatty acid methyl ester fraction and a glycerol-based fraction including glycerol and water. The process makes it possible to efficiently separate the fatty acid methyl esters from glycerol, without the need for complete glycerol distillation.

Abstract: The invention provides a process for separating monoethylene glycol from a mixture comprising monoethylene glycol and 1,2-butanediol, said process comprising the steps of: a. providing a first stream comprising monoethylene glycol and 1,2-butanediol to a first distillation zone operated at a first pressure and under conditions to remove a first bottoms stream comprising 1,2-butanediol and to remove a first azeotrope of monoethylene glycol and 1,2-butanediol from the first distillation zone as a first overheads stream; b. withdrawing said first overheads stream from said first distillation zone; and c. providing said first overheads stream to a second distillation zone operated at a second pressure higher than said first pressure and under conditions to remove a second bottoms stream comprising monoethylene glycol and providing a second azeotrope of monoethylene glycol and 1,2-butanediol as a second overheads stream; d.