{ "authors": [], "basis": { "capacity": "1000 t/a neat benzyl chloroformate: 565 batches/a of 1770 kg in 7920 h on a dedicated train (126.3 kg/h year average), ASSUMED (DESIGN.md D-002, D-003, D-013)", "location": "generic fine-chemicals site with a captive phosgene unit (not chosen)", "operating_hours_per_year": 7920 }, "benchmarks": [ { "dataset": "benzyl-chloroformate-by-semi-batch-phosgenation-of-benzyl-alcohol-1000-t-a", "expression": "feed:BNOH / product:BCF", "family": "chlorinated-organics", "kpi": "bcf-specific-benzyl-alcohol", "no_open_reference": "No open source with a plant's or a pilot's benzyl alcohol use per kg of benzyl chloroformate found (searched 2026-11-05: Google Patents US 6 696 590 B2 and US 3 966 786 A read, laboratory and continuous examples only; web search for benzyl chloroformate production yields and consumption). US 6 696 590 B2 Ex. 3 implies 0.79 kg/kg (217 g of alcohol for 275 g of product, an 81 % isolated laboratory yield), a single value and the dataset's own basis of conditions; the stoichiometric floor is 0.634 kg/kg.", "problem": "1 to kg/kg needs core's foundation.units (pip install 'cheme-as-code[units]')", "reference": null, "status": "unchecked", "title": "Benzyl alcohol consumption per kg of benzyl chloroformate", "unit": "kg/kg", "value": null }, { "dataset": "benzyl-chloroformate-by-semi-batch-phosgenation-of-benzyl-alcohol-1000-t-a", "expression": "feed:PHOS / product:BCF", "family": "chlorinated-organics", "kpi": "bcf-specific-phosgene", "no_open_reference": "No open source with a plant's phosgene use per kg of benzyl chloroformate found (searched 2026-11-05 as for bcf-specific-benzyl-alcohol); US 6 696 590 B2 states a preferred excess of 1.5 to 2.5 mol per mol of alcohol and uses 1.27 in Ex. 3 (the dataset's ratio), no plant figure; the stoichiometric floor is 0.580 kg/kg.", "problem": "1 to kg/kg needs core's foundation.units (pip install 'cheme-as-code[units]')", "reference": null, "status": "unchecked", "title": "Phosgene consumption per kg of benzyl chloroformate", "unit": "kg/kg", "value": null } ], "chemistry": { "inputs": [ { "chemical": "benzyl-alcohol", "grade": null, "inventory_key": "feed:BNOH", "note": "Dry benzyl alcohol (benzyl-alcohol-1, reagent grade at least 99.8 wt%, linked as a proxy for the dry alcohol), 0.636 kg/kg BCF", "role": "feedstock" }, { "chemical": "phosgene", "grade": null, "inventory_key": "feed:PHOS", "note": "Liquid phosgene (phosgene-1, captive), evaporated and dosed as a gas, 0.738 kg/kg BCF (1.27 mol per mol of alcohol)", "role": "feedstock" }, { "chemical": "sodium-hydroxide", "grade": null, "inventory_key": "feed:NAOH", "note": "Caustic soda 50 wt% (chlor-alkali-1) for the off-gas scrubber, 1.086 kg/kg BCF, counted by mass of the solution", "role": "feedstock" }, { "chemical": "water", "grade": null, "inventory_key": "feed:PW", "note": "Process water diluting the scrubber's caustic to 10 wt%, 4.34 kg/kg BCF", "role": "feedstock" }, { "chemical": "nitrogen", "grade": null, "inventory_key": "consumable:nitrogen", "note": "Nitrogen (asu-1) for inerting R-101, breaking its vacuum and padding the transfer, 15 kg per batch, 8.5 g/kg BCF (ASSUMED)", "role": "feedstock" } ], "outputs": [ { "chemical": "benzyl-chloroformate", "grade": null, "inventory_key": "product:BCF", "note": "Neat benzyl chloroformate, 99.2 wt%, degassed and not distilled, to cold storage", "role": "main-product" }, { "chemical": "wastewater", "grade": null, "inventory_key": "product:WW", "note": "Spent scrubber liquor, 5.80 kg/kg BCF: 9.1 wt% NaCl, 3.0 wt% Na2CO3, 0.85 wt% NaOH, to treatment", "role": "waste" } ], "utilities": [ { "chemical": "electricity", "grade": null, "inventory_key": "feed:POWER", "note": "0.051 kWh/kg BCF: R-101 agitator, vacuum pump, scrubber pump (ASSUMED)", "role": "utility" }, { "chemical": "steam", "grade": null, "inventory_key": "feed:LPS", "note": "0.069 kWh/kg BCF of LP steam to the tempered water of the phosgene evaporator and the degassing", "role": "utility" }, { "chemical": "chilled-water", "grade": null, "inventory_key": "product:BRINE", "note": "0.163 kWh/kg BCF removed by brine at 248 K: the charge's cool-down (Q1) and the heat of phosgenation with the heat of absorption of the dosed phosgene (Q2, the semi-batch model's, core ADR 0063) (the registry has chilled water, not brine: closest entry)", "role": "utility" }, { "chemical": "cooling-water", "grade": null, "inventory_key": "product:CW", "note": "0.354 kWh/kg BCF: the scrubber's heat of neutralisation and phosgene destruction (ASSUMED heats)", "role": "utility" } ] }, "description": "Benzyl alcohol is charged to an enamelled 2.5 m3 reactor, cooled to 278 K, and phosgene from\nthe site's phosgene unit (1.27 mol per mol of alcohol, the ratio of US 6 696 590 B2 Ex. 3) is\nevaporated and dosed into it as a gas over 10 h at 50 kPa(a), without base or solvent. The\nalcohol reacts to benzyl chloroformate and HCl; HCl leaves the liquid as it forms (95 % of it,\nthe rest dissolved), 5 % of the dosed phosgene passes straight to the vent, and two side\nreactions make the impurities the patent reports (benzyl chloride with CO2, dibenzyl\ncarbonate). The crude, holding about 11 wt% dissolved phosgene, is degassed in the same vessel\nat 20 kPa(a) to 0.05 mol% phosgene and leaves as the product: 99.2 wt% benzyl chloroformate,\n0.51 wt% benzyl chloride, 0.26 wt% dibenzyl carbonate, 98.9 % yield on the alcohol. It is not\ndistilled (the chloroformate decomposes on heating). The reactor's vent and the degassing gas\npass the vacuum pump to a caustic scrubber that absorbs the HCl and destroys the phosgene; the\nspent liquor (NaCl, Na2CO3) goes to wastewater treatment. No HCl or phosgene is recovered.\n\nThe batch is modelled with cheme-as-code's semi-batch reactor with a vent and a partly absorbed\ngas dose (core ADR 0050, 0054), a batch still for the degassing (ADR 0055) and the batch recipe\nover three steps of one vessel (ADR 0051, 0052, 0057): the dosing, post-reaction and degassing\ntimes come from the models, the reactor is the bottleneck (cycle 14.0 h, 565 batches a year on\na dedicated train), the recipe sizes the vessel and checks its jacket, and gives the vent's peak\ngas rate and the scrubber's load per batch (429 kg of vent gas, 233 kg of degassing gas). The\nkinetics are ASSUMED (no open data): a fast second-order reaction, dosing-controlled; the\nphosgene's heat of solution is the dose's (core ADR 0063), the heats of reaction on the\ndissolved basis. Thermal screening: dT_ad 494 K (the side reaction to benzyl chloride run on all\nthe alcohol, with the dose's heat of solution; 323.4 K for the main reaction alone), accumulation\nat most 17 % (the deliberate phosgene excess, at the end of the dosing), MTSR 357 K (set by the\nside reaction to dibenzyl carbonate, counted on purpose; 294.1 K for the main reaction alone)\nagainst an MTT of 281 K (the boiling point of phosgene, which the excess would boil off). The\ngas a cooling failure releases at the MTSR, 3219 m3/h by the screening, is 18.6 times what the\nvacuum pump vents (173 m3/h), and 21.9 times (3788 m3/h, phosgene vapour 0.15 of it) with the\nliquid's vapour on a trial with core 1.10.0's vent vapour: a design finding for a dosing\ninterlock and an emergency relief to the scrubber. The vent and scrubber are the\nsafety-critical path; no class without a TD24. See DESIGN.md for every assumption.\n", "design_basis": { "assumptions": [ "ASSUMED route: phosgene gas dosed into neat benzyl alcohol at 278 K and 50 kPa(a), no base, no solvent (D-001), the reduced-pressure batch route of US 6 696 590 B2 Ex. 3.", "ASSUMED rate laws (second order) and the side reactions' constants set to Ex. 3's impurities; the heats of PHOSG and CLBN from formation enthalpies, CARB's ASSUMED (D-005).", "ASSUMED 95 % of the dosed phosgene taken up by the liquid and 95 % of the HCl leaving as it forms (D-005).", "ASSUMED degassing at 20 kPa(a) and 278 K with constant relative volatilities to 0.05 mol% phosgene (D-006).", "ASSUMED caustic scrubber destroying the HCl and phosgene, 99.99 % (D-007); no phosgene or HCl recovery.", "All flows are year averages of the recipe (D-003); duties and power concept estimates (D-009); accuracy +/-30 % not demonstrated." ], "source": "process/design-basis.yaml" }, "engineering": { "description": "Benzyl chloroformate by semi-batch phosgenation of benzyl alcohol at reduced pressure with an HCl vent, a batch plant, concept stage (issue ChemE-as-Code/process-library#153)", "name": "Benzyl chloroformate", "requires": "cheme-as-code>=1.10", "stage": "concept", "stages": [ { "id": "concept", "title": "Concept and feasibility" }, { "id": "basic", "title": "Basic engineering" }, { "id": "detail", "title": "Detail engineering" } ], "tool": "plantcode" }, "facets": { "feedstock_basis": [ "fossil", "mineral", "electricity" ], "product_classes": [ "chemicals" ], "region": "generic", "unit_operations": [ "reaction", "evaporation", "stripping", "absorption" ] }, "families": [ "chlorinated-organics" ], "gap_count": 1, "gates": null, "id": "benzyl-chloroformate-1", "issues": { "closed_count": 0, "list_url": "https://github.com/ChemE-as-Code/process-library/issues?q=is%3Aissue%20label%3A%22process%3Abenzyl-chloroformate-1%22", "new": { "action": "https://github.com/ChemE-as-Code/process-library/issues/new?template=1-action-item.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1", "change": "https://github.com/ChemE-as-Code/process-library/issues/new?template=4-design-change.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1", "hold": "https://github.com/ChemE-as-Code/process-library/issues/new?template=2-engineering-hold.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1", "process": "https://github.com/ChemE-as-Code/process-library/issues/new?template=6-process-development.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1", "tq": "https://github.com/ChemE-as-Code/process-library/issues/new?template=3-technical-query.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1", "tracker": "https://github.com/ChemE-as-Code/process-library/issues/new?template=7-process-tracker.yml&labels=process%3Abenzyl-chloroformate-1&process=benzyl-chloroformate-1" }, "open": [], "open_by_gate": {}, "open_count": 0, "private": false, "repository": "ChemE-as-Code/process-library" }, "keywords": [ "benzyl chloroformate", "Cbz-Cl", "Z-Cl", "chloroformate", "benzyl alcohol", "phosgene", "phosgenation", "semi-batch", "batch", "dosing", "gas evolution", "HCl vent", "degassing", "caustic scrubber", "fine chemicals", "protecting group reagent" ], "lca": { "allocation": null, "backend": "factors", "boundary": "cradle-to-gate", "categories": [ { "id": "climate-change", "method": "GWP100", "title": "Climate change", "unit": "kg CO2-eq" } ], "contributions": [], "data_sources": [], "factors_status": "none", "functional_unit": { "amount": 1, "chemical": "benzyl-chloroformate", "grade": null, "label": "1 kg benzyl chloroformate", "product": "BCF", "product_name": "Benzyl chloroformate", "product_title": "Benzyl chloroformate (neat) to cold storage", "unit": "kg" }, "goal": "Preliminary gate-to-gate life cycle inventory of benzyl chloroformate made by the semi-batch phosgenation of benzyl alcohol at reduced pressure, degassed and not distilled, with the HCl and the excess phosgene destroyed in a caustic scrubber, at the concept stage: which raw materials, utilities and wastes the batch plant exchanges per kg of product, as the foreground for a later cradle-to-gate study. No impact results: most backgrounds are not mapped yet (D-012).", "inventory": [ { "direction": "input", "key": "feed:BNOH", "kind": "material", "phase": "operation", "provenance": "assumed", "quantity": 0.635607, "title": "Benzyl alcohol (merchant)", "unit": "kg" }, { "direction": "input", "key": "feed:PHOS", "kind": "material", "phase": "operation", "provenance": "assumed", "quantity": 0.738359, "title": "Liquid phosgene (phosgene-1)", "unit": "kg" }, { "direction": "input", "key": "feed:NAOH", "kind": "material", "phase": "operation", "provenance": "assumed", "quantity": 1.08571, "title": "Caustic soda 50 wt% (chlor-alkali-1)", "unit": "kg" }, { "direction": "input", "key": "feed:PW", "kind": "material", "phase": "operation", "provenance": "assumed", "quantity": 4.34285, "title": "Process water (caustic dilution)", "unit": "kg" }, { "direction": "input", "key": "feed:POWER", "kind": "energy", "phase": "operation", "provenance": "assumed", "quantity": 0.0514668, "title": "Electric power", "unit": "kWh" }, { "direction": "input", "key": "feed:LPS", "kind": "energy", "phase": "operation", "provenance": "assumed", "quantity": 0.0690213, "title": "LP steam 350 kPa(a) (to the tempered-water circuits of the phosgene evaporator and the degassing)", "unit": "kWh" }, { "direction": "output", "key": "product:BCF", "kind": "material", "phase": "operation", "provenance": "calculated", "quantity": 1.0, "title": "Benzyl chloroformate (neat) to cold storage", "unit": "kg" }, { "direction": "output", "key": "product:WW", "kind": "material", "phase": "operation", "provenance": "calculated", "quantity": 5.80249, "title": "Spent scrubber liquor to wastewater treatment", "unit": "kg" }, { "direction": "output", "key": "product:BRINE", "kind": "energy", "phase": "operation", "provenance": "assumed", "quantity": 0.163023, "title": "Chilled brine return (253 K)", "unit": "kWh" }, { "direction": "output", "key": "product:CW", "kind": "energy", "phase": "operation", "provenance": "assumed", "quantity": 0.353537, "title": "Cooling water return", "unit": "kWh" }, { "direction": "input", "key": "consumable:nitrogen", "kind": "material", "phase": "operation", "provenance": "assumed", "quantity": 0.00847686, "title": "Nitrogen for inerting R-101, breaking its vacuum and padding the transfer", "unit": "kg" } ], "no_total": { "baseline": { "climate-change": { "gaps": 10, "reason": "every-contribution-a-gap" } } }, "not_computed": [ "climate-change" ], "pcf": [], "publishable": true, "result": { "classification": "partial", "gaps": 10, "label": "partial screening carbon footprint", "publication": "public" }, "sources": [ "lca/README.md", "lca/dataset.yaml", "lca/factors.yaml", "lca/gaps.csv", "lca/inventory.csv", "lca/lca.yaml", "lca/mappings.yaml", "lca/results.csv", "lca/results.md" ], "totals": { "baseline": {} }, "withheld_reason": null }, "lci_gaps": [ { "dataset": "benzyl-chloroformate-by-semi-batch-phosgenation-of-benzyl-alcohol-1000-t-a", "key": "product:BRINE", "link": "technosphere", "type": "output" } ], "maintainers": [ { "name": "Artur Schweidtmann" } ], "maturity": "concept", "preliminary": true, "provenance": { "library_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174", "previews": { "sheets": [ "BFD", "PFD" ], "source_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174", "tool": "cheme 1.6.0 (pyDEXPI 2.1.0)" }, "previews_stale": false, "source_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174" }, "publication": { "license": "CC-BY-4.0", "status": "public" }, "references": [ { "title": "Bonnard, H.; Ferruccio, L.; Gauthier, P.; Senet, J.-P. (SNPE, 2004) US 6 696 590 B2, Process for the synthesis of aliphatic, cycloaliphatic or araliphatic chloroformates (description: reduced pressure, temperature, phosgene excess, degassing, off-gas traps; Ex. 3 and 4: benzyl chloroformate at 500 and 250 mbar, yields, purities, impurities)", "url": "https://patents.google.com/patent/US6696590B2/en" }, { "title": "Rozsa, L.; Meszaros, L.; Mogyorodi, F. (Eszakmagyarorszagi Vegyimuevek, 1976) US 3 966 786 A, Method for producing chloroformates (background: the batch route in enamelled or lead-lined vessels with excess phosgene at 0-10 C, nitrogen flushing, its drawbacks; Ex. 8: benzyl chloroformate in a continuous reactor at 170 C, not used)", "url": "https://patents.google.com/patent/US3966786A/en" }, { "title": "NIST Chemistry WebBook, SRD 69, benzyl chloroformate: liquid enthalpy of formation -376.2 kJ/mol (Finch and Salem 1987, Thermochim. Acta 116, 65-69, solution calorimetry)", "url": "https://webbook.nist.gov/cgi/cbook.cgi?ID=C501531&Units=SI&Mask=2" }, { "title": "PubChem CID 10387, Benzyl chloroformate (identity)", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/10387" }, { "doi": "10.1002/9783527621606", "title": "Stoessel, F. (2008) Thermal Safety of Chemical Processes, Wiley-VCH (accumulation and MTSR of a semi-batch; method reference, not data)" } ], "repository": { "access": "public", "path": "processes/benzyl-chloroformate-1", "url": "https://github.com/ChemE-as-Code/process-library" }, "representations": [ { "bytes": 30964, "id": "BFD", "kind": "bfd", "preview": "artifacts/benzyl-chloroformate-1/BFD.svg", "source": "process/BFD.xml", "status": "preview", "title": "Block flow diagram" }, { "bytes": 94874, "id": "PFD", "kind": "pfd", "preview": "artifacts/benzyl-chloroformate-1/PFD.svg", "source": "process/PFD.xml", "status": "preview", "title": "Process flow diagram" }, { "id": "process-model", "kind": "process-model", "source": "process/flowsheet.yaml", "status": "viewer", "title": "Flowsheet and stream table" }, { "id": "equipment-list", "kind": "equipment-list", "source": "equipment/equipment-list.yaml", "status": "viewer", "title": "Equipment list" }, { "id": "lca", "kind": "lca", "source": "lca/lca.yaml", "status": "viewer", "title": "Life cycle assessment" } ], "summary": "A batch plant: phosgene gas (phosgene-1) is dosed over 10 h into neat benzyl alcohol at 278 K and 50 kPa(a), the HCl vented as it forms; the crude is degassed in the same vessel and leaves neat, the off-gas to a caustic scrubber. Concept stage, 1770 kg per batch every 14.0 h, preliminary gate-to-gate LCI.", "title": "Benzyl chloroformate by semi-batch phosgenation of benzyl alcohol at reduced pressure (1000 t/a, batch)", "validation": { "notes": "Concept batch PFD with closed mass, component and element balances (cheme validate, cheme process streams: 3 blocks and 7 steps within tolerance). Every stream is calculated by cheme process propagate from the feeds: the semi-batch R101 with its HCl vent and partly absorbed phosgene dose from its ASSUMED rate laws, the degassing T101 as a batch still with ASSUMED constant relative volatilities, the scrubber S101 as a conversion step; no balance script. The recipe's year-average rate of the product agrees with the flowsheet (cheme process recipe, no cheme.recipe-basis finding), and the jacket removes the model's peak duty (31.65 kW of 34.35 kW, with the phosgene's heat of solution). The duties of R101 (Q2, 19.88 kW) and T101 (Q4, 1.177 kW) are the models' year averages written by cheme process propagate (core ADR 0059); Q2 holds the heat of solution of the absorbed phosgene (the dose's heat_of_solution, assumed, with the heats of reaction on the dissolved basis, core ADR 0063; D-015). Thermal screening (cheme process reactor-hazards): dT_ad 494.0 K (with the dose's heat of solution, 102.6 K), accumulation 0.173, MTSR 357.1 K against an MTT of 280.65 K (phosgene's boiling point, hazard.mtt), all set by the side reactions, every reaction counted on purpose (hazard.reactions, CARB included as the conservative choice; CLBN's heat for the dT_ad, CARB for the MTSR); the main reaction PHOSG alone gives dT_ad 323.4 K (220.8 K without the heat of solution) and MTSR 294.1 K, still above the MTT (DESIGN.md D-011). The gas release at the MTSR, 3219 m3/h at 357.1 K and 50 kPa(a), is 18.6 times the vent capacity of 173 m3/h (the vacuum pump, hazard.vent_capacity, assumed); with the phosgene vapour (vent.vapour, core ADR 0062, on a scratch copy, not adopted) it is 3788 m3/h, 21.9 times, and the relief is to be sized on that (DESIGN.md D-014, D-015). The two warnings cheme.reactor-hazard-mtsr and -vent are design findings, kept (D-011, D-014); no criticality class without a TD24 from calorimetry. The kinetics are assumed: the accumulation rests on that assumption (k/10 and k/100 in DESIGN.md D-011). Preliminary gate-to-gate LCI with the nitrogen purges as a per-batch consumable; benzyl alcohol, phosgene, caustic soda and nitrogen linked to benzyl-alcohol-1, phosgene-1, chlor-alkali-1 and asu-1, the other backgrounds gaps. cheme maturity reaches no level (assumed feeds, kinetics and separations); the claim `maturity: concept` is the lowest value of the schema, not an evidenced level. Not reviewed. Needs cheme-as-code 1.10 (the dose's heat_of_solution, ADR 0063; from 1.9 the model duties and energy_port, ADR 0059, hazard.reactions and vent_capacity, ADR 0058; and from 1.8 batch.vent, dosing.absorbed, still:, recipe units:, ADRs 0054, 0055, 0057).", "status": "unreviewed" }, "viewer": { "commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174", "dirty": false, "sheets": [ "process/BFD.xml", "process/PFD.xml" ], "skipped": [], "snapshot": "snapshots/benzyl-chloroformate-1/", "stale": false, "tool": "cheme-as-code 1.6.0", "views": [ "checks" ] } }